JP2007532297A - Method and apparatus for improving immersion membrane throughput and operating life - Google Patents

Abstract

  A submerged membrane assembly comprising a membrane having a first surface, a second surface, and a vertical axis, wherein molecules having a size less than a predetermined size can pass between the first surface and the second surface. A first fluid compartment in fluid communication with the first surface of the membrane and containing a first fluid having a first specific gravity; and a second fluid in fluid communication with the second surface of the membrane and having a second specific gravity. Means for imposing a head differential between a second fluid compartment, a first fluid contained in the first fluid compartment, and a second fluid contained in the second fluid compartment; Means for changing the specific gravity. The second column height is selected with respect to the first column height to generate a selected pressure difference across the membrane along the vertical axis with a modified second specific gravity.

Description

  The present invention relates to a method and apparatus for processing, refining, and / or treating liquid compositions of liquid compositions. More specifically, the present invention relates to a membrane separation method and apparatus utilizing selective, semipermeable, microporous or other distribution membranes for processing, purifying and / or treating liquid compositions, such as membrane wastewater. The present invention relates to a purification method and apparatus.

Background Art on Vertical Bioreactors Efficient wastewater treatment has become increasingly important as the world's population continues to grow. While the amount of water that humans need for consumption and other uses increases at a rapid pace, the amount of water that is naturally available remains unchanged. Increasing demand for available water purification makes wastewater reclamation an essential element of population growth and development.

  In the US and other developed countries, as existing metropolitan areas become overcrowded, developers are encouraged or required to build new homes in previously undeveloped areas. Many of these undeveloped areas lack sufficient water for consumption, irrigation and similar purposes, and there is a need to regenerate and reuse available water resources. Therefore, for successful development in these areas, sewage derived from water used by residents, commonly called wastewater, is the main target for reuse.

  Residential wastewater has a high water content, but since human excrement and other filth are mixed, sufficient processing is required before it can be reused. On-site, ie, on-site wastewater treatment and reuse is very advantageous or essential to achieve the reuse of domestic wastewater in many newly developed areas isolated from existing sewage treatment facilities.

A wide variety of different wastewater treatment systems have been proposed to reuse domestic sewage and other categories of wastewater. One such system disclosed in U.S. Patent No. 6,057,097 incorporates a simple sedimentation tank to separate solid waste or "sludge" from wastewater. After sedimentation, the sludge is conveyed to a digestion system where it is deposited such that a clear aqueous liquid separates from the sludge. The clarified liquid is reintroduced into the settling tank. Unfortunately, this system has a number of drawbacks and is inefficient. In particular, the system includes a relatively coarse precipitation system, which merely allows the incoming sludge to be separated and does not facilitate the treatment of the sludge by aeration or in some other manner.
US Pat. No. 2,528,649

  Many wastewater treatment processes include “biological” systems that utilize microorganisms contained in activated biomass or sludge to remove COD, phosphorus and / or nitrogen from wastewater. These processing steps typically include a plurality of processing phases or “zones”: (1) a preliminary processing region, (2) a primary processing region, and (3) a secondary processing region. Pretreatment mainly relates to the removal of solid minerals from untreated wastewater. Typically, this pretreatment comprises a two-stage treatment process in which the debris is removed by screen and / or precipitation. The organic matter is carried in the liquid stream for further processing. Primary treatment includes physical steps in which a portion of the organic matter, including suspended solids such as feces, food particles, etc., is removed by floating or sedimentation. The secondary treatment typically includes a biological treatment step that is utilized to remove organic matter, nitrogen and phosphorus from the microorganisms from the wastewater stream. Microbial growth and metabolic activity is utilized and controlled through the use of controlled growth conditions.

In large scale urban or industrial applications, biological treatment processes typically utilize basins or other reservoirs where the wastewater is mixed with a biomass / sludge suspension. Subsequent growth and metabolism of the microorganism and treatment of the resulting wastewater are carried out under aerobic and / or anaerobic / oxygen deficient conditions. In most large city or industrial processing systems, the various elements of the processing process are performed in separate reservoirs or reactors. Therefore, there is a continuous wastewater flow from one process step to the next process step. Biomass containing active microorganisms may be recycled from one process step to another. For example, the conditioning of such biomass to enhance the growth of identified microbial subgroups that have a tendency to perform certain types of metabolic processes, such as phosphorus removal, nitrogen removal, is described in US Pat. It was the subject of numerous patents including. Optimization of other elements or aspects of biological wastewater treatment has resulted in various patents, including US Pat.
U.S. Pat. No. 4,056,465 US Pat. No. 4,487,697 US Pat. No. 4,568,462 US Pat. No. 5,344,562 US Pat. No. 2,788,127 US Pat. No. 2,875,151 U.S. Pat. No. 3,440,669 U.S. Pat. No. 3,543,294 US Pat. No. 4,522,722 US Pat. No. 4,824,572 US Pat. No. 5,290,435 US Pat. No. 5,354,471 US Pat. No. 5,395,527 US Pat. No. 5,480,548 US Pat. No. 4,259,182 U.S. Pat. No. 4,780,208 US Pat. No. 5,252,214 US Pat. No. 5,022,993 US Pat. No. 5,342,522 US Pat. No. 3,957,632 US Pat. No. 5,098,572 US Pat. No. 5,290,451 Canadian Patent No. 1,064,169 Canadian Patent No. 1,096,976 Canadian Patent No. 1,198,837 Canadian Patent 1,304,839 Canadian Patent No. 1,307,059 Canadian Patent 2,041,329

Biological removal of organic carbon, nitrogen and phosphorus compounds from wastewater requires consideration of special environmental conditions within the treatment facility. For example, in order for bacteria and other microorganisms to convert organic carbon compounds (measured as BOD) into carbon dioxide and water, a well-stirred aerobic environment is required. Approximately one pound of oxygen is required per pound of BOD removed (454 g). In order to convert nitrogen compounds into nitrogen gas and carbon dioxide, nitrosoma bacteria and nitrobacter bacteria operate in an aerobic environment that consumes inorganic carbon. Approximately 4.6 pounds of oxygen is required to convert 1 pound of ammonia N to nitrate N (assuming sufficient alkalinity). Conditional bacteria then operate in an anaerobic environment, consuming organic carbon and releasing nitrogen gas. About 2.6 pounds of oxygen is recovered when 1 pound of nitrate N is converted to nitrogen gas. In order to biologically bind phosphorus to the cell population, an anaerobic step to produce volatile fatty acids is required. This is followed by a poly-P microorganism that metabolizes the volatile fatty acids in an anaerobic environment and consumes a large amount of phosphorus necessary to concentrate the phosphorus in the biomass (Non-Patent Document 1).
Dr. W. Wilson, Western Canada Water and Westwater Conference, Calgary AB, January 2002, Proceedings.

  Ideally, the combination of these many biological processes results in a biological nutrient removal (BNR) process, sometimes referred to as a tertiary treatment. However, well-designed tertiary processing activities require the cooperation and sequencing of complex combinations of elements, processes and conditions. Each of the component biological processing steps proceeds at a unique rate and requires specific environmental parameters. Efficient tertiary treatment requires the correct amount of special microorganisms to maintain the microbial population and perform specific processing functions.

Conventional wastewater treatment systems that seek to provide tertiary treatment include upflow sludge bed filtration (USBF), batch activated sludge (SBR), and membrane separation activated sludge (MSAS) systems. The batch activated sludge method is an improvement over the conventional activated sludge treatment method. Patent Document 30 discloses a vertical long-axis aerator used in the SBR method. The SBR process utilizes a number of distinguishable steps that typically include injecting, reacting, precipitating, and decanting waste water into the biomass in an enclosed reactor. In the first step of the method, the wastewater is transferred to a reactor containing biomass and mixed to form a mixture. In the reaction step of this treatment method, the biomass microorganisms metabolize and / or ingest using nitrogen, phosphorus and / or organic nutrient sources in the wastewater. The latter reaction is carried out under conditions of anaerobic conditions, oxygen deprivation conditions, aerobic conditions or a combination thereof to manipulate the growth, community dynamics and contaminant treatment of the organism. The length of this stage depends on the nature of the wastewater, the biomass concentration and other factors. Following the reaction cycle, the biomass in the mixture is allowed to settle. A sludge blanket settles to the bottom of the reactor and the treated supernatant flows out. The treated and clarified water (i.e. the effluent water) is then decanted and discharged. The reactor vessel is then refilled and the process cycle is resumed. In this way, batch reactor processes are based on time-separated work, while other wastewater treatment processes are spatially-separated work, for example, by performing different reactions in separate vessels. Based.
US Pat. No. 5,503,748

  Many of the additional wastewater treatment designs are equipped with air-lift reactors, which are mechanically characterized by liquid circulation in a constant circular pattern through a set of specially designed channels. It is a simple gas-liquid mixing flow device. The movement of the liquid is due to the average density difference between the upstream (riser) and downstream (downcomer) sections of the reactor. Typically, an airlift reactor is made up of distinct zones with different liquid flow patterns. Upflow is typically a zone where sμ is injected to create a liquid density difference, and both liquid and gas phase upflow occurs. At the top of the reactor is a gas-liquid separator section, which is typically the region of horizontal liquid flow and flow direction reversal where bubbles desorb from the liquid phase. Downstream is a zone where gas-liquid dispersed or degassed liquid is normally recirculated to the upflow. Depending on whether the liquid velocity is faster than the free rise rate of the bubbles, the downflow zone may be single phase, cocurrent two-phase or cocurrent-countercurrent mixed two-phase. Indicates any downfall. The bottom section of the lower end of the vessel communicates the downflow outlet and the upflow inlet.

Airlift reactors have been used predominantly in microbial fermentation methods such as ICI single cell protein production. However, many systems are known that utilize an airlift reactor for wastewater treatment. Among these examples, there are a Betz reactor (Non-Patent Document 2) and a deep shaft bioreactor for treated water (see Non-Patent Document 3).
Gasner, Biotech. Bioeng. 16: 1179-1195, 1974 Hines et al., Chem. Eng. Sym. Ser. U. K. 41: D1-D10, 1975

Following the development of the deep shaft bioreactor prototype, recent efforts have led to improvements in the vertical long axis bioreactor system for wastewater treatment. Of these improvements, US Pat. Nos. 6,028,036 to Pollock disclose improved vertical long axis bioreactor systems for biodegradable wastewater and / or sludge treatment, respectively. Generally, these vertical axis bioreactor systems include a bioreactor, a solid-liquid separator, and an intervening device in communication with the bioreactor and the solid-liquid separator. The bioreactor includes a circulation system that includes two or more vertical parallel or concentric chambers including a downflow chamber and an upflow chamber. These chambers are connected at the upper end through a surface basin and communicated at the lower end via a common “mixing zone” adjacent to the lower end of the downflow chamber.
U.S. Pat. No. 4,279,754 US Pat. No. 5,645,726 US Pat. No. 5,650,070

In addition to the mixing zone, these reactors are equipped with a “plug flow” zone located below and in communication with the mixing zone. As described above, the term “plug flow” refers to the movement of solid particles as a whole downward from the mixing zone toward the treated water outlet located at the lower end of the reactor. In one application to sludge degradation, Guild et al. (Non-Patent Document 4) reported that the overall downward movement includes only local back mixing, In operation, inter-zone mixing occurs.
Guided et al., Proceedings WEF conf. , Atlanta Ga. , October 2001

  Liquid containing waste (mixed liquor) is placed in the circulation system by injecting an oxygen-containing gas, usually air, near the bottom of the reactor (eg, in the mixing zone and plug flow zone). Driven through (ie, between the downflow chamber and the upflow chamber, between the surface zone and the mixing zone). A part of this circulating flow is led to the plug-like flow zone and removed as treated water at the lower end of the plug-like flow zone. In wastewater treatment reactors, air is typically injected 5-10 feet (1.524-3.048 meters) from the bottom of the reactor, optionally at the bottom of the downflow chamber. It is injected directly below. The deepest air injection point divides the plug-like flow zone into a quasi-plug flow zone above the deepest air injection point and a full plug-like flow zone below the deepest air injection point. Although backmixing occurs, the latter is reported to not occur.

  When the bioreactor starts up, air is injected into the upflow chamber like an air lift pump, and the liquid is circulated between the upflow chamber and the downflow chamber. The liquid in the downflow chamber is denser than the gas-liquid mixture in the upflow chamber, thus providing sufficient upward force to maintain circulation.

  Once bioreactor circulation is thus initiated, all of the air injection is transferred to the mixing zone and / or plug flow zone. Bubbles exiting these zones are directed to the ascending chamber and are excluded from the descending chamber where the descending flow rate of the mixture exceeds the ascending rate of the bubbles. Dissolved oxygen in the circulating mixture is a major reactant in biochemical degradation of filth. When the mixed liquid rises in the ascending chamber and reaches a region where the hydrostatic pressure is low, oxygen and other dissolved gases are separated to form bubbles. Gas separation occurs when the gas-liquid mixture from the ascending chamber enters the surface zone. To facilitate this purpose, it is necessary for the mixture to release spent gas across most of the surface area before it re-enters the downflow chamber for further processing. To force it, a horizontal baffle is usually attached to the top of the rising chamber in the surface section.

U.S. Pat. No. 6,057,034 discloses a method in which incoming wastewater is introduced deep into the riser chamber through an outlet arm that is directed upwardly into the inlet conduit. When the circulating flow reverses from descending to ascending, a turbulent zone is created at the lower end of the descending chamber by the changing velocity head. This mixing zone is not clear, but is typically 15-25 feet deep (4.572-7.62 meters). A part of the mixed liquid in the mixing zone flows downward to the top of the plug-like flow in response to an equal amount of the treated water removed from the lower end of the plug-like flow zone described above to the treatment water line. . During the operation of the bioreactor, the flow of the mixed liquid flowing into the bioreactor and the mixed liquid flowing out of the bioreactor is controlled in response to changes in the liquid level in the communicating upper surface section.
US Pat. No. 5,650,070

  The reaction between filth, dissolved oxygen, nutrients and biomass (including active microbial communities) is essentially the upper circulation zone of the bioreactor defined by the surface zone, the upflow chamber, the downflow chamber and the mixing zone Happens in. The majority of the contents of the mixing zone circulate upward and enter the upflow chamber. In this upflow chamber, the undissolved gas, mostly nitrogen, expands to help provide the gas lift necessary to drive the circulation of the mixed liquid at the top of the reactor. When the spent gas crosses the horizontal baffle in the surface section, the spent gas is released from the mixed liquid. The plug-like flow zone located below the upper circulation zone provides the final treatment, i.e. polish, polish, of the mixed liquid flowing downward from the mixing zone to the treated water extraction at the lower end of the reactor.

  The injected oxygen-containing gas readily dissolves in the plug-like flow zone mixed liquid under pressure, but the plug-like flow zone contains local, localized, due to the slow downward movement of the mixed liquid. There is backmixing. Non-dissolved gas (bubbles) moves upward under pressure to a very turbulent mixing zone. The gas-to-liquid transfer in this zone is very efficient and the overall reactor oxygen transfer efficiency exceeds 65%. The reaction products are carbon dioxide and further biomass, which forms sludge (or biosolid biosolid) with unreacted solids present in the incoming wastewater.

  In addition to aerobic degradation of BOD, it is becoming increasingly important to combine biological nutrient removal (BNR) of nitrogen and phosphorus compounds with conventional wastewater treatment. As the demand for high quality processed liquid discharges increased, the need for technology such as that provided by the present invention became increasingly difficult. Previous secondary biological treatment standards of BOD 30 mg / L and TSS 30 mg / L are no longer sufficient in many jurisdictions, and now limits are often set for nitrogen and phosphorus as well. Effective removal of these nutrients is essential from the standpoint of existing and developing environmental legislation aimed at preventing eutrophication of natural water and resulting ecosystem damage.

  Basically, nitrogen removal is achieved by converting ammonia contained in the mixed liquid into nitrite and nitrate in the presence of oxygen, which is known as the aerobic nitrate stage. The conversion of ammonia to nitrite is performed by a microorganism known as Nitrosomonas, but the conversion of nitrite to nitrate is accomplished by Nitrobacter. The conversion of nitrate to nitrogen occurs in an oxygen-deprived denitrification stage that proceeds in a suspended growth environment lacking dissolved oxygen. Nitrogen, carbon dioxide and water are produced and the gas is exhausted from the system. Nitrification rate is temperature, dissolved oxygen level (DO), pH, solids residence time (SRT), ammonia concentration and BOD / TKN ratio (total Kjeldahl nitrogen, TKN is organic nitrogen, ammonia and ammonia It can be optimized by adjusting interdependent wastewater parameters such as salt-derived nitrogen). High temperatures and high dissolved oxygen levels tend to promote increased nitrification rates, as well as pH levels in the range of 7.0 to 8.0. A sludge residence time of 3.5 to 5 days, preferably 5-8 days, dramatically increases the nitrification rate, but for longer periods, the efficiency tends to remain constant. Increasing ammonia concentration increases the nitrification rate to the maximum achievable level, but higher concentrations of ammonia do not contribute significantly to the increase in nitrification rate. It has also been shown that the speed is maximized at a BOD / TKN ratio of less than 1.0 (see, for example, Non-Patent Document 1).

  Physical / biochemical phosphorus removal is the system's first anaerobic suspension growth zone and a sludge fermenter that supplies volatile fatty acids (VFA's) to meet the energy demands of phosphorus-degrading organisms (Acinetobacter) Is typically required. Recently, it has been reported that anaerobic force mains can generate enough volatile fatty acids to allow substantial biological phosphorus removal.

A refractory treatment and polishing stage may be added to the process downstream of the final clarification stage. In many wastewater streams, the majority of organic compounds (80% -90%) are readily biodegraded. The remaining fraction biodegrades more slowly and is called “persistent”. Prior art biological nutrient removal designs incorporate, for example, a single sludge and a single clarification tank such as US Pat. In order to satisfy the above, the oxidation rate of the entire system must be lowered.
US Pat. No. 3,964,998

Biological nutrient removal (BNR) systems may take various process configurations. One such embodiment is the five-stage modified Bardenpho ™ method based on US Pat. This method provides anaerobic, oxygen deficient and aerobic steps for the removal of phosphorus, nitrogen and organic carbon. More than 24 Badenho (TM) processing plants are in operation, and most use a five-step process rather than the previously designed four-step process. Most of these facilities require subsidized chemical inputs to meet the phosphorus concentration limit of treated water below 1.0 mg / L. Plants using this process utilize a variety of aeration methods, tank configurations, pump equipment and sludge handling methods. Non-patent document 5.
WEF Manual of Practice No. 8, "Design of Municipal Water Treatment Plants", Vol. 2, 1991.

In the context of vertical bioreactor technology, Pollock (US Pat. No. 6,057,059 issued July 29, 1997, incorporated herein by reference) describes a vertical bioreactor connected to a submerged filter via a flotation sorter. Disclose innovative methods to use. According to this design, an improvement in reaction rate is achieved by separating the biomass into an aerobic organic carbon fast removal step followed by an aerobic nitrification step using another nitrifying biomass. These steps are followed by desorption in an oxygen-deficient environment created by providing a mixed liquid flowing into that zone for providing an organic carbon source and consuming oxygen and returning mixed liquid or treated water. A nitriding step follows.
US Pat. No. 5,651,892

  Incorporation of anaerobic processing steps for phosphorus removal is typically performed in a separate reactor due to the long fermentation required for volatile fatty acid production. In addition, the biomass rich in phosphorus produced in the anaerobic part of the process should not be contacted with the anaerobic fermentation reactor product because it may re-solubilize the captured phosphorus, so it is a single mixed liquid system Phosphorus removal at is difficult to perform. In other cases, biological phosphorus removal is facilitated by the addition of metal salts such as ferric chloride or alum. These may be added directly to the aerobic zone of the reactor for chemical bonding with phosphorus.

  Accordingly, various treatment systems including combinations of vertical axis reactors and SBRs have been successfully used to provide tertiary wastewater treatment. However, these tertiary treatment systems include a single mixed liquid process in which all of the special microorganisms involved in the process are mixed together. These include autotrophic organisms that use inorganic-derived energy (for example, nitrosomonas and nitrobacter), aerobic BOD-removing bacteria, and Acinetobacter that are biological phosphorus-removing bacteria using organic energy sources. And heterotrophic organisms including fungi (bio-P organisms). Thus, in all of these types of systems, the rate of treatment is controlled by the slowest microorganism, usually the nitrosoma that converts ammonia to nitrite. Due to the slow overall processing speed, these once mixed liquid systems are called long-time aeration systems and are very energy intensive.

  In spite of the development and advancement of the above mentioned wastewater treatment technology, there is an urgent need for an improved wastewater treatment system that satisfies a wide range of applications and can perform expanded and enhanced functions that are not met by existing wastewater treatment systems. There remains a need in the art. For example, a simplified wastewater treatment process that provides enhanced biological nutrient removal (BNR) and, in some embodiments, can produce class A biosolids required for unconstrained land use. And there is a long-standing need in the art for devices. Furthermore, there remains an unmet need for wastewater treatment systems and methods that meet these expanded functions while minimizing the cost and environmental impact associated with the installation and operation of conventional wastewater treatment plants. .

Background on membrane separation technology and use of membranes in wastewater treatment bioreactors Membrane separations utilizing selective, semi-permeable or distributable membranes, such as those used in modern membrane wastewater purification methods and equipment, This is a rapidly evolving aspect of industrial separation technology for processing, purifying and / or processing liquid compositions. In a typical membrane separation apparatus and method, a first liquid composition, for example, an incoming liquid wastewater stream, contacts the first surface of the membrane, often as a result of one or more driving forces, Typically, one or more components of the first liquid composition pass through the membrane to form a second liquid composition, eg, a stream of treated water, on the second surface of the membrane. This eliminates or remains one or more components of the first liquid composition that has been separated or dispensed (ie, these components remain on the surface of the first membrane). Distributed or retained and remains in solution or suspension of the first liquid composition or in contact with the first liquid composition).

  The liquid composition processing, purification and processing membrane separation techniques available within the method and apparatus of the present invention include microfiltration, ultrafiltration, nanofiltration, reverse osmosis, electrodialysis, electrodesalting, and pervaporation. Membrane extraction, membrane distillation, membrane stripping, membrane aeration and other methods of utilizing membranes. Depending on the type of membrane separation used, various driving forces to enable and enhance membrane function may be utilized alone or in combination with other driving forces disclosed herein. is there. Pressure-drive membrane filtration, also known as membrane filtration, includes microfiltration, ultrafiltration, nanofiltration and reverse osmosis, using pressure as the driving force, but electrodialysis and electrofiltration. In desalting, an electric driving force is used.

  Historically, membrane separation methods or systems for water treatment have been cost-effective due to the detrimental effect that membrane scaling, membrane fouling, membrane degradation and the like imposes a burden on the efficiency of removing solutes from water streams. It was not considered expensive. In recent years, however, technological advances have made membrane separation a more commercially viable technique for treating aqueous-like liquid compositions suitable for industrial and domestic wastewater treatment.

  Membrane-based solid-liquid separation technology has made rapid progress in the wastewater treatment industry and other membrane separation technology areas. In the early membrane wastewater treatment plant, the expected service life of the membrane was about 5-7 years. Now, the service life of membranes for wastewater treatment applications is often over 8 years.

  In North America and other parts of the world, water restrictions have become increasingly common even in cities with normally good water sources such as Vancouver, Seattle and Calgary. In many parts of the Great Plains and desert states, water supply restrictions have become a demand. The soil moisture content in some areas is already less than the so-called “30 dirty” units. A major factor in the increase in water supply restrictions is that existing water treatment plants cannot produce sufficient quantities of purified water to meet the growing domestic and commercial demand. In connection with this problem, there is a need to improve wastewater treatment capacity to increase production of medium quality water for irrigation, which is conventionally produced more expensively by waterworks plants.

Currently, a number of membrane bioreactor plants are operating in excess of 8 million gallons per day (8 MGD, 3.028 million m ³ ), and 12 MGD (45.42 million m ³ ) plants are under construction in Europe. Has been. The new hotel is designed to have two sets of pipes, one for drinking water and one for reused water such as flush toilets.

  Most growing cities in North America separate surface rainwater piping from sewage piping. Wherever existing surface stormwater piping is located, install recycled water return pipes with smaller diameter inside thicker stormwater piping without the high costs associated with drilling and new piping installation Is possible. In this development model, cross-contamination is not a significant issue because it does not require reused water when it rains. Furthermore, the reused water piping is pressurized with water of higher quality than rainwater. Less expensive reclaimed water can be distributed to most places in the city for irrigation and / or maintenance of roads, golf courses, parks, sod farms, nurseries, lawns .

  Alternatively, small processing plants, such as using an improved vertical long-axis bioreactor that provides tertiary treatment, are strategically placed in urbanized areas and operated privately and without municipal involvement There is a case. During periods of low demand, the small-scale treatment plant may be discharged directly into the surface stormwater drainage channel, thereby substantially reducing the burden on municipal plants.

  The improved vertical long axis bioreactor achieves BNR processing in a single integrated bioreactor, each using sequential zones dedicated to a specific part of the overall process. Thus, each zone may be optimized individually.

  Technological advances in membrane separation, processing and processing technologies are taking place at a fast pace. While the permeation flux of the membrane (flow rate per square foot of membrane surface area) increases, the cost per square foot decreases steadily. In addition, the cost of membranes used in modern processing plants has declined and will decline significantly over the next decade. These factors together will encourage the use of membranes in the treatment of recycled wastewater, among other processes. For example, recent membrane bioreactor (MBR) pilot plant attempts in San Diego are $ 3.05 and $ 1.92 per 1000 gallons (3.785 cubic meters) when manufactured in 1 MGD and 5 MGD scale plants, respectively. It will be shown that this would be the case. This cost includes capital depreciation and full year operating and maintenance costs. At least one golf course in Seattle pays $ 3.96 per 100 cubic feet of drinking water on a seasonal demand basis.

  Membrane bioreactors require periodic cleaning to maintain their performance. The frequency of cleaning depends on the type of membrane and its operating environment, but is typically once every few months. Existing reactors typically shut down during membrane cleaning, causing temporary and periodic loss of wastewater treatment capacity. In addition, cleaning often involves the use of expensive and specialized chemicals and requires compliance with environmental regulations for use and disposal.

  While improved vertical long axis bioreactors offer unique advantages compared to other bioreactors, there is a need for methods and apparatus for incorporating membranes into such reactors.

  Aspects of the present invention meet these needs and achieve additional objects and advantages that will become apparent from the following description and the accompanying drawings.

SUMMARY OF THE INVENTION The present invention provides a method and apparatus in which the throughput and operating life of a submerged membrane for biological treatment of wastewater is improved and the period between cleaning and maintenance of the membrane is extended. More specifically, the present invention relates to membrane separation methods and apparatus that utilize selective, semi-permeable, microporous or other distribution membranes for processing, purifying and / or treating liquid compositions, such as membrane wastewater purification. The present invention relates to a method and an apparatus. Another aspect of the invention improves gas diffusion in the liquid by creating a substantially uniform pressure differential between the two sides of the membrane.

  In one aspect of the present invention, an immersion membrane assembly and associated methods and apparatus are provided. The submerged assembly typically includes a membrane having at least a first surface and a second surface that include opposing surfaces of a generally planar membrane. In some embodiments, the opposing surfaces of the membrane are square or rectangular, and the membrane has a vertical axis (eg, a vertical defined by one side of a square membrane or the long side of a rectangular membrane). Have. The membrane is permeable between the first surface and the second surface by molecules less than a predetermined size.

  Within another aspect of the present invention, the submerged membrane assembly includes a first liquid compartment, the first liquid compartment having a first specific gravity in liquid communication with the first surface of the membrane. Contains liquid. The assembly also includes a second liquid compartment, the second liquid compartment including a second liquid having a second specific gravity in liquid communication with the second surface of the membrane.

  The membrane assembly further includes means for imposing a hydraulic head difference between the first liquid contained in the first compartment and the second liquid contained in the second compartment; And means for changing the specific gravity. The means for imposing the head differential may include a first liquid compartment and a second liquid compartment, the first liquid compartment defining a first column height and the second liquid compartment defining a second column height. To do. The second column height is selected with respect to the first column height such that the first specific gravity and the changed second specific gravity produce a selected pressure difference across the membrane along the vertical axis of the membrane. (In other words, the second specific gravity is changed from the first second specific gravity value to the second specific gravity value after the change by the operation of the means for changing the second specific gravity). The first and second column heights may only be established by gravity and the configuration and design of the first and second liquid compartments (the liquid column height of the first liquid compartment in relation to the vertical axis of the membrane. (Typically by providing a port or opening for outflow or overflow of the second liquid compartment at a lower location). Alternatively, the means for imposing the water head difference may include means for applying a pressure difference between the first liquid compartment and the second liquid compartment. For example, a negative pressure generating means or vacuum may be applied to the second compartment or the second liquid to generate a lower pressure on the second liquid compared to the hydraulic pressure of the first liquid in the first compartment. is there. Alternatively, a positive pressure generating means or pressurizing device is applied to the first compartment or the first liquid in order to generate a higher pressure compared to the hydraulic pressure of the second liquid in the second compartment. There is.

  In various embodiments of the present invention, the means for changing the second specific gravity may include means for directly or indirectly introducing a gas into the second liquid in the second compartment. For example, the gas may be dissolved directly in the second liquid or introduced into the second liquid in the form of bubbles, thereby reducing the second specific gravity to the second specific gravity value after the desired change. Let Typically, the first liquid contains dissolved gas and permeates through the membrane from the first side to the second side either in the liquid state or in the form of microbubbles or larger bubbles. As a result, gas is introduced from the first liquid into the second liquid. In some embodiments, dissolved gas (e.g., air or oxygen) in the first liquid permeates between the first and second surfaces of the membrane to form the second surface or the second surface. In the vicinity of to form bubbles to be taken into the second liquid. When the means for introducing the gas includes transferring dissolved gas from the first liquid to the second liquid, the gas may agglomerate at or near the second surface of the membrane, This may include agglomeration and / or dissolution of gas into the second liquid either between the first and second surfaces or at the second surface in the second liquid compartment. Alternatively, the means for introducing the gas can achieve the introduction of dissolved gas from the first liquid to the second liquid without gas dissolution and bubble formation, which is alternatively May occur after gas introduction or may not occur at all. In a further embodiment, the dissolved gas of the first liquid aggregates in response to a mechanical action imparted by passing through the membrane or a pressure difference across the membrane, or between the first and second liquids. In the second liquid in response to the difference in dissolved gas level between them. In some other embodiments, the means for changing the second specific gravity may include a gas inlet port coupled to the second liquid compartment for introducing gas into the second liquid. When the gas is introduced into the second liquid through the gas introduction port by introducing a pressurized gas state or other state, for example, a liquid saturated with a gas mixed with the second liquid. There is.

  Another aspect of the invention provides a submerged membrane assembly. The submerged membrane assembly includes a membrane having a first surface, a second surface, and a vertical axis, wherein the membrane can transmit molecules less than a predetermined size between the first surface and the second surface. . The assembly further includes a first liquid compartment, a second liquid compartment, and means for changing a second specific gravity, wherein the first liquid compartment contains a first liquid having a first specific gravity at a first column height. And includes a second liquid having a second specific gravity at a second column height and in fluid communication with the second surface of the membrane. . The second column height is selected with respect to the first column height to generate a selected pressure difference across the membrane along the vertical axis with a first specific gravity and a second specific gravity after change. The means for changing the second specific gravity may include a gas added to the second liquid, and the gas is typically introduced by direct or indirect gas introduction into the second liquid (a bubble state is typical). May optionally be added at the beginning). In a typical embodiment, the means for changing the second specific gravity is second by the dissolved gas of the first liquid that permeates the membrane and is in the vicinity of the second liquid or aggregates in the second liquid. Contains gas added to the liquid. The gas may agglomerate on the second surface of the membrane or in the vicinity of at least a portion of the second surface, and optionally (first of the membrane when agglomeration occurs inside the membrane). Due to aggregation and / or mechanical effects of bubbles rising in the second liquid (between the surface and the second surface, or more typically at or near the second surface of the membrane). Provides the desired polishing action.

  Optionally, the membrane assembly is coupled to the second liquid compartment for direct introduction of gas into the second liquid (eg, dissolved in the liquid or in a pressurized gas). Gas inlet ports may be included.

  The assembly may include a liquid collector that collects liquid from the second compartment, for example through an overflow port at or near the second liquid column height. In some embodiments, the first liquid compartment may be the head tank or saddle tank of a vertical bioreactor or other wastewater treatment device.

  For wastewater treatment applications, the membrane assembly of the present invention provides particle exchange between the first and second sides with particles of a size larger than the selected size indicated for treated water (treated water). It typically includes a semipermeable membrane that eliminates permeation). For most treated wastewaters, the pore size of the selected membrane will be about 2 microns or less, more typically 0.5 microns or less, often 0.1 microns or less. The membrane may include any of a variety of commercially available membranes for wastewater treatment, such as planar membranes or hollow fiber membranes.

  In a related aspect of the present invention, the submerged membrane assembly is a membrane having a first surface, a second surface, and a vertical axis, wherein molecules having a size less than a predetermined size are between the first surface and the second surface. Includes a permeable membrane. The assembly includes a first liquid compartment containing a first liquid having a first column height and a first specific gravity and in liquid communication with the first surface of the membrane. The assembly also includes a second liquid compartment containing a second liquid having a second specific gravity at a second column height and in fluid communication with the second surface of the membrane. The second liquid contains or is modified to contain a sufficient amount of gas to prepare the second specific gravity closer to the first specific gravity. In an exemplary embodiment, the gas contained in the second liquid is in a bubble state. A liquid collector is in liquid communication with the second compartment at the second liquid column height for recovering liquid from the second compartment. The second column height is selected with respect to the first column height so as to generate a selected pressure difference between the two sides of the membrane along the vertical axis. Further, the first liquid compartment may include a first liquid outflow at the first column height. The first liquid dissolved gas may be included. The gas in the second liquid may include bubbles formed by the dissolved gas of the first liquid, and the dissolved gas of the first liquid permeates the membrane (in the vicinity of the second liquid or in the vicinity of the second liquid). Thus, for example, by agglomeration at or near the second surface of the membrane. Bubbles rising in the second liquid may have a function of cleaning the second surface of the film. The second liquid compartment introduces gas directly into the second liquid (as an alternative or complementary gas introduction means from the first liquid and between the first and second surfaces of the membrane). In order to do so, a gas inlet port may optionally be included. The first column height and the second column height are established without mechanical equipment, for example as determined only by gravity, negative pressure applied to the second liquid or positive pressure applied to the first liquid. May be.

  The method and apparatus of the present invention is applicable to a wide range of liquid processing methods and apparatus. Utilizing membranes, the present invention offers substantial advantages in a variety of processing steps and devices where liquids containing solids tend to foul the membrane and have a slow permeation rate of clean liquids. . In the case of drinking water, the lifetime of the membrane can be extended by adding carbon dioxide to the first and / or second liquid, which is also desirable for adjusting the pH of the water. Industrial filters, such as filters for removing precipitates and precipitated proteins from chilled beer, are also advantageous for recarbonation prior to bottling. Inert gas filtration, such as gasoline purification using nitrogen gas, is also suitable for optimization using the method and apparatus of the present invention. In this case, a gas recovery system may be provided downstream of the membrane and a repressurization system may also be used. Nitrous oxide may also be used as an additive gas (eg, as a gas introduced into the second liquid) to make the desired fuel / additive.

  In the case of viscous liquids such as lubricants, treatment of such liquids is also facilitated by the methods and apparatus of the present invention, particularly by using an inert gas within the scope of the present method and apparatus. Let ’s go. An active gas such as methane will only dissolve in water in a small amount, so it will have only a more limited use within the scope of the present invention. Some gases are sensitive to pH changes. For example, sodium bicarbonate dissolves in water without pressure, but a change in pH will cause carbon dioxide to be released in the same way that a pressure change occurs.

  Other liquid treatment techniques to which the methods and apparatus of the present invention can be applied include, for example, desalination plants, biotechnology and biomedical separation procedures (eg, dialysis of blood and other body fluids) and environmental decontamination treatment (eg, sea water). And oil and other petroleum decontamination from freshwater bodies).

  In a more detailed aspect of the present invention, a liquid treatment method by membrane separation utilizing a selective, semi-permeable, microporous or other parting membrane to process, purify and / or treat the liquid composition, for example, A membrane wastewater purification method and apparatus are provided. These methods contain a first liquid having a first specific gravity, contain a second liquid having a second specific gravity, a first surface in fluid communication with the first liquid, and a second liquid. A semipermeable membrane having a second surface in fluid communication with the first surface and a vertical axis, wherein a molecule having a size less than a predetermined size can pass between the first surface and the second surface. Separating one liquid from the second liquid. The method may include a first liquid and a second liquid (e.g., passively by a difference in gravity and chamber overflow water level, or actively by applying positive or negative pressure as described herein). And adjusting the second specific gravity (typically by introducing gas) and recovering the second liquid. Imposing the head differential further includes containing a first liquid at a first column height and containing a second liquid at a second column height, wherein the second column height is a first specific gravity and adjustment. The first column height is selected such that a selected pressure difference occurs between the first and second surfaces of the membrane along the vertical axis of the membrane with a specific gravity on the rear platform.

  Another aspect of the present invention is a method of treating a liquid by membrane separation utilizing selective, semi-permeable, microporous or other distribution membranes to process, purify and / or treat the liquid composition, for example, A membrane wastewater purification method and apparatus are provided. The method includes containing a first liquid having a first specific gravity at a first column height and containing a second liquid at a second column height. The method separates the first liquid from the second liquid with a permeable membrane having a first surface in liquid communication with the first liquid and a second surface in liquid communication with the second liquid. including. The membrane has a vertical axis and allows molecules less than a predetermined size to pass between the first surface and the second surface. The membrane includes adjusting the second specific gravity to approximate the numerical value of the first specific gravity. Alternative normalization of the specific gravity between the first liquid and the second liquid can be achieved in other ways, for example by introducing a non-gaseous solute into the first liquid. In some embodiments, the second specific gravity is adjusted to within about ± 5% of the first specific gravity (ie, up to a value of 95% of the first specific gravity value). In another embodiment, the second specific gravity is adjusted to within about ± 2.5% of the first specific gravity. The method includes, for example, providing or selecting a second column height that is different from the first column height, thereby adjusting the first and second surfaces of the membrane along the vertical axis of the membrane with an adjusted second specific gravity. And generating a selected pressure difference between. In a more detailed embodiment, the method further includes recovering the second liquid, for example, by overflowing or draining the second liquid as treated water.

  Another aspect of the present invention provides an improved vertical shaft bioreactor and associated methods for wastewater treatment. The vertical bioreactor and associated methods are as described herein above. The bioreactor accepts an influent wastewater containing biodegradable materials for processing and produces an treated flow that is directed to the submerged membrane assembly of the present invention. The bioreactor improvements include a membrane compatible head tank that functions as a normal vertical shaft bioreactor head tank, but is adapted to receive and contain the treated water stream and removably receive the submerged membrane. . The immersed film includes a permeable film having a first surface, a second surface, and a vertical axis, and a film that allows molecules having a size less than a predetermined size to pass between the first surface and the second surface. The first surface of the membrane is in fluid communication with the treated water flow in the head tank, and the second surface is in fluid communication with a second liquid having a second specific gravity and contained in the second liquid compartment. The improvement includes a means for imposing a head difference between the treated water stream contained in the tank and a second liquid contained in a second liquid compartment, and for adjusting a second specific gravity. Means. In a more detailed embodiment, the improvement also includes a liquid collector that recovers the second liquid.

  In another detailed aspect, the present invention provides an improved ioreactor for wastewater treatment that accepts influent wastewater containing biodegradable material for treatment to produce effluent treated water having a first specific gravity. The improvement is to include a tank, which receives and stores the effluent treated water at the first column height, and is detachably mounted with a submerged membrane assembly and a liquid collector for collecting the second liquid. Yes. The submerged membrane assembly includes a permeable membrane having a first surface, a second surface, and a vertical axis, wherein the membrane transmits molecules less than a predetermined size between the first surface and the second surface. be able to. The first surface of the membrane is in liquid communication with the effluent treated water. A second liquid compartment (separated from the head tank by the membrane) contains a second liquid having a second specific gravity at a second column height, and the second surface of the membrane is in fluid communication with the second liquid. ing. The improvement further includes means for adjusting the second specific gravity. The second column height is selected with respect to the first column height so as to generate a selected pressure difference between the first surface and the second surface along the vertical axis at the modified second specific gravity. The Part of the stored spilled effluent is exposed to normal atmospheric pressure.

  In yet another detailed aspect, the present invention provides a submerged membrane gas diffusion apparatus. The apparatus includes a membrane having a first surface, a second surface, and a vertical axis, wherein the membrane allows molecules less than a predetermined size to pass between the first surface and the second surface. The device includes a first housing member, which is typically a tubular housing member, the first housing member being in fluid communication with a bubble capture opening and a first surface of the membrane. And a first chamber in fluid communication with the first membrane attachment portion and the bubble trapping opening, the first chamber being in the vicinity of the bubble trapping opening and having a first vertical length Part. The apparatus further includes a second housing member, which is typically a tubular housing member, the second housing member being in fluid communication with the gas discharge opening and the first surface of the membrane. And a second chamber in fluid communication with the gas discharge opening, the second chamber being in the vicinity of the gas discharge opening and having a second vertical length shorter than the first vertical length. Includes a gas reservoir having a length. In particular, the first and second receiving members are constructed according to various designs and function in the manner disclosed herein below, have dimensions according to the designs, and are tubular as described herein. The design is provided for illustration purposes only.

  Another aspect of the invention provides an immersed membrane diffuser assembly. The assembly includes a membrane having a first surface, a second surface, and a vertical axis, wherein the membrane can transmit a separation of less than a predetermined size between the first surface and the second surface. The assembly includes an aeration compartment containing a first liquid and rising bubbles, a stationary liquid compartment containing a second liquid, and a liquid containing a pre-treatment liquid in fluid communication with the second surface of the membrane. Processing compartment. The assembly includes a bubble capture opening disposed in the aeration compartment, a first membrane attachment portion in fluid communication with the first surface of the membrane, a first membrane attachment portion and a fluid communication with the bubble capture opening. A first chamber that includes a rising bubble trapping portion in the vicinity of the bubble trapping opening and having a first vertical length. The assembly includes a second tubular member having a gas discharge opening disposed in the stationary liquid compartment, a second membrane attachment portion in fluid communication with the first surface of the membrane, a second membrane attachment portion, A second chamber in liquid communication with the gas discharge opening, wherein the second chamber includes a gas reservoir in the vicinity of the gas discharge opening and has a second vertical length shorter than the first vertical length.

  A further aspect of the invention provides a method for aeration in a target liquid. The method includes using a membrane to permeable the target liquid from a gas, the membrane being in contact with the gas and a second surface in contact with the target liquid. And molecules less than a predetermined size can pass between the first surface and the second surface. The method also includes capturing the gas by receiving a first liquid containing rising bubbles of the gas into a bubble capture opening of the first chamber, the first chamber being proximate to the bubble capture opening. It includes a rising bubble trap and has a first vertical length. The method further includes imposing a head on the gas in the first chamber using buoyancy of the gas in the first liquid to displace the first liquid from the bubble trap. Imposing the water head forces the gas to flow between the bubble capture portion of the first chamber and the first membrane attachment portion of the first chamber, but the first chamber is the first of the membrane. It is in fluid communication with one surface. The method further includes allowing at least a portion of the gas to permeate through the membrane and into the target liquid in response to imposing the water head. Further, the gas flows between the second chamber attachment portion that is in fluid communication with the first surface of the membrane and the second chamber. The second chamber has a gas storage part in the vicinity of the gas discharge opening and a second vertical length shorter than the first vertical length. The method automatically discharges the gas from the gas discharge opening when the water head displaces the second liquid from the storage tank.

  Additional aspects of the invention are listed in detail in the following description and accompanying drawings.

DESCRIPTION OF SPECIFIC EMBODIMENTS As shown in the accompanying drawings, the present invention provides a vertical long shaft bioreactor 10 for wastewater treatment. The bioreactor of the present invention shares many structural and functional features with previously described vertical shaft bioreactor systems (eg, US Pat. 4,279,754, 5,645,726 and 5,650,070), which differ in several important and novel aspects.

  Referring to FIG. 1, a vertical shaft bioreactor 10 of the present invention includes at least one upflow channel 14 and at least one in fluid communication in a detour, open or closed path. Features a wastewater circulation system that includes two or more substantially vertical channels, including downflow channels 12. The downflow and upflow channels are typically in communication at the upper end of the channel via a surface section or head tank 16, which has a port or opening 20 at the bottom of the downflow channel. It may be open or closed at the lower junction corresponding to the mixing zone 18 located below.

  The downflow channel 12 and the upflow channel 14 are typically defined by separate conduits, for example, pipes having separate cylindrical walls. Alternatively, the downflow channel 12 and the upflow channel 14 may be in interconnected compartments or channels sharing one or more walls, eg, in an elongated, compartmentalized reactor vessel or frame. It may be defined as parallel channels separated by partition structures (eg radial partitions or partitions). The downflow and upflow channels are preferably oriented substantially parallel to each other, for example in a parallel or coaxial arrangement.

  Typically, the downflow channel 12 and the upflow channel 14 are defined as separate conduits, at least a portion of their length. As an example, the downflow channel is a downflow conduit (eg, a steel pipe) 22 having a separated cylindrical wall, and the downflow conduit is in an upflow conduit 24 having a larger diameter cylindrical wall. Built up coaxially, the upflow conduit often corresponds to the outer wall or casting of the entire bioreactor assembly. Accordingly, the accompanying drawings are generally to be construed as schematic illustrations, and for convenience of illustration, a drawing showing a downflow conduit displaced laterally with respect to the upflow conduit is a larger upflow. The intent is to show schematically an alternative arrangement in which downcomers are incorporated in parallel or coaxially within the conduit.

In one embodiment of the present invention adapted for residential use, the wastewater treatment bioreactor 10 of the present invention is built for a small residential community with a population of about 5000 people. Typically, two parallel bioreactors are installed in a vertical underground shaft that is drilled using conventional drilling techniques according to EPA overlap requirements. In various embodiments, the bioreactors of the present invention have secondary characteristics or are constructed and tuned to provide secondary and / or tertiary levels of processing listed below. There is a case.
(A) Only secondary treatment (BOD and TSS removal) (b) Secondary treatment and nitrification of ammonia (conversion of ammonia to nitrate)
(C) Secondary treatment and nitrification and denitrification (removal of ammonia and nitrate)
(D) Secondary treatment and nitrification, denitrification and chemical dephosphorization (tertiary treatment). Some biological dephosphorization occurs at low loads.
(E) Thermophilic and aerobic decomposition and disinfection of sewage sludge to produce class A biosolids.

  As a simple reference for the following description, the secondary process of (a) is performed in both the zone 1 head tank 16 and the downflow channel 12 of the zone 1, and the zone 2 upflow channel 82 and the head tank 15. May be completely aerobic. This configuration consists of a shaft approximately 30 inches (0.762 m) in diameter and 250 feet (76.2 m) deep and a zone 1 head approximately 6 feet (1.829 m) in diameter and 10 feet (3.048 m) in depth. Requires a tank and a concentric zone 2 head tank about 12 feet in diameter and 10 feet deep. The concentric clarifier is approximately 28 feet in diameter and 10 feet deep and is equipped with a rake mechanism to assist in sludge removal. In a more detailed embodiment, this reactor treats domestic wastewater from at least 2500 people and produces treated water of <30 mg / L TBOD and <30 mg / L TSS.

  The secondary processing step of (b) is also completely aerobic and has the same general dimensions as (a) except that the zone 2 head tank has a diameter of about 16 feet (4.877 m). Most of the air originating from the bottom of zone 1 is diverted to zone 2 using diversion mechanism 84. The processing system of (c) is designed for oxygen deprivation conditions in the zone 1 head tank and downflow channel. In some embodiments, the reactor treats domestic wastewater from at least 2500 people and produces treated water of <1 mg / L ammonia-N, <15 mg / L TBOD and <15 mg / L TSS.

  Only a small fraction of the air from the bottom of zone 1 is diverted to zone 1 upstream channel 40. In addition to the untreated influent wastewater supplied to the upper end of zone 1, nitrified treated water that is recycled, the clarifier, or alternatively, reactivated sludge from zone 2 head tanks is oxygen deficient. Is added to the untreated influent wastewater.

  In this process step, the reactor is expanded to about 36 inches in diameter, the zone 1 head tank is increased to about 8 feet in diameter, and the zone 2 head tank is increased to about 16 feet in diameter. The concentric clarifier has an outer diameter of about 30 'and includes a rake mechanism. In a more detailed embodiment, this process treats domestic wastewater from a population of 2500 or more to produce treated water of <5 mg / L TKN, <10 mg / L TBOD and <10 mg / L TSS.

  The processing system of (d) has almost the same dimensions as (c). Within the processing step (d), ferric chloride alum may be added inside Zone 2 for chemical precipitation of phosphorus. Since a pre-fermentation step to produce volatile fatty acids (VFA) may be required, only the biological phosphorus removal process is required to achieve high phosphorus removal (eg residual amount 2-3 mg / L) in a small plant. It is usually not economical to use. Typical characteristics of treated water from this plant are TBOD <10 mg / L, TSS <10 mg / L, TN <5 mg / L, PO4 <1 mg / L.

  In the case of sludge treatment (e), the reactor may be zone 1 surrounding the zone, zone 1 may be in the vicinity of zone 2 over most of the length of the reactor, or zone 2 head tank 15 'Surrounds the zone 1 head tank 16'. Zones 1 and 2 are in hydraulic communication at the bottom of Zone 2 through an automatic self-batching air lock that prevents the contents of Zone 1 from entering Zone 2 and processes at least each batch. . The volume of the thermophilic aerobic digester of configuration (e) is about half of the volume of the wastewater treatment reactor producing biomass. Since one sludge provision can be built more economically than duplication in the reactor, one is required per two treatment reactors. Therefore, a small town with a population of about 5000 requires two processing reactors and one sludge decomposition tank of the same size. The above example is a typical design for a small community with a population of about 5000.

  Since about 80% of the air gap (air rise) occurs at the top 80-100 feet (24.88-30.48 m) in any airlift reactor, the upper channel is 150-50 feet (45 to 45 inches) deep. .72 to 15.24 m), preferably 80 to 88 feet (24.38 to 26.82 m), which is the standard length of two joints of random double pipes May be effective. Off-the-shelf air compressors are readily available in 100, 125, and 150 psi models that correspond to shaft depths of 200, 250, and 300 feet. Airlift reactors have been constructed at a depth of 60 to 500 feet, but a more general range is 150 to 350 feet deep, and a range of 200 to 300 feet is now the most common.

  Conventional water well rigs can drill holes up to about 48 inches (1.219 m), and deep foundation equipment can drill holes up to about 10 feet in diameter. An auger can drill up to about 20 feet in diameter (where geographically permitted), but is limited to a depth of about 200 feet. The mined shaft is up to 30 feet in diameter, but the depth can be virtually any depth.

  Small urban plant reactors (population 5000) are typically installed with conventional well rigs, preferably about 24 to 48 inches in diameter.

  Larger communities (population 10,000-50,000) require shafts 5-10 feet in diameter x 200 feet deep, provided by deep foundation piles and augers, and are very large industrial plants ( For example, a paper mill) may require a shaft provided by a mining method.

  The vertical long shaft bioreactor 10 of the present invention receives inflow, typically waste water or sludge, through an inflow conduit 30 that introduces the inflow into the inflow channel 32. The inflow flows down to the bottom of the inflow channel, exits through an inflow port 34 shielded at the bottom, and is mixed with the upflow in the upflow channel 40 of zone 1 delimited at the lower end by the inflow port. . The inflow port is flipped upside down or otherwise blocked so that bubbles from the lower zone 1 upflow channel do not enter the inflow channel.

  In an alternative embodiment of the present invention, the inflow channel 32 may selectively accept a liquid recirculation flow from the zone 1 head tank 16 portion of the bioreactor 10. This flow is regulated by zone 1 recirculation regulator 50, such as a manual or motor driven baffle, valve or other flow regulator. In this context, the inflow through the zone 1 recirculation regulator 50 is typically throttled through an inflow throttle control mechanism. This may be, for example, a valve or baffle actuator 52 and an optional flow sensor 53 or 53 'for determining inflow and / or zone recirculation flow, or alternatively a dissolved oxygen DO probe that monitors the oxygen level. It may include a system control unit 51 (eg, a system control microprocessor) that is operably coupled. Inflow control through the regulator works in part by adjusting the air lift in the zone 1 upflow channel 40 to promote gravity inflow. The mixed stream in the zone 1 upflow channel contains bubbles (see below) that are deficient in a small amount of oxygen and therefore rises because it is lighter than the liquid in the inflow channel 32. Bubbles deficient in oxygen mean bubbles that predominately contain gases other than available oxygen. The flow in the zone 1 upflow channel 40 traverses the degassing plate 54, descends in the downflow channel 12 by gravity, substantially free of contained bubbles, and in the vicinity of the mixing zone 18 the main upflow channel 14. The mixing zone is aerated for cooperation.

  Compressed air or other oxygen-containing gas or liquid that serves as an oxygenation source for the bioreactor 10 is delivered through one or more dedicated oxygenation lines where the compressed air is typically transfer tube 62. It is typical. A dedicated compressed air line is connected at the surface to a compressed air supply and leads downwardly parallel to the upflow channel (eg, incorporated in the upflow conduit 24) and into the oxygenation port, typically upflow. An air supply port 64 that opens in fluid communication with the channel 14 extends. The air supply port 64 is typically located under the air supply header to release the compressed air for diffusion through the air supply header 60 as described above. In some embodiments of the invention, compressed air (or other oxygen-containing gas or liquid) is optionally or additionally delivered into the bioreactor by a dual-use aeration / solids extraction line 66. The function of this piping is controlled, for example, by the system control unit 51 described above to optionally deliver compressed air or other oxygen-containing gas or liquid, and in the second mode of operation, at the bottom of the upflow channel. It serves as a filth solid extraction pipe 66 for removing filth solid from the sewage reservoir 67 portion of the reactor disposed. The filth solids extraction piping extends from the surface (eg, from the filth solids extraction / floating reservoir located on the surface) to an aeration / solids extraction port opening in fluid communication with the sewage reservoir. Solid particles that accumulate in the sewage reservoir accumulate during operation. During most of the bioreactor's operating time, the aeration / solids extraction piping is continuously washed by the flow of compressed air so that the sewage sump 67 is substantially mixed and aerated to provide a functional zone 18 Part may be formed. By periodically depressurizing the aeration / solids extraction line, the accumulated solids in the sewage sump collect at the top of the reactor to be cleaned. These solids will be highly aerated, well stabilized (foul odor disappears) and will voluntarily float in viscous sludge due to the high gas content.

  In a related embodiment of the invention, the improved vertical shaft bioreactor 10 generates upward flow and enhances the formation of small and diffused bubbles to supply process air into the virtual reality, Features two aeration pipes or ports that operate. The use of two aeration pipes is embodied by a dedicated compressed air pipe 62 and an aeration / solid matter extraction pipe 66 having two functions. The compressed air pipe 62 and the aeration / solid matter extraction pipe 66 are Each operates in compressed air delivery mode for at least the majority of the bioreactor process time. In this mode, the two pipes come together to provide the compressed air injection mechanism of the present invention that cooperates from multiple sources, which mechanism includes turbulence and small bubbles in the mixing zone 18. To enhance the forming capability, the mixing zone 18 is expanded by the cooperation of multiple compressed air lines or ports. In one aspect of this enhanced mixing / bubble formation mechanism, the first aeration pipe opening is located above the second pipe opening below the diffuser header 60, but the first aeration pipe opening is a dedicated air pipe. The second aeration pipe opening is embodied by an aeration / solids extraction port 68 having two functions. The compressed air released from this lower aeration port stimulates liquid mixing and bubble formation in the vicinity of the bottom of the upstream channel 14 forming the first circulation path or vector. As a result, the circulating liquid-bubble mixture collides upward and / or laterally against the mixture of liquid and bubbles generated by the introduction of compressed air from the upper first air pipe 62. This results in increased shear forces in the enlarged mixing zone and smaller bubbles compared to results achieved with a single aeration line operation (see FIG. 1).

  In connection with utilizing a cooperative multi-source compressed air circulation scheme as described above, some embodiments of the present invention are enhanced by the provision of multiple interacting aeration sources. To enhance the mixing / bubble formation mechanism, whether it is an improved (typically stepped, chambered or baffled) header or a multi-component header complex Capture. In one aspect, a cooperating second shear header 70 is mounted in the upflow chamber 14 below the main bubble dispersion header 60 and is two vertically stepped as generally described above. Operates in conjunction with an aeration source. The shear header enhances components that flow upward and / or sideways or radially in the mixing zone generated by a second aeration source located at the bottom (implemented as aeration / solids extraction port 68) There may be any flow diverting or channeling device. In one exemplary embodiment, the shear header includes a draft tube with an inner staircase attached by a vertical post to the underside of the diffuser header. The compressed air supplied to the aeration / solids extraction pipe 66 creates an airlift effect in the stepped draft tube, thus establishing a separate circulation pattern or vector at the bottom of the mixing zone as shown in FIG. This upward and / or lateral or radial circulating flow collides with the mixed liquid and bubbles generated by the introduction of compressed air from the upper first air pipe 62 near the edge of the diffuser header. The interaction is partly regulated by the air sent through the aeration / solids extraction port, while the balance of processing air is sent through a dedicated air supply port 64. This creates a very fast flow rate inside the serrated skirt at increasing shear forces with a diffuse header that substantially assists in shearing the bubbles to a smaller size. While conventional bioreactors typically generate bubbles at distribution sites in the range of about 1/2 inch to 3/4 inch (1.27 to 1.905 cm) in diameter, the present invention The new interactive flow mechanism and the collaborative header design are typically about 1/4 to 1/2 inch (0.635 to 1.27 cm) in diameter, often Produces substantially smaller bubbles with a diameter of less than a quarter inch, one-fifth to one-eighth inch, or less. For example, a study published in Water Environment Research, May / June 1999, pages 307-315 (incorporated herein by reference) shows that about 2 mm of bubbles are at the optimum diameter for mixing and oxygen transport. Decided to be. However, bubbles of this size will not spontaneously form at the orifice without any mechanism for shearing the bubbles. The bubble size is determined when the buoyancy is equal to the attractive force at the orifice, and the bubble size does not necessarily correlate with the size of the orifice. Bubbles in this size range have an ascent rate in the water of about 0.8-1.0 feet / second and a downward circulation rate in excess of 1 foot / second near the serrated skirt 60 shears the bubbles from the orifice. . The circulation speed is adjusted by the amount of air injected into the pipe 68 and can be adjusted independently with the air applied to the orifice 64. Samples that are periodically extracted in piping 66 may be measured for dissolved oxygen. The circulation rate between the aeration elements 60 and 70 may be adjusted to maximize oxygen transport. This novel design provides enhanced mixing and bubble dispersion without the unacceptable risk of clogging. When the aeration / solids extraction pipe is used for biomass disposal, the air flow in the dedicated air pipe maintains the reactor circulation. At this point, when the aerating barrel of the shear header is depressurized, a new batch of waste biomass is transferred from the mixing zone 18 to the sump and the shear header's The aeration barrel resumes.

  Further additional embodiments of the present invention are distinguished because of novel features for the diversion, circulation and separation of liquid, gas and / or biomass in the reactor 10. These features can be changed and combined in alternative reactor configurations and / or tuned within the scope of additional aspects of the present invention, such reactors for different wastewater treatment applications and results. Allows use or modification. In a general aspect, the bioreactor of the present invention features a first processing or processing “zone” termed zone 1 in which waste, dissolved oxygen, nutrients and (active microbial communities) are included. ) The majority of the main reaction between the biomass occurs (eg, greater than 80%, up to 90-95% or more). In some embodiments, this zone is the main reaction including the upper circulation zone of the bioreactor including the surface section or head tank 16 and the central volume of the upstream channel 14, downstream channel 12 and mixing zone 18. And chamber 80.

  Most of the contents of the mixing zone 18 represent a liquid-bubble mixture that is less dense than the liquid in the downflow channel 12 and therefore circulates upwardly from the mixing zone to the main reaction chamber 80. Non-dissolved gas, primarily nitrogen, expands to help provide the necessary gas levitation to drive the liquid circulation at the top of reactor 10 in the pattern shown by the arrows throughout the drawing. The products of this main reaction are carbon dioxide and additional biomass, which form sludge (or biosolids) with unreacted solids present in the incoming wastewater.

  As shown in FIG. 1, in some embodiments of the present invention, the liquid upflow in the main reactor channel 80 is separated into a plurality of small upflow channels in the upper section of the bioreactor 10. In one exemplary embodiment, the upflow from the main reactor channel is the zone 1 upflow channel 40 shown in FIG. 1 and the zone 2 upflow channel 82 (typically operating as a polishing zone). Is branched into at least two separate upper riser channels. In one exemplary configuration design, the diversion from the main reactor channel to a plurality of upper channels is similar to a fixed or adjustable diversion plate 84 that is anchored near the top of the main reactor channel. This is accomplished by using a device that branches the flow.

  The diversion plate 84 is configured and dimensioned to separate the upward flow of the main reactor channel 80 into a plurality of upper channels. The diverter plate interrupts the total upward flow volume of the liquid-bubble mixture from the main reactor channel, depending on the desired mode of operation of the bioreactor 10, as will be described in more detail below. Typically, it has a configuration and dimensions that divert the stroke into selected “aerobic” upflow channels. In the exemplary embodiment shown in FIG. 1, the flow diverter plate features a vertical baffle 86, which baffle produces a greater fraction of the total upflow volume of liquid and bubbles from the main reactor channel, Inside the main reactor channel toward a diversion extension pipe 88 that is angled upward and laterally or radially extends upward in a diversion plate that diverts to one or the other of zone 1 upflow channel 40 or zone 2 upflow channel 82. Facilitates the separation and splitting of the liquid-bubble mixture flowing upwards. Therefore, a smaller fraction of the total rising dragon volume of liquid and bubbles is allowed to flow into the remaining upper ascending channel 40, thereby making it a major process determinant within this channel as desired. This limits the passage of aerated liquid into this remaining channel to contribute to the generation of oxygen deficiency conditions.

  The selection, placement and adjustment of the diversion mechanism depends on the selected operating mode of the bioreactor 10. In an alternative embodiment, the diversion plate 84 achieves a more aerobic environmental condition in the selected channel, while an upflow (especially for liquids containing high concentrations of oxygen) is less aerobic, One or two upflows of the liquid-bubble mixture from the main reactor channel 80 so as to limit it to one or more upper channels selected for environmental conditions that are even oxygen deficient. It may have an arrangement, shape and / or size for switching the channel to the upper channel and / or be adjusted. The examples illustrate the following steady state functions of adjustable baffles 86 and 84. In FIG. 1, 10 bubbles are drawn to rise uniformly to the top of the zone 1 immediately below the baffle 86. The baffle is adjusted so that three bubbles are separated into region 39 and seven are separated into region 81. However, the flow to region 81 is approximately equal to inflow / outflow flow rate Q + nitridation recirculation flow rate 1.75Q = 2.75Q. In this representative design, diversion to region 39 is controlled to 5Q. Accordingly, the flow rate per bubble in the region 39 is 5/3 per bubble, that is, 1.7Q, and in the region 81, 2.75 / 7 = 0.4Q per bubble. Similarly, the oxygen demand and supply in the upper channel and head tank can be calculated. Typically, the average BOD in regions 39 and 81 is about 10 mg / L, the average ammonia-N concentration to be removed is 15 mg / L (after being used for cell synthesis), and the denitrification recirculation flow rate is 1 .75Q. Therefore, the average ammonia concentration would be 15 / 1.75 = 8.57 mg / L. This level of ammonia-N is equivalent to a BOD equivalent of 8.75 mg / L-Nx4.6 # oxygen / # N = 39 mg / L. Thus, the total load on Zone 2 is 2.75Q (10 + 39) = 134Q oxygen units. Since the bubble oxygen unit is 7, the load per bubble is 134/7 = 19 required oxygen units / bubble. Similarly, the load on region 39 is 5Q × 10 mg / LBOD = 50Q required oxygen units. However, in channel 40 above port 34, the load increases to 50Q units + Qx200 units for a full load 250Q required oxygen unit (assuming an inflow BOD of 200 mg / L). Since there are only 3 bubble oxygen units available, the required oxygen per bubble is 250/3 = 83 oxygen units. Therefore, the required oxygen amount per bubble oxygen unit is 83/19 = 4.3 times higher in the head tank 16 than in the head tank 15. As a result, when there is measurable dissolved oxygen in the head tank 16, there is surplus DO in the head tank 15, and when there is surplus DO in the head tank 16, the mixing zone 18 moves downward from the baffle 86. There is substantially more DO at any level up to. Thus, the baffle 86 can be adjusted to meet a wide range of load and flow criteria.

  Thus, in one aspect of the present invention, the improved vertical long shaft bioreactor functions for multipurpose wastewater treatment that provides aerobic degradation of BOD and for single mixed liquid treatment BNR treatment. Referring to FIG. 2, the diverter 84 diverts a majority fraction of the total upflow volume of the liquid-bubble mixture from the main reactor channel into the zone 2 upflow channel 82 while liquid and bubbles. To limit the upflow volume of the main reactor channel 80 to the zone upflow channel 40 (as opposed to an alternative shunt configuration / setting shown by dashed line 90). Built to have. The volume ratio between the flow into the inflow channel 32 and the flow into the zone 1 upflow channel (which blocks only a small fraction of bubbles from the main reactor channel) can be finely controlled. Accordingly, a relatively small amount of air lift and slow circulation rate may be provided to the zone 1 upstream channel compared to the lift and circulation in the zone 2 upstream channel in this shunt configuration. Accordingly, the residence time of the liquid mixture in the zone 1 upflow channel 40 increases and the oxygen carrying capacity of the zone 1 upflow channel 40 decreases due to bubble upflow. Notably, oxygen is consumed greatly in the lower and middle parts of zone 1 (particularly including mixing zone 18 and main reactor channel 80 below the diverter), so zone 1 upflow channel The bubbles inside are mostly nitrogen.

  Within this embodiment and the regulation / operational mode of the bioreactor 10, the upper channel referred to as zone 1 upstream channel 40 can be selected, in part, to provide an oxygen-deficient environment, This can be achieved by a low oxygen relative inflow and a high oxygen demand in the process influent stream. This oxygen-depleted zone continues through the circulation path between zone 1 upstream channel and downstream channel 12, as schematically illustrated by the arrows in FIG. Within this oxygen-deficient zone, denitrification of nitrogen initially contained in the liquid mixture in the zone 1 upflow channel, which is the final step of the BNR process, occurs. Following this path, re-aeration of the oxygen-deficient liquid stream exiting the lower downflow port 20 occurs when this mixture reaches the mixing zone 18, and residual BOD that has not been removed in the oxygen-deficient zone (mixed) Oxygenated at the bottom of zone 1 (including the zone and main reactor channel 80). Thereafter, part of the upflow in the main reactor channel flows upward into the zone 1 upflow channel 40 and the top of this zone 1 is designed to be oxygen-deficient, so that The number decreases. The air lift effect is also greatly reduced to slow the upflow in this part of the reactor. In addition, the ability to control the inflow through the zone 1 recirculation regulator 50 also allows for adjustment of air lift and flow in the zone 1 upflow channel.

  Within the above operating modes of the bioreactor 10, the major portion of the rising air flow rate in the main reactor channel 80 moves upwards and other upper ascensions embodied in the zone 2 upflow channel 82. Flows into the channel. A fraction of the upward flow of the relatively lower liquid separated in this way (e.g., dedicated air piping that works with the bubble dispersion header 60 and the optional shear enhancement mechanism embodied by the shear header 70). 62 and most of the bubbles originating from the lower end of Zone 1 (such as those generated by optional multipurpose aeration / waste solids extraction piping 66). This active liquid-bubble mixture separated into zone 2 by the operation of flow divider 84 enters the zone 2 upstream channel and recirculates zone 2 (recirculating liquid from zone 2 head tank 15). Mix with active recycle stream entering zone 2 through channel 110. This recirculation flow is optionally regulated by a zone 2 recirculation flow regulator 112, such as a manual or motor driven baffle, valve or other flow regulator. The recirculation regulator optionally includes a system control unit 51 (eg, a system) operatively connected to a valve or baffle actuator 52 and an optional flow sensor 53 for determining zone 2 recirculation flow. It is also controlled by a control microprocessor.

  When the bioreactor 10 is configured in this way and / or tuned for BNR removal, the nitrification of the mixed liquid is carried out in zone 2 of the bioreactor according to the above configuration and operation details. Can be implemented and controlled efficiently. When a portion of the mixed liquid from zone 2 is discharged to a separate solid-liquid separator (clarifier) 120 or an integrated solid-liquid separator (clarifier) 120 ' (See, eg, FIGS. 2-4 and 6). A part of the mixed liquid from the zone 2 may be returned to the inflow channel 32. In the inflow channel 32, denitrification is performed as described above, and the circulation cycle is repeated. Optionally, some clarified treated water may be returned to channel 32 for low flow return to remove more nitrogen compounds overall.

  In a more detailed embodiment of the invention, influent water, clarified return treatment water (eg, recycled from separated clarifier 120 or integrated clarifier 120 '), return activated sludge, Are combined in a preselected ratio to facilitate operation of the bioreactor 10. This can be accomplished by documenting the various flow control configurations of the present invention and is facilitated in part by the incorporation and controlled operation of zone 1 activated sludge return channel 122 and zone 2 activated sludge return channel 124. However, the zone 1 activated sludge return channel 122 and the zone 2 activated sludge return channel 124 receive activated sludge (eg, through a sludge extractor pipe 126 connected to the clarifier) and receive the sludge, respectively. To the zone 1 inflow channel 32 or to the zone 2 recirculation channel 110 (see, eg, FIGS. 2-4 and 8). Through the accompanying drawings, the flow control within and between each of the illustrated supply, flow and drain piping and ports is operably interconnected with a valve or baffle actuator 52 and / or flow sensor. All of these are operably integrated and controlled by one or more system control units 52, although this can easily be accomplished using the flow regulator 50.

The selected mixing ratio per inflow volume of typical municipal wastewater is as high as 3 volumes of clarified treated water vs. 1 volume of return activated sludge, and as low as 1 volume of clarified treated water vs. 1 volume of returned activated sludge. There are cases up to things. About 85% of the total nitrogen is converted to N ₂ with 1.75 volumes of clarified treated water or mixed liquid per volume of influent (eg, Naohiro Taniguchi et al., Incorporated herein by reference, nitrification and (See Report on Air Lift Recirculation for Denitrification, Japan Sewage Treatment Agency Research and Development Department, 1987). However, it should be noted that some industrial wastewaters may require 100 times more volume of recirculated water per influent water volume.

  Regarding the nitrification process function of the bioreactor 10, this can be further modified or enhanced by selecting or adjusting the various reactor configurations and operating parameters described above. In addition, the system can easily incorporate or combine additional system configurations or components to enhance BNR process capabilities. BOD is low in Zone 2, organisms that remove BOD are almost minimal, and nitrifying bacteria can be dominated by biomass. In addition to this advantage, a substantial improvement in the conversion rate of ammonia to nitrite and nitrate can be achieved by increasing the concentration of nitrifying bacteria. Since nitrifying organisms are attached organisms, the attachment site in the mixed liquid is a sponge ball, suspension media, small diameter plastic or rubber (elastic body) polyethylene tubing bits, a thread suspended in a liquid of porous fibers. And the like can be used very effectively within the scope of the apparatus and method of the present invention (eg, Keith Ganze “Moving Bed Aerobic Treatment” Industrial Waste Water Nov, which is incorporated herein by reference). See / Dec 1998). For example, referring to FIG. 4, the BNR process of the bioreactor is substantially accomplished by including a suspending medium 130 that encloses or provides a substrate for the nitrifying bacteria in the recirculation path of Zone 2. (See also T Lessel et al., “Erfahrungen mittachten Festbethornfurdie Nitrifikation” 38. Jahrgang, Heft 12/165, 16/1991, which is incorporated herein by reference.) Is facilitated by the novel relative arrangement and the inter-zone separation between zone 1 and zone 2. The moving bed medium can be prevented from flowing into the treated water by a simple screen, for example. Alternatively, fixed media 132 may be fixed in the head tank to increase the biomass of microorganisms adapted for BNR processing. These modifications provide excellent BNR performance. For example, a combination of the Zone 2 management method that minimizes bacteria that remove BOD and biomass increased by adherent growth of nitrifying bacteria (eg, 15-20 g / L equivalent nitrifying organisms) is a bioreactor of the present invention. Provides very effective BNR processing within the range of A single sludge long-term aeration process typically includes 15-20% of nitrifying bacteria (by weight or as a percentage of sludge biomass community). However, when adherent media are used within the scope of the present invention, the biomass of nitrifying organisms is up to over 30% of the system community, often up to 60-70%, up to a large number of over 75-85%. Can increase. This is related to the relative exhaustion of BOD in this process stage and zone of the system and the effective use of adherent media, either fixed or circulating, in zone 2. These novel configurations and features distinguish the improved single sludge system of the present invention from other single sludge processes.

Within the scope of additional aspects of the present invention, a novel nitrification process is provided, but substantially or completely in residual dissolved oxygen originating near the bottom of Zone 1 as the source of oxygen driving the process. Dependent. Yet another benefit and attribute that arises from using unused expectations from Zone 1 in this manner is the high level of available CO ₂ , which is necessary as a source of inorganic carbon for nitrifying bacteria. In other nitrification systems, the primary source of inorganic carbon depends on the alkalinity of the wastewater and is typically determined by the presence of CaCO ₃ . Therefore, the bioreactor processing system of the present invention is more compact and requires less energy than the conventional long-time aeration system. Bioreactors constructed and operated in accordance with the present invention produce higher quality biomass that is easy to separate from the mother liquid (including class A biosolids if desired).

  To further enhance the function and operation of the bioreactor 10 of the present invention, various connected or integrated configurations can be incorporated into the bioreactor for enhanced wastewater treatment. As shown in FIG. 2, the bioreactor of the present invention for wastewater treatment may incorporate a conventional stand-alone settling clarifier 120. The bioreactor is optionally in fluid communication with a biofilter 133 and / or an ultraviolet light disinfection chamber 134 and / or a backwash tank that is polished by aeration. In some embodiments, piping 136 returns backwash water to the incoming water.

  Alternatively, FIGS. 3 and 8 (conceptual view and partial cross-sectional perspective view, respectively) show an integrated circular sediment clarifier 120 ′ (this vertical Fig. 4 shows an additional embodiment of the bioreactor 10 of the present invention, characterized in that in the reactor all three tanks are concentric. In these embodiments, the deposited activated sludge is returned to either zone 1 or zone 2 by attraction.

  An alternative embodiment of the bioreactor 10 shown in FIG. 4 includes a movable bed media 130 that circulates in zone 2 and, additionally or alternatively, a fixed media 132 suspended in the head tank 15 of zone 2. And features. Another embodiment shown in FIG. 5 is an optional exhaust collector 136 (off-gas that drives a pressurized head tank 135 and, for example, an airlift inflow pump 137 where exhaust is required to overcome head tank pressure. collector, eg, US Pat. No. 4,272,379 granted to Pollock, incorporated herein by reference), and an optional that operates to separate biomass from liquid under pressure Membrane filtration cartridge 138 (see, for example, George Heiner et al., “Membrane Bioreactors” Pollution Engineering, December 1999, incorporated herein by reference) and also serves as a backwash water reservoir for membrane backwash. , UV disinfection chamber 1 for clean water 39. Yet another embodiment shown in FIG. 6 features an integrated clarifier 120 ′ in liquid communication with the aerated and polished biofilter 133, an ultraviolet light disinfection chamber 134, and a filter backwash tank. .

  Typically, for a vertical long shaft bioreactor, the optimal biological air feed rate required for the biooxidation process is the upper rise channel embodied by zone 1 rise channel 40 and zone 2 rise channel 82. And an excessive “voidage” at the top of the reactor, which can be contrasted in this case. Excess porosity creates undesirable slugging that can cause reactor damage due to vibration. The generation of slugging gas voids means that the oxygen carrying properties in the circulating liquid are poor. The present invention addresses these challenges in a number of ways, including providing a novel means for adjusting the circulation rate and modulating the gas content in selected portions or channels of the reactor.

  Since the oxygen carrying rate and oxygen utilization are relatively slower than the upward liquid velocity in the reactor 10, increasing the velocity only reduces the operating efficiency of the reactor. Increasing the flow rate reduces bubble contact time, delays oxygen delivery, and requires more aeration to optimize the process. Similarly, reducing aeration reduces reactor capacity. One of the methods proposed to solve the air voids and related problems is a US patent application filed on May 11, 2000 which describes the VerTreat II "bioreactor (incorporated herein by reference). 09 / 570,162. This disclosure reduces the flow rate in an advantageous manner by incorporating an orifice plate in the lower section of the upflow channel. However, this solution does not substantially solve the problem of slagging, and the orifice plate poses additional problems including the risk of fouling and fluid flow abnormalities, especially in small urban plants.

  The bioreactor 10 of the present invention solves these problems in part by incorporating a new relative configuration of Zone 1 and Zone 2. The “VerTreat I” bioreactor (eg, US Pat. No. 5, issued July 22, 1997, incorporated herein by reference), where zone 2 is below zone 1 and void control in zone 2 is not possible. Unlike 650,070, the present invention allows the flow rate and gas content of each zone to be controlled independently. Conventional prior art “deep shaft” type reactors start slugging at an upward speed of about 2 feet per second. The above-described VerTreat II reactor with an orifice plate can be operated down to about 1.25 feet per second. Within the scope of the present invention, this number can drop to 0.25 to 0.5 feet per second below the riser channel. When the ascending rate is lower, some heavier solid particles will settle in the sewage sump 67. These solids are conveniently extracted by purging dual-use aeration / solids extraction piping 66 when desired, along with excess biomass (eg, circulating through shear header 70 and surrounding mixing zone 18). .

  The present invention provides a novel configuration and method for slowing down, and provides a substantially more efficient configuration and method than prior art methods, which, as described above, include one of the reactors. Including the ability to dilute the airlift flow in one or more upper riser channels with bubble-free liquid. The advantages of these configurations and methods to the VerTreet II technology include eliminating the possibility of clogging the orifice plate in the inaccessible section below the upflow channel, which is particularly problematic in small diameter reactors.

  In a vertical long shaft airlift reactor such as the bioreactor 10 of the present invention in which a liquid / gas mixture is circulated in a vertical channel, the volume of gas in a fixed volume of liquid changes with pressure (gas law). As a result, at the bottom of the reactor, the volume (gap) of the gas in the liquid is small, but at the top of the reactor, the volume of the expanded gas with respect to the same liquid volume is several times larger. Since a 34 foot water column is equal to about 1 atmosphere, 1 cubic foot (1 scf) at the surface is 0.5 cubic foot at a depth of 34 feet and 0.33 cubic foot at a depth of 68 feet. At 102 feet, it can easily be calculated to be 0.25 cubic feet. Thus, the area integral under the curve in the volume vs. depth graph indicates that the gas volume porosity is 78% at the top 102 feet of the reactor.

  Many studies on airlift pumps and other bubbles / water columns show that water slugging occurs with a porosity of 11-14%. What makes slagging undesirable is that the bubbles coalesce into large air pockets and vibrate in the reactor, most importantly, the large bubbles have very poor oxygen carrying properties. Control of voids proposed to improve these effects has been attempted in at least two different ways. One proposed control is to increase the cross-sectional area of the reactor sufficiently to allow the gas to be pulled away from the gas / liquid mixture. Alternatively, efforts have been made to maintain the residual pressure of the gas / liquid mixture at the top of the reactor. Each of these proposed controls has disadvantages that are undesirable to utilize within the bioreactor of the present invention. For example, some airlift reactor head tank designs are provided such that a liquid pressure of 1/2 atm (17 feet) is used. This reduces the maximum air gap by 17%, but head tanks deeper than 17 feet are difficult to construct. In addition, a high head tank on the ground requires pumping the incoming water against significant heads, wasting considerable energy.

  The present invention provides a novel arrangement and method for controlling air gaps and improving the harmful effects of slagging. Briefly, these configurations and methods can be used to add liquid in one or more selected channels or chambers of reactor 10 by either adding more liquid or reducing gas. Reduce the amount of bubbles per unit. In a more detailed aspect, the liquid flow rate in one or more top upflow channels of the reactor is passed through a degassing step from the top segment of the reactor (eg, 60-90 ′) to near the bottom of the top segment. Increased by recirculating liquid to a lower recirculation inflow point (eg, 60-90 feet below the surface). It is generally believed that the total gas flow (air flow) is determined by biological optimization requirements, however, this total gas flow uses a novel flow control mechanism as described herein. Can also be assigned to a selected upper riser channel in the upper part of the reactor.

  Since approximately 75-80% of the void occurs at the top 60-90 feet of the reactor (optionally nested, the zone 1 recirculation input is connected to the zone 1 recirculation port 140, the zone 2 recirculation channel 110, The recirculation channel (which is embodied by the inflow channel (L-32) receiving from) is only about 25-35% of the total depth of a typical bioreactor and occupies only a fraction of the reactor cross-section and volume. . In practice, zones 1 and 2 of the reactor expand in volume due to nitrification by increasing the diameter of zone 2 head tank 15. The zone 2 recirculation channel gap is designed to operate over a wide range of operations by designing a sufficient and adjustable recirculation flow rate of degassed liquid from the zone 2 head tank 15 to be adjusted by the zone 2 recirculation regulator 112. It can be easily controlled by conditions. Thus, the volume of bubbles in the zone 1 upflow channel 40 can be diluted with degassed liquid to an extent that is limited by the acceptable range of maximum and minimum values of somewhat limited influent. To overcome this limitation, a regulated amount of liquid may be diverted through the zone 1 recirculation port by adjustment of the zone 1 recirculation flow regulator 50 (provided by the operation of the system control unit 51). Controlling the flow rate from the head tank in this coordinated manner is necessary to maintain the gravity feed of the treated water.

  The present invention thus provides a number of separate and optional collaborative mechanisms and methods to alleviate the problem of slagging when the flow rate of the bioreactor 10 is low. In another aspect, this problem is mitigated by providing a choice of an adjustable diverter or baffle device embodied by a fixed or adjustable diversion mechanism 84. This typical shunt plate configuration (including size, shape, location and orientation) can be fixed at the time of reactor construction and installation. Alternatively, these other shunt parameters may be used, for example, by system controller 51 (eg, to control position and orientation parameters) by utilizing a manual or motor driven shunt plate adjustment mechanism. Can be changed to selectable. The operation of the diverter directs more or less fractions of the rising bubbles from the main reactor channel 80 into one or more selected upper channels, for example, A larger fraction of the liquid-bubble mixture is diverted towards the zone 2 upstream channel 82 and serves to pass a smaller fraction upward into the zone 1 upstream channel 40.

  Once the desired fractional bubbles are thus diverted to zone 2 upflow channel 82, the porosity of this channel can be determined by changing the zone 2 recirculation flow rate through adjustment of zone 2 recirculation flow regulator 112. Can be easily modified. (From zone 2 upstream channel 82, through zone 2 degassing plate 150, zone 2 recirculation flow regulator 112, zone 2 recirculation channel 110, and following the arrow to zone 2 shielded recirculation port 152) The surface zone or zone 2 head tank 15 together with zone 2 comprises polishing the bioreactor driven by exhaust from zone 1 and the optional nitrification configuration. The configuration of the shunt separating the flow to the upper riser channel is that the liquid flow from zone 2 to zone 1 because the flow in both the liquid and air zone 2 riser channel 82 is unidirectional upward. To prevent. In this regard, as described above, the zone 2 circulation characteristics are ideal for applications with stationary media 132 (FIG. 4) and, alternatively or cooperatively, with membrane separation components (FIG. 5). A mobile bed media 130 (FIG. 4) is also available, but this circulates zone 2 completely separate from zone 1 to enhance nitrification within an alternative process mode of the reactor. Because.

Hydrodynamically, any of the streams entering the zone 1 of the bioreactor 10 (and either the finer 120 or the required external recirculation stream from the zone 2 head tank 15) are at the bottom of zone 2. You must exit Zone 1 by entering. Since Zone 1 is a closed loop, in particular, Zone 1 upstream channel 40, Zone 1 head tank 16, downstream channel 12 and main reactor channel 80, the number of recirculations of this loop and the liquid flow rate are determined by the flow dividing plate. 84 directly depends on the volume of bubbles diverted to the zone 1 upstream channel 40 For example, in a typical municipal treated water of 200 mg / L BOD, the number of internal recirculations is approximately equal to the quotient of BOD in mg / L divided by the O ₂ potential in the reactor and the oxygen carrying efficiency. In a 250 foot deep reactor, oxygen is injected at about 7.3 atmospheres. The solubility of O ₂ in water at 1 atmosphere and 20 ° C. is about 8 mg / L. This means that the dissolved oxygen potential at 7.3 atmospheres is 7.3 × 8 = 59 mg / L or about 40 mg / L with an oxygen carrying efficiency of 70%. Therefore, the minimum number of recirculations is 200 ÷ 59 × 0.70 = about 5. In practice, 6 or 7 recirculations may be used as a safety factor. The calculation of the water pressure loss determines the fraction of air required for 6 or 7 internal recirculations, for example 30% of the air applied to the bottom of zone 1. As the organic load on the plant increases or decreases, the proportion of air is adjusted and the number of internal recirculations is increased or decreased to meet the BOD requirements. However, 30% of the applied air is consistent and constant as determined by the arrangement of the diverting plate 84. Field trimming is accomplished, for example, by adjusting the regulator valve 50, which changes the recirculation flow rate in the air lift section in the zone 1 upflow channel 40 to provide its airlift capability. Is reduced or enhanced.

  Similarly, any flow from zone 1 that enters zone 2 must exit as treated water from zone 2. The lower portion of Zone 2, including the upstream channel 82 and the adjacent downstream channel 110, typically has no internal recirculation communication with Zone 1, so Even air will simply cause circulation in the upper channel of zone 2 without any change in the circulation rate of zone 1 (but the change in the proportion of air in zone 1 will affect the circulation rate in zone 2, but the reverse Does not happen).

  However, in some aspects of the invention, for example, diverting 70% of the air originating from the bottom of zone 1 to zone 2 only affects zone 2 circulation, and zone 2 circulation is It can be easily controlled by the recirculation flow regulator 112. Hydrodynamically, the inflow flow rate from zone 1 upflow to zone 2 and the treated water flow rate from zone 2 inside reactor 10 are quantitatively equal, that is, the flow flowing into the reactor in zone 1 is zone 2. Go out through. For prior art vertical bioreactors treating municipal wastewater, the internal recirculation flow rate is about 10 to 12 times the inflow or outflow. As described above, the process of the present invention featuring novel air lift control can reduce this flow rate by 2-3 times, often 5-6 times or more.

  The main reactor channel is selected by adjusting the configuration of the flow divider (generally refers to any of the diverters to separate the flow from the main reactor channel 80 into a plurality of upper riser channels). Only the bubble fraction is any desired number of channels (typically 2, 4 or 6 depending on the size and purpose of the reactor) (typically not the same as the liquid flow fraction) Can be separated at any ratio selected to achieve optimal operation of Zone 1 and Zone 2 (each upper channel shown in FIG. 8 has a pair of channels on the opposite side, Note that is a typical layout for a large reactor using two or more finers, which has four channels and a central downflow chamber as shown in FIG. Keshika no.). For example, a typical flow rate value in zone 1 upflow channel 40 is 6-8 times the flow rate entering zone 2 at the top of zone 1 (directly under zone 2 upflow channel 82) at the level of diversion plate 84. (Alternatively, it may be selected to be 2 to 3 times the BNR), but only 20-30% of the air volume is required to produce an airlift effect that does not cause slagging. Alternatively, when BNR is not used, the flow rate into the zone 2 upflow channel is about one sixth of the flow rate in the zone 1 upflow channel, but conversely about 75-85 of the air. May be selected to receive%. Thus, the air flow rate setpoint into the zone 2 upflow channel can be a wide range of flow settings such as 10-15%, 20-30%, 30-50%, 50-75%, 75-90% or more. May be set to a value.

  For example, after diluting the zone 2 upflow using 8 to 10 times the recirculation flow from the zone 2 head tank 15 through the zone 2 recirculation flow regulator 112, the airlift effect in the zone 2 upflow channel is Easy to control. This affected fish is a novel mechanism and method listed above for separating streams in an aerated and flowing vertical column, with different distribution ratios in two or more other upper vertical columns Relies on mechanisms and methods that provide for selectable switching of flow channels while providing bubbles to be distributed at completely different ratios between these vertical columns. This new capability of airlift control depends on the time available at the pressure to dissolve oxygen, which time correlates with the flow rate, and the dissolved (although largely independent of the amount of bubbles present). Allows a better biological fit between respiratory rate and oxygen utilization (which depends on oxygen).

  In yet another aspect of the present invention, novel configurations and methods are provided for solving the challenges associated with disposal of byproduct sludge and / or surplus biosolids from the bioreactor 10 process. Recognizing the nutritional value of these biosolids, the US Environmental Protection Agency (EPA) established various process standards in 1993 to achieve Class A biosolids for unlimited use as soil additives. Federal Regulation 40CFR503 was adopted. Whenever possible, beneficial reuse of biosolids is encouraged. One set of class A biosolids standards is that the minimum specific volatile solids reduction and time-temperature correlation, for example, a 38% reduction in volatile solids at 60 ° C for 5 hours, is a Class A product. Require to be certified. FIG.

  Within the scope of a modified embodiment of the present invention and referring to FIG. 7, the bioreactor 10 may alternatively function as a waste sludge decomposer to produce a minimum volatile solid for class A biosolids production. Designed to have material reduction and time-temperature correlation. In this regard, the reactor is 5-6 days, often 3-4 days or less, using thermophilic bacteria functioning at 58-65 ° C, typically 58-62 ° C, often 60 ° C. Specially designed and operated with a unique flow rate and zone separation recipe provided to produce Class A biosolids in a short period of time. The 38% reduction in volatile solids is a measure of the stability of the biomass, or vector attraction reduction (VAR), while the high temperature controls E. coli and removes most of Salmonella Disinfect the product. Consuming 38% of the volatiles minimizes the possibility of malodor and is sufficient to allow thermophilic bacteria to rise to temperatures above 60 ° C without heating the reactor temperature from the outside or food Provide energy.

  Published data indicate that there are two areas of concern for existing vertical shaft bioreactors attempting to produce Class A biosolids (eg, Report on VerTad operations King County WA, project incorporated herein by reference). 30900 May 20001). First, a small vertical bioreactor such as the “VerTad reactor as described in US patent application Ser. No. 09 / 570,162, filed May 11, 2000, incorporated herein by reference. "Is characterized in that zone 2 (polishing zone) is relatively disposed below zone 1. These reactors have a relatively large surface area to volume ratio, and excess heat is lost to the surrounding land. Small scale reactors therefore require additional heat to support class A biosolids production, but this heat is used at an extra cost by recapturing waste heat from the compressor or hot process water stream Is possible.

  A second area of concern for conventional vertical bioreactors aimed at high quality biosolids production is inadequate liquid-liquid separation between zones 1 and 2. Published data from tracer studies in the VerTad reactor, zone 2 (polishing zone) behaves like a plug flow reactor with the important feature of local backmixing. Over a period of about 8 hours, Zone 2 begins mixing with Zone 1 and the entire system (Zone 1 and Zone 2) is mixed in 16-20 hours. Therefore, some solid particles that may contain salmonella and other prohibited contaminants are not exposed to the retention time at the disinfection temperature required to meet the requirements of class A biosolids, From 1 to zone 2 may precipitate.

  Because the improved bioreactor / degrader 10 'of the present invention is configured in a unique manner where zone 1 surrounds zone 2 (FIG. 7), the surface area to volume ratio for any particular volume of the reactor is high. Because it is smaller than the reactors described above that are directed to quality biosolids production, much less heat is lost to the surrounding land. The improved bioreactor / degrader provides enhanced liquid-liquid separation at the transition point between Zone 1 and Zone 2. The transition point is defined by an airlock mechanism 172 (eg, a diaphragmless air driven valve) that typically includes the airlock baffle 170 shown in FIG. The baffle is directed upward by introducing clean pressurized air from a dedicated air line 62 having an air delivery port 64 or an aeration / solids extraction line having a corresponding port 68 located in the vicinity of a sewage reservoir 67. Extends into the formed air pocket. Zone 1 is aerated through port 69.

  In this aspect of the invention, when the device is used as an aerobic thermophilic sludge decomposer, bubbles from zone 1 enter zone 2 because of the risk of reinfection with zone 2 disinfected products. must not. To prevent this from happening, the pressure in the airlock is maintained by fresh and clean compressed air, liquid flow or contact between zone 1 and zone 2, or the blowing of contaminated air from zone 1 to zone 2. There is no. The airlock is designed to prevent mixing across the zone of liquid between batches, ensuring that zone 1 does not re-infect pathogens in zone 2 disinfected biomass during batch processing. Illustratively, one batch of sludge is processed every 5-8 hours to ensure that a reference time temperature of 5 hours 60 ° C. is always met in each batch.

  In the operation of this embodiment of the invention, waste biomass is fed continuously or intermittently into the reactor / decomposer 10 ', for example, into the zone 1 head tank 16'. When the water level of the zone 1 head tank rises to the level of the zone 2 head tank 15 ′, a pressure difference is created through the central baffle 170 in the airlock. Over time, the liquid level in the zone 1 in the airlock exceeds the height of the baffle, and the liquid is transferred from the zone 1 to the zone 2. The air supply of the pipe 64 is arranged slightly below the liquid water level in the zone 2 in the air lock, and bubbles are flushed into the zone 2 in the first series of flows between the zone 1 and the zone 2, and the air The lock breaks. When the head tank level is again equal, the flow stops and the airlock is automatically re-established. The batch may be initiated by draining the zone 2 head tank 15 '. FIG. 7 shows the zone 2 head tank being discharged and the airlock approaching batch transfer. The size of the batch is the product of the head tank water level variation and the tank surface weir. Thus, the baffle 170 need only enter one or two feet into the airlock 172 because the change in liquid level of 1-2 feet in the head tank typically represents a complete batch. Because it is. Additional hydraulic considerations in this aspect of the invention are similar to those listed for the previously described embodiments.

  When the bioreactor 10 ′ functions as a waste sludge decomposer (see, eg, FIG. 7), typically 4-5% by weight solid waste sludge is, for example, through the inlet conduit 30 described above. Supplied into the reactor. Depending on the operation of the wastewater treatment system generating the sludge, the supply may be continuous or batchwise. Untreated sludge typically falls into the reactor through the inflow channel 32 and encounters a zone 1 upflow 40 'containing an increased proportion (eg, 10-15%) of bubbles. The merged flow is less dense than the incoming flow 32 'or the flow in the downflow channel 12', so that downward circulation is induced in the downflow and inflow channels. In this way, the incoming water is drawn into the reactor and circulation and aeration occur in zone 1. In FIG. 7, the head tank circulation from the zone 1 upstream channel 40 'to the downstream channel 12 is in front of the zone 2 head tank 15' as indicated by the dashed arrows.

  In addition to Zone 1 and Zone 2 that are hydraulically separated by a diaphragm-less air valve (Air Lock 172), the bottom of each zone functions as a false plug flow zone, while the top of each zone passes through the upper channel. Circulate and mix well. As a result, each of zones 1 and 2 is further divided into two additional small zones in order to provide a double guard against reinfection of the finished product with untreated influent. When the present invention is used as a sludge breaker, the baffle 86 extends to about 70-90% of the reactor depth and the baffle 84 completely seals the bottom of zone 1 to zone 2. To ensure that no cross contamination occurs, Zone 2 may be further sealed with a second outer wall 197 in the vicinity of the outer casing 196, as shown in FIGS. Airlock 170 is shown entering the bulkhead between zone 1 and zone 2 at a location above baffle 84 and below ports 34 and 152. Zone 1 has an aerated volume below zone 2 of at least one batch volume, preferably 2 batch volumes.

Accordingly, the reactor / decomposer 10 'of FIG. 7 is very similar in operation to the wastewater treatment reactor shown in FIG. 1, but differs in the following four main aspects.
1. Zone 1 surrounds zone 2.
2. Zone 2 extends about 70-90% down the reactor depth.
3. Each zone has its own aeration means.
4). Through the use of airlock 172, there is a separation between liquids between zones 1 and 2.
5). Each of zones 1 and 2 is further divided into an upper circulation zone and a lower false plug flow zone.

  Once the sludge enters the reactor / cracker 10 ', the average residence time is about 2 to 3 days in Zone 1 and 2 to 3 days in Zone 2. The EPA standard for class A biosolids production specifies the time between batches, which varies with temperature, for example, the batch residence time at 60 ° C. is 5 hours, ie about 4.8 per day. Batch. Thus, zones 1 and 2 theoretically contain 9.6 to 14.4 batches, respectively. In practice, however, each batch is about 8 hours and zones 1 and 2 each contain 6 to 9 batches. The overall residence time is determined by the biodegradability of the sludge. For Class A biosolids, processing must achieve a minimum of 38% volatile solids reduction, which typically takes 3.5-5 days. Batch batch time is determined by temperature (see, eg, FIG. 12). A preferred operating temperature of 58-62 ° C requires about 8-4 hours.

  As described above, the air line 62 is operable to maintain the air pressure in the air lock 172 of the reactor / decomposer 10 'to control batching. Stopping the pipe 62 and the air flow triggers the discharge of the batch after an appropriate processing time has elapsed. The batch is also triggered by lowering the liquid level in the zone 2 head tank 15 '. Once the batch in zone 2 is discharged, the head tank water level in zone 1 is automatically lowered by an equal amount by the action of an automatic batch valve located between the bottoms of zones 1 and 2, The cycle is repeated. As the batch is processed through the reactor, the solids content is reduced from about 4-5% to about 2-3%. This product (Class A biosolids) may be dehydrated.

  A study published by The University of Washington (Guild et al., Proceedings of WEF Conference, Atlanta GA, 2001, incorporated herein by reference) is a vertical shaft reactor that is partly in common with the reactor of the present invention. When the aerobic and aerobically decomposed sludge is supplied to a low temperature anaerobic degradation organism, the retention time in the anaerobic degradation organism is reduced and the overall reduction of volatile solids is improved. However, the dewaterability is improved and less polymer is required. The thermophilic aerobic degrading organisms function with a retention time of about 2 days and can generate enough heat to comply with Class A biosolids.

  It is well reported in the literature that ammonia nitrification is minimal at temperatures above 42 ° C during aerobic thermophilic decomposition of biomass. In the anaerobic decomposition of biomass (which does not cause air stripping), ammonia and carbon dioxide react to form ammonium bicarbonate. In a vertical aerobic thermophilic cracker, it is reasonable to believe that ammonium bicarbonate is formed due to the large amount of both ammonia and carbon dioxide remaining in solution due to pressure.

  The choice of operating temperature is very important in a long axis vertical thermophilic aerobic cracker because ammonium bicarbonate decomposes at about 60 ° C. Ammonium bicarbonate is very important in the efficiency of the solids liquid separation (dehydration) step of this process. For example, when operating a deep vertical thermophilic aerobic digester at 55-58 ° C, the digested sludge sample is very granular prior to drying of the sample rather than after drying at about 104 ° C. It is. On occasions when the head tank is opened without cooling the reactor (for emergency repair of the float switch), the inner surface, especially the access cover without insulation, is a small white square crystal resembling white sugar or salt It was covered with. These crystals then disappeared and were not found at higher operating temperatures. Another common observation is that when a batch of product is transferred into the soaking zone at about 58 ° C (having little biological activity), the temperature rises and remains constant for about 2 hours and then runs in hot water. Cool at the reactor cooling rate. The heat of crystallization of ammonium hydrogen carbonate 10,000 g / mL was commensurate with the apparent heat generation in the immersion zone. Empirically, these observations suggest ammonium bicarbonate crystal formation below 60 ° C. This is inconsistent with the fact that ammonium bicarbonate dissolves very well in water, but not so well in the presence of high levels of other dissolved solids, and perhaps the surface chemistry of the microorganism promotes crystallization. . For example, struvite (magnesium ammonium phosphate) is readily formed by anaerobic degradation of plants using biological dephosphorization, but not by plants with chemical dephosphorization. Controlling the reactor temperature below 60 ° C. allows the formation of ammonium bicarbonate crystals, which separate from the sludge and float for use.

  Table 1 (Tables 1-1 and 1-2) shows the suspension characteristics, nutrient fractionation and dehydration of thermophilic aerobically decomposed sludge obtained from a deep vertical thermophilic aerobic decomposition tank similar to the present invention. Compare ability characteristics. It is known that thermophilic differentiated sludge has a higher dehydration capacity than anaerobically decomposed biosolids, but requires a higher polymer dosage. Past studies have investigated the cause of the high polymer requirements, and monovalent ions such as sodium, potassium, and especially ammonium ions interfere with the charge-bridging mechanism at the floc. There is a case. In conventional thermophilic aerobic digesters, ammonia nitrification is inhibited above 42 ° C, and the ammonia produced is largely in solution, as evidenced by the high pH typically. is there. The carbon dioxide produced is substantially removed by the large air flow required for these crackers, leaving only a small amount of carbon dioxide in solution to form ammonium bicarbonate. The environment is not favorable for the formation of ammonium bicarbonate because the bubble contact is on the order of seconds and the dissolution rate of ammonia is much faster than carbon dioxide.

Table 1
Nutrient fraction CF is the concentration factor pH 7.8-8.0
Temperature T ° C 60 or less (59-60.5)
4.8% degraded Vertad sludge

pH 8.5-8.8
Temperature T ° C above 60 (61.5-63.5)
3. 80% decomposed Vertad sludge

  Below 60 ° C, it is believed that ammonium bicarbonate is formed in a deep vertical bioreactor because of the high levels of carbon dioxide and ammonia in contact under extended pressure conditions. Above 60 ° C., very similar to conventional thermophilic aerobic treatment, ammonium bicarbonate decomposes and carbon dioxide and ammonia are removed along with the air stream. When the final product treated below 60 ° C is acidified with sulfuric acid, alum, ferrous sulfate, etc., ammonium sulfate is formed, carbon dioxide is released, and sludge is levitated. Unexpectedly, levitated products are exceptionally well dehydrated. A recent report by Murthy et al. (Incorporated herein by reference, Mesophilic Aeration of Auto Thermal Thermophilic Aerobically Digested Biosolids to Improve Plant Operations, Water Environment Research 72, 476, 2000; and Aerobic Thermophilic Digestion in A Deep Vertical Reactor, Project 30900, Prepared for King County Department of Natural Resources, March 28, 2001) for thermophilic aerobic degradation. The concentration of biopolymers (proteins and polysaccharides) can be minimized by limiting the residence time of thermophilic degradation. The present invention is one-third to one-half of the residence time of a conventional thermophilic aerobic cracker. The presence of biopolymers and monovalent ions, particularly ammonia, in solution correlates well with increased polymer consumption. The formation of ammonium bicarbonate significantly reduces ammonium ions.

  The biosolids are floated to a concentration of about 10-12% by lowering the pH to about 5.0 with acid. If the pH is lowered to 4.5-4.0 or lower, flotation separation can be performed more quickly, but it may be necessary to adjust to a pH range of the sludge before decomposition, for example, pH 5.5-6.0. Decomposition below 60 ° C controls the reactor pH to 7.8-8.0, while decomposition above 60 ° C results in operating at pH 8.6-8.8. Reflects the effect of more free ammonia due to ammonium degradation. Flotation separation is better in all categories at temperatures above 60 ° C and below 60 ° C, the less acid used, the thicker the floater blanket and the better the nutritional fraction. These biosolids can be centrifuged to a solids concentration of 30-35% using a low polymer dosage of about 15 pounds of polymer per ton of biomass dry weight. The acidification process may cause cell lysis in part, which is also useful for sludge dehydration.

  These results are substantially better than conventional thermophilic aerobic digestion processes that require 30-50 pounds of polymer per ton of biomass dry weight and can only be centrifuged at 20-25% solids concentration. Acidifying the product of a conventional thermophilic aerobic cracker does not float and separate the solids, probably because there is no ammonium bicarbonate.

  Examining the data in Table 1 shows a tremendous effect on levitation, dehydration and nutrient fractionation between operating the reactor below 60 ° C and above 60 ° C. Operation below 60 ° C. results in lower amounts of free ammonia and higher amounts of ammonium bicarbonate, resulting in lower pH and less ammonia in the exhaust. To obtain a common basis for comparing between the two sets of data, the enrichment factor was calculated. The concentration factor (CF) is the ratio of the final concentration to the starting concentration.

  Looking at the “below 60 ° C.” data set, the floated solids are 2.2 times concentrated compared to the cracked sludge solids, and the total nitrogen in the floated materials is 2.4 times concentrated, The ammonia in it was concentrated 1.6 times and the total phosphorus was concentrated 2.8 times. With the exception of ammonia, the nutrient concentration factor ranged from 2.4 to 3.1 when the solids concentration factor was 2.2.

  Looking at the “above 60 ° C” data set, the floated solids were concentrated 1.5 times compared to the cracked sludge solids, and the total nitrogen in the floated material was 1.7 times concentrated, The ammonia was concentrated 1.2 times, the organic nitrogen was concentrated 2.1 times, and the total phosphorus was concentrated 1.3 times. The nutrient concentration factor containing ammonia ranged from 1.2 to 2.1 when the solid concentration factor was 1.5.

  These data strongly suggest that the nutrients are fractionated into sludge solids at approximately the same ratio as the solids concentration factor (except for ammonia below 60 ° C. described below). The same fraction is expected to occur during dehydration of floating solids.

  However, looking at the concentration factor of floated solids in contrast to subnatants or recirculating flows, a completely different and surprising discovery appears.

  The “below 60 ° C.” data set shows that the total nitrogen in the float is concentrated 7.1 times the recycle, and the ammonia in the float is 1. Double concentration, organic nitrogen is concentrated 500 times, and total phosphorus is 24 times concentrated. With the exception of ammonia, all nutrients moved dramatically from clear recycle to sludge solids. In other words, with the exception of ammonia, other nutrients are substantially removed from the recycle stream, thereby making the processing plant operational and increasing the nutritional value of the biosolids.

  The “above 60 ° C.” data set shows that the total nitrogen in the float is 3.4 times more concentrated than in the recycle, the ammonia in the float is 1.8 times more concentrated, and the organic nitrogen is 10 times more concentrated. Double concentration indicates that the phosphorus was 1.6 times concentrated. With the exception of ammonia and phosphorus, nutrients moved significantly from turbid recycle to solids, but were not as dramatic.

  A possible explanation for the minimal transfer of ammonia to solids is that the acidification of ammonium bicarbonate results in a very stable and very soluble ammonium sulfate. The transition of organic nitrogen to sludge solids is likely to occur because organic nitrogen is present in the decomposed sludge granules and is probably levitated and separated. Even though ammonium bicarbonate crystals may remain after acidification, they may float and separate as particulates. The transfer of phosphorus to sludge solids due to sludge acidification can be explained by the formation of insoluble precipitates in the presence of high concentrations of metals naturally present in the sludge. This effect is not so pronounced above 60 ° C., probably because of poor levitation separation and the small particles that form during the t point are less likely to float.

  In constructing and installing the improved vertical shaft bioreactor 10 of the present invention, the two bioreactors are covered with a case and made of concrete (approximately 36 inches in diameter) (to meet the EPA overlap requirement). Often, it is installed in a steel shaft that is 250 feet deep. The exemplary ranges and reactor designs described herein for purposes of illustration are suitable for about 5000 artificial communities that require a tertiary treatment plant with biological nutrient removal, including: Proceed as follows. Illustrated herein for purposes of illustration, it is to be understood that the design of a novel modular bioreactor assembly is not necessary to utilize the modular assembly method.

  The inner head tank for this exemplary configuration is about 8 feet in diameter and about 12 feet in height. The interior of the factory-produced reactor contains a bundle of six flanged pipes, each about 40 feet long. The bottom 40 foot length (first length) is made up of diffuser 60, shear header 70, and air piping 62 and 66 attached to a short length downflow channel. The bundle of second, third and fourth pipes includes a 40 foot modular section 190 which is centrally fitted with air pipes 62 and 66 (see, eg, FIGS. 9-11). Typically, a downcomer conduit 22 is included. These sections are sequentially connected together with the previous section in a modular section coupler 192, for example with bolts, as the sections are lowered in sequence into the shaft. The top two sections 5 and 6 include downcomer air piping and upper channels formed as a unit by using a central downflow channel 22 and a radial channel partition 194. After installation, the radial partition experiences a light press fit on the outer shell of the reactor (eg, against the inner wall 196 of the riser conduit 24).

  To facilitate modular construction of the bioreactor 10, the radial partition 194 that forms the upper channel is centered (eg, downflow 22) in a direction that is generally orthogonal to the radial partition (eg, see FIG. 11). It is loosened from the inner wall 196 of the reactor when inserted by expanding the diameter of the conduit. In order to expand the downcomer in this manner, FIG. 9 shows a new conduit expander 198, which has a size and dimensions for insertion into the downcomer, for example. Provided in the form of a spreader. The spreader typically has spreader parts 200, 202 that reciprocate relative to each other, the spreader parts being manually reciprocated between a relaxed configuration and an expanded configuration. (E.g., engaging each of the reciprocating spreader parts to cause the parts to expand in the direction of the outward arrow in FIG. 9 or to cooperatively relax in the opposite direction). ). Accordingly, FIG. 10 provides a schematic end view of the reactor internal cross-section showing downflow and radial baffles. An expansion tool 198 in the center of the downcomer conduit 22 is shown in its relaxed position. Therefore, in this figure, the downflow is also in a relaxed position. FIG. 11 provides a schematic end view of the reactor internal cross section showing the downflow forced from a circle to an ellipse by the expansion tool in an expanded configuration, and a radial baffle 194 connected to the downflow. Is forced away from the inner case wall 196 and retracted, into which the reactor section 190 is inserted. When the present invention is used as a decomposer, a sealed zone 2 can be provided by adding a second outer wall 197 to the half of the assembly. Since this second wall is applied to only half of the circumference, it does not prevent the spreader from deforming the central piping and relieving the pressure on the partition wall during installation.

  After assembly to this stage is complete, the zone 1 head tank 16 is bolted to the top of the last section. Zone 2 head tank 15 is assembled on-site from prefabricated sections. The bundle of modular reactor piping can be delivered to the installation site by a single truck, and the head tank is delivered by a second truck. The outer shell of the finer 120 may be cast in situ using concrete or made from a prefabricated steel section. The finer is adapted with a conventional skimmer mechanism. Finally, compressors and other auxiliary equipment are connected. Because of the small footprint, these small plants can be easily accommodated in buildings.

  To further understand the unique and diverse wastewater treatment methods using the novel equipment provided herein, FIG. 13 is used to identify various flow patterns and to further understand the interrelationship of unit processes. Provide a representative block-flow diagram that can be used. FIG. 13 is divided into four regions defined by broken lines. The lower left area is the entire conventional treatment area, and the wastewater is passed through the fine screen of unit A and degrated by the hydroclone separator C. Screen residue and sand are collected in hopper B and sent to landfill.

  The upper left area of FIG. 13 is the wastewater treatment and BNR section of the bioreactor of the present invention and represents its typical components. Unit D represents a deoxygenation step or a pre-denitrification step and refers to channel 40, channel 32 and recirculation 50 of FIG. Unit D is agitated with oxygen-deficient exhaust originating from the bottom of zone 1 (channel 80 in FIG. 1). The piping 301 schematically represents the exhaust transportation from the lower zone 1 (channel 80) to the upper zone 1 (channel 40), but in this aspect of the invention, the lower zone 1 is directly below the upper zone 1 and the conveying piping. Is not necessary. Unit D receives untreated incoming water from channel C (channel 30), recirculation from head tank E, and nitrified recirculation from zone 2 (unit H). The purpose of Unit D is to remove any available molecular oxygen and accept nitrate from the recycle and ammonia and BOD from the untreated influent.

1. Unit E
Unit E represents the head tank 16. This unit accepts oxygen-deficient gas from unit D which serves to mix the contents of the head tank 16. Unit E accepts untreated wastewater containing about 25 mg / L ammonia and 1.75 volumes of nitrified recycle without ammonia or applicable BOD. After mixing, nitrate in 1.75 volumes of the nitrified recycle is converted to nitrogen gas, and the concentration of the influent is, for example, 1Q × 25 mg / L ammonia + 1.75 × zero ammonia / 2.75Q = 25/2 Diluted with .75 = 9 mg / L ammonia and 200 / 2.75 = 72 mg / LBOD as well. In the denitrification step, for example, about 2.6 mg oxygen / mg denitrified nitrogen is released, and an alkaline part is recovered. These amounts are representative and beneficial to the process. Denitrification is a very fast reaction and is accomplished by microorganisms that are naturally present in the wastewater.

2. Unit F
Unit F receives about 2.75 volumes of denitrification wastewater containing, for example, about 9 mg / L ammonia and 72 mg / LBOD. Since there is no molecular or bound oxygen, biomass is anaerobic and uses some of the protein in the untreated sewage to make amino acids. PolyP microorganisms in the system add their phosphorus to the VFA. There is some evidence that VFA can be produced in anaerobic sodium sewers where anaerobic slime has accumulated on the pipe wall. A rope-like open weave tube (131) may be suspended from the head tank into the clean bore channel 12. Unlike other prior art reactors, there is no tangled air or other pipe, so there is minimal risk of plugging the channel. It is expected that anaerobic biomass will accumulate in the rope, producing some VFA and allowing some biological phosphorus to be removed. Monitoring the weight of the rope will give some indication of the amount of biomass present. The flexibility of the rope and the speed of the water drop it into the sewage reservoir of the chamber 67 where excess biomass can be dropped and removed as waste sludge.

3. Unit G
Unit G represents the lower part of zone 1. This region is highly aerated and is designed to re-aerate the anaerobic liquid mixture as quickly as possible. The mixed liquid entering the bottom of zone 1 is rich in BOD, ammonia and sufficient VFA, so the oxygen demand at the bottom of zone 1 will be greatest for any part of the reactor. The BOD removal step requires 5% of BOD or about 4 mg / L of cell synthesis ammonia. (4 consumed in 9-cell synthesis in zone 1) = There is a 2.75Q feed forward stream that contains about 5 mg / L of ammonia and is transferred to zone 2. Experience in a vertical bioreactor has shown that some of the ammonia is actually nitrified in the lower zone 1. It is not uncommon to find 2-3 mg / L nitrate in a bioreactor designed not to nitrify. In the case of a BNR plant designed to nitrify, due to the 1.75Q recirculation flow from zone 2 to zone 1, some of the nitrifying bacteria will eventually arrive at zone 1. In addition, there is a 5Q flow (including 2 mg / L nitrate) from zone 1 to deoxygenation unit D. These streams are denitrified and further remove nitrogen from the system. Conservatively, the treated water from Zone 1 to Zone 2 will not contain more than 5 mg / L BOD, 3 mg / L ammonia and 2 mg / L nitrate. The 3 mg / L ammonia will be completely converted to nitrate in Zone 2. Thus, the treated water will end up with less than about 10 mg / L BOD, less than 10 mg / L TSS and less than 5 mg / L total nitrogen.

4). Unit H
Unit H represents the head tank 15 and operates at a very low load speed. The feed rate to the zone 2 head tank is 2.75Q and contains 3 mg / L ammonia and 10 mg / L BOD. Zone 2 receives the air supply from zone 1 (schematically shown as piping 302). Due to the low BOD, biomass production is low and the biomass produced by nitrification is one fifth to one third of the BOD reduction. Due to the slow growth of nitrifying bacteria, it cannot be allowed to flow to the 1.75 recirculation flow from zone 2 to zone 1. Fortunately, these bacteria are adherent microorganisms that grow on either fixed or mobile bed media. In the present invention, the lower end of the zone 2 is designed not to allow any back flow to the zone 1, and simple screening can prevent the media from escaping at the top, so that the movable bed media is advantageously used. it can. Although fixed media may be used, fixed media tends to clog up occasionally and requires cleaning or replacement. Movable bed media is self-cleaning but degrades over time.

5). Unit I
Unit I is a conventional sedimentation clarifier that separates the biosolids from the treated water and returns the biosolids (activated sludge, RAS) to units D or E. In the BNR plant, RAS never becomes oxygen-deficient because nitrate and RAS in the treated water are denitrified and sludge starts to float in the clarifier. The present invention may provide treated water from zone 2 with high DO but low oxygen demand, preventing oxygen deficiency in the clarifier. Very high DO in the treated water is prevented because ammonia and phosphorus resolubilization may occur in the clarifier.

  Although expensive, membrane separation eliminates many of the operational aspects of the BNR plant clarifier. The present invention enables MLSS with very high membrane separation and smaller reactors. Membrane separation provides a higher quality recirculated water than current standards require.

  The upper right of FIG. 13 is the final chemical treatment of tertiary treated water to satisfy the recirculation water quality standard. According to current methods, chemical flocculation, filtration and residual chlorine must be used. Unit M is a flocculation tank with a mechanical mixer. Unit N is a rotary cross disk filter. Unit P is a UV disinfection channel and attached backwash tank. Unit O is a chlorination step where just enough chlorine is added to maintain the residual concentration in the piping. Unit Q is a backwash pump that can be used to backwash the cross filter or membrane as required.

  The lower right of FIG. 13 is the thermophilic aerobic decomposition section of the plant. Unit R represents the first aerobic stage (zone 1) in a two-stage process. Unit S represents the second stage or zone 2 of the decomposition. These two zones are connected by an air lock valve. Unit W represents the acid levitation thickening step. Unit T is an acid feeder. Unit V represents the dehydration step, in this case a centrifuge with unit U of the polymer feeder.

  The BNR process was examined in detail in FIG. 13 to illustrate the advantages of the process not reported in the bioreactor design described above. One advantage of these new processes is that the screened and desanded influent is fed into the deoxygenation channel 40 and mixed with the denitrified liquid from the head tank 16. The head tank 16 is agitated with an oxygen-deficient gas having a DO produced in the channel 40 of less than 0.05. The denitrified liquid from the head tank 16 descends through the channel 12 under oxygen deficient or optionally anaerobic conditions to complete the denitrification process or optionally generate VFA. .

  It is further noted that the downflow in channel 12 enters the bottom of zone 1 in the vicinity of the aeration disperser in the region of intense mixing. Channel 80, the main part of Zone 1, is highly aerobic and removes BOD, oxidizes VFA while consuming phosphorus, and in some cases nitrifies a portion of the ammonia.

  Of further note is the fact that the rising liquid in the channel 80 is divided into deoxygenation regions and some rises into zone 2. Zone 2 substantially decomposes the remainder of the BOD and converts the remainder of ammonia to nitrate.

  In an additional aspect, exhaust from channel 80 circulates through deoxygenation channels 32 and 40 to provide oxygen for BOD and ammonia biooxidation in Zone 2.

  It should also be noted that a portion of the nitrified liquid may be returned to the denitrification step, where the nitrate nitrogen (nitrate-N) is converted to nitrogen gas while the second portion. Goes to the clarification step where the biomass is separated from the treated water. The biomass returns to the denitrification step, and the clarified treated water is discharged.

  In a related embodiment, an oxygen deficient gas is used to mix the oxygen deficient liquid. Unit D not only deoxygenates the various liquid streams, but also deoxygenates the gas stream passing through the units. This deoxygenated gas may then be used to mix the contents of the denitrification unit E. This eliminates the need for a mechanical mixer and saves energy, maintenance and capital.

  Additional embodiments of the present invention provided a novel anaerobic process. Unit F is a long vertical channel that may be converted to an anaerobic chamber for the purpose of generating VFA. In the present invention, the unit F has no air piping or extraction piping. This allows the use of media such as open weave ropes or tubes suspended in the reactor without the risk of clogging the channel or tangling with other pipes. The purpose of stationary media is to accumulate anaerobic bacteria (acid producing organisms) that adhere and grow. The amount of stationary media and anaerobic biomass can be adjusted from the surface of the liquid by rolling up a portion of the rope or fibrous tube. The area of the media and can be monitored online by measuring the weight of the rope. The downward velocity of the liquid in the channel 12 prevents excess biomass from forming, and any excess biomass falls. Since the channel 12 is open at the bottom, the discarded anaerobic biomass is collected in the sewage reservoir 67 and removed through the unit J of the floating tank.

  In yet an additional embodiment, discarding sludge through the air line 66 or 69 provides for immediate spontaneous levitation upon depressurization. Disposing of sludge from the well-aerated and mixed part of Zone 1 (WAS) is a process that has not been attempted in conventional designs and is advantageous for trapping phosphorus in the sludge. The floated solids are suitable for decomposition without further thickening.

Membrane Separation System This description next describes membrane separation systems, methods and apparatus that utilize selective, semi-permeable, microporous or other distribution membranes for processing, purifying and / or processing liquid compositions, such as Take up membrane wastewater purification process and equipment. These systems, methods and apparatus provide improved throughput and / or improved operational lifetime of submerged membranes, particularly membrane bioreactors that provide biological treatment of wastewater.

  There are several technical considerations for incorporating membrane bioreactors in wastewater treatment facilities including vertical long shaft bioreactors. The first consideration is the widespread misconception that treated water with an extraordinary quality can be produced with a membrane alone. This is not always accurate, because treating the wastewater to the quality of the recirculated water is mainly the result of biological treatment because the membrane itself does not produce the quality of the recirculated water. However, the microfiltration membrane is responsible for physically separating substantially all microorganisms up to about 0.1 microns in diameter from water. Viruses smaller than 0.1 microns can typically be removed because about 99% of the viruses are attached to the host bacteria. The better the bioreactor, the better the quality of the treated water.

  If inorganic dissolved solids must also be removed, the treated water from the biological treatment membrane reactor may be further treated using ultrafiltration, nanofiltration or reverse osmosis (RO). This water quality is suitable for aquifer recharging and the like.

  A second consideration is that recirculated water not only needs to remove biological oxygen demand (BOD) and total suspended solids (TSS), but also nutrients, nitrogen and phosphorus (N & P). Need to be removed to such a low level that it does not support growth in water. This requires the use of a good biological nutrient removal (BNR) process. A typical existing membrane bioreactor process operates on a single sludge backmix bioreactor, which is less efficient and expensive to construct and operate than the improved vertical long shaft bioreactor. .

  For example, the currently proposed two 0.25 MGD (0.5 MGD total) conventional membrane bioreactor installation costs about $ 1.2 million (reactor and membrane only), occupies about 8000 square feet, It is estimated that it takes about 75 HP and requires 1000 standard cubic feet per minute (scfm) of air. In contrast, two improved vertical long shaft 0.25MGD bioreactors would cost about $ 1 million, including an estimated membrane price of $ 400,000. The improved vertical long shaft bioreactor will occupy about 1000 square feet and will take about 30 HP. Since only 100 scfm of air is required for the improved vertical long shaft bioreactor, the exhaust treatment is reduced to an amount equivalent to a domestic kitchen or toilet ventilation fan. The improved vertical long shaft bioreactor operates in a plug flow configuration with an internal recirculation flow. It is known that plug flow reactors produce treated water with better water quality than backmixing reactors. This is because in plug flow reactors, treated water is the lowest concentration achievable with that biomass. In a backmixing reactor, the treated water component is at the same concentration as the reactor contents. In fact, in some cases, in the back mixing reactor, a part of the influent water may be short-circuited and directly enter the treated water. Also, in a single sludge bioreactor where special microorganisms such as nitrification organisms must compete with BOD microorganisms that have strong vitality and grow rapidly, a larger amount of biomass (to prevent nitrification organisms from being washed away) It is also known that it is necessary. This leads to a larger reactor.

  A further consideration is that aside from the biological advantages of the improved vertical long shaft bioreactor, there are certain hydrodynamic advantages not possible with other reactors. Several unique hydrodynamic features observed in existing long shaft vertical aeration reactors are that membrane separation systems work better in vertical aeration reactors than surface backmixing reactors due to the substantial concentration of supersaturated dissolved abstinence I suggest that.

  To confirm this prediction for supersaturated dissolved gas, a membrane separator was adapted to an existing vertical long shaft aeration reactor. The main hydrodynamic feature of a vertical aeration apparatus is that the reactor circulates a mixture of biosolids, liquids, dissolved gases and dispersed gases (bubbles) in a very long vertical path. The pressure at the lower end of this path may be up to 150 psi. As a result of the pressure, there is a substantial concentration of supersaturated dissolved gas in the liquid, even when carried to the surface. These supersaturated gases represent a significant resource of stored energy. For example, in a modified 0.25 MGD vertical long shaft bioreactor, the surface area in contact with the liquid moving in the reactor varies from approximately 4000 square feet in the reactor to 20 million square feet in the membrane cell. When a liquid containing a supersaturated dissolved gas contacts a large surface area, the dissolved gas tends to go out of solution and create a polishing action. This is like removing stains on clothes using soda water. In fact, there are many cleaners that use a foaming agent to improve the polishing effect.

  In the case of a vertical long shaft bioreactor with a submerged membrane bioreactor, the filtration flux rate since the action of the supersaturated dissolved gas in the mixed liquid helps keep the membrane surface in the vicinity of the mixed liquid sufficiently clean. It is predicted that the (flow rate of liquid passing through the membrane) and the cleaning interval time will increase. There are several observed factors of the vertical long shaft bioreactor that support this prediction. For example, a vertical bioreactor that has been operating for 22 years has recently been demolished. The head tank was made of steel, sandblasted and coated with 6 mil (0.006 ") epoxy. The rest of the reactor was bare steel. The epoxy coated surface was exceptionally clean. Even the bolts in the epoxy-coated head tank could be easily loosened, with the epoxy surface having a very slow flux (probably 0.1-0.5 feet / second) There was no evidence of biomass accumulation even near the downstream end, the dissolved gas content at that point was about 25-35 mg / L and the colloidal gas content was about 40-50 ml / L (50-65 mg). / L) How many places where the epoxy coating peeled off and caused local accumulation of biomass attached to bare steel? In the rest of the reactor, the bare steel surface was covered with a gray slime layer, both in areas with high turbulence and high dissolved gas content. This gray biomass slime, which is typically found, is useful in protecting bare steel from corrosion, including phospholipids, and is called bio-passivation.

  To further confirm these findings, a rubber hose approximately 100 feet long, with a 90 foot steel pipe on top of the bottom, was used in the vertical shaft aerator as the air piping in the downflow chamber. . The liquid flow rate at the top of the downflow chamber was on the order of 3-4 feet / second. The hose could be wound on a reel to change the air injection point in the downflow chamber. There was no biomass accumulation in the zone where dissolved gas was present at the upper end of the hose, but there was significant biomass accumulation in the zone where these gases were redissolved due to increased pressure in the downflow chamber. The liquid flow rate was the same in both the upper and lower zones in the downflow chamber. This hose was designed for air and was not permeable to air from the inside. This observation indicates that biomass accumulates when there is no dissolved gas in the downflow chamber, providing an oxygen-deprived / anaerobic zone.

  In further studies, the early design vertical bioreactor was equipped with a glass fiber downflow chamber. The plant is still in operation with no reported failures. Another plant built at the same time also used a glass fiber downfall chamber, but was closed and filled with clean water. Video inspection showed no biomass accumulation behind the glass fiber tube and no damage to the resin and fiber layers. Typically, glass fibers are not permeable to dissolved gases.

  In another study, a small vertical aeration shaft was inspected approximately 26 months after operation. The ABS down chamber was in good condition and there was no biomass accumulation. A similar vertical aerator was fitted with a steel downflow chamber. Inspection found a coating of phospholipid biomass common in steel reactors.

  To further confirm this finding, a rubber downcomer was installed in the early stages of vertical bioreactor development to reduce suspended weight and prevent backflow. Three of these downcomers failed due to damage to the tube wall layer between the rubber surface and the reinforcing fibers. These tubes were designed for water and were permeable to dissolved air. The tube manufacturer claimed that dissolved air was trapped between the inner and outer layers of rubber, causing failure. This phenomenon is seen in tubeless radial tires, where tire air leaks into the cord layer and causes layer damage.

  In another study, another vertical aeration reactor was tested for corrosion after 20 years of operation. The only part that had significant wear was the outlet of the airlift inlet pump located in the reactor's rise time. In this extreme mission, the air / water flow rate was sufficient to remove the protective coating of phosphoric acid, allowing corrosion of bare metal.

  Frequent observations regarding the surface condition of multiple head tanks that have been inspected after long periods of operation often cause the epoxy coating to deteriorate at locations characterized by a sudden change in liquid flow rate, such as immediately after the baffle. These areas may be considered “hydraulic shadows”.

  Release of the dissolved gas and its stored energy has a powerful polishing effect on the epoxy and / or metal surfaces. This energy level is sufficient to strip the epoxy, but not enough to significantly damage the metal surface. However, as evidenced by the formation of a light rust coating on the metal surface, the bacterial slime coating found everywhere in the reactor and even adjacent to the shadow is removed.

  Similarly, when the test membrane was installed in the Y-shaped branch of the vertical shaft reactor described below, there was an air line near one corner of the membrane. The air line did not contact the membrane, but acted as a baffle, causing a “hydrodynamic shadow” over approximately 10-15% of the surface area at one corner and one side of the membrane. In this “hydrodynamic shadow”, the membrane started to peel off a little. The membrane is probably 10-20 microns in diameter, made of non-woven polyolefin chains that are compressed and sintered by some means, perhaps heat and pressure, and under a microscope, about 1/8 inch in length, surface There were hair-like whiskers protruding at right angles. These whiskers were found only in the vicinity of the air pipe on the air pipe side surface of the membrane. A sudden change in flow rate can cause agglomeration of dissolved gases and corrosion / abrasion of the polymer surface. Cavitation may occur because the whiskers project outward and appear to lift from the surface. The rest of the membrane was not affected by high levels of dissolved gas and there was no evidence of surface degradation when examined under a microscope.

  The amount of dissolved gas is staggering. As an example, the solubility of air in water at 1 atmosphere is about 21 mg / L. A 500 foot deep vertical shaft bioreactor can theoretically dissolve 287 mg / L of air. Assuming a dissolution efficiency of 70% and a recovery efficiency of 70%, the liquid in the reactor head tank will have about 140 mg / L of air. Since 1 ml of air weighs 1.29 mg, this means that about 10% of the volume of the liquid comes from dissolved gas. This represents a volume of dissolved (storage) bubbles that is substantially greater than the volume of dispersed bubbles used to circulate the contents of the vertical bioreactor. Surprisingly, the dissolved bubble volume is greater than the dispersed bubble volume (4-6%) required to circulate either the Kubota or Zenon membrane reactor. Furthermore, this storage bubble volume represents a significant storage energy.

  It is anticipated that a very powerful cleaning action can be produced by releasing this stored energy to the membrane surface at a controlled rate at a critical time. In fact, sufficient energy is stored in this manner to cause the film to peel / cavitate when released in an uncontrolled manner, such as occurs in the vicinity of the air line. The observation of a rubber downflow chamber in which this phenomenon has failed will be described.

  The total dissolved gas in the liquid in the vertical reactor may be calculated very accurately by using a dissolved oxygen probe. Under no load, ie, no BOD load, the total dissolved air is approximately 2.61 times the dissolved oxygen reading. Under load conditions, the oxygen reading decreases, but oxygen consumption can be calculated from the BOD value. At the time of this study, the vertical bioreactor was operating with a typical diurnal organic loading pattern. Note that when the rising air is maintained at a substantially constant value (55-65 scfm), the dissolved oxygen value increases almost twice when only 43 scfm of downflow air is applied. This indicates that the downflow air is mainly related to the dissolved gas, and the upflow air is mainly related to the dispersed gas. More importantly, the dissolved oxygen level in the permeate (although it is reduced by 50-60% by the BOD reaction) reaches a supersaturated value (thus nitrogen and carbon dioxide gases are higher) and in the liquid It is proved that the supersaturated gas easily passes through the membrane. As an example, if the residual dissolved oxygen in the permeate was 10 mg / L and 50% of the oxygen was consumed in the reaction, the starting value would be at least 20 mg / L. Thus, the starting dissolved air will be 2.6 × 20 = 52 mg / L and the nitrogen fraction will be 32 mg / L. This is conservative and the amount of dissolved gas has passed through the membrane. Note that a portion, perhaps half, of the dissolved gas is precipitated outside the membrane.

  In view of the degree of observed polishing effect of uncontrolled gas agglomeration for multiple surfaces, a shunt device positioned between each level of the membrane was redesigned within the scope of the present invention. The new design consists of a series of adjustable and / or removable baffles that generate a low level but controlled “hydraulic shadow” effect before and after the membrane. This controlled effect is similar to, but much weaker than that unintentionally generated / discovered in the vicinity of the air line.

  The importance of this discovery is that this type of vertical aeration reactor was thought to be able to supply only a fraction of the air needed to operate the membrane, but in fact it is a form of “stored energy” (ie dissolved The state) is too much air. It is now possible to remove an appropriate amount of the stored gas at critical locations to achieve the new objectives and advantages disclosed herein.

  Accordingly, the present invention provides for the use of supersaturated dissolved gases to clean surfaces in contact with liquids in liquid processing methods and apparatus. Various observations confirming these results include the following:

  a) The surface of a polymer immersed in a liquid stream at a wide range of speeds from about 0.1 to 4.0 feet / second is about 20-30 mg / L dissolved gas and / or about 30-50 mg in the liquid. Biomass does not accumulate in the presence of / L colloidal gas.

  b) Non-polymeric surfaces (bare metal exposed by damage to the polymer coating) immersed in a wide range of liquid flow rates from about 0.1 to 4.0 ft / sec. Biomass accumulation occurs even in the presence of -30 mg / L dissolved gas and / or about 30-50 mg / L colloidal gas.

  c) Biomass accumulation occurs when there is no dissolved gas even at a relatively fast liquid flow rate of 3-4 feet / second.

  d) Biomass accumulation may occur on metal (steel) surfaces at flow rates up to about 4 feet / second. This biomass contains phospholipids that protect the gold loss by biopassivation.

  e) In the presence of large amounts of air (greater than about 100 mg / L), flow rates faster than about 10 feet / second prevent biomass accumulation and accumulation of phospholipids that inhibit corrosion. As a result, metal corrosion and metal erosion occur.

  f) The impermeable polymer membrane may peel off when the pores do not penetrate the wall.

  g) The high air flow rate suggested by the membrane manufacturer is not necessary for efficient operation of the submerged membrane in the presence of supersaturated dissolved gas. Kubota, a leading membrane manufacturer, is a literature on solid-liquid separation membranes of mixed liquids, and forms thin film biomass on the membrane surface to increase the efficiency of removing small particles. Insist that The flux rate is about 0.5 gallons / hour / square foot and the membrane cleaning interval is about 6 months. A minimum air velocity of about 40 scfm / 1000 square feet is required and a minimum permeate liquid velocity of about 1 foot / second is required.

  Zenon membranes operate at a flux rate approximately twice that of Kubota membranes, but there are provisions for pulsed backwashing. In one mode of operation, a 10 second pulse is applied every 10 minutes of operation. Zenon also uses a mechanically applied vacuum to aspirate the membrane. Overall, Zenon's technology requires a lower air flux than Kubota's membrane to stimulate and clean the membrane.

  The air flow rates suggested by these two leading membrane manufacturers are 8 to 10 times faster than the air flow typically available for improved vertical shaft bioreactors. Both Kubota and Zenon have designed membranes to operate in relatively shallow surface areas. The improved vertical long shaft bioreactor is configured on the vertical axis and can maintain enough driving head in the reactor to circulate the system even when the membrane is stacked 2-5 units high To. In shallow tanks, the driving head that causes air / liquid circulation through the membrane is no more than a few inches. In an improved vertical long shaft bioreactor plant, the drive head may be 10-12 feet. A redistribution header is placed between each deck of the membrane, allowing the same air to be used 4-5 times. As the cross-sectional (footprint) area is reduced by laminating the membrane, the shallow permeate flow (actually the upflow) before and after the membrane increases. Although not optimized, the 0.25MGD improved vertical long shaft bioreactor plant, the first tentative design incorporating membrane bioreactor technology, has about half the air velocity recommended by the membrane manufacturer and a liquid flow rate. It shows that about one third is supplied. For the reasons described above and the evidence gathered, the dissolved air fraction in the liquid stream is a much more important factor in keeping the membrane cleaner than either the air flow rate or the liquid flow rate. Over-design should be avoided as it can wash the membrane too much and destroy the required thin biofilm. The polishing action can be adjusted by using fewer membrane decks or less air. Conversely, air or deck can be added whenever a higher flow rate and / or polishing action is required.

  h) Since dissolved salts and particles less than 0.04 microns permeate the microfiltration membrane, there is no reason to suspect that the dissolved gas does not permeate. Dissolved gas passing through the membrane may help keep the inside of the membrane clean.

  Since the membrane can be washed with bleach, the material blocking the pores is most likely organic.

  Typically, membrane reactors require fine screening of untreated influent, because the plant may handle completely untreated sewage.

  These findings and conclusions were further verified by installing a membrane bioreactor in a deep shaft vertical reactor that began operation in August 2003 in Virden, Manitoba, Canada. The Virden reactor was the first commercial deep shaft vertical reactor installed in North America in 1978. The processing plant started operation in 1980 and has been in continuous operation since then. The plant is an older deep shaft design where both downstream and upstream air is utilized for circulation and aeration of the shaft contents. The reactor is 30 "in diameter and 500 'deep. The downflow chamber is 18" in diameter, and the upflow channel is formed in an annular space between the casing wall and the downflow chamber. At the top of the reactor is a Y-shaped branch that allows the liquid mixture to transfer from the upflow to the downflow via the head tank. The head tank is approximately 25 feet long, 6 feet wide and 4.5 feet deep. This reactor configuration is ideal for testing because the ratio of dissolved air to dispersed air can be selectively changed. Applying a larger amount of down air results in more dissolved air, and applying a larger amount of up air results in more dispersed air (bubbles). As will be shown later, the ratio of dissolved air to dispersed air produces a 9-fold difference in membrane flux with the same head.

  In order to battle the membrane bioreactor in the Virden reactor, it was necessary to cut an access passage at the top of the head tank. The access passage is located directly above a Y-shaped branch with an inner diameter (ID) 21 ″. When the head tank is opened after 23 years of continuous operation, it is opened after another 22 years of continuous operation. The same pattern of biofouling found on the vertical long shaft bioreactor was found on the epoxy coating, the patterns were almost identical, in each case both the liquid flow rate and the bubble content were the lowest. The head tank floor had minimal biomass deposition, which is contrary to the membrane manufacturer's teaching that recommends a faster rate and a higher bubble content, but the bubbles above the bed It should be noted that the liquid should have been supersaturated with dissolved gas, although it would have been little if any. This observation further supports the conclusion that it is a dissolved gas that aggregates on the polymer surface, while the other tested bioreactor shaft was specified for the treatment of industrial wastewater with hot ionic strength, The fact that the Virden shaft is treating cold municipal wastewater with low ionic strength appears to have little effect on this phenomenon.

  A test membrane solid / liquid separator was installed in a Virden deep shaft reactor for a month to evaluate the improved throughput and operating life of the submerged membrane assembly of the present invention. The test membrane was removed from the reactor and carefully inspected. Notably, all of the outer surface material was easily washed away in water, despite the fact that the membrane was clean and had been operating in a highly concentrated viscous liquid for a month. In addition, it was observed that the treatment water flux from the membrane was different for different air velocities in the reactor. When the downflow air increased (the more dissolved air circulated), the reactor circulation flux decreased, but the transmembrane flux increased. Conversely, when more upflow air (more dispersed air) was applied, the circulating flux in the reactor increased, but the transmembrane flux decreased. This is contrary to the traditional understanding of membrane function and operation, as evidenced by the membrane manufacturer's operating instructions. In conventional membrane plants, a high aeration rate was required to maintain a transmembrane circulation flux. Typically, conventional plants used (at a minimum) about twice the transmembrane flux and 8-10 times the air flow available in deep shaft type reactors.

  In additional work to clarify the disclosure herein, the test bioreactor was fitted with a sample port in a head tank located near the outlet of the membrane. The dissolved gas concentration before and after the membrane is measured with a dissolved oxygen meter (DO meter), and the reactor circulation rate before and after the membrane is calculated from the time of circulation through a tracer such as soap. The permeation flux from the membrane was measured in a calibrated flask, but the water head is maintained by overflow to the flotation tank. In this test case, the water head above the membrane was maintained at 1 foot. A drop leg was provided to produce a 1 m siphon effect, a typical operating value for this type of membrane. The membrane support frame can hold a lower membrane soaked between about 6-9 feet and an upper membrane soaked between about 1-4 feet. The overflow height is the same at both membrane locations.

  Tables 2 and 3 below show the effect of various air flow rates on membrane performance.

  Table 3 is a plot of the data points in Table 2. The data in Table 2 does not reflect the importance of the dissolved air fraction. However, the effects of air flow changes are noted and information is provided in Tables 2 and 3. There are two sets of data that show the importance of downdraft (dissolved air). Point 1 and point 2 have the same total air volume applied (108 scfm). Point 1 has 108 scfm of rising air (mostly dispersed air) and no downflowing air (ie no dissolved air). Recall that the previous teaching was that high speeds and high air flow rates would result in the highest membrane flux. However, in the trial run (point 1), the maximum flow rate and maximum circulation flow rate are the lowest membrane flux.

  At point 2, the total air flow is 108 scfm, but this time 43 scfm is applied to the downflow. The effect of downflow air is to lower the circulation flow rate. Although the prior teaching predicts that the membrane flux will also decrease, in the trial run, the membrane flux increased 9-fold.

  In addition, at points 3 and 4, both upflow air is 75 scfm, while point 4 has downflow of 55 scfm, which helps to reduce the circulation rate. The output from the membrane increases three times.

  Therefore, the dissolved air fraction in wastewater has a dominant effect on membrane throughput. Other factors also affect membrane performance. Among these factors are biomass concentration, sludge age, sludge biological health, extracellular polymer abundance, membrane condition, and the like. These factors are expected to have only a minor impact on the overall results because most of the results are from a one-day operation where the sludge conditions are not expected to change within the time period in question.

  One important cause of increased membrane throughput within the scope of the present invention relates to the gas dynamics of vertical bioreactors. In particular, the deep shaft reactor system provides significant advantages over other reactors and liquid processing equipment by providing a high dissolved air fraction. In addition, the deep shaft reactor system includes unique biochemical and physicochemical processes, such as oxidation of organic carbon and dissolution of oxygen and other gases, such as carbon dioxide, that provide the desired gas supersaturation level.

  In liquid mechanics, the term “rheology” describes a complex non-linear relationship between liquid deformation and strain that occurs in the liquid flow pattern. The phenomenon of increased throughput is believed to be related to changes in rheology at the membrane surface. Due to the large amount of dissolved gas in the liquid, the rheology of both biomass (solids including liquids and gases) and liquid media will change upon contact with the membrane, presumably making the membrane more permeable.

  The test membrane was adapted to transparent vinyl tubing, which allows permeate flow visualization. The permeate will probably contain a significant amount of air bubbles with a diameter of 1/16 to 1/8 inch. It is estimated that 10-15% of the permeate is made up of discrete bubbles. Dissolved gas permeates through the membrane unimpeded and agglomerates at or near the surface of the membrane, but this is between the surfaces, at the membrane surface, or in the liquid near the membrane surface. It may contain agglomeration and cause an airlift effect near the membrane surface. It is reasonable to predict that discrete bubbles will not penetrate the semipermeable membrane at a high level. The air lift on the permeate side of the test membrane is unpredictable unless there is dissolved air present in the water that permeates the membrane (or alternatively, air that forms bubbles on the clean water side of the membrane). This air lift caused by the bubbles has a significant pumping effect because the permeate flow from the membrane can rise to almost the surface of the liquid water level in the head tank when the permeate piping is installed. It is. Since the liquid outside the membrane that is filtered contains about 9% voids, the volume of gas in the agglomeration inside the membrane is also about 9 to allow the liquid to flow out of the membrane with similar inner and outer heads. % Gas void. Since it is clear that the dissolved gas fraction helps keep the outer surface of the membrane clean, the dissolved gas fraction inside the membrane will also help keep the inside of the membrane clean.

  In conventional membrane applications, the water inside the membrane (permeate side) contains very little air and is much denser than the water outside the membrane containing air for polishing. Thus, in conventional systems, water is not used unless a light vacuum is applied to the treated water side (Zenon uses a vacuum pump) or the incoming water is pressurized (Kubota uses compressed air). It will not flow out of the firewood. When a vacuum is applied, water tends to flow preferentially through the pores closest to the top of the membrane. When pressure is applied with compressed air, the resulting head is due to the difference in water density between the inside and outside of the membrane, the head required to cause the flow through the pores, and the liquid head. It is the sum of any hydraulic losses due to movement. In an improved vertical long shaft bioreactor system, the water head due to density difference is significantly removed and dissolved gas enters the membrane that may be sufficient to cause sufficient air lift to overcome head loss through the pores be able to.

  FIGS. 14-1 through 14-7 illustrate several aspects of a submerged permeable membrane assembly 400 for membrane separation of the present invention. In this exemplary embodiment, the membrane assembly is a U-shaped assembly, but various alternative designs and configurations of the assembly according to the disclosure herein may be constructed and operated. It will be understood. As shown in FIG. 14-1 (a cross-sectional view along the vertical axis 402 of the submerged membrane assembly), a representative membrane assembly includes a U-shaped container 405, which is six feet high and is first. It has a liquid compartment t420 and a second liquid compartment 430. In this exemplary embodiment, the compartment is separated by a separator membrane 414 and a membrane 410, which is 3 feet high and is located at the bottom of the U-shape where the two liquid compartments communicate. . The film 410 has a first surface 411, a second surface 412, and a vertical axis 402. The first liquid compartment 420 is configured to include a first liquid 424 that is in liquid communication with the first surface 411 of the membrane 410. Second liquid compartment 430 is configured to include a second liquid 434 that is in liquid communication with second surface 412 of membrane 410. The first liquid 424 has a first specific gravity or density, and the second liquid has a specific gravity on the table.

The membrane 410 represented schematically in FIGS. 14-1 to 14-7 may be any membrane structure including plates, frames, tubes, hollow fibers and spiral windings. The membrane may be a selective, semi-permeable, microporous or other distribution membrane, such as a membrane wastewater purification process and apparatus, for processing, purifying and / or treating liquid compositions. The membrane may be made of any material and may contain one or more selected from cellulose, acetate, polyvinyl chloride, polysulfone, polycarbonate and polyacrylonitrile. Membrane 410 is generally permeable to molecules less than a predetermined size and includes pores 415 between first surface 411 and second surface 412, the pores having a first surface 411 of molecules smaller than the removal size. And has a pore size that allows movement between the second face 412 but rejects larger molecular movements. The particle removal size of semipermeable membranes used in membrane bioreactor applications is typically between 10.0 and 0.05 microns. The particle removal size may be selected in relation to other parameters associated with the particular application of the membrane, but in some embodiments, particles in the range of between about 0.05 and 0.1 microns. It is common for semipermeable membranes with a removal size to give good results in wastewater filtration. This range removes most viruses, most long molecules (polymers) and all bacteria. In another embodiment, it is generally expected that membranes that substantially remove particles larger than 0.1 microns will give satisfactory results in wastewater filtration.

  FIGS. 14-1 through 14-7 illustrate liquids 420 and 430 that are contained at various vertical column heights within the assembly 400. FIG. A typical U-shaped assembly has a maximum column height of 6 feet and the drawing includes other exemplary dimensions of the vertical column height along the vertical axis 402 from 0 to 6 feet, where 0 foot is the set. Starting from the maximum height of solid 400, 6 feet starts at the maximum depth of membrane 410. In FIG. 14-1, first liquid compartment 420 contains first liquid 424 at a first column height 422 of 6 feet. The second liquid compartment 430 contains the second liquid 434 with a second column height 432 of 6 feet.

  As further shown in FIGS. 14-1 to 14-7, the vertical axis 402 of the membrane 410 is typically aligned corresponding to the first chamber vertical axis 423 and the second chamber vertical axis 433. . In general, the first chamber vertical axis 423 and the second chamber vertical axis are substantially parallel and correspond to an effective vertical axis that roughly matches the rising direction of the bubbles in the first and / or second chambers. Typically, the direction of bubble rise is vertical in the first and second chambers. When the film is oriented vertically, the vertical axis of the film is approximately parallel to the first chamber vertical axis 423 and the second chamber vertical axis. However, in some embodiments, the film may not be oriented vertically, for example, the film may be configured such that the first and second surfaces are in the direction of rising bubbles and the vertical axes of the first and second chambers. There is a case where it is arranged at an angle. In these embodiments, the vertical axis 402 of the membrane is not parallel to the first and second surfaces of the membrane, but rather corresponds to the direction of bubble rise in the first and / or second chambers.

  As shown in FIG. 14-1, the first liquid compartment 420 contains a first liquid 424 for filtration, such as sewage, waste water or sewage to be filtered, and the second liquid compartment 430 is purified and reusable. A second liquid 434 as a filtrate such as fresh water or permeate is contained. The submerged membrane assembly 400 is shown with a first liquid 424 shown as sewage and a second liquid 434 shown as clean water. Both liquids (420, 430) have a specific gravity of 1. In FIG. 14-1, neither the second liquid 434 in the second liquid compartment 430 nor the first liquid 424 in the first liquid compartment 420 are air or bubble present. It can easily be calculated that the pressure at the surface of each liquid (liquid column height 0) is 0 psig, the pressure at depth 3 'is 1.298 psig and the pressure at 6' is 2.597 psig. The pressure at each face of the membrane is equal at any particular depth on the membrane. The pressure at any depth of the liquid column is the product of the average density and the column height. For example, the density of water is 62.4 # / square foot. A 6 foot column of water has a pressure of 6 × 62.4 = 374.4 # / square foot or 2.6 # / square inch. The gauge pressure is not taken into account at atmospheric pressure, so the pressure at the bottom of the water column in this case is about 2.6 psig.

  As shown in FIG. 14-2, the gas in the form of bubbles 426 is present in the first liquid 424 contained in the first liquid compartment 420. Bubbles 426 may be added to polish and clean the first surface 411 of the membrane. In a typical conventional membrane installation, the amount of bubbles 426 present in the first liquid 424 (sewage) in order to properly polish the first surface 411 of the membrane 410 can reduce the specific gravity of the first liquid 424 from 1.0. Reduce to about 0.9. Also, the pressure at the top of the assembly 400 can be calculated as 0 psig. The pressure at the top of the membrane 410, ie, the second side 412 (purified water side) of the membrane 3 feet above the column height is 1.298 psig and the pressure at the first side 411 (sewage side) is 1.168 psig. Similarly, the pressure at the bottom of the membrane 410, ie, the second surface 412 (purified water side) of the membrane at a height of 6 feet of the column height is 2.597 psig and the first surface 411 (sewage side). ) Pressure is 2-337 psig. In this hydrostatic test, the second liquid 434 (purified water) tends to flow through the membrane 410 to the first liquid (sewage) due to the reverse pressure difference. Note also that the pressure difference at the top of the membrane 410 is 0.13 psig, but the pressure difference at the bottom of the membrane is 0.26 psig. Not only does water try to flow in the wrong direction, but more water passes through the membrane at the bottom of the membrane than at the top of the membrane.

  FIG. 14-3 illustrates that the second column height 432 or liquid level of the second liquid 434 contained in the second liquid compartment 430 (purified water) is reduced by 0.62 feet relative to the first column response 422, the bottom, That is, the pressure on both the second surface 412 (clean water side) and the first surface 411 (sewage side) of the membrane at the column height of 6 feet is equal and is 2.337 psig. However, the pressure on the top of the membrane 410, ie the second side 412 (purified water side) of the membrane at 3 feet of column height is 1.03 psig, but the first side 411 (sewage side) of the membrane is Note that the pressure is 1.168 psig. This produces a pressure difference of 0.13 psig at the 3 foot height. Under the above conditions, the liquid flows through the correct path from the first surface 411 (sewage side) of the membrane 410 to the second surface 412 (purified water side). Since the pressure difference at the bottom of the membrane 410 is 0.0, water does not flow in either direction, but at the top of the membrane, water flows from the sewage side (430) of the membrane 410 to the purified water side (420). . Interestingly, if the second liquid column height 432 is reduced by 0.4 feet, water flows in the correct direction at the top of the membrane 410, but in the wrong direction at the bottom of the membrane. The second liquid column height 432 provides an outlet or overflow for the second liquid 434 at a selected height, applies negative pressure to the second liquid 434, and / or positively charges the first liquid 424. It may be varied relative to the first liquid column height 422 by any suitable method, apparatus, or means, including applying pressure.

  14-4 illustrates the pressure differential across the membrane 410 resulting from a change in specific gravity of the second liquid 434 of the membrane assembly 400 of FIG. 14-3 according to an embodiment of the present invention. In FIG. 14-4, the gas of the form of the bubble 426 exists in the 1st liquid 424 (sewage) accommodated in the 1st liquid compartment 420, and forms aeration water. Sufficient bubbles 436 are provided in the second liquid compartment 430 to change or adjust the specific gravity of the second liquid to approximate the specific gravity of the second liquid to the first specific gravity of the first liquid 424 contained in the first compartment 420. May be added to the second liquid 434 (purified water) contained in the water. This reduces the second specific gravity of the second liquid 434 to the first specific gravity of the first liquid 424. As shown in FIG. 14-1, the pressure at the membrane 410 at various depths along the column height can be calculated. The pressure is 90% of the pressure in FIG. 14-1, because in this case the specific gravity of the aerated water (434) is 90% of the specific gravity of the non-aerated water. Note that the pressure difference across the membrane 410 is zero at all heights. According to an embodiment of the present invention, in addition to generating a uniform pressure difference along the vertical axis of the immersed permeable membrane 410, air in the vicinity of the second surface 412 (water purification side) of the permeable membrane. The presence of 436 rising bubbles provides a polishing action on the second surface 412 of the membrane.

  14-5 has a selected water head difference 452 imposed between the first liquid 424 contained in the first liquid compartment 420 and the second liquid 434 contained in the second liquid compartment 430. 1 illustrates an immersion membrane assembly 401 according to an embodiment of the present invention. An alternative embodiment for imposing a head differential is described below. When the specific gravity of the second liquid 434 is adjusted to approximate the specific gravity of the first liquid 424 and a squeezed head difference 452 is imposed between the first liquid 424 and the second liquid 434, the membrane A selected pressure difference before and after 410 is provided along the vertical axis of the membrane 410. As shown in FIG. 14-5, the second specific gravity is adjusted to be equal to the first specific gravity, and a 2.0 foot head difference 452 is further imposed between the first liquid 424 and the second liquid 434. As before, the pressure at the top and bottom of the membrane 410 can be calculated. The pressure differential across the membrane 410 is uniform (0.779 psig) along the vertical axis from top to bottom. Each pore of the membrane 410 is subjected to substantially the same driving pressure, and each pore transmits substantially the same amount of water. Using the entire membrane surface, the membrane assembly 401 typically generates more flow than a membrane assembly having an unequal pressure difference, for example in FIGS. 14-3 and 14-6. If the second specific gravity after adjustment or change is not very close to the first specific gravity, the selected pressure difference across the membrane is expected to change only slightly along the vertical axis of the membrane. . For example, the pressure differential variation along the vertical axis is generally uniform when the second specific gravity is adjusted within about ± 5% of the first specific gravity, ie, ± 30% per foot on the vertical line. It is expected that only the following will change.

  In the embodiment shown in FIG. 14-5, the first liquid is generated to generate a selected pressure difference across the membrane 410 along the vertical axis between the first specific gravity and the adjusted or modified second specific gravity. By selecting the second liquid column height 432 relative to the column height 422, a water head difference 452 is imposed. FIG. 14-5 shows the selected second column height 3432 of 4.0 feet and the first column height 422 of 6.0 feet, which generates 2.0 feet of the selected head differential 452. As described in conjunction with FIG. 14-4, providing an outlet or overflow for the second liquid 434 at a selected height, applying a negative pressure to the second liquid 434, and / or positively applying to the first liquid 424. The second column height 432 may be changed relative to the first column height 422 by any suitable method, apparatus, or means, including applying pressure. In an embodiment using gravity, the column heights 422 and 432 provide a liquid outlet or overflow from the first liquid compartment 420 at 6.0 feet and an outlet or overflow from the second liquid compartment 430 at 4.0 feet. May be probable.

  In an alternative embodiment, the head differential 452 is imposed by surrounding the first liquid compartment 420 and applying pressure, such as by compressed air generated by a mechanical compressor, so that the vertical dimension of the first liquid compartment. The first column height 422 can be increased without physically increasing. In another alternative embodiment, the head differential 452 can be imposed on the second liquid compartment 430 by applying a negative pressure, such as generated by a mechanical vacuum pump, to determine the vertical dimension of the second liquid compartment. The second column height 432 can be reduced without being physically reduced. Because attraction does not require any mechanical devices that consume power and require maintenance, it may be considered desirable to use gravity just to impose a head differential 452. Furthermore, using gravity alone eliminates any problems associated with maintaining an enclosed liquid compartment.

  An additional configuration of the embodiment shown in FIGS. 14-5 includes flowing the first liquid 424 through the first surface 411 of the membrane 410 while maintaining the first column height 422. This embodiment allows the second liquid 434 to be recovered from the second liquid compartment 430 as filtered clear water or purified water while still maintaining the second column height 432 selected to impose a head differential 452. Enable.

  FIG. 14-6 shows a comparison of how existing Zenon or Kubota membranes typically react to the 2.0 foot head differential imposed as shown in FIG. 14-5. Existing devices and methods for moving these membranes do not change or adjust the specific gravity of the second liquid 434 to approximate the specific gravity of the first liquid 424. Simply imposing a hydraulic head difference 452 across the membrane 410 does not achieve a substantially uniform pressure difference across the membrane along the vertical axis. This only results in a much higher pressure differential at the top of the membrane than at the bottom. In other words, the pressure difference varies along the vertical axis of the membrane.

  This description will then take an embodiment for changing or adjusting the second specific gravity by including a dispersed gas or bubble 436 in the second liquid 434 as described above in conjunction with FIGS. 14-5. As described in conjunction with FIGS. 14-5, aspects of the present invention include changing and / or adjusting the second specific gravity to approximate the numerical value of the first specific gravity. In some embodiments, the second specific gravity is adjusted within about ± 5% of the first specific gravity. In another embodiment, the second specific gravity is adjusted to within about ± 2.5% of the first specific gravity.

  FIGS. 14-5 and 14-7 illustrate the present invention for including bubbles 436 in the second liquid 434 to change the second specific gravity and optionally to polish the second surface 412 of the membrane 410. An alternative embodiment of is shown. In the embodiment shown in FIG. 14-5, the bubble 436 originates from a supersaturated dissolved gas present in the first liquid 424. As described above, the long shaft vertical reactor receives a liquid having a significant concentration of supersaturated dissolved gas in the head tank. When the liquid 424 is a liquid having a considerable concentration of supersaturated dissolved gas, a part of the supersaturated dissolved gas is aggregated on the first surface 411 of the film 410. The aggregated gas gives a polishing action to the first surface 411 when the aggregated bubbles rise in the liquid 424. Another portion of the supersaturated dissolved gas in the liquid 424 exits from the first surface 411 along the pores of the film to the second surface 412 or the vicinity of the second surface 412 and enters the second liquid 434. A part of the supersaturated dissolved gas that has passed through the membrane 410 aggregates to form bubbles 436, and a dispersed gas is added to the second liquid 434. The mechanism by which the supersaturated dissolved gas aggregates in the second liquid 434 is not fully understood. Aggregation may occur in whole or in part by the mechanical action of dissolved gas passing through the membrane 410. Alternatively, agglomeration is imposed in whole or in part by a hydraulic head difference 452 between the first liquid 424 in the first compartment 420 and the second liquid 434 in the second liquid compartment 430. May be caused by pressure difference. Further alternatively, agglomeration may be caused by a difference in dissolved gas levels between the first liquid 424 and the second liquid 434. Aggregation may occur in the second surface 412, in the second liquid 434, in the second liquid 434 in the vicinity of the second surface 412, or in the membrane 410. The bubbles 435 aggregate on or in the vicinity of the second surface 412 and provide a polishing and / or cleaning action on the second surface as the bubbles rise in the second liquid 434.

  14-7 illustrates a submerged membrane assembly 402 of an embodiment of the present invention having a head differential 452 and a gas inlet 438. FIG. The assembly is substantially similar to the membrane assembly 401 of FIGS. 14-5 but has an optional inlet 430 added in communication with the second liquid compartment 430. Optional inlet 438 includes a configuration for adding air or gas to second liquid compartment 430 to form bubbles 436 in second liquid 434. The air may be added by providing air or gas to the inlet 438 and dispersing the air or gas in the second liquid compartment 30. A dispersing device may be included in inlet 438 to assist in bubble formation in the second liquid compartment. Alternatively, the air or gas is first dispersed in another liquid, which then flows through the inlet 438 into the second liquid compartment 430 to approximate the first specific gravity, optimal Under certain conditions, an amount sufficient to adjust the second specific gravity to equalize the first and second specific gravity may be added to the second liquid 434. In a further alternative embodiment, air or gas bubbles 436 may be provided from other sources such as chemical reactions, ultrasonic devices and microwave devices.

  14-6, the soaked membrane process of Zenon and Kubota uses a submerged membrane assembly 402 having a gas inlet 438 as shown in FIG. 14-7 to provide air or air to the second liquid compartment 430 (purified side) of the membrane 410. It can be improved by adding gas. Adding gas directly to the second liquid compartment 430 of the Zenon and Kubota process is an improvement for these processes, but on the second side resulting from supersaturated mixed liquid media such as present in a vertical long shaft bioreactor. It is not expected that the polishing effect of the second surface 412 on the water purification side will be the same as the polishing effect caused by the bubble aggregation.

  FIGS. 15 and 16 show an improved vertical long shaft bioreactor 500 for wastewater treatment of an embodiment of the present invention having a membrane bioreactor head 503 that includes a plurality of submerged membrane bioreactor assemblies. The vertical long shaft bioreactor may be any type of vertical long shaft bioreactor having a significant concentration of supersaturated dissolved gas at the head tank 502 level, such as the bioreactor of FIG. 5 or FIG. Absent. FIG. 15 is a perspective view of a membrane bioreactor head 503 having a bioreactor head tank 502 and a plurality of saddle tanks 506A-D to which the membrane bioreactor assembly 510 is attached. FIG. 16A is a perspective view of the saddle tank 506A of the membrane bioreactor head 503, showing a top membrane bioreactor assembly 510D that includes a plurality of flat plate semipermeable membranes 511. FIG. FIG. 16B is a cross-sectional side view of a bioreactor head tank 502 and a saddle tank 506A having a stack of four-stage membrane bioreactor assemblies 510A-D.

  FIGS. 15 and 16 illustrate a membrane bioreactor head 503 having a four-layer stacked or column membrane bioreactor assembly 510 disposed circumferentially around the outside of the head tank 502 and in fluid communication with the head tank. The embodiment of is shown. In practice, typically eight saddle tanks are used to completely surround the head tank 502 and maximize membrane filtration. In FIG. 15, each saddle tank 506 includes four stages of submerged membrane assemblies 510A-D arranged vertically on top of each other. Each assembly 510 is about 4 feet high because the total column height 424 of the membrane bioreactor head 503 is about 16 feet. If a membrane fails, it can be replaced by shutting down only one of the saddle tanks 506 so that the reactor and the other seven saddle tanks can continue to operate. The uppermost immersion membrane assembly 510D can be inspected from the top of the saddle tank 506, while the lower three-stage immersion membrane assembly 510A-C is shown for assembly 510A in FIG. 15 and for assembly 510C in FIG. 16B. It is inspected through a tip-out drawer.

  Each membrane bioreactor assembly 510 includes a plurality of flat plate semipermeable membranes 511 connected to an external manifold 514 by membrane output piping 512. The external manifold 514 is connected to the recovery trough 538 by a recovery pipe 516. The flat membrane 511 typically includes a frame that supports two rectangular semipermeable membranes having second surfaces 412 opposite to each other, and the semipermeable membrane cooperates with the frame and the semipermeable membrane. An internal second liquid compartment is defined between the frame. The first surface 411 of the semipermeable membrane is exposed to a liquid that birdclines outside the membrane assembly 510. The recovery pipe 516 may be made of any tubular member suitable for carrying permeate or liquid output by the flat membrane 511. The collection line 516 is transparent and allows the user to visually inspect the bubble 436 content and clarity of the output from each individual flat membrane 511.

  As shown in FIG. 16B, the recovery pipes 510A-C cause the permeate to flow upward into the recovery trough 538. The recovery pipe 510D is formed to be a siphon that flows the permeate from the membrane 511 downward and discharges it to the trough 538. The first column height 422 is defined between the lowest point of the lowermost membrane 511 and the water level of the outflow 528 from the saddle tank 506. The second column height 432 is defined between the lowest point of the lowermost membrane 511 and the water level of the trough 538.

  In an embodiment of the present invention, each membrane assembly 510 includes 75 flat membranes. By using eight separate saddle tanks 506A-D around the head tank 75 and 506E-H (not shown), the total of the flat membrane bioreactors 511 in this configuration is 75 / stage × 4 stages / Saddle tank x 8 saddle tanks = 2,400. Experience with the flat membrane shows that this arrangement processes an average of about 0.3 MGD and a peak flow rate of 0.6 MGD. In this embodiment, the diameter of the head tank 502 is about 9 feet, and together with the saddle tank 506, the diameter of the reactor is about 13 feet.

  During operation, the first liquid 424 as an inflow 526 of treated water from the vertical long shaft bioreactor flows from a vertical long shaft bioreactor (not shown) into the bottom of the saddle tank 506A. The first liquid 424 has a first specific gravity and includes bubbles 426 and supersaturated dissolved air. When the first liquid 424 passes through the saddle tank 506A through the submerged membrane bioreactor assembly 510A-D and overflows the saddle tank at a height of 12 feet, it becomes an outflow 528. Outflow 528 returns to the vertical long shaft bioreactor for further processing or removal from the reactor. The individual flat film 511 filters the first liquid 424 as described with reference to FIGS. 14-1 to 14-7, mainly with reference to FIG. 14-5. The first liquid 424 has a first column height 422 of 16 feet between the bottom of the bottom flat membrane 511 and the outflow 528. The second liquid 434 has a 12 foot second vertical column height 434 established by a collection trough 538 and a collection line 516 leading to it. As a result, a head differential 452 is imposed between the first liquid 424 or treated water and the second liquid 434 or permeate or filtered water.

  Furthermore, as described with FIGS. 14-1 to 14-7, the dissolved gas of the first liquid 424 in the second liquid 434 is aggregated, and the gas partial pressure on the first surface 410 (sewage side) of the film is Along the vertical axis of each membrane 511 of each submerged membrane bioreactor assembly 510 by creating equal gas partial pressures on the second surface 411 (purified side) of the membrane (including the vertical conduit leading to the recovery trough) An approximately uniform pressure differential can be maintained at 1.168 psig. As shown in FIG. 14-5, the pressure difference at the top of each membrane 511 is the same as the pressure difference at the bottom, and the pressure difference across the top of membrane 510D (under the siphon head) is the membrane 510A. It is exactly the same as the pressure difference before and after each of the other three stages of -C. As a result, each and every membrane in the saddle tank 506 is expected to generate the same flow rate. A pressure difference of 1.168 psig is equivalent to about 33 inches of water.

  In the conventional system, the second liquid 434 has no gas agglomeration, so the difference in pressure difference between the top and bottom of the 1 m (40 ") high membrane 511 is 40" x 10% = 4 inches. Equal to water. While this may not look significant, it is sufficient to make the flow through all membranes uneven.

  For peak flow, the pressure differential across all membranes 511 can be increased evenly by simply increasing the sewage column, ie, the first column height 422. Note that the bubble 426 is used four times as it moves from the bottom membrane assembly 510A to the top 510D.

  In an alternative embodiment, the membrane bioreactor assembly may be located inside the head tank 502 and the saddle tanks 506A-H may be removed.

  FIG. 17 illustrates a folding saddle tank system 550 of an embodiment of the present invention that includes a first folded saddle tank 556A and a second folding saddle tank 556B that together carry the membrane assembly 510A-C. In some cases, a vertical four-stage submerged membrane assembly 510A-C, for example as shown in FIGS. 15 and 16, may result in a too high plant. In that case, a folding saddle tank such as the folding saddle tank 556 can be advantageously used. In the configuration of FIG. 17, the membrane assembly 510A-B is accommodated in the first folding saddle tank 556A, and the membrane assembly CD is accommodated in the second saddle tank 556B. Second saddle tank 556A includes an inlet 568 for fluid communication of an inflow 526 of treated water from a bioreactor (not shown). A liquid communication member 558 connects the outflow 558 of the first saddle tank 556A to the second saddle tank 556B.

  The second saddle tank 556B is opened to atmospheric pressure, but the first folding saddle tank 556A is not opened. The second column height 432 exists as two segments of the folding saddle tank system 550: a first portion 432A before and after the first saddle tank 556A, and a portion 432B on the platform before and after the second saddle tank 556B. Although the first column height 422 is not shown in FIG. 17, its effective dimensions are from the outflow water level 558 of the saddle tank 556B to the platform of atmospheric pressure, and the maximum of the membrane plate of the submerged membrane assembly 510A of the first saddle tank 556A. Up to the lower point. System 550 includes two collection troughs 538A and 538B that receive permeate or purified water (532) from submerged membrane bioreactor assemblies 510A-D in first and second saddle tanks 556A and 556B, respectively.

  In operation, the folding saddle tank system 550 functions substantially similar to the system 500 of FIGS. Inflow 526 enters first saddle tank 556A through inlet 568 and flows upward through submerged membrane bioreactor assemblies 510A and 510B. The liquid overflow and pressurized exhaust 559 is routed through the liquid communication member 558 to the bottom of the second saddle tank 556B and flows upward through the submerged membrane bioreactor assemblies 510C and 510D. Hydrodynamic calculations are the same as for the 4-stage arrangement. As before, each membrane has the same pressure differential from top to bottom and from stage to stage. A substantially uniform pressure differential of about 1.75 psig is created between the first and second sides of the membrane of the membrane assembly. The outer diameter of the head tank 502 (not shown) remains 9 feet, but the overall outside diameter of the folding saddle tank system 550 increases to 18 feet. Again, bubble 436 (not shown) is used four times as it passes through each of the four stages of membrane 510.

  FIG. 17 shows a plurality of pressure gauges [P] 571 and valves 570 for clarity and understanding. The pressure in psig at each gauge location is shown next to the gauge. There are no pressure gauges or valves in the actual plant, because when the valve is closed, the dissolved air comes out of the solution and the density of the liquid in the membrane outlet pipe changes. However, for this drawing, consider that at some point during normal operation, the valve is momentarily closed and the pressure indicated on the gauge is obtained. The 1.75 psig selection is the nominal pressure imposed by 4 feet of water and is typical for the design of this type of saddle tank.

  Note that all gauge pressures in the outlet pipe from the membrane are equal. The pressure (water head) in the outlet pipe of the membrane in the saddle tank 556A is due to an exhaust pressure of 3.5 psi (equivalent to 8 feet of water) pressurized redundantly with the liquid in the tank 556A. The pressure at the recovery trough 538A is reduced to 1.75 psi (4 feet of liquid head) in the outlet pipe of the membrane 510B and 3.5 psi (8 feet of head) in the outlet pipe of the membrane 510A.

  Similarly, the outlet piping from membrane 510C is under 1.75 psi (4 feet) of water head and the outlet piping from membrane 510D is under 1.75 psi (vacuum) siphon. Experience in the field indicates that bubbles are allowed in the siphon piping, provided that the siphon piping is of an appropriate size to maintain a suitable discharge flow rate, typically greater than 2 feet / second.

  In order to further elucidate the various aspects of the present invention, a bench test apparatus was constructed in accordance with the teachings herein, and a series of membrane throughput benches under conditions that varied membrane conditions and levels of dispersed air in the water. Used to carry out tests. FIG. 18 shows a series of test results performed by the bench test apparatus.

  Field observations show that membrane permeability improves as the dissolved gas increases. See, for example, Table 3 where the addition of dissolved air resulted in a significant increase in permeate throughput. Other field observations demonstrate the polishing effect that pressurized gas in the reactor liquid has on membranes and other surfaces. In vertical shaft bioreactors, a significant cleaning action occurs at strategic locations within the reactor, which is typically where dissolved gases exit the solution.

  As described above, the bench test apparatus was fabricated using the same type of Kubota membrane used in the field test described in Table 3. These tests demonstrated that the dissolved gas increased by adding downflow air into the reactor liquid has a significant effect on the permeate flux. FIG. 18 shows the performance of Kubota membrane fragments that have been used in the reactor for more than two months previously. A series of eight permeability tests were performed on the Kubota membrane over a period of one week using the bench test apparatus. The film piece of the test apparatus had an area of about 1/130 on both sides of a full size (1/2 m × 1 m) Kubota film.

  The test apparatus was configured as an aeration shaft having an outer casing with an inner diameter of 3.488 "and a downflow chamber with an inner diameter of 1". The liquid circulation was driven by a large aquarium air pump with two injection ports near the bottom of the downflow chamber. A membrane is placed in a recess machined in the bottom of a 3.5 "diameter tube to support the membrane so that a removable bottom cover does not move downward. The bottom cover plate is a groove in the Kubota membrane. A series of machined grooves of similar dimensions as the groove, with a single coarse felt blotter membrane taken from a field trial membrane unit between the membrane and the permeate collection system. A membrane outlet tube was installed both vertically and downwardly vertically from the lower surface of the membrane, and the lower tube was a siphon for removing permeate from the lower side of the membrane or Can be used as a drain.

  A permeability test was performed to measure the effect of dissolved gas on the flux through the membrane. To do this, the effect of the air lift effect in the membrane outlet pipe must be separated from the effect of the increased flux due to degassing. As a result, the membrane is horizontally oriented at the bottom of a Plexiglas tube having a height of 24 "and a diameter of 3.5". The first test used a membrane glued to the bottom of the cylinder. This test simply determined that a gas-saturated liquid would pass through the membrane, but the effect of vacuum, the effect of the wicking layer under the skin of the membrane, or the permeate shunted There was no measure for the effect of the collection system.

  The test apparatus used a porous felt layer under the membrane and a shunt permeate recovery system similar to the Kubota design. The area of the test film is 9.5 square inches, that is, 1/130 of the area of both sides of the field test Kubota film. The field used membrane was (1/2 meter x 1 meter) with a nominal surface area of 8.6 square feet or 1298 square inches.

  In the field trial, only 1 foot of positive head was available. 150U. S. In order to obtain a gallon / membrane / day flux, a vacuum of up to 28 "was successfully applied to the permeate side. However, in the test device, when there is almost no gas in the permeate, the 1/8 inch diameter transparent vinyl discharge pipe from the membrane is very useful when used as a siphon in the first, third and fourth test runs. In fact, in the third run, the number and size of bubbles in the siphon could be estimated visually.

  In the saddle tank design described in conjunction with FIG. 15, the top membrane operates under siphon flow. Test data was collected from the test equipment under a negative head. In the 5th trial (fresh soda water), there was sufficient transport of dissolved gas through the membrane to interfere with the operation of the siphon, but using soda water for about 12 hours after preparation made the siphon effect good again. worked.

  Airlift circulation through upstream and downstream: Initially it was thought that tap water and / or soda water would permeate the membrane over a long period without throughput loss. This was not correct. When tap water is left in the test equipment, the flow slows with time. When soda water is left in the test equipment, there is almost no drop in flow. However, when airlift circulation was used with tap water, there was no appreciable drop in flow, presumably due to membrane polishing. The soda water product probably uses reverse osmosis water, while the city water is sand filtration. Initially, it was thought that there might be a measurable difference in water quality, but it turned out to be incorrect on the eighth attempt. Thereafter, it is shown that the gas aggregation effect on the downstream side of the membrane has a dominant effect on the permeation flux.

  The flux was calibrated at microliters / minute: The method used for flux measurement involved measuring the change in liquid height in a small diameter cylindrical catch tube with a stopwatch. This method is very accurate and reproducible (± 25 microliters), as evidenced by the good fit of the data points to the curve.

  FIG. 18 is a plot of test trial results. The first step was to establish. The first two trials were to establish the baseline of the initial permeation flux that was observed in the field. The first time, tap water and dirty membrane were used. The water circulated with an airlift. The second was done in the same way, except that fresh soda water was used as the liquid. The airlift circulation was not used the second time because there were too many bubbles.

  The second step was to clean the membrane according to field observations. Soda water was air circulated before and after the membrane surface. This stimulated the bubble aggregation concept seen locally.

  The third step was to establish a permeate flux baseline on a clean membrane. The third time was using soda water that was ventilated overnight and was exhausted. The fourth time was using tap water.

  The fourth step was to determine the effect of gas content on the permeate flux (correlated with the elapsed time of soda water from the bottle) compared to tap water. The 5th time used soda water after 1 hour. The sixth time used tap water. The seventh time used 12 hours of soda water.

  The fifth step was to approximate the liquid gas content in a typical bioreactor. In the eighth round, 50% tap water and 50% soda water were used. In order to keep the soda water elapsed time "out of the bottle" less than 30 minutes, the soda / tap water mixture was frequently changed. On site, carbon dioxide in the vertical long shaft reactor was replenished every 6-10 minutes, so the eighth is modest.

  The test trial plot of FIG. 18 illustrates several aspects of the present invention. A 24 "head is used as a common pressure for comparison purposes between trials.

  1) Tap water with air circulation was a dirty membrane, operated at 24 "head pressure, and a permeation flux of about 1050 microliters was obtained. There were no visible bubbles in the siphon piping, maintaining a vacuum Was easy.

  2) Fresh soda water was used on the same soiled membrane to obtain 1875 microliters permeation flux, an increase in flux of about 78%. This is approximately the same performance improvement as a field trial when the bioreactor liquid is supersaturated with dissolved air (ie, downflow air is added). The soda water used was fresh and had an elapsed time of 1 to 5 hours, but the degree of flocculation on the membrane was sufficient to stop the use of a 24 to 32 inch hydrohead siphon. This was interpreted as evidence that dissolved gas readily penetrates the membrane.

  3) Soda water was circulated through the membrane surface for an additional 12 hours. The permeate piping was blocked and the dissolved gas impinged on the membrane surface and almost no fluid or gas permeated. This stimulates a condition in the reactor where the polymer surface is said to be able to be effectively cleaned by foaming. The clogging of the permeate discharge pipe was eliminated, and the permeate flux at the 24 "head reached 2200 microliters / minute. Both the soda water (third time) and tap water (fourth time) When treated with a clean membrane, the former increased the flux by 40% over the latter, and the test trial did not matter whether tap water or soda water was circulated first, fresh soda water always Note that the results are better than tap water, and that the complete siphon effect was achieved without dissolved gas, and that no bubbles were observed in the outlet pipe. Recall that the differential effect must be ignored in these trials, so that when the membrane is clean, the improvement in permeation flux is only related to the effect of dissolved gas agglomeration in or on the membrane. These results show that the gas in the fluid It is predicted that the dissolved gas has a supersaturated pressure in the liquid on the upstream side of the membrane, but has a relative pressure on the downstream side of the membrane. The gas moves from high pressure to low pressure through the membrane, possibly with fluid.

  The Zenon membrane has a higher flux per square foot than the Kubota membrane, but the Zenon membrane uses negative pressure in the permeate outlet piping. The Zenon membrane is affected by a decrease in partial pressure before and after the membrane, and may exhibit an agglomerated gas effect. From the standpoint of density difference before and after the film, the 40 "high Kubota film should perform better than the 60" high Zenon film.

  4) In order to quantify the effect of the membrane cleaning process in step 3, tap water was again passed over the membrane that was supposed to be cleaned. This time, the permeation flux increased from 1050 microliters / minute in Test 1 to 1575 microliters in Test 4. This represents a 50% increase in permeate flux due to impingement / aggregate gas cleaning.

  Fresh soda water (1-6 hours) was treated on a clean membrane, and the permeation flux (2400 microliters / minute) was the third time using soda water that was vented after 12 hours. Just a little better (9%) than (2200 microliters / min). Again, it can be seen that a very high level of dissolved gas is not necessary to be effective.

  The sixth time was tap water, and the permeation flux increased from 2575 microliters / minute (44%) to 1575 microliters / minute in the previous fourth tap water, both using clean membranes. . The sixth tap water had a slightly lower permeation flux than the fifth soda water (5%).

  Void soda water (12 hours) was treated with a clean membrane. The permeate flux (1950 microliters / minute) was 23% lower than the permeate flux of soda water (2400 microliters / minute) after 1-6 hours. The permeate flux of soda water after 12 hours (1950 microliters / minute) was surprisingly lower (16%) than the sixth tap water (2275 microliters / minute). When the filter is clean, the physical properties of soda and tap water are similar. The data show that the difference in permeate flux between the two soda water trials is related to the soda water elapsed time, which correlates with the amount of dissolved gas present. In this case, however, the permeation flux of tap water is higher than that of soda water, indicating that there is no real difference in the physical properties of the two fluids when treated with a clean membrane. This credits the idea that increased permeation flux is associated with gas aggregation rather than a difference in the physical / chemical properties of the two fluids.

  Since it was determined that the physical properties and physical / chemical properties of the two water sources were similar (once the dissolved gas was equilibrated), the last 8th 50% tap water and 50% Fresh soda water was evaluated. In this case, the mixture was often replenished at intervals of less than 30 minutes to better approximate the characteristics of the vertical shaft bioreactor. In this eighth round, the permeation flux reached 2600 microliters / minute, an increase of 15% over tap water alone and 8% over fresh soda water alone. The 8th time of 2600 microliters / minute is 130U. S. Equivalent to gallon / day / full size membrane. Also note that these numbers are only 24 "heads and were operated with heads up to 39 inches in the field.

  The above observations strongly indicate that dissolved gas aggregation plays a role in membrane permeation flux. These data strongly indicate that the dissolved gas assists the cleaning process. The amount of dissolved gas affects the permeation flux, but the amount of dissolved gas in the bench test apparatus is time-dependent. Fortunately, the dissolved gas content in the sludge in field tests is constant unless deliberately changed.

  Another commissioning was performed to investigate the correlation between dissolved gas content and exposure time to atmospheric pressure. Fresh soda water was treated on the soiled membrane at three different head pressures. The permeation flux changed as follows.

Table 4
Water head 18 ”

Table 5
Water head 8.5 "

Table 6
Water head 7 ”
(With the same soda water as in Table 5, water head pressure

  These tests show that soda water with an age of more than 1 hour is very stable (less than 0.75 microliters / minute) and all data points on the curve (except for the 8th time) ) Is for fresh soda water after at least 60 minutes. On a clean membrane, the difference between 1-5 hours of soda water and more than 12 hours of soda water is about 25% at a 24 "head. Because it is always freshly saturated with carbon dioxide every 6-10 minutes, it may achieve much greater throughput than these tests show.

  These tests also perform well with fresh or nearly clean membranes of soda water in all cases than tap water. Once the membrane is washed with soda water (including a small amount of citric acid), there is not much difference between tap water and soda water. The membrane of the test apparatus was visually cleaner after 5 days exposure to soda and tap water than at the start of the test.

  The variation in pressure difference from the top to the bottom of the Kubota membrane is 4-6 ″ water head, and about 6-8 ″ for Zenon membrane. The 8th treatment of a 50% tap water and 50% soda mixture with a clean membrane shows a throughput of 2600 microliters / minute with a head of 24 ". Pressure differences of 4", 6 "and 8" are , Corresponding to 15%, 25% and 35% of the total permeation flux, respectively. The effect on the flux due to the pressure difference variation from top to bottom of the vertically oriented membrane is in addition to the increase in flux due to the above degassing phenomenon occurring at the surface of the membrane. When combined, these two effects can double membrane throughput. Based in part on the above, the increase in permeate flux through the membrane is one or more selected from the effects of changing the gas partial pressure, the effects of agglomerated gas, or the effects of stored energy release. This is because of factors.

  FIG. 19 shows the results of a series of temperature, viscosity and flux tests performed on the bench test apparatus. Several trial runs were performed on the test equipment to see what differences the temperature would make in the membrane permeation flux. Viscosity and temperature were inversely correlated, and throughput flux was predicted to correlate strongly with temperature. FIG. 19 quantifies these factors based on multiple trial runs on the test equipment to confirm their predicted relationship. Importantly, the viscosity varies by about 10% between 15 and 25 ° C. However, between 15 ° C and 25 ° C, the flux varies by approximately 50% or 550 microliters / minute. As shown in FIG. 19, the membrane is sensitive to temperature and viscosity changes in the range of 15 to 25 ° C.

  The vertical long shaft bioreactor is installed in the ground and thus produces a huge thermal flywheel effect over time. That is, the treated water temperature should be much less variable than the conventional plant and much less difficult to handle temperature variations than the conventional process.

  While the above description is for aspects of the invention that separates available water from wastewater, sewage, or sludge using the immersion membrane of FIGS. 14-19, the invention is not so limited. The method and apparatus of the present invention can be readily utilized for membrane separation of other desirable fluids from a stream comprising raw fluid and any undesirable material. For example, aspects of the invention may include salt water desalination, chemical process separation, or any other situation where a membrane is utilized to separate solute particles, suspended solids and other contaminants from a fluid or solvent. In order to improve membrane throughput and / or membrane self-cleaning.

  Accordingly, the present invention includes treating influent water, including improving membrane throughput and removing target fluid from the influent water. The method of the present invention typically includes a flowing influent stream comprising a fluid containing dissolved gas and a flowing permeate stream consisting essentially of fluid and gas. The two flows are separated by a permeable membrane having a first surface in fluid communication with the influent water flow and a second surface in liquid communication with the permeate. The membrane allows molecules less than a predetermined size to permeate between the first and second surfaces, and the permeable size allows the target fluid to permeate the incoming water stream and reject unwanted components. Selected to be able to. The gas may be dissolved in the fluid in any manner such as, for example, injection and the result of a chemical process that occurs in the influent. The amount of dissolved gas in the fluid of the influent flow is an amount that increases the flux of the permeate flow over the flux of the permeate flow when the inflow of water does not contain the dissolved gas. It is. This amount may vary depending on the nature of the fluid, gas and operating parameters of the system performing the membrane separation. The amount of dissolved gas in the influent water fluid may be at least at a saturation level of the gas. The dissolved gas may include air or an air component such as carbon dioxide. The target fluid may be water, blood, or other fluid.

  Another aspect of the present invention involves treating with influent water, including those that provide a self-cleaning action on the membrane surface. The method includes a flowing influent stream that includes a fluid containing dissolved gas and a flowing permeate stream that consists essentially of the fluid and the gas. The two flows are separated by a permeable membrane having a first surface in fluid communication with the incoming water and a second surface in liquid communication with the permeate. The membrane allows molecules less than a predetermined size to pass between the first and second surfaces, and the permeable size allows the target fluid to pass the incoming water stream and rejects unwanted components. Selected to be able to. The fluid of the inflowing water contains dissolved gas in an amount that permeates the membrane and aggregates in the vicinity of the second surface. The fluid of the inflowing water may include an amount of dissolved gas that provides a polishing action on the first surface. The influent water flow fluid may contain an amount of dissolved gas that agglomerates on the second surface to impart a polishing action to the second surface. Aggregation of the gas in the vicinity of the membrane surface provides a polishing action on the surface that helps clean the surface. This increases the operational life of the membrane by increasing the time between scheduled membrane cleaning cycles where the membrane is removed for inspection. FIGS. 14-17 thus far illustrate aspects of the present invention that produce a selected pressure differential across the membrane along the vertical axis in a liquid-liquid system. However, embodiments of the apparatus of the present invention may be used to produce a selected pressure differential along the vertical axis of the membrane in a gas-liquid or gas-liquid system.

Membrane Diffuser The conventional prior art uses a low pressure, horizontally oriented membrane diffuser, typically a flat membrane placed horizontally on the floor of an aeration tank. The floor area is relatively small compared to the volume of the tank to be aerated, even if it is completely covered with a membrane. In such a horizontal application, the liquid to be aerated is contained on the membrane. This liquid applies hydraulic pressure across the membrane surface. The disadvantage of this horizontal membrane design is that the generated bubbles are very large when leaving the surface of the membrane. This is before the bubbles are detached. This is because the bubbles must grow in a low pressure horizontal membrane system until the buoyancy exceeds the attractive force. Low pressure horizontal membrane systems typically generate bubbles of about 1-2 millimeters in diameter. A conventional practice is to increase the internal gas pressure to about twice the hydrostatic pressure of the liquid to pull the bubbles away from the horizontal membrane. This creates small, fine bubbles, but requires a lot of energy to compress the gas.

  A recently emerging design places the membranes in a vertical configuration and allows the aerated liquid to flow between the membranes. The membrane surface area in the aeration tank is greatly increased by placing the membrane vertically and the generated bubbles are smaller due to the shearing action of the liquid flow between the membranes. Very low energy requirements of 20-30% of conventional horizontal membrane systems have been reported. However, in a vertical layout, the top of the film is deeper than the bottom of the film, so the liquid pressure is low. This results in a non-uniform air flow along the vertical axis of the membrane surface. A common complaint of this design is that vertically oriented membranes “wet out” and air flow through the membranes stays. In general, the “wet out” starts at the deepest part of the membrane and progresses upward. The lack of air flow at the bottom of the membrane allows water to enter the membrane, which limits or stops gas dispersion by the membrane.

  FIG. 20 schematically shows an immersion film diffuser 600 according to an embodiment of the present invention. FIG. 21 is a partial cross-sectional front view of the air diffuser 600 of FIG. The membrane diffuser 600 includes three separate compartments: a fluid treatment compartment 601, a foam fluid compartment 602, and a static fluid compartment 603. The compartments (601, 602, 603) are preferably arranged close to each other for convenience. The membrane diffuser 600 includes at least one membrane bundle that disperses gas within a liquid. In the exemplary embodiment shown in FIG. 20, three hollow fiber membrane bundles 610A-C are placed at different heights within the fluid treatment compartment 601 of the diffuser 600. This embodiment of the present invention may alternatively utilize one or more membranes. The membrane may be of any type suitable for membrane aeration, such as plates and frames, tubular, hollow fibers and spiral wound membranes. Further, the membrane may be made of any suitable material such as cellulose, acetate, polyvinyl chloride, polysulfone, polycarbonate, and polyacrylonitrile.

  The components of the immersion membrane diffuser 600 include a membrane bundle 610, a membrane attachment member 612, a fluid treatment compartment 601, a foam fluid compartment 602, and a stationary fluid compartment 603. For clarity when viewing FIG. 20, detailed reference is generally provided only for the bottom membrane bundle 610A and the associated membrane attachment member 612. Membrane bundles 610B and 610C are substantially similar to membrane bundle 610A. Typically, each membrane bundle is about 6 inches in diameter and about 30 inches long and typically includes a plurality of hollow fiber membranes. The hollow fiber membrane has a typical inner diameter of about 1 inch. FIG. 21 shows a membrane bundle comprising three hollow fiber membranes 610A-1, 610A-2 and 610A-3. However, any number of tubular membranes may be present in each stage membrane bundle 610. The membrane bundles 610A-610C are oriented so that the fluid to be treated 634, such as a mixed liquid, flows between the tubular membrane bundles of the plurality of stages during aeration. Each tubular membrane has a first surface and a second surface, as described with reference to FIGS. 14-1 to 14-7, and molecules less than a predetermined size can pass between the first surface and the second surface. It is.

  Each membrane attachment member 612, which is a tubular member having a right hand 612R and a left hand 612L in a preferred embodiment, attaches or transports each end of the membrane bundle 610 at the membrane attachment. Each membrane attachment member 612 provides a chamber 614 that provides liquid communication FC between the foam fluid compartment 602, the respective first surface 411 of the membrane bundle 410 attached to the attachment member, and the static water compartment 603. including. The chamber 614L of the left hand portion 612L of the membrane attachment member 612 includes a substantially vertically oriented bubble capture chamber 617, shown in FIG. 21 as a portion of the rising expected bubble capture member 615, and a bubble capture opening 619. Membrane 615 is coupled with mounting member 612L to form an assembly. The chamber 614R of the right hand portion 612R of the membrane attachment member 612 includes a substantially vertically oriented gas storage chamber 618, shown as part of the dispersion member 616 in FIG. Member 616 is coupled to mounting member 612R to form an assembly. Chambers 617 and 618 each have a vertical length, and the vertical length 654 of chamber 617 is greater than the vertical length 656 of chamber 618.

  For purposes of describing embodiments of the present invention, the dispersion target fluid 620 is described as air 620. In other embodiments, the fluid to be dispersed 620 may be any type of gas or liquid. Diffusion is described herein as aeration, but is not so limited of the present invention. Further, the liquid 634 to be treated where the dispersion occurs is described as waste water or water. In other embodiments, the fluid to be treated 634 can be any type of liquid or gas.

  The fluid treatment compartment 601 includes a configuration that contains waste water 634, such as a reactor surface section tank that contains a high concentration of suspended solids or mixed liquid for treatment and aeration. Typically, the wastewater 634 flows into the fluid treatment compartment 601 for aeration, undergoes aeration, and usually flows out for further processing or disposal.

  Foamed fluid compartment 602 includes a configuration that includes a first fluid 632 and rising bubbles of air 620. The first fluid 632 is described as purified water 632, but may be any fluid having a specific gravity heavier than air 620. Compartment 602 optionally includes a source of bubbles 626, which may include a gas inlet port 622 that receives air 620 formed in bubbles 626 within water 632. The port may receive air 620 from an external source, but forms a bubble 626 when it enters the foam fluid compartment 602 and the purified water 632. Alternatively, the port 622 may receive purified water 632 that includes bubbles 626 in the compartment 602. The gas inlet 622 may include any device that forms bubbles 626 in the water 632.

  The stationary fluid compartment 603 includes a configuration that includes a stationary fluid 636 described as purified water 636, but the stationary fluid can be any fluid and any fluid having a specific gravity heavier than air 620. Optionally, the compartment 603 is configured such that the user can observe with the naked eye whether any bubbles of the gas 620 are emitted or present from the diffuser opening 611 of the diffuser member 616. Including.

    FIG. 20 shows an assembly 600 disposed with a foamed fluid compartment 602 and a stationary water compartment 603, each in contact with a fluid treatment compartment 601. The compartment may be defined in a single tank or structure. Alternatively, the compartments may be separate tank structures, one or more of which contact each other. In an alternative arrangement, compartments 602 and 603 may also touch each other. In another alternative arrangement, one compartment may be remote from another compartment. FIG. 19 shows a height “zero” at the lowest point of the device 600, but the height increases upward or vertically. In assembly 600, three-stage hollow fiber membrane bundles 610A-C are mounted in fluid treatment compartment 601 at heights of 4.0, 6.5, and 9.0 feet, respectively. In practice, any suitable number of membrane bundles 610 may be used, and the membrane bundles may have some separation and may be several inches apart.

  As shown in FIGS. 20 and 21, the rising bubble trapping portion of the first chamber 614 </ b> L shown as the trapping member 615 and the bubble trapping opening 619 are disposed in the foaming fluid compartment 602. The gas reservoir of the second chamber 614R, shown as the dispersion member 616 and the diffuser opening 611, is located in the still water compartment 603. The rising bubble trapping members 615 are shown with a vertical length of 2.5 feet measured from the bubble trapping opening 619 to which they are connected to the lowest height of each membrane bundle 610. The diffuser 616 is shown with a vertical length of 2.0 feet measured from the diffuser opening 611 to which they are joined to the lowest height of each membrane bundle 610. The rising bubble capturing member 615 and the diffuser member 616 may have any length. However, the air diffuser 616 is shorter than the rising bubble capture member 615. A difference in length of 0.5 feet is expected for satisfactory results. When there is a significant difference in the specific gravity between the aerated purified water 632 and the stationary purified water 636, the difference in length between the rising bubble capturing member 615 and the diffuser member 616 has an automatic aeration function described below. Adjusted to provide.

  In use, the foam fluid compartment 602 is filled with aerated purified water 632 and the stationary water compartment 603 is filled with stationary purified water 636. The fluid treatment compartment 601 is filled with waste water 634 that has been aerated to a level sufficient to immerse the membranes 610A-C. Wastewater 634 optionally flows through compartment 601 from a low height to a high height near the second side of the membrane in a manner that facilitates aeration and out of the compartment.

  FIG. 20 shows an initial hydrostatic level of 12 feet within assembly 600, which then increases to 12.6 feet in compartments 601 and 602 when water 632 and wastewater 634 are aerated. Air 620 is pumped through the port 622 to the foaming fluid compartment 602 at a relatively low pressure, and bubbles 626 are formed in the purified water contained in the compartment to form aerated water 632. Only a small amount of air pressure is needed to pump air 620 through port 622 to compartment 602 and save energy compared to existing systems that require high pressure to force foam from the diffuser membrane become. Bubbles 626 are formed with a diameter sufficient to raise the bubbles in aerated water 632. The bubble 626 rises in the aerated water 632, and a part of the bubble rises through the bubble capturing opening 619 of the capturing member and is captured by the chamber 617 of the rising bubble capturing member. In chamber 617, rising bubbles 626 collide and eventually release air 620 above aerated water 632 / air 620 interface 658 in capture member chamber 617. The capture member chamber 617 is in fluid communication with the membrane attachment member portion of the chamber 614, and the chamber 614 is in fluid communication with the first surface of the membrane of the membrane bundle 610, so that the released air 620 passes through the liquid communication path FC. Along the first surface of the membrane or in fluid communication with the first surface.

  The vertical position of v in the capture member chamber 617 relative to the minimum membrane height of the membrane assembly defines a gas column 652 having a vertical length, which can also be described as a head or head difference. The gas column 652 imposes a head on the air 620, which correlates with the buoyancy of the air 620 in the aerated water 632. The imposed head is transferred to the portion of air 620 that is in fluid communication with the first surface of the membrane of the tubular membrane bundle 610. If the specific gravity of the aerated water 632 and the waste water 634 is substantially similar, the membrane bundle 610 exposed to the fluid 634 in fluid communication with the first surface 411 of the membrane exposed to the chamber 614 and the fluid treatment compartment 601. The water head between the second side 412 of the membrane is approximately equal to the head generated by the gas column 652. FIG. 20 shows gas column length 652 as 1 foot of miss 632, establishing a head of water equal to 1 foot of water. The 1 foot head applies pressure to the air 620 molecules in fluid communication with the membrane first surface 411 of the membrane bundle 610 to push some of the air molecules through the pores of the membrane to form water. Aeration bubbles 628 are formed in 634.

  The vertical length of the gas column and the resulting head differential are established by the amount of bubbles 626 in the foaming fluid compartment 602 that enters the bubble capture opening 619. As the number of bubbles 626 formed in the aerated water 632 increases, the number of bubbles rising in the bubble capture openings 619 increases and the flow of air into the membrane attachment member chamber 614 increases. This increased air flow exceeds the air flow that can permeate the membrane 610 with existing heads. Air 620 accumulates in chambers 614, 617 and 618, and the vertical height of the aerated water 632 / air 620 interface 658 within the capture member chamber 617 decreases. This increases the gas column length 652, increases the water head imposed on the released air 620, and allows the air flow through the membrane to reach parallel in response to the amount of bubbles in the foaming fluid compartment 602. Increase. The internal pressure of the membrane bundle 610 automatically adjusts to the air flow provided by the bubbles 626. The higher the airflow provided by the bubbles 626, the lower the water level of the water 632 of the rising bubble capture member 615 and the greater the water head difference 652.

  If the hollow tube of the membrane bundle 610 is clogged or if trapped bubbles 626 generate more air 620 than the membrane of the membrane bundle 610 can diffuse, the air will enter the diffuser chamber 618. Accumulate in tube membrane bundle 610 until full and overflow. This release is because the diffuser chamber 618 is smaller than the vertical length of the rising bubble capture member chamber 617, so that the air 620 releases the air 620 before it fills the overflow bubble capture member chamber and overflows. The appearance of bubbles in the purified water 636 of the compartment 603 indicates that excess air 520 is being supplied to the membrane bundle 610 or that the membrane bundle needs to be cleaned. Since the membrane bundle 610 is connected to the water purification compartments 602 and 603, fouling inside the membrane should not occur.

  At the start of operation, the membrane surfaces of the tubular membrane bundle 510 have different vertical heights. Taking membrane bundle 610C as an example, the top hollow tube membrane of the bundle is 9.0 feet high and the bottom hollow tube membrane is 8.5 feet. Initially, the top membrane has a slightly larger pressure difference than the bottom membrane, but this is because the depth is small, until the maximum flow velocity is reached and the internal pressure of the air 620 increases and the bottom membrane approaches the maximum transition, A little more bubbles 628 are generated.

  The water head generated by gas column 652 is calculated as follows. Since the water 634 in the fluid treatment compartment 601 is aerated as a result of its treatment, there is a porosity of about 2-10%. For purposes of illustrating the system 600, the porosity is assumed to be 5%. The dynamic water level in both compartments 601 and 602 is 12 feet x 105% = 12.6 feet. The water head between the first and second surfaces of the membrane of the top bundle tube of membrane bundle 610C is the difference between the water pressure outside the second surface 412 minus the air pressure inside the first surface. The pressure of the outer water 634 is (12.6-9.5) /2.31x0.95=1.27 psig, the pressure of the inner air 620 is (12.6-8) /2.31x0.95=1 89 psig. The water head is 0.62 psig. Similarly, the pressure of water 634 outside the bottom membrane bundle 610A is (12.6-4.5) /2.31x0.95=3.333 psig and the pressure of the inner air 620 is (12.6-3). ) /2.31×0.95=3.94. Again, the head differential is 0.62 psig. These calculations illustrate aspects of the invention that provide a selected head or pressure differential across all membranes of assembly 600.

  Sometimes it is necessary to shut down the diffuser 600 and the purified water 632 and 636 enter the membrane 610. When the air 620 is resumed, water is expelled from the diffuser 616 and enters the still water compartment 603 to automatically clean the tubular membrane air passages of the membrane bundle 610. In an alternative embodiment, the compartment 603 can be filled with a cleaning solution for periodic membrane cleaning by stopping the bubbles 626.

  It should be noted that there are many uses for which the device 600 can be used. Some examples include drinking water ozonation (03), chlorination (Cl2) or recarbonation (CO2) and disinfection of wastewater or reoxygenation of treated water using pure O2, or NH3, CH4, Biochemical nutrient addition or storage such as SO2.

  Although the foregoing invention has been described in detail by way of illustration for purposes of clarity of understanding, those skilled in the art will recognize certain changes or improvements from this disclosure and that for purposes of illustration and not limitation. It can be practiced without undue experimentation within the scope of the invention as described in the specification. All publications, patents and patent applications mentioned in this specification are herein incorporated by reference in their entirety for all purposes.

The longitudinal cross-sectional schematic diagram of one embodiment of the bioreactor for wastewater treatment of this invention. The longitudinal cross-sectional schematic diagram of one embodiment of the bioreactor for wastewater treatment of this invention. It is a longitudinal cross-sectional schematic diagram of one embodiment of the bioreactor for wastewater treatment of this invention. The longitudinal cross-sectional schematic diagram of one embodiment of the bioreactor for wastewater treatment of this invention. The longitudinal cross-sectional schematic diagram of one embodiment of the bioreactor for wastewater treatment of this invention. The longitudinal cross-sectional schematic diagram of one embodiment of the bioreactor for wastewater treatment of this invention. The longitudinal cross-sectional schematic diagram of one embodiment of the bioreactor for a biosolid process of this invention. The longitudinal cross-sectional schematic diagram of one embodiment of the bioreactor for wastewater treatment of this invention. The decomposition | disassembly schematic diagram of the internal channel and downflow chamber of the reactor of this invention. The cross-sectional schematic diagram of the reactor of this invention. The cross-sectional schematic diagram of the reactor of this invention which shows the downflow chamber deform | transformed with the expansion tool. Graph showing class A biosolids EPA time temperature requirements. 1 is a representative block diagram of the present invention for producing recirculated water, class A biosolids, clean odorless exhaust. The hydraulic schematic diagram of the operation mode of the present invention. The hydraulic schematic diagram of the operation mode of the present invention. The hydraulic schematic diagram of the operation mode of the present invention. The hydraulic schematic diagram of the operation mode of the present invention. The hydraulic schematic diagram of the operation mode of the present invention. The hydraulic schematic diagram of the operation mode of the present invention. The hydraulic schematic diagram of the operation mode of the present invention. The schematic diagram of the head tank and saddle tank of the bioreactor of this invention. The upper surface schematic diagram of the saddle tank of FIG. The longitudinal cross-sectional schematic diagram of the head tank of FIG. The block diagram of the folding saddle tank system of this invention. The graph which shows the film | membrane throughput test result by the bench test apparatus of embodiment of this invention. The graph which shows the test result of the temperature vs. viscosity by the bench test apparatus of the embodiment of the present invention. The longitudinal cross-sectional schematic diagram of the diffuser of this invention. The expansion schematic diagram of the aeration apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bioreactor 12 Downflow channel 14 Upflow channel 15 Head tank 16 Head tank 18 Mixing zone 20 Opening 22 Downflow conduit 24 Upflow conduit 30 Inflow conduit 32 Inflow channel 34 Shielded inflow port 39 Area 40 Upstream channel 49 DO probe 50 Recirculation flow regulator 51 System control unit 52 Baffle actuator 53 Flow rate sensor 54 Deaeration plate 60 Air supply header 62 Compressed air piping 64 Air supply port 66 Aeration / solids extraction piping 67 Sewage reservoir 68 Aeration / solids extraction port 69 Port 70 Shear head 80 First reactor channel 81 Region 82 Ascending channel 84 Dividing mechanism 86 Vertical baffle 88 Dividing extension pipe 90 Broken line 110 Zone 2 recirculation channel 112 Zone 2 recirculation flow rate Gurator 120 Solid-liquid separator 122 Zone 1 activated sludge return channel 124 Zone 2 activated sludge return channel 126 Sludge extractor 130 Suspension media 132 Fixed media 133 Biofilter 134 UV disinfection chamber 135 Head tank 136 Pipe 137 Air lift inflow pump 138 Membrane filtration cartridge 139 UV disinfection chamber 140 Zone 1 recirculation port 150 Zone 2 degassing plate 152 Zone 2 shielded recirculation port 170 Airlock baffle 172 Airlock mechanism 190 Modular section 192 Modular section coupler 194 Radial channel partition 196 Outer casing 196 Inner wall 197 Second outer wall 198 Conduit expansion device 200 Spreader component 202 Spray Parts 204 Expansion driver 400 Dipped permeable membrane assembly 402 Vertical axis 405 U-shaped container 410 Membrane 411 First side 412 Second side 414 Separator membrane 415 Pore 420 First liquid compartment 422 First column height 423 First 1 chamber vertical axis 424 first liquid 426 bubble 430 second liquid compartment 432 second column height 433 second chamber vertical axis 434 second liquid 438 inlet 452 water head difference 500 bioreactor 502 head tank 503 membrane bioreactor head 506 saddle tank 510 Submerged membrane bioreactor assembly 511 Flat semi-permeable membrane 512 Membrane output piping 514 External manifold 516 Recovery piping 526 Inflow 528 Outflow 532 Permeate or purified water 538 Recovery trough 550 Folding Saddle tank system 556 Folding saddle tank 558 Liquid communication member 559 Exhaust 568 Inlet 570 Valve 571 Pressure gauge 600 Immersion membrane diffuser 601 Fluid treatment compartment 602 Foam fluid compartment 603 Static fluid compartment 610 Membrane bundle 611 Aeration opening 612 Membrane attachment member 614 Chamber 615 Ascending gas bubble capturing member 615 Ascending bubble capturing member 616 Dispersing member 617 Bubble capturing chamber 618 Gas storage chamber 619 Bubble capturing opening 620 Dispersion target fluid 622 Gas inlet port 626 Ascending bubble 632 First fluid 634 Processing target fluid 636 Still fluid 652 Gas column 654 Vertical length of chamber 617 656 Vertical length of chamber 618 658 Interface

Claims (79)

A film including a first surface, a second surface, and a vertical axis, wherein molecules having a size less than a predetermined size can pass between the first surface and the second surface;
A first fluid compartment in fluid communication with the first surface of the membrane and containing a first fluid having a first specific gravity;
A second fluid compartment in fluid communication with the second surface of the membrane and containing a second fluid having a second specific gravity;
Means for imposing a head differential between a first fluid contained in the first fluid compartment and a second fluid contained in the second fluid compartment;
And a means for changing the second specific gravity. The means for imposing a head differential includes a first fluid compartment defining a first column height and a second fluid compartment defining a second column height;
The second column height is selected with respect to the first column height to generate a selected pressure differential across the membrane along the vertical axis with a modified second specific gravity. Submerged membrane assembly.   The submerged membrane assembly of claim 1, wherein the first column height and the second column height are each established solely by gravity.   The submerged membrane assembly of claim 1, wherein the means for imposing a head differential includes a pressure device for applying a positive pressure to the first fluid compartment.   The submerged membrane assembly of claim 1, wherein the means for imposing a head differential includes a vacuum device for applying a negative pressure to the second fluid compartment.   The immersion membrane assembly according to claim 1, wherein the means for changing the second specific gravity includes a dispersed gas added to the second fluid. The first fluid contains dissolved gas,
The dissolved gas is added to the second fluid by permeating the membrane from the first surface to the second surface and aggregating in the vicinity of the surface of the second surface or in the second fluid. 7. The immersion membrane assembly according to 6.   The submerged membrane assembly of claim 7, wherein gas dissolved in the first fluid aggregates in response to mechanical action imparted by permeating the membrane.   The submerged membrane assembly according to claim 7, wherein the gas dissolved in the first fluid aggregates in response to a pressure difference across the membrane.   The submerged membrane assembly according to claim 7, wherein the gas dissolved in the first fluid aggregates on the second surface of the membrane.   The immersion membrane assembly according to claim 7, wherein the gas dissolved in the first fluid aggregates in the second fluid.   The submerged membrane assembly of claim 1, wherein the means for changing the second specific gravity includes a gas inlet port in communication with the second fluid compartment.   The immersion membrane assembly according to claim 1, wherein the membrane is a semipermeable membrane. A membrane having a first surface, a second surface, and a vertical axis, wherein molecules less than a predetermined size are permeable between the first surface and the second surface;
A first fluid compartment in fluid communication with the first surface of the membrane and containing a first fluid having a first specific gravity at a first column height;
A second fluid compartment in fluid communication with the second surface of the membrane and containing a second fluid having a second specific gravity at a second column height;
Means for changing the second specific gravity,
A submerged membrane assembly, wherein the second column height is selected relative to the first column height to generate a selected pressure differential across the membrane along the vertical axis at a first specific gravity.   15. A submerged membrane assembly according to claim 14, wherein the means for changing the second specific gravity includes a gas added to the second fluid.   The submerged membrane assembly of claim 15, wherein the gas is added by agglomeration of a gas dissolved in the second fluid.   15. The means for changing the second specific gravity includes a gas added to the second fluid as a gas dissolved in the first fluid permeates through the membrane and aggregates in the second fluid. The immersion membrane assembly according to claim 1.   18. A submerged membrane assembly according to claim 17, wherein the gas agglomerates on at least a portion of the second surface of the membrane and polishes a portion of the membrane by rising in a second fluid. .   The submerged membrane assembly of claim 14, wherein the assembly includes a gas inlet port in communication with a second fluid compartment.   The submerged membrane assembly of claim 14, wherein the assembly includes a fluid collector that recovers fluid from a second fluid compartment.   The submerged membrane assembly of claim 14, wherein the first fluid compartment comprises a bioreactor head tank.   15. The submerged membrane assembly of claim 14, wherein the first fluid compartment includes a bioreactor saddle tank.   The submerged membrane assembly of claim 14, wherein the membrane is a semipermeable membrane.   15. The submerged membrane assembly of claim 14, wherein the membrane includes a configuration that removes particles greater than 0.05 microns.   The submerged membrane assembly of claim 14, wherein the membrane effectively excludes particles larger than 0.1 microns.   The submerged membrane assembly according to claim 14, wherein the membrane is a flat membrane.   The immersion membrane assembly according to claim 14, wherein the membrane is a hollow fiber membrane.   The submerged membrane assembly according to claim 14, wherein the first fluid comprises water.   The submerged membrane assembly of claim 14, wherein the first fluid comprises waste water. A permeable membrane having a first surface, a second surface and a vertical axis, wherein molecules less than a predetermined size are permeable between the first surface and the second surface of the membrane;
A first fluid compartment in fluid communication with the first surface of the membrane and containing a first fluid having a first specific gravity at a first column height;
A second fluid compartment in fluid communication with the second surface of the membrane and containing a second fluid having a second specific gravity and a gas at a second column height;
A submerged membrane assembly comprising a fluid collector for recovering fluid from a second fluid compartment,
The amount of gas is sufficient to adjust the second specific gravity to approximate the second specific gravity value to the first specific gravity value;
A second column height is selected with respect to the first column height to generate a selected pressure difference across the permeable membrane along the vertical axis with a modified second specific gravity. Solid.   31. A submerged membrane assembly according to claim 30, wherein the first fluid compartment includes a first fluid outflow defining a first column height.   31. The submerged membrane assembly according to claim 30, wherein the first fluid includes dissolved gas, and bubbles are formed by a portion of the gas that has permeated the membrane.   33. The submerged membrane assembly according to claim 32, wherein at least some of the bubbles agglomerate in the vicinity of or in contact with the second surface of the membrane.   32. The submerged membrane assembly of claim 30, wherein the second fluid compartment includes a gas inlet port.   31. A submerged membrane assembly according to claim 30, wherein the first column height and the second column height are each at least partially established by gravity.   31. The method of claim 30, wherein the adjusted second specific gravity value is approximately 90% or more of the first specific gravity value.   32. The method of claim 30, wherein the adjusted second specific gravity value is within approximately ± 2.5% of the first specific gravity value. Containing a first fluid having a first specific gravity;
Containing a second fluid having a second specific gravity;
Separating the first fluid and the second fluid with a permeable membrane having a first surface in fluid communication with the first fluid, a second surface in fluid communication with the second fluid, and a vertical axis;
Imposing a head differential between the first fluid and the second fluid;
Approximating the value of the second specific gravity to the value of the first specific gravity and collecting the second fluid;
The method of treating a fluid, wherein the membrane allows molecules less than a predetermined size to permeate between a first surface and a second surface.   40. The method of claim 38, wherein the adjusted second specific gravity value is within about ± 5.0% of the first specific gravity value.   40. The method of claim 38, wherein the adjusted second specific gravity value is within ± 2.5% of the first specific gravity value. Imposing the head differential includes
Containing a first fluid at a first column height;
Containing a second fluid at a second column height;
39. The second column height is selected relative to the first column height to generate a selected pressure differential across the permeable membrane along the vertical axis with a modified second specific gravity. The method described in 1.   40. The method of claim 38, wherein adjusting the second specific gravity comprises adding a dispersed gas to the second fluid. Containing a first fluid having a first specific gravity at a first column height;
Containing a second fluid having a second specific gravity at a second column height;
Separating the first fluid and the second fluid with a permeable membrane having a first surface in fluid communication with the first fluid, a second surface in fluid communication with the second fluid, and a vertical axis;
Adjusting the second specific gravity to approximate the value of the second specific gravity to the value of the first specific gravity;
Recovering the second fluid;
The membrane allows molecules less than a predetermined size to pass between the first surface and the second surface,
The second column height is selected relative to the first column height to generate a selected pressure difference across the permeable membrane along the vertical axis with a modified second specific gravity, processing fluid. how to.   44. The method of claim 43, wherein the adjusted second specific gravity value is within about ± 5.0% of the first specific gravity value.   44. The method of claim 43, wherein the adjusted second specific gravity value is within ± 2.5% of the first specific gravity value.   44. The method of claim 43, comprising flowing a first fluid in the vicinity of the first surface of the membrane.   44. The method of claim 43, wherein adjusting the second specific gravity includes adding a gas to the second fluid to change the second specific gravity.   44. The method of claim 43, wherein the first fluid comprises waste water. An improved bioreactor for wastewater treatment,
The bioreactor accepts influent water for wastewater containing biodegradable materials for treatment to produce treated water having a first specific gravity,
The improvement
A head tank fluid compartment for receiving and containing the treated water flow and removably attaching a submerged membrane assembly;
A separate second fluid compartment containing a second fluid having a second specific gravity;
Immersion membrane assembly
A molecule having a first surface, a second surface, and a vertical axis and having a size less than a predetermined size can pass between the first surface and the second surface, and the first surface is a flow of the treated water. The second surface is in fluid communication with the second fluid, and imposes a hydraulic head difference between the permeable membrane, the treated water contained in the tank, and the second fluid contained in the fluid compartment. Means to
Means for changing the second specific gravity;
An improved bioreactor for wastewater treatment comprising a fluid collector for recovering a second fluid. An improved bioreactor for wastewater treatment,
The bioreactor accepts an influent of wastewater containing biodegradable organisms for treatment to produce treated water having a first specific gravity,
The improvements are:
A tank that receives the treated water flow, accommodates the first column height, and removably attaches the submerged membrane assembly;
A second fluid compartment containing a second fluid having a second specific gravity at a selected second column height;
The immersion membrane assembly is
A molecule having a first surface, a second surface, and a vertical axis and having a size less than a predetermined size is permeable between the first surface and the second surface, and the first surface is a flow of the treated water. A permeable membrane in fluid communication with the second surface and in fluid communication with the second fluid;
Means for adjusting the second specific gravity;
A fluid collector for collecting the second fluid;
The second column height is selected with respect to the first column height to generate a selected pressure difference across the permeable membrane along the vertical axis with a modified second specific gravity, for wastewater treatment Improved bioreactor.   51. The improved bioreactor for wastewater treatment according to claim 50, wherein the stored treated water stream is exposed to normal atmospheric pressure.   51. The improved bioreactor for wastewater treatment according to claim 50, wherein the flow of treated water has undergone BOD removal.   51. The improved bioreactor for wastewater treatment according to claim 50, wherein the treated water stream has undergone BNR removal.   51. The improved bioreactor for wastewater treatment according to claim 50, wherein the treated water stream comprises dissolved gas.   51. The improved bioreactor for wastewater treatment according to claim 50, wherein a transparent tube connects the fluid compartment with the fluid collector.   51. The improved bioreactor for wastewater treatment according to claim 50, wherein the tank and membrane assembly can be removed from the head tank while treated water is contained in the tank.   51. The improved bioreactor for wastewater treatment according to claim 50, comprising a plurality of membrane assemblies.   58. The improved bioreactor for wastewater treatment according to claim 57, wherein at least one membrane assembly is positioned vertically upward of another membrane assembly.   51. The improved bioreactor for wastewater treatment according to claim 50, wherein the tank comprises a head tank of the bioreactor.   51. The improved bioreactor for wastewater treatment according to claim 50, wherein the tank comprises a saddle tank of the bioreactor. A membrane having a first surface, a second surface, and a vertical axis, wherein molecules less than a predetermined size can pass between the first surface and the second surface;
A bubble capture opening; a first membrane attachment portion in fluid communication with the first surface of the membrane; and a first chamber in fluid communication with the first membrane attachment portion and the bubble capture opening, wherein the bubble A first tubular member including a first chamber in the vicinity of the capture opening and including a rising bubble capture portion having a first vertical length;
A gas release opening; a second membrane attachment portion in fluid communication with the first surface of the membrane; and a second chamber in fluid communication with the second membrane attachment portion and the gas release opening, wherein the gas A submerged membrane diffuser comprising: a second tubular member including a second chamber including a gas storage portion in the vicinity of the discharge opening and having a vertical length shorter than the first vertical length.   62. The submerged membrane diffuser of claim 61, wherein the bubble trap defines a gas column having a vertical length that does not exceed a second vertical length of the second chamber.   64. The submerged membrane diffuser according to claim 62, wherein a gas column is formed in the bubble trap when the bubble trap captures the gas from the rising bubble.   64. The submerged membrane diffuser of claim 63, wherein the trapped gas imposes a water head on the first surface of the membrane.   64. The submerged membrane diffuser of claim 62, wherein the gas discharge opening automatically discharges gas from the second chamber when the gas column exceeds a second vertical length.   The submerged film diffuser according to claim 61, wherein the gas discharge opening discharges the gas downward. A membrane having a first surface, a second surface, and a vertical axis, wherein molecules less than a predetermined size can pass between the first surface and the second surface;
An aeration compartment containing a first fluid and rising gas bubbles;
A static fluid compartment containing a second fluid;
A fluid treatment compartment containing a fluid to be treated in fluid communication with the second side of the membrane;
A bubble capture opening disposed in the aeration compartment, a first membrane attachment portion in fluid communication with the first surface of the membrane, and a first fluid attachment portion in fluid communication with the first membrane attachment portion and the bubble capture opening. A first tubular member including a first chamber including a rising bubble capturing portion having a first vertical length in the vicinity of the bubble capturing opening;
A gas discharge opening disposed in the stationary fluid compartment, a second membrane attachment portion in fluid communication with the first surface of the membrane, and a fluid communication with the second membrane attachment portion and the gas discharge opening. A second tubular member including a second chamber, the second chamber including a gas storage portion in the vicinity of the gas discharge opening and having a second vertical length not shorter than the first vertical length. A submerged membrane diffuser assembly.   68. The assembly of claim 67, wherein the aeration compartment includes an inlet port.   68. The assembly of claim 67, wherein an air bubble forming member is disposed between the inlet port and the aeration compartment.   68. The assembly of claim 67, wherein a bubble forming means is disposed between the inlet port and the aeration compartment.   68. The assembly of claim 67, wherein the fluid to be treated includes waste water.   68. The submerged membrane assembly according to claim 67, wherein the second fluid comprises a membrane cleaning solution. A method of dispersing a gas in a target fluid,
Separating the target fluid from the gas in a permeable manner using a membrane, the membrane comprising: a first surface in contact with the gas; and a second surface in contact with the target fluid. Having permeable separation, wherein molecules of less than a predetermined size are permeable between the first surface and the second surface;
Capturing the gas by receiving a first fluid containing a rising bubble of the gas into a bubble trapping opening of a first chamber, the first chamber being in the vicinity of the bubble trapping opening, Trapping the gas, including a rising bubble trap having a vertical length;
Imposing a water head on the gas in the first chamber using the buoyancy of the gas in the first fluid to displace the first fluid from the bubble trap; and
Directing a gas flow between the bubble capture portion of the first chamber and the first membrane attachment portion of the first chamber in fluid communication with the first surface of the membrane;
Allowing at least a portion of the gas to permeate into the target liquid through the membrane;
Directing a flow of gas between a second chamber attachment portion in fluid communication with the first surface of the membrane and a second chamber, wherein the second chamber is in the vicinity of the gas discharge opening. Directing a gas flow having a portion and a second vertical length shorter than the first vertical length;
Releasing the gas through the gas discharge opening when the water head displaces a second fluid from the gas reservoir.   74. The method of claim 73, wherein the first fluid and the second fluid comprise the same gas.   75. The method of claim 73, comprising detecting gas release by observing gas bubbles released into the second fluid.   74. The method of claim 73, wherein the gas is air.   74. The method of claim 73, wherein the target fluid comprises waste water. Means for containing a first fluid having a first specific gravity at a first column height;
Means for containing a second fluid having a second specific gravity at a second column height;
Means for separating the first fluid from the second fluid, comprising: a first surface in fluid communication with the first fluid; a second surface in fluid communication with the second fluid; and a vertical axis; Means for allowing molecules less than a predetermined size to pass between the first and second surfaces;
Means for adjusting the second specific gravity to approximate the value of the second specific gravity to the value of the first specific gravity;
Means for recovering the second fluid;
The second column height is selected with respect to the first column height to generate a selected pressure difference across the permeable membrane along the vertical axis with a regulated second specific gravity. Solid. Means for separating the first fluid from the gas, having a first surface, a second surface and a vertical axis, wherein molecules less than a predetermined size are permeable between the first surface and the second surface;
A bubble capture opening, a first attachment in fluid communication with the first surface of the means for separating, and a first chamber in fluid communication with the first attachment and the bubble capture opening, A first means for fluid communication comprising a first chamber in the vicinity of the bubble trapping opening and including a rising bubble trapping portion having a first vertical length;
A gas release opening, a second mounting portion in fluid communication with the first surface of the means for separating, and a second chamber in fluid communication with the second mounting portion and the gas discharge opening, A second means for fluid communication including a second chamber including a gas storage portion in the vicinity of the gas discharge opening and having a second vertical length shorter than the first vertical length. Qi device.

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