KR20240102958A - biological treatment device - Google Patents

Abstract

A biological treatment device comprising: (a) a vessel; (b) an inlet conduit for providing feed water to the inlet area; (c) an outlet conduit for removing treated water from the outlet area; (d) an inlet distributor comprising an inlet duct, each of which is in fluid communication with both an inlet region and a porous surface section of the inlet duct wall; (e) an outlet distributor comprising a plurality of outlet ducts, each in fluid communication with both the outlet region and the porous surface section of the outlet duct wall; and (f) a media bed comprising particles in fluid communication with porous surface sections of both the inlet duct wall and the outlet duct wall; The ratio of the length of the inlet duct to the minimum distance between the inlet and outlet ducts is between 15:1 and 2:1.

Description

biological treatment device

Cross-reference to related applications

This is an international application claiming the benefit of priority to European Patent EP 202130908, filed on September 28, 2021, the entire contents of which are incorporated herein by reference.

It is often necessary to remove impurities from water using purification processes such as ultrafiltration (reverse osmosis or nanofiltration). One common difficulty in such purification processes is biofouling, which is the growth of bacteria in the device. For example, if the purification process involves passing water through a membrane, the growth of a biofilm may occur on the membrane.

Biological treatment systems have been used to pretreat water prior to ultrafiltration. These systems typically remove oxygen from the water and elements of the water that are conducive to microbial growth, such as nutrients, such as organic carbon, nitrates, and phosphates, creating an unfavorable environment for the growth of microorganisms within the ultrafiltration module. For example, US10301206B1 discloses a biological treatment device comprising a particulate bed configured to allow water to flow through the particulate bed before entering the reverse osmosis unit. There is a need to provide improved methods for pretreating impure water.

The following is a description of the present invention.

The present invention relates to biological treatment devices. These devices are:

(a) container;

(b) an inlet conduit for providing feed water to the inlet area of the vessel;

(c) an outlet conduit for removing treated water from the outlet area of the vessel;

(d) a plurality of inlet ducts in the vessel, each of the inlet ducts comprising an inlet duct wall surrounding a first flow channel, wherein the first flow channel communicates fluid with both the inlet region and the porous surface section of the inlet duct wall. a plurality of inlet ducts, in communication;

(e) a plurality of outlet ducts within the vessel, each of the outlet ducts comprising an outlet duct wall surrounding a second flow channel, the second flow channel being configured to flow fluid with both the outlet region and the porous surface section of the outlet duct wall. a plurality of outlet ducts in communication; and

(f) a media bed located within the vessel, the media bed comprising a particulate media bed positioned within the vessel, the media bed being in fluid communication with a porous surface section of both the inlet duct wall and the outlet duct wall. media bed, containing particles

Including,

The ratio of the length of the inlet duct to the minimum distance between the inlet duct and the outlet duct is between 15:1 and 2:1.

The following is a brief description of the drawing.
1A and 1B show top and side views, respectively, of an embodiment of the invention within a cylindrical container.
Figure 2 shows an embodiment of the invention.
3 shows the biological treatment device and downstream components.

The following is a detailed description of the present invention.

As used herein, the following terms have the defined definitions unless the context clearly dictates otherwise.

As used herein, “resin” is synonymous with “polymer.” Unless otherwise specified, all percentages are by weight. Vinyl monomers have non-aromatic carbon-carbon double bonds that can participate in free radical polymerization processes. Vinyl monomers include, for example, styrene, substituted styrene, dienes, ethylene, ethylene derivatives, and mixtures thereof. Monofunctional vinyl monomers have exactly one polymerizable carbon-carbon double bond per molecule. Multifunctional vinyl monomers have two or more polymerizable carbon-carbon double bonds per molecule.

Category “acrylic monomers” include acrylic acid; methacrylic acid; Substituted or unsubstituted alkyl esters of acrylic acid or methacrylic acid; and acrylonitrile. As used herein, a “vinyl aromatic monomer” is a vinyl monomer containing one or more aromatic rings.

A polymer is a vinyl polymer wherein at least 90% (preferably at least 95%, preferably at least 99%) of the polymerized units, based on the weight of the polymer, are polymerized units of one or more vinyl monomers. The vinyl aromatic polymer may comprise at least 50% by weight (preferably at least 80%, preferably at least 90%, preferably at least 95%) of the polymerized units, based on the weight of the polymer, of one or more polymerized units of vinyl aromatic monomer. It is a phosphorus polymer.

A resin is considered to be crosslinked herein if the polymer comprises polyfunctional vinyl monomer polymerized units, i.e., if the polymer comprises at least 1% polyfunctional vinyl monomer polymerized units. For beads, the weight of polymer is considered to be the dry weight of the bead. The resin beads may contain typical functional groups used for ion exchange, or may be non-functionalized “adsorptive” resin.

The degree to which a particle is spherical is characterized by its sphericity (Ψ), which is defined using the three main orthogonal axes of the object: a (longest), b (middle) and c (shortest) as follows: Ψ = c/a.

“Roundness” (R) is defined as the ratio of the average radius of curvature of the corners and edges of the silhouette to the radius of the largest circle that can be inscribed within the silhouette of the object. Sphericity and circularity are determined according to the literature [H. Waddell, The Journal of Geology, vol. 41, pp. 310-331 (1933)], described in more detail. The minimum dimension of a particle is the shortest distance across the particle that passes through the center of mass (for example, this minimum dimension is the same as the diameter for both spherical particles and elongated cylindrical bodies, but it is may be the same as the thickness).

As impure feed water flows through the media bed, biomass can form on the surface. Biofilms may form, comprising dead cells, living cells, and extracellular polymeric substances (EPS). As the biofilm continues to grow, it can increase flow resistance for fluid moving through the media bed. At the same time, biofilm within the media bed can deplete assimilable nutrients in the feed water.

The biological treatment device 10 of the present invention reduces the potential for biological growth downstream by treating impure water, referred to herein as “feed water.” One such embodiment is shown in FIGS. 1A and 1B. The depicted apparatus includes a vessel (12) having a media bed (14), an inlet duct (16), and an outlet duct (18). The feed water passes through the media bed 14 and primarily travels through the media bed 14 from an opening in the inlet duct 16 to an opening in the outlet duct 18. The pressure drop and flow associated with the feed water passing through vessel 12 can be monitored.

As the microorganisms grow, the resistance to flow through the media bed 14 increases, resulting in reduced flow at the same pressure differential or through the inlet conduit 20 and outlet conduit 22 to achieve the desired flow. The pressure difference between them increases. (Resistance to flow is approximately proportional to the pressure drop across the media bed 14 and inversely proportional to the measured flow. More precisely, it is defined as the pressure drop per unit distance divided by the velocity. The measured resistance value (R Since =ΔP/d/v) depends on velocity, resistance to flow is defined herein for short distances with an average superficial velocity of 1 cm/sec, and therefore it is not an operating condition. During normal operation of the device of the present invention, by measuring the pressure drop across the medium, by measuring the absolute pressure downstream of the biocontactor, or by measuring changes in flow rate. Monitoring the formation of biomass may be considered. Other methods of quantifying biomass include measuring the consumption of dissolved oxygen or phosphorus by the biomass, measuring the consumption of nutrients other than phosphate, such as nitrogen and carbon; and measurements of bioassimilable carbon and BOD.

In a preferred embodiment, media bed 14 comprises particles with a minimum dimension greater than 0.1 mm. More specifically, particles with a minimum dimension greater than 0.1 mm have a median minimum dimension between 0.2 mm and 6 mm. Preferably, particles with a minimum dimension greater than 0.1 mm have at least the median minimum dimension of the medium as measured by measurement of absolute pressure downstream of the biocontactor, or measurement of change in flow rate. Other methods of quantifying biomass include measuring the consumption of dissolved oxygen or phosphorus by the biomass, measuring the consumption of nutrients other than phosphate, such as nitrogen and carbon; and measurements of bioassimilable carbon and BOD.

In a preferred embodiment, media bed 14 comprises particles with a minimum dimension greater than 0.1 mm. More specifically, particles with a minimum dimension greater than 0.1 mm have a median minimum dimension between 0.2 mm and 6 mm. Preferably, particles with a minimum dimension greater than 0.1 mm have a median minimum dimension of at least 0.95, with the median dimension in accordance with the restrictions regarding minimum dimension medians described in this paragraph. For non-spherical particles, the diameter is the diameter of a particle with the same volume.

Preferably, the media particles are made of glass, metal or polymer. Preferably, the media particles are resin beads. The resin beads may contain common functional groups used for ion exchange (e.g., sulfonate, carboxylate, amino, quaternary amino), but are preferably non-functionalized “adsorptive” resins. Preferably, the resin beads are polymerized acrylic monomers, polymerized vinyl aromatic monomers, or a polymerized combination of acrylic and vinyl aromatic monomers. Preferably, the media bed 14 has a packing density of 50 to 75%, calculated by dividing the volume of media particles by the total bed volume, i.e., excluding biofilm. Preferably, the height of the media bed 14 at any point does not vary more than 20%, preferably more than 15%, from the arithmetic mean height of the bed.

Inlet conduit 20 provides feed water to inlet region 24. In the embodiment of FIG. 1B , inlet conduit 20 is a spigot above vessel 12 and provides a continuous or periodic flow of feed water into vessel 12 to maintain the desired range within vessel 12. Maintain the supply water level. In a similar embodiment, inlet conduit 20 may be submerged within vessel 12 so that its ends are not connected to vessel 12 or components within vessel 12. Alternatively, as shown in FIG. 2, inlet conduit 20 may preferably be attached to a physical structure, such as a port within vessel 12 or a pipe having a number of holes defining inlet region 24. there is. In the preferred geometry, the vessel water level is maintained above the particle bed and below the vessel wall level. The water level control means 28 may include a spill way, an actuated float valve, or a computer controlled flow regulator.

Inlet conduit 20 provides feed water to inlet region 24, which may distribute feed water to various inlet ducts 16 within vessel 12. Inlet region 24 may be located inside or outside vessel 12, or may be located partially in each, although inlet region 24 may act as a manifold for several inlet ducts 16. In some preferred embodiments, inlet region 24 is created by a physical device or pipe, connected to inlet conduit 20 and having individual holes and connections suitable for attachment to individual inlet ducts 16. In another preferred embodiment, inlet region 24 may be an open section of vessel 12 where a plurality of inlet ducts 16 are exposed. An example of this is shown in Figure 1, where a plurality of inlet ducts 16 extend above the media bed 14, allowing feed water to flow from the inlet conduit 20 into each inlet duct 16 with low resistance. Let it happen. The resistance to flow through the inlet region 24 (ascertained through pressure drop for a particular flow velocity and path geometry) will be greater than that for flow through a similarly shaped section containing particles in the media bed 14. It is important to be much smaller than the resistance. Preferably, during operation, the average resistance to flow through the inlet region 24 is less than 10% of the resistance to flow through the media bed 14 for a similarly sized path and distance. Usually it is less than 5% or even less than 1%. In another embodiment, the average distance to the nearest surface within the inlet region 24 is greater than the median particle diameter within the media bed 14, more preferably at least 1 mm, even more preferably at least 10 mm. Particles in media bed 14 separate inlet duct 16 and outlet duct 18. Multiple flow paths between the particles exist through the media bed 14 between the inlet and outlet ducts.

Each inlet duct 16 includes an inlet duct wall 50 surrounding a first flow channel 54 in fluid communication with both the inlet region 24 and the porous surface section 58 of the inlet duct wall 50. do. Likewise, each outlet duct 18 includes an outlet duct wall 52 surrounding a second flow channel 56 in fluid communication with both the outlet region 26 and the porous surface section 60 of the outlet duct wall. . Particles within the media bed are in fluid communication with porous surface sections 58, 60 of both the inlet and outlet duct walls 50, 52. Because there is much greater resistance to flow through the media than through the inlet or outlet ducts, placing multiple inlet and outlet ducts 16, 18 allows for many short paths through the media bed 14. It becomes. The main path through which the medium passes between the inlet duct and the adjacent outlet duct 18 is preferably shorter than the length of either the inlet or outlet duct 18. In a preferred embodiment, the average distance between the inlet duct 16 and its nearest outlet duct 18 is less than 50% of the average length of the inlet duct 16. More preferably, the average distance between any inlet duct and its nearest outlet duct 18 is less than 50% of the inlet duct.

Preferably, the biological treatment system includes a plurality of parallel inlet ducts (16) and a plurality of parallel outlet ducts (18). Most preferably, the inlet duct 16 is also parallel to the outlet duct 18. For purposes of this description, it is assumed that the parallel inlet duct 16 and outlet duct 18 are oriented in the same direction within about 10°. In a preferred embodiment, at least one set of parallel inlet ducts 16 or parallel outlet ducts 18 are oriented within 10° of the vertical, such that the length of these ducts approximately matches their height.

The ratio of the length of the inlet duct to the minimum distance between the inlet duct and the outlet duct 18 is 15:1 to 2:1, preferably 12:1 to 3:1, preferably 10:1 to 4:1. . Preferably, the inlet duct 16 and outlet duct 18 are substantially vertical (e.g., within 15° of vertical, within 10° of vertical, within 5° of vertical); In this case the minimum distance between the inlet duct and the outlet duct 18 is measured horizontally. Preferably, the ratio of the number of inlet ducts 16 to the number of outlet ducts 18 is 2:1 to 1:2, preferably 1.5:1 to 1:1.5, preferably 1.2:1 to 1:1. It is 1.2. Preferably, the number of inlet ducts 16 is 5 to 500; preferably at least 8, preferably at least 10; Preferably it is 300 or less, preferably 200 or less, preferably 100 or less, preferably 50 or less. Preferably, the total volume of ducts and conduits is no more than 20%, preferably no more than 10%, of the volume of media bed 14. Preferred materials of construction for ducts and conduits include metals, polymers, and polymers with inorganic fillers (e.g., glass fibers (fiberglass) or mineral particles); Preferably they include polymers and polymers with inorganic fillers. Preferred polymers include, for example, polyethylene and polypropylene.

The shape of the duct is not critical, but it is preferred that its cross-section be circular, square or rectangular. (In FIG. 1A the duct is shown as cylindrical, but in FIG. 2 the shape of the duct is not specified.) In a preferred embodiment of the invention, the duct has a narrow rectangular cross-section, such that the duct has the appearance of a plate. For example, the thickness of the duct is 25% or less, preferably 20% or less, preferably 15% or less, preferably 10% or less of the next smallest dimension. Preferably, the largest side of the duct is within 10% of vertical, preferably within 5%, i.e. the angle between the side of the duct and the top of the media bed 14 is within this percentage relative to 90°. , a duct with a narrow rectangular cross-section is arranged. Preferably, in ducts having a narrow rectangular cross-section, the number of ducts is 3 to 50; Preferably at least 5, preferably at least 7, preferably 40 or less, preferably 30 or less. The duct is porous, that is, it has openings that allow water to flow outside the duct and into the media particles (in the case of the inlet duct 16) or to allow water to enter from the medium (in the case of the outlet duct). The size of the openings is not critical, but preferably the openings have a minimum dimension that is smaller than 99% of the particles in the media bed 14, preferably smaller than 99.9% of the particles in the media bed 14. In a preferred embodiment, the porous region within the duct has openings that prevent particles of 0.1 mm diameter from passing through.

Outlet region 26 acts as a manifold for connecting a plurality of outlet ducts 18 to outlet conduit 22. Like inlet region 24, outlet region 26 may be located inside or outside of vessel 12, or may be located partially inside each. In some preferred embodiments, outlet region 26 is created by a physical device or pipe, connected to outlet conduit 22 and having individual holes and connections suitable for attachment to individual outlet ducts 18. In another preferred embodiment, outlet region 26 may be an open section of vessel 12 exposing a plurality of outlet ducts 18 , which are connected to outlet conduits 22 . As with the inlet region 24, the resistance to flow through the outlet region 26 (ascertained through the pressure drop for a particular flow velocity and path geometry) is similar to that of the inlet region 26 containing particles in the media bed 14. It is important that the resistance to flow through a section of the geometry is much smaller. Preferably, during operation, the average resistance to flow through outlet region 26 is less than 10% of the resistance to flow through media bed 14 for a similarly sized path and distance. Usually it is less than 5% or even less than 1%. In another embodiment, the (volume) average distance to the nearest surface in outlet region 26 is greater than the median particle diameter in media bed 14, more preferably at least 1 mm, even more preferably at least 10 mm. .

Preferably, the outlet conduit 22 of the biological treatment device 10 is located upstream and in fluid communication with an ultrafiltration system 31 comprising at least one ultrafiltration module 32. The term "fluid communication" is defined herein as the existence of a continuous path from one piece of equipment to another, and the entire path need not always be filled with fluid, for example a path through a pump. Two articles separated by a pump may be in fluid communication even if some of them are sometimes not filled with fluid. The biological treatment device 10 may include nutrients, such as components of water that are conducive to microbial growth, such as organic carbon, nitrate, and phosphate; and oxygen removal, thereby reducing microbial growth on the ultrafiltration membrane. Preferably, the ultrafiltration system 31 comprises at least one pump, preferably a high pressure pump 34, between the biological treatment device 10 and the ultrafiltration module 32. Preferably, the high pressure pump used in this configuration is capable of providing pressurized feed to the ultrafiltration module.

More short processing paths through the medium make it possible to operate with lower pressure drops. Preferably, the biological treatment device 10 is configured to allow flow through the device through gravity alone. Preferably, the biological treatment device does not use a pressurized feed source or pressure vessel. Preferably, gravity provides at least 80% of the outward force exerted on the container wall. In a preferred embodiment, suction from the downstream low pressure pump 36 may provide additional pressure differential (less than 1 atmosphere) between the inlet conduit 20 and outlet conduit 22. Preferably, the pressure difference between inlet conduit 20 and outlet conduit 22 is less than 2 atmospheres and more preferably less than 1 atmosphere. Preferably, the downstream low pressure pump 36 creates at least one-third of the pressure differential across the media bed 14.

A downstream pump low pressure 36 may be used to draw flow from the outlet conduit 22 or pressurize the flow from the outlet conduit 22 of the device, but preferably forces water into the inlet distributor, media bed 14. , and no pump is used at the inlet to pass the outlet distributor. Preferably, the inlet conduit 20 is at a higher vertical position than the outlet conduit 22. Preferably, the inlet conduit 20 is within or above the top 20% of the vessel (i.e., the vertical distance from the bottom of the vessel 12 is at least 80% of the height of the vessel), preferably within or above the top 10%. It is located above. Preferably, outlet conduit 22 is located within or below the lower 10%, preferably 5%, of vessel 12. Preferably, the device includes level control means for maintaining the liquid level in the vessel 12 within a desired range. The preferred water level control means 28 comprises a water level sensor coupled to the water intake valve, and a pressure sensor coupled to the water intake valve to measure the pressure drop across the device.

Preferably, the path between the outlet conduit and the downstream ultrafiltration module 32 is sealed to prevent the introduction of oxygen, which may itself be a limiting reagent for biological growth. The vessel containing the media bed is preferably not suitable for excessive pressurization (e.g. greater than 1 bar relative to atmospheric pressure) and in some embodiments may be an open tank. However, the container may be sealed to prevent contact with air. For example, the cover shown in Figure 2 can prevent air exchange even without pressurizing action. Shroud 30 extending into and down the line of water may restrict the movement of air and likewise restrict oxygen exchange into the water.

Preferably, the device includes means for distributing gas 38 through the media bed 14 to displace particles within the media bed 14 and eliminate growing microorganisms in the media bed 14. Preferably, the gas is air, oxygen-depleted air, nitrogen or a noble gas; Preferably it is air, oxygen-depleted air or nitrogen. Preferably, the means for distributing the gas 38 is a distributor having a plurality of pipes and openings (e.g. a fractal distributor or other known distributor used to distribute the flow in a vessel) or It contains several ports near the bottom of the vessel for introducing gas. In a preferred embodiment, the device comprises means for introducing a chemical agent, alone or in combination with a gas, to eliminate growing microorganisms. Preferred chemical agents include bleach and alkalis (NaOH, KOH). Preferably, the means for introducing the chemical agent are the same as the means for dispensing the gas, as described above, but these means should be compatible with the agent used; This can be easily determined through charts of chemical compatibility for various constituent materials.

In some preferred embodiments, the device is configured such that excess growth of microorganisms can be removed from the surface of the duct through mechanical movement of the duct or parts adjacent to the duct relative to the media bed 14. For example, the ducts can be raised or rotated relative to the media bed 14, for example by rotation of cylindrical ducts or translation of rectangular ducts, individually or together. Additionally, the blade can be used to scrape off the surface of the duct any microorganisms that have grown and attached to the particles, especially in the case of ducts (plates) with a narrow rectangular cross-section. Preferably, this mechanical movement against the media bed 14 is used to remove particles and biofilm, especially from the external surface of the inlet duct 16. In a preferred embodiment, the vessel 12 further includes a waste removal conduit 48 connected to the vessel for discharge of waste.

Preferably, the device includes a plurality of similarly configured media beds (14), inlet and outlet ducts (16, 18), inlet and outlet regions (24, 26), and inlet and It further includes a parallel vessel (12) with outlet conduits (20, 22). Outlet conduits 22 from each of the plurality of parallel vessels 12 may provide treated feedwater to the same ultrafiltration system 31 . Via the isolation valve 40, a subset of the plurality of parallel vessels 12 can be isolated from other subsets for cleaning purposes. Preferably, the device allows at least one of the vessels 12' to remain unused for any specified period of time while the remaining vessels 12 are activated and sufficient to handle the desired water treatment rate and to promote overgrowth of microorganisms. It includes a plurality of vessels 12, sufficient to enable a cleaning process to be removed.

In some embodiments, a particle filter 46 is disposed between the outlet conduit and the at least one ultrafiltration module.

In some preferred embodiments, effluent from a plurality of parallel vessels 12 containing media for biological treatment is transferred to a downstream container surrounding resin beads containing phosphate removal resin 42, e.g., precipitated iron oxide. You can send it to This subsequent container is preferably located after the vessel 12 containing the media for biological treatment and before the ultrafiltration module 32. Containers for phosphate removal resins can, for example, be pressurized to suit operation above 2 bar.

Biological treatment device 10 includes a plurality of flow paths 44 through vessels 12, each vessel 12 comprising: an inlet conduit 20, an inlet region 24, an inlet duct 16, and a medium. It is configured to sequentially pass through each of the bed 14, the outlet duct, the outlet area 26, and the outlet conduit 22. Multiple flow paths 44 through vessel 12 simultaneously allow for slower velocities and shorter paths, thereby providing similar residence times for species moving through vessel 12, thereby allowing downstream In the ultrafiltration system 31, most assimilable materials that are prone to fouling can be removed. At the same time, larger amounts of feed fluid can be processed with the same pressure drop compared to feed fluid passing through the medium without inlet and outlet ducts 16, 18. In a preferred embodiment, the combined cross-sectional area of all vessels 12 containing the resin is less than the combined cross-sectional area of all housings (pressure vessels) containing ultrafiltration modules 32 in the first step after biological treatment.

The invention also relates to a method for treating water using the biological treatment device 10 described herein, preferably having one or more of the preferred limitations described herein for the device. Preferably, the feed water entering the device through the inlet conduit 20 is not pressurized and is at or below 5% of the normal atmospheric pressure at which the device is located. Preferably, the pressure difference between the inlet conduit 20 and the outlet conduit 22 is between 0.25 bar and 2 bar, more preferably between 0.5 bar and 1.5 bar. Preferably, the average residence time within vessel 12 is less than 1 minute, preferably 1 to 30 seconds; preferably at least 2 seconds, preferably at least 3 seconds; Preferably it is 20 seconds or less, preferably 15 seconds or less. Preferably, the biological treatment device 10 operates at ambient temperature, preferably within 10°C, preferably within 20°C, but preferably above 5°C. Preferably, the resistance to flow throughout the device (pressure difference between inlet conduit 20 and outlet conduit 22 divided by flow) is at least as small as from its initial value (on initial start-up or after a previous cleaning step). If there is an increase of 10%, preferably at least 20%, preferably at least 30%, overgrown microorganisms are removed from the biological treatment device 10. For this resistance measurement, the flow and pressure difference can be determined to be 0.5 bar between the inlet conduit 20 and the outlet conduit 22. For example, if the system is operating at constant flow, the resistance is proportional to the observed pressure drop across the medium between the inlet conduit 20 and outlet conduit 22. Preferably, the device can be cleaned with chemicals after the pressure difference between the inlet conduit 20 and the outlet conduit 22 exceeds a predefined value.

Preferably, overgrowth is removed by passing gas through the media bed 14 using a distributor or port, as described above.

In a preferred embodiment of the method, a chemical agent as described above is added to vessel 12 to remove overgrowth of microorganisms. Preferably, in more intensive cleanings, the chemical agent is heated to at least 40° C., more preferably to 50° C. In another embodiment, an inoculation of biological cells is provided to the biological processing device 10 after washing.

Claims (14)

As a biological treatment device,
(a) container;
(b) an inlet conduit for providing feed water to the inlet region of the vessel;
(c) an outlet conduit for removing treated water from the outlet area of the vessel;
(d) a plurality of inlet ducts within the vessel, each of the inlet ducts comprising an inlet duct wall surrounding a first flow channel, the first flow channel comprising an inlet region and a porous surface section of the inlet duct wall. a plurality of inlet ducts, all in fluid communication;
(e) a plurality of outlet ducts within the vessel, each of the outlet ducts comprising an outlet duct wall surrounding a second flow channel, the second flow channel comprising an outlet region and a porous surface section of the outlet duct wall. a plurality of outlet ducts, all in fluid communication;
(f) a media bed located within said vessel, comprising particles in fluid communication with porous surface sections of both the inlet duct wall and the outlet duct wall.
Including,
A biological treatment device wherein the ratio of the length of the inlet duct to the minimum distance between the inlet duct and the outlet duct is from 15:1 to 2:1. According to paragraph 1,
wherein the media bed comprises particles having a minimum dimension greater than 0.1 mm, and the particles having a minimum dimension greater than 0.1 mm also have a median minimum dimension between 0.2 mm and 6 mm. According to paragraph 1,
The outlet conduit is located upstream and in fluid communication with an ultrafiltration system comprising at least one ultrafiltration module, the ultrafiltration system comprising at least one pump between the biological treatment device and the at least one ultrafiltration module. and wherein the at least one pump is capable of providing pressurized feed to the at least one ultrafiltration module. According to paragraph 3,
A plurality of pumps are positioned between the biological treatment device and the at least one ultrafiltration module, wherein at least one of the plurality of pumps induces a greater differential pressure between the inlet conduit and the outlet conduit to thereby increase flow through the media bed. A biological treatment device suitable for increasing . According to paragraph 3,
Preventing treated water between the outlet conduit and the at least one ultrafiltration module from contacting atmospheric oxygen. According to paragraph 1,
wherein the particles have a sphericity of at least 0.90 and a median diameter of 0.2 mm to 2 mm. According to paragraph 1,
A biological treatment device, further comprising an air distributor suitable for supplying air bubbles that mix particles in the media bed. According to paragraph 1,
A biological treatment device, further comprising a waste removal conduit connected to the vessel for discharge of waste. According to paragraph 1,
A biological treatment device, further comprising water level control means for maintaining the level of liquid in the vessel within a specific range. According to clause 4,
The biological treatment device further comprising a particle filter between the outlet conduit and the at least one ultrafiltration module. According to clause 4,
The biological treatment device further comprising a resin suitable for removing phosphate positioned between the outlet conduit and the at least one ultrafiltration module. According to clause 4,
A biological treatment device, further comprising a plurality of parallel vessels containing media, and a valve suitable for isolating at least one of the plurality of parallel vessels. According to clause 4,
A biological treatment device further comprising biocontactor units operated in parallel, wherein one biocontactor unit is occasionally taken out of service for cleaning. According to paragraph 1,
The biological treatment device of claim 1, wherein the particles have a packing density of 50 to 75%.