KR100460942B1 - Process for Treating Waste Water and Device Thereof Using Septic Tank and Sequencing Batch Reactor - Google Patents

Abstract

PURPOSE: To provide a process for treating wastewater, which is able to perform an advanced treatment of the wastewater without treating sludges for a long period of time by using a septic tank and a sequencing batch reactor, a device therefor. CONSTITUTION: The device comprises a septic tank (100) that treats wastewater anaerobically and a sequencing batch reactor (200) that treats the wastewater supplied from the septic tank aerobically. The septic tank includes a sludge isolation wall (114), a first septic chamber (120) that anaerobically ferments deposited sludges, a second septic chamber (130) that anaerobically digests the wastewater that is flown over the sludge isolation tank and an oil collection chamber (140) that is divided by an oil isolation wall (115) to accumulate the oil contained in the wastewater. The sequencing batch reactor includes a device for agitating and aerating the wastewater (211), a treated water discharge device (212) that discharges purified treated water to the outside after activated sludge is deposited and a remaining sludge return device (213) that returns the remaining sludge to the septic tank.

Description

Process for Treating Waste Water and Device Thereof Using Septic Tank and Sequencing Batch Reactor

(Technology)

The present invention relates to a sewage treatment method and apparatus, and more particularly, to a sewage treatment method and apparatus using a continuous batch reaction tank which is a digestion tank and a biological reaction tank.

(Background)

Various sewage is generated in various facilities such as houses, apartments, shopping malls, schools, and amusement parks. Such sewage has long been treated using a decay tank, which is a kind of septic tank.

A decay tank is a kind of pretreatment facility that does not require any mechanical maintenance other than just cleaning to remove sludge after a fixed period of use, and decomposes solids by collecting them by gravity precipitation and digesting them in anaerobic conditions for about one year. Process. The decay tank does not require mechanical devices such as screens, organics and insoluble solids are settled in the tank and the suspended solids are held in the form of a scum on top by the septum.

Under more stringent water quality control, effluents discharged from decay tanks are not discharged to rivers or rivers, but are discharged after passing through secondary treatment facilities, such as abandoned facilities. Most of these secondary treatment facilities are biological treatment facilities utilizing fixed bed media and aerobic bacteria.

However, this secondary treatment facility not only has a problem of clogging media due to inflow of sand, soil, grease, etc., but also a problem of maintenance of the facility, a problem that cannot remove substances causing eutrophication such as nitrogen or phosphorus, etc. As a result, today's more stringent advanced treatment is no longer an option for sewage treatment.

In addition, in the conventional treatment facility that combines the decay tank and the secondary treatment facility, it is inconvenient to periodically remove and clean the sludge in order to avoid the sludge deposited in the decay tank into the secondary treatment process.

As the first activated sludge system using the inflow-discharge method, there is a continuous batch sewage treatment method using a sequencing batch reactor, which is one of biological systems. The continuous batch sewage treatment method is not used very much, but it has been reactivated since the 80's due to the development of automated facilities.

The continuous batch sewage treatment method is an advanced treatment method for biological control that can simultaneously achieve the secondary and tertiary treatment objectives in a single reaction tank. Nitrogen and phosphorus can be removed as well as oil.

Bacterial activity in the continuous batch sewage treatment method is based on anoxic conditions, which means that there is no free dissolved oxygen available except in the form of nitrates, simply by using a timer, and anaerobic conditions in which free oxygen is not available even in the form of nitrates in sewage. Regardless of the conditions and the presence of nitrates, it can be controlled to aerobic conditions that can use free dissolved oxygen in sewage.

Continuous batch sewage treatment methods are constantly being investigated for all the possibilities raised by all processes that can be controlled, such as influent quality, inlet mode, reaction time, and dominance of biological reactions.

One of the advantages of the continuous batch sewage treatment method is that the inflow mode can be used to control the activity of bacteria as well as sedimentation. In other words, it is well known that activated sludge can be easily separated by simple gravity sedimentation by allowing a large number of bacteria to grow in a given reactor.

For example, the rapid introduction of new feeds into the reactor can observe very effective biological selection effects, which allows for the efficient separation of activated sludge and the effluent being very clean. This type of inflow mode also offers several other benefits, such as enhanced activity, which is desirable for the removal of organic materials, which is related to the amount of organic material that bacteria can use for food at any given time during actual operation. have. This combination of supply mode and enhanced activating power saves time in achieving overall sewage organics capacity.

The present inventors have completed the present invention on the basis of the technique related to the decay tank as described above and the technique related to the continuous batch reactor, the basic principle of which is already known, and it is expected that a very reliable sewage treatment system can be provided. .

It is an object of the present invention to provide a sewage treatment method and apparatus capable of highly treating sewage without treating sludge, which is a by-product generated in sewage treatment, for a long period of more than five years.

1 is a side schematic view of an exemplary sewage treatment apparatus according to the present invention;

2 is a schematic top view of an exemplary sewage treatment apparatus according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: sewage treatment apparatus 100 of the present invention: digester

111: inlet line 112: outlet line

113: floor 114: sludge isolation wall

115: oil separation wall 116: treated water separation wall

120: 1 fire hydrant 130: 2 fire hydrant

140: oil collection chamber 200: continuous batch reactor

211: Stirring and aeration device 212: Treatment water discharge device (line)

213: surplus sludge conveying apparatus (line) 214: treated water conveying apparatus (line)

300: sewage feeder 400: in-discharge tank

411: in-removal device 500: control device

According to the present invention, there is provided a sewage treatment method for treating sewage by combining a biological reaction tank such as a digestion tank and a continuous batch reactor.

In the sewage treatment method according to the present invention, supplying the sewage to be treated to the digester, accumulating the sewage in the digester, maintaining the scum formed in the upper part of the sewage in the upper part of the digester and the sedimentable solids are settled downward as sludge Biologically treating the sewage and sludge in the digestion tank under anaerobic conditions, transferring the amount of treated water from the digester to a continuous batch reactor containing sludge, stirring and abandoning the sewage in the continuous batch reactor. Activating the sludge and purifying the sewage, stopping the stirring and aeration for a predetermined time to settle the dispersed sludge, discharging the purified water of the sludge upper layer after the predetermined time settling, into the continuous batch reactor Removing the excess sludge formed, and the continuous batch reaction The excess sludge removed from is characterized by including the step of transferring to said digester further digested under anaerobic conditions.

Preferably, the digester has a sludge isolation wall extending from the bottom to the upper part, and the sludge isolation wall is divided into a digestion chamber 1 in which sludge is deposited and anaerobic fermentation and a digestion chamber in which sewage is anaerobic digested. The sewage of the digester flows from the first chamber to the second chamber beyond the sludge isolation wall.

Preferably, the transfer of sewage from the digester to the continuous batch reactor may be selected to be transferred from the digestion 1 chamber or from the digestion 2 chamber, depending on the conditions of the treated sewage.

According to the present invention, a sewage tank comprising a digestion tank in which anaerobic fermentation of sediment sludge and anaerobic digestion of sewage takes place, and a continuous batch reactor for biologically highly treating the sewage supplied from the digestion tank through a sewage feeder under aerobic conditions. A processing device is provided.

The digester is located in a sludge isolation wall extending from the bottom to an upper portion of the sludge isolation wall, and a digestion chamber 1 in which sludge is deposited and anaerobic fermentation takes place, and located downstream of the sludge isolation wall to provide the sludge isolation wall. Oil that separates the sewage from the sewage that flows through the anaerobic digestion chamber and the oil separation wall extending downward from the upper side of the digestion chamber so that the oil contained in the sewage accumulates upstream of the digestion chamber. Includes collection room.

The continuous batch reactor includes a device for agitating and abandoning sewage, a treated water discharge device for discharging the purified water from the upper layer after the sludge settled out, and an excess sludge conveying device for conveying excess sludge to the digester.

That is, the digester is provided with the isolation wall from the bottom to the inside of the digester so that the digester is divided into primary and secondary reaction zones, and sludge flowing together with the sewage flows into the digestion 1 chamber, precipitates, and accumulates, so that anaerobic fermentation is performed. Precipitated solids are anaerobically digested in the second digestion chamber. Inflow of sewage flows through the sludge isolation wall from the fire extinguishing chamber 1 and flows into the fire extinguishing chamber 2. The sewage treated under anaerobic conditions in the digestion chamber 2 is transported for treatment in the continuous batch reactor, which is a biological reactor.

Hereinafter, with reference to the accompanying drawings will be described in detail the sewage treatment method and apparatus according to the present invention. The following embodiments are merely illustrative of the sewage treatment method and apparatus according to the present invention, but are not intended to limit the scope thereof.

1 is a side schematic view of an exemplary sewage treatment apparatus according to the present invention, and FIG. 2 is a top schematic view of an exemplary sewage treatment apparatus according to the present invention.

As shown in FIG. 1, the sewage treatment apparatus 1 of the present invention in which the sewage treatment method according to the present invention is implemented includes a digestion tank 100 and a continuous batch reactor 200 which is a biological reaction tank. In addition, the sewage treatment apparatus 1 of the present invention also includes a sewage transport apparatus 300 such as a pump for transferring sewage from the digester 100 to the reactor 200. Each will be described in detail below.

1.Digester

As shown in FIG. 1, sewage is introduced into the digester 100 through the inflow line 111 and the treated water is discharged through the discharge line 112. Sludge isolating wall 114 is extended to the bottom 113 of the digester 100, the digester 100 is the digestion chamber 100 and the sewage and sedimentary solids in which sludge is precipitated and anaerobic fermentation occurs. Digestion anaerobic digestion is divided into two chambers (130). Then, the sewage flows from the fire extinguishing 1 chamber 120 to the fire extinguishing 2 chamber 130 beyond the upper portion of the sludge isolation wall 114.

An upstream wall of the fire extinguishing chamber 120 is provided with an isolation wall 115 for floating oil to form an oil collecting chamber 140, and an oil collecting chamber 140 has non-emulsification contained in the introduced sewage. Grease or suspended oil accumulates.

The oil separation wall 115 has a separation distance from the bottom 113 of the digester 100 in consideration of the state in which the grease component and scum accumulated on the surface can be collected even when the level of the digester 100 is minimized. Is determined.

Digestion 1 chamber 120 is divided by the sludge isolation wall 114 mainly serves as an anaerobic sludge fermenter, and as the concentration of solids increases, the digestion reaction of the microorganism is enhanced. Digestion 2 chamber 130 further proceeds the mesocarbonization reaction of the accumulated solids.

The digester 100 including the digester 1 chamber 120 and the digester 2 chamber 130 is determined to have a capacity to serve as a flow control tank as well as a function as the digester.

Reference numeral 116 denotes a treated water separation wall installed upstream of the sewage feeder 300 (pump) to prevent the treated water from flowing upstream.

2. Continuous Batch Reactor

The continuous batch reactor 200 is a biological reactor that highly treats sewage under aerobic conditions. The reactor 200 is provided with a device 211 (eg, a jet aeration device) for agitating (mixing) and abandoning the sewage. Aeration device 211 may perform aeration and agitation to activate activated sludge and purify sewage.

The continuous batch reactor 200 is provided with a treatment water discharge device (line) 212. The treatment water discharge device 212 is a device for discharging the purified water purified in the upper layer out of the reaction tank 200 after mixing, aeration and precipitation of activated sludge for a predetermined time. The treatment water discharge device 212 can be selected according to site conditions, such as fixed or floating.

As a method of removing the excess sludge generated in the continuous batch reactor 200, the oil collection of the fire extinguishing chamber 1 (120) is collected by using an excess sludge conveying apparatus (line) 213 such as an air lift pump connected to a blower and an air pipe. It can be conveyed to the chamber 140 or the fire extinguishing chamber 130 (refer FIG. 2). It is also possible to use other pumps instead of air lift pumps.

1 and 2, a sewage feeder 300 such as a pump is used to transfer sewage from the digester 100 to the continuous batch reactor 200. The capacity of the sewage feeder 300 is designed and selected so that the rapid inlet mode can be executed from the lowest level to the highest level of the batch reactor 200.

As shown in Figure 2, when the advanced processing of the phosphorus may be installed a separate phosphorus-release tank 400. That is, in order to prevent the phosphorus contained in the excess sludge accumulated in the digester 100, the phosphorus is discharged from the phosphorus-discharge tank 400 so that the sludge is digested through the sludge conveying line 213. 100, and the supernatant containing a lot of phosphorus is returned to the digester 100 after the phosphorus is adsorbed and removed through the phosphorus-removing device 411.

The continuous-batch reactor 200 transfers the phosphorus-rich sludge to the phosphorus-release tank 400 to settle the sludge under anoxic conditions and further anaerobic conditions. Therefore, phosphorus is released back to the supernatant within a certain time. The phosphorus-release tank 400 separates phosphorus from the settling sludge to allow sufficient agitation to take place by batch discharge of the sludge.

Phosphorus-released sludge is separated by gravity sedimentation and returned to the digester 100, and the phosphorus-containing supernatant is a phosphorus-removing device such as a phosphorus adsorption filter for adsorbing and removing phosphorus using soil or media. Phosphorus is removed by passing through. The medium for adsorption and removal of phosphorus is periodically replaced, and the used medium is used again as a fertilizer.

Hereinafter, the sewage treatment method according to the present invention will be described.

3.1 Flow rate and organic matter equalization

In connection with the transfer of the sewage using the sewage feeder 300 (pump) from the digester 100 to the continuous batch reactor 200, the digester 100 is in accordance with the amount of raw water introduced and the operating cycle of the sewage feeder. It acts as an equalizer to control the changing water level.

In the method according to the present invention, the batch inflow mode from the digester 100 to the continuous batch reactor 200 is typically a rapid feed mode in which a rapid inflow within 5 minutes up to 30 minutes is applied. The digester 100 equalizes the load of sewage so that there is no excessive flow of sewage to the extent that it interferes with the function of the continuous batch reactor 200 as a final treatment device.

In this way, the highest load of all organics is equalized in the digester 100, and the final treatment in the continuous batch reactor 200 is effected by physico-chemical changes such as concentrations of organic matter, toxic substances and various cleaning agents, and changes in pH or temperature. Protected from being affected. Anaerobic biomass is very resistant to these dangerous substances, providing an effective protection for the final aerobic treatment.

The digester 100 serves as an equalizer and anaerobic digester of organic matter and hydraulic load. Digestion tank 100 is a low-speed anaerobic digester that can be easily decomposed by the anaerobic methane bacteria present in the digestion tank 100 and the aerobic bacteria present in the continuous batch reactor (200). It can be broken down into organic acid chemicals. The sludge residence time or the sludge age of the fermenting biomass can be adjusted by the height of the sludge isolation wall 114 separating the fermentation portion and the digestion portion. For further adjustment of the sludge age, the influent sewage can be flowed directly to the continuous batch reactor 200.

3.2 Oil Capture

In order to prevent the continuous batch reactor 200 from being blocked by the floating oil of grease or solids like other secondary treatment equipment, an oil separation wall 115 is installed to form an oil collecting chamber 140. If necessary, excess oil floating on the top can be removed through the manhole.

3.3 Removal of Fibers and Insolubles

Fibrous solids, such as paper or cloth, and other inorganic and insoluble materials are settled and accumulated in the digester 100. These substances are eliminated to some extent by natural dissolution and by long-term digestion.

3.4 Removal of Organic Solids

Organic solids settled in the digester 100 are very effectively extinguished, and a small amount may be accumulated depending on the extinguishing temperature which affects the digestion of these solids. The digested portion of these solids is removed in the form of carbon dioxide, methane and hydrogen sulfide gas.

3.5 Anaerobic Treatment

Anaerobic treatment occurs in the digester 100 and is mainly broken down into two forms.

(1) fermentation of organic matter

In the present organic fermentation, an acid transfer reaction in which the complex organic material is decomposed into fatty acid compounds in the form of organic acids of acetate, butylate and propionate. These organics present in the simplest organics can be stored and / or adsorbed by aerobic microorganisms or anaerobic methane microorganisms for later use. These fatty acids are first stored and adsorbed by aerobic biomass in a continuous batch reactor. This is particularly advantageous when biological phosphorus removal is required. The fermentation process is only a transition and does not reduce the organic load of the sewage.

(2) methane digestion

Mecarbonization is the second stage of anaerobic treatment in which organic matter is digested. During the methane digestion, the BOD load decreases as organic matter is used for the growth of anaerobic methane bacteria and is primarily broken down into methane or carbon dioxide. Depending on the temperature of the digester contents, the concentration of anaerobic methane bacteria and the residence time, the reduction is generally between 35% and 80%.

This process uses anaerobic treatment in a controlled manner in accordance with the required effluent quality criteria. In other words, if biological phosphorus removal is required, the residence time of the sewage through the digester 100 is controlled so that the organic acid is contained in the sewage before proceeding to the subsequent batch reactor process. This control is controlled by resetting the discharge point from the digester to the inlet line 111 side (ie, fire extinguishing chamber 1) instead of the normal discharge at the end of the digester 100 when maximum BOD reduction is needed without removing phosphorus. can do. In this case half of the digesters are simply used for the accumulation and digestion of solids.

When biological phosphorus-removal is not needed, the discharge line 112 of the digester 100 is located at the end of the digester (ie, digestion 2) so that the sewage has a maximum residence time. Such a process maximizes the reduction in BOD load, allowing for maximum energy savings. In conclusion, these fatty acids are consumed by anaerobic methane bacteria which affect the reduction of organic load.

The process using the digester 100 is to be in the form of hydraulic plug flow as much as possible, so that the physical and biological reactions in the digester 100 are short-circuit or eddy. Prevent it so that it is achieved sequentially.

3.6 Maintaining efficient processing during no inflow

When the inflow or flow of sewage is stopped for a long time, the organic matter stored in the digester 100 is used to feed the continuous batch reactor 200 in the present invention. Such a method is preferable to preserve the operating state of the continuous batch reactor 200 when the inflow into the digester 100 such as a school or camping facility without inflow for a long time is stopped for several weeks or months.

The operation of the system applied to the present invention is controlled by the control panel 500. When the inflow amount of the digester 100 is exhausted, the control panel 500 may automatically recognize such matters and return the final treated effluent to the digester 100 through the treated water conveying device (line) 214 again. By automatically repeating as described above, as long as the organic substance remains in the digestion tank 100, the continuous batch reactor 200 can be always kept in a normal state.

3.7 Sludge Treatment

The present invention is a great advantage that all the sludge generated can be used without sludge treatment for a long time by being digested without treating it. The sludge generated in the sewage treatment apparatus 1 of the present invention can be accumulated and digested for more than 5 years, even from 10 to 15 years, without being removed from the digester 100.

The digester 100 accommodates all sludge arising from the primary precipitation and excess sludge from the continuous batch reactor 200. The digester 100 serves as the primary sedimentation basin, scum removal, and digester.

Very long sludge residence times are used in the present invention, and sludge accumulation cannot generally be calculated using conventional models (calculations) such as traditional treatment plants that use sludge residence times of 5 to 90 days, including digestion.

Under very long sludge residence times, several different reactions will occur which will further reduce the amount of sludge actually accumulating in the digester. These reactions will affect the following depending on the type of solids present.

(1) Anaerobic Digestion of Biodegradable Volatile Solids

Biodegradable organics depend on the temperature of the digester, but are fully digested within one month of operation. Thus, most biodegradable organics are quickly converted to gaseous form and do not occupy much of the digester volume even after years of operation.

(2) anaerobic digestion of non-biodegradable volatile solids

Most of these solids are fibrous materials, paper, cloth, hair, etc. and cannot be decomposed with sludge residence time of 5 to 90 days. However, the present invention has a long residence time of more than 5 years, more than 10 to 15 years, such a non-biodegradable is converted to biodegradation and completely digested does not occupy a large volume of digester.

(3) removal and reduction of inert materials

In local sewage, the inert matter content is 10% to 30% of the total solids, usually around 20%. These solids do not accumulate and decompose in chloride, soil, sand, plastics, etc. without volume reduction. Therefore, the sludge residence time will be more than 5, 10 or 15 years depending on the content of these inerts in the influent sewage.

The sewage treatment method and apparatus according to the present invention described above can organically combine a digestion tank and a continuous batch reaction tank to treat sewage without cleaning sludge, which is a by-product generated in sewage treatment, for a long period of more than 5 years, Not only can the reactor achieve the secondary and tertiary treatment objectives at the same time, but the periodic use of the bacterial activity can also remove nitrogen and phosphorus as well as organic matter and suspended fractions, thus becoming more stringent. It is expected to be a desirable sewage treatment method under water quality control.

Claims (4)

The digester is divided into a digestion chamber 1 which is sludge deposited by the sludge isolation wall 114 extending upward from the bottom 113 and digestion chamber 2 which is anaerobic fermented and digestion chamber 2 where sewage is digested anaerobicly. Supplying the digestion tank 100 with sewage to be treated so as to flow from the digestion 1 chamber 120 to the digestion 2 chamber 130 over the sludge isolation wall 114; Accumulating sewage in the digester (100), Maintaining the scum formed in the upper portion of the sewage in the digester 100, the settling solids to be settled downward as sludge, Biologically treating sewage and sludge in the digester 100 in anaerobic conditions, Transferring a predetermined amount of treated water from the digester 100 to a continuous batch reactor 200 containing sludge, Agitating and abandoning sewage in the continuous batch reactor 200 to activate sludge and purify sewage, Stopping the stirring and aeration for a certain time to allow the sludge to be dispersed, Discharging the treated water of the upper sludge after settling for a predetermined time, Removing excess sludge formed in the continuous batch reactor (200), and The excess sludge removed in the continuous batch reactor 200 is transferred to the digester 100 to further digest under anaerobic conditions, Sewage treatment method using a digestion tank and a continuous batch reaction tank comprising a. delete The method of claim 1, wherein the transfer of sewage from the digestion tank 100 to the continuous batch reactor 200, one of the one digestion chamber 120 and the second digestion chamber 130, depending on the conditions of the treated sewage. Sewage treatment method using a digestion tank and a continuous batch reactor, characterized in that selected to be transported from. Digestion tank 100 in which anaerobic fermentation of sediment sludge and anaerobic digestion of sewage take place, and a continuous batch reactor in which the sewage supplied from the digester 100 through the sewage feeder 300 is biologically highly treated under aerobic conditions. 200; The digester 100 is located in an upstream of the sludge isolation wall 114 and the sludge isolation wall 114 extending upward from the bottom 113, the digestion chamber 1 in which sludge is deposited and anaerobic fermentation occurs. Located downstream of the sludge isolating wall 114, the digestion 2 chamber 130, the sewage flowing over the sludge isolation wall 114 anaerobic digestion, and from the upper side of the digestion 1 chamber 120 from below A fraction collecting chamber (140) separated by a fraction separating wall (115) extending in such a manner as to accumulate oil contained in the sewage upstream of the first chamber (120); The continuous batch reactor 200 is a device 211 for agitating and abandoning sewage, a treated water discharge device 212 for discharging the purified treated water out of the upper layer after activated sludge settling, and the excess sludge in the digester 100 Sewage treatment apparatus comprising a digestion tank and a continuous batch reaction tank, characterized in that it comprises a surplus sludge conveying apparatus (213) to be conveyed.