WO2011122217A1

WO2011122217A1 - Method and device for biologically treating organic wastewater

Info

Publication number: WO2011122217A1
Application number: PCT/JP2011/054748
Authority: WO
Inventors: 繁樹藤島; 倫明田中
Original assignee: 栗田工業株式会社
Priority date: 2010-03-31
Filing date: 2011-03-02
Publication date: 2011-10-06

Abstract

Disclosed is a multi-step activated sludge method employing the predatory activity of microorganisms, which is intended to improve treatment efficiency, reduce the sludge volume, and improve treated water quality by giving priority to filtration-predatory microorganisms. Organic wastewater is introduced to a first biological treatment tank (1) and subjected to biological treatment by bacteria; a first biologically treated water that contains, in a dispersed state, the bacteria from the first biological treatment tank (1) is passed through a second biological treatment tank (2) to obtain a second biologically treated water which is then subjected to solid-liquid separation. A microorganism-supporting carrier (22) is disposed in the second biological treatment tank (2) and a portion of the sludge is removed, treated in an anaerobic tank (4), and then returned to the second biological treatment tank (2).

Description

Biological treatment method and apparatus for organic wastewater

The present invention relates to a biological treatment method and apparatus for organic wastewater that can be used for treatment of organic wastewater in a wide concentration range including domestic wastewater, sewage, food factories and pulp factories. The present invention relates to a biological treatment method and apparatus for organic wastewater that can improve the treatment efficiency and reduce the amount of excess sludge generation without deteriorating water quality.

The activated sludge method used when biologically treating organic wastewater is widely used for sewage treatment, industrial wastewater treatment, and the like because of its advantages such as good treated water quality and easy maintenance. However, since the BOD volumetric load in the activated sludge method is generally about 0.5 to 0.8 kg / m ³ / d, a large site area is required. Further, since 20 to 40% of the decomposed BOD is converted into bacterial cells, that is, sludge, a large amount of excess sludge treatment is also a problem.

For high load treatment of organic waste water, a fluidized bed method with a carrier added is known. When this method is used, it is possible to operate with a BOD volume load of ³ kg / m ³ / d or more. However, this method has a disadvantage that the amount of generated sludge is about 30 to 50% of the decomposed BOD and is higher than that of the normal activated sludge method.

In Japanese Patent Laid-Open No. 55-20649, organic wastewater is first treated with bacteria in a first treatment tank, and organic matter contained in the wastewater is oxidatively decomposed and converted into non-aggregating bacterial cells. It is described that excess sludge can be reduced by precipitating and removing the sticking protozoa in the second treatment tank. Further, this method enables high-load operation and improves the processing efficiency of the activated sludge method.

A number of wastewater treatment methods using protozoa and metazoan predation located at high levels of bacteria have been proposed.

For example, Japanese Patent Application Laid-Open No. 2000-210692 proposes a countermeasure for deterioration in processing performance due to fluctuations in the quality of raw water, which is a problem in the processing method of Japanese Patent Application Laid-Open No. 55-20649. As specific methods, “adjust BOD fluctuation of treated water to within 50% from median average concentration”, “measure water quality in first treatment tank and first treated water over time”, Methods such as “add seed sludge or microbial preparation to the first treatment tank when the quality of the first treated water deteriorates” have been proposed.

In Japanese Examined Patent Publication No. 60-23832, bacteria, yeasts, actinomycetes, algae, molds, wastewater treatment primary sludge and surplus sludge are precipitated by protozoa and metazoans by ultrasonic treatment or mechanical stirring. Have proposed a method for making these foods smaller in size than the animal's mouth.

In addition, as an invention relating to multi-stage treatment of a fluidized bed and an activated sludge method, there is one described in Japanese Patent No. 3410699. In this method, the latter activated sludge method is operated at a low load of BOD sludge load 0.1 kg-BOD / kg-MLSS / d, so that the sludge can be self-oxidized and the amount of sludge extraction can be greatly reduced.

The multistage activated sludge method using the predatory action of such minute animals is actually used for organic wastewater treatment. Depending on the target wastewater, the treatment efficiency is improved and the amount of generated sludge is reduced by about 50%. Is possible. There are two types of micro-animals that contribute to sludge reduction: the filtration predation type and the aggregate predation type. Among these, the aggregate predation type micro-animal can be preyed while gnawing the flocked sludge. Therefore, when the aggregate predation type micro-animal is prioritized, the quality of the treated water is deteriorated. Therefore, in order to improve the quality of treated water, it is effective to give priority to the filter predation type among the micro animals, but conventionally, the growth of the filter predation type micro animal and the aggregate predation type micro animal No method has been proposed for controlling the growth of water, and when sludge reduction using micro animals is performed in wastewater treatment, there has been a problem of unexpected deterioration of treated water depending on the operating conditions.

The activated sludge method includes a membrane activated sludge method that uses a membrane separator for solid-liquid separation of sludge and treated water, and a sedimentation basin type activated sludge method that uses a sedimentation basin.
The membrane activated sludge process maintains a higher sludge concentration than the sedimentation basin type activated sludge process and can be operated with a high volumetric load. There is an advantage that treated water of quality can be obtained.

However, in the membrane activated sludge method, depending on the properties of the sludge in the activated sludge tank, the membrane is likely to be clogged and the frequency of membrane cleaning is high.

Japanese Patent Laid-Open No. 9-294996 proposes a method for reducing sludge adhesion to the membrane and preventing the membrane from being blocked by adding a carrier to the aeration tank.

However, even when the carrier is added to the aeration tank, the membrane may not be sufficiently blocked.
Further, even when the activated sludge treatment is operated at a low load, fine SS is generated by sludge dismantling and the membrane is blocked. In addition, if the number of micro-animals that prey on flocs in activated sludge increases rapidly due to water temperature, load, and SRT (solid content retention time), refinement of sludge is promoted, leading to deterioration of treated water, and solid-liquid separation. There is also a problem that the operation management of the membrane separator becomes difficult.

JP-A-55-20649 JP 2000-210692 A Japanese Patent Publication No. 60-23832 Japanese Patent No. 3410699 JP-A-9-294996

The invention according to the first aspect provided by the present invention (hereinafter referred to as “first invention”) is a multi-stage activated sludge method utilizing the predatory action of micro animals, giving priority to filtered predatory micro animals, It is an object of the present invention to provide a biological treatment method and apparatus for organic wastewater that improves treatment efficiency and further reduces the sludge volume and further improves the quality of treated water (Problem I).

The invention according to the second aspect provided by the present invention (hereinafter referred to as “second invention”) greatly reduces the amount of generated sludge in biological treatment of organic wastewater to which the membrane activated sludge method is applied. At the same time, it is an object to provide a biological treatment method and apparatus for organic wastewater that prevents clogging of the membrane, reduces the frequency of membrane washing, improves treatment efficiency by high-load operation, and achieves stable treated water quality ( Issue II).

As a result of intensive studies to solve the above problem I, the present inventors have suppressed the growth of swimming aggregate predatory microanimals by drawing out the biological treatment tank sludge in the latter stage and passing it through the anoxic tank. In addition, it is possible to prevent the deterioration of treated water quality, and in addition, by installing a micro animal holding carrier in the latter biological treatment tank, it is possible to hold the fixed filtration predation type micro animal, and the latter biological treatment tank. It was found that even if the sludge was extracted and introduced into the oxygen-free tank, these micro-animals were not affected, and as a result, predation-type micro-animals could be prioritized.

The first invention has been achieved based on such knowledge, and the gist thereof is as follows.

The biological treatment method for organic wastewater according to the first aspect of the first aspect of the present invention introduces organic wastewater into a first biological treatment tank of an aerobic biological treatment tank provided in two or more stages and performs biological treatment with bacteria. In the biological treatment method for organic wastewater, the first biological treatment water containing the dispersed bacteria from the first biological treatment tank is passed through the biological treatment tanks subsequent to the second biological treatment tank for biological treatment. A biological treatment tank after the biological treatment tank is provided with a carrier for holding micro-animals, and part of the sludge in the biological treatment tank after the second biological treatment tank is extracted and treated in an oxygen-free tank, and then the second organism. It returns to the biological treatment tank after a processing tank, It is characterized by the above-mentioned.

In the biological treatment method for organic wastewater according to the second aspect of the first invention, in the first aspect, at least a part of the first biological treatment water passes through the anoxic tank and the biological substance after the second biological treatment tank. Water is passed through the treatment tank.

The biological treatment method for organic wastewater according to the third aspect of the first invention is the first aspect or the second aspect, wherein a part of the organic wastewater is introduced into the anoxic tank and the remainder is the first biological treatment tank. It is characterized by being introduced to

The biological treatment method for organic wastewater according to the fourth aspect of the first invention is characterized in that, in the first to third aspects, the oxygen-free tank holds a carrier.

A biological treatment method for organic wastewater according to a fifth aspect of the first invention is the biological treatment method according to any one of the first to fourth aspects, wherein a carrier for holding a micro animal is provided in the biological treatment tank after the second biological treatment tank. It is characterized by being.

In the biological treatment method for organic wastewater according to the sixth aspect of the first invention, in any one of the first to fifth aspects, the SRT (solid content residence time) of the biological treatment tank after the second biological treatment tank is 60. It is characterized by extracting sludge so that it is less than a day.

According to a seventh aspect of the biological wastewater treatment method of the first invention, in any one of the first to sixth aspects, the treated water in the biological treatment tanks after the second biological treatment tank is subjected to solid-liquid separation, and separated sludge is obtained. Is returned to the biological treatment tank after the second biological treatment tank.

The biological treatment apparatus for organic wastewater according to the eighth aspect of the first invention comprises an aerobic biological treatment tank provided in two or more stages, and the organic wastewater is introduced into the first biological treatment tank so that the organism can be In the biological treatment apparatus for organic wastewater, the first biological treatment water containing the dispersed bacteria from the first biological treatment tank is passed through the biological treatment tank after the second biological treatment tank for biological treatment. A carrier for holding micro animals is provided in a biological treatment tank after the second biological treatment tank, and after removing a part of sludge in the biological treatment tank after the second biological treatment tank and processing the second biological An oxygen-free tank that is returned to the biological treatment tank after the treatment tank is provided.

According to a ninth aspect of the biological wastewater treatment apparatus of the first aspect of the present invention, in the eighth aspect, at least a part of the first biological treatment water passes through the anoxic tank and the biological substance after the second biological treatment tank. It has a means for passing water through the treatment tank.

A biological treatment apparatus for organic wastewater according to a tenth aspect of the first invention, according to the eighth aspect or the ninth aspect, means for introducing a part of the organic wastewater into the anoxic tank, and the remainder of the organic wastewater It has a means to introduce | transduce into a said 1st biological treatment tank, It is characterized by the above-mentioned.

The biological treatment apparatus for organic wastewater of the eleventh aspect of the first invention is characterized in that, in any of the eighth to tenth aspects, a carrier is held in the anoxic tank.

A biological treatment apparatus for organic wastewater according to a twelfth aspect of the first invention according to any one of the eighth to eleventh aspects, wherein a carrier for holding a micro animal is provided in the biological treatment tank after the second biological treatment tank. It is characterized by being.

In the biological wastewater treatment apparatus according to the thirteenth aspect of the first invention, in any one of the eighth to twelfth aspects, the SRT (solids residence time) of the biological treatment tank after the second biological treatment tank is 60. A biological treatment apparatus for organic wastewater, characterized in that sludge is drawn out to be less than a day.

A biological treatment apparatus for organic wastewater according to a fourteenth aspect of the first invention, according to any of the eighth to thirteenth aspects, separates and separates treated water from biological treatment tanks after the second biological treatment tank. It has a means which returns at least one part of sludge to the biological treatment tank after the said 2nd biological treatment tank.

As a result of intensive studies to solve the above-mentioned problem II, the present inventors have provided a tank for temporarily treating organic matter in the biological treatment tank in the previous stage in the multistage activated sludge method utilizing the predatory action of micro animals. Inhibiting the growth of aggregate (floc) predatory micro-animals that cause membrane occlusion by generating dispersal bacteria and actively prioritizing the necessary micro-animals in subsequent biological treatment tanks; For this purpose, a micro-animal holding carrier is provided in the biological treatment tank at the latter stage, and the fixed predation-type micro-animal that contributes to the solid-liquid separation property of sludge and the improvement of the treated water quality by preserving the dispersed bacteria efficiently is retained. , It was found that the membrane-type activated sludge method can prevent clogging of the membrane and enable stable high-load treatment.

The second invention has been achieved on the basis of such knowledge, and the summary is as follows.

The biological treatment method for organic wastewater according to the first aspect of the second invention is characterized in that organic wastewater is introduced into a first biological treatment tank of an aerobic biological treatment tank provided in two or more stages and biologically treated with bacteria. The first biological treatment water containing the dispersed bacteria from the first biological treatment tank is passed through the biological treatment tank after the second biological treatment tank for biological treatment, and the biological treatment tank after the second biological treatment tank In the organic wastewater biological treatment method for solid-liquid separation of the treated water, a biological treatment tank after the second biological treatment tank is provided with a carrier for holding a micro animal, and the biological treatment tank after the second biological treatment tank The solid-liquid separation of the treated water is performed by membrane separation treatment.

The biological treatment method for organic wastewater according to the second aspect of the second invention is characterized in that, in the first aspect, the membrane separation treatment is performed by an outside-type membrane separation apparatus.

In the biological treatment method for organic wastewater according to the third aspect of the second invention, in the first aspect or the second aspect, the carrier provided in the biological treatment tank after the second biological treatment tank is fixed to the biological treatment tank. It is characterized by being a supported carrier.

According to a fourth aspect of the biological wastewater treatment method of the second aspect of the present invention, in any one of the first aspect to the third aspect, the second part of the organic wastewater is not passed through the first biological treatment tank. It introduce | transduces into the biological treatment tank after a biological treatment tank, It is characterized by the above-mentioned.

In the biological treatment method for organic wastewater according to the fifth aspect of the second invention, in any one of the first to fourth aspects, the SRT (solid content residence time) of the biological treatment tank after the second biological treatment tank is 60. It is characterized by extracting sludge so that it is less than a day.

A biological treatment method for organic wastewater according to a sixth aspect of the second invention is the method according to any one of the first to fifth aspects, wherein a part of the sludge in the biological treatment tank after the second biological treatment tank is extracted. After the treatment in the oxygen tank, it is returned to the biological treatment tank after the second biological treatment tank.

A biological treatment apparatus for organic wastewater according to a seventh aspect of the second invention comprises an aerobic biological treatment tank provided in two or more stages, and the organic wastewater is introduced into the first biological treatment tank and is biologically produced by bacteria. The first biological treatment water containing the dispersed bacteria from the first biological treatment tank is passed through the biological treatment tank after the second biological treatment tank for biological treatment, and the biological treatment after the second biological treatment tank In the organic wastewater biological treatment apparatus characterized by solid-liquid separation of the treated water in the tank, a carrier for holding micro animals is provided in the biological treatment tank after the second biological treatment tank. A membrane separation treatment apparatus is provided as a solid-liquid separation means for treated water in biological treatment tanks after the biological treatment tank.

The biological treatment apparatus for organic wastewater according to the eighth aspect of the second invention is characterized in that, in the seventh aspect, the membrane separation device is an outside-type membrane separation device.

The biological wastewater treatment apparatus according to the ninth aspect of the second invention is the biological wastewater treatment apparatus according to the seventh aspect or the eighth aspect, wherein the carrier provided in the biological treatment tank after the second biological treatment tank is fixed to the biological treatment tank. It is characterized by being a supported carrier.

A biological treatment apparatus for organic wastewater according to a tenth aspect of the second invention is the biological wastewater treatment apparatus according to any one of the seventh aspect to the ninth aspect, wherein the second part of the organic wastewater is not passed through the first biological treatment tank. It has a means to introduce into a biological treatment tank after a biological treatment tank.

The biological treatment apparatus for organic wastewater according to the eleventh aspect of the second invention, according to any one of the seventh to tenth aspects, has an SRT (solids residence time) of 60 in the biological treatment tanks after the second biological treatment tank. It is characterized in that sludge is drawn out to be less than a day.

A biological treatment apparatus for organic wastewater according to a twelfth aspect of the second invention, according to any one of the seventh aspect to the eleventh aspect, extracts a part of sludge in the biological treatment tank after the second biological treatment tank. After that, an oxygen-free tank is provided for returning to the biological treatment tank after the second biological treatment tank.

In the first invention, in the multi-stage activated sludge method utilizing the predatory action of micro animals, a micro animal holding carrier is provided in a biological treatment tank holding micro animals, and the sludge in the biological treatment tank is extracted and processed in an oxygen-free tank. After returning, it becomes possible to preferentially proliferate the filtration predation type micro-animal by suppressing the growth of the aggregate predation type micro-animal in the micro-animal holding biological treatment tank, and to improve the quality of the treated water be able to.

In the second invention, in the multistage activated sludge method utilizing the predatory action of the micro animals, the micro-animal holding carrier is provided in the bio-processing tank holding the micro animals, so that the dispersal bacteria can be efficiently eaten in the bio-processing tank. To hold solid filtration and predation type micro-animals that contribute to improving sludge solid-liquid separation and quality of treated water, thereby blocking the membrane of the membrane separation device for membrane separation treatment of biologically treated water in this biological treatment tank And the frequency of chemical cleaning of the membrane can be reduced.

For this reason, according to the 1st invention and the 2nd invention, the efficient biological treatment of organic waste water is attained, and the following effects are produced.
1) Significant reduction of sludge generated during wastewater treatment 2) Improvement of treatment efficiency by high load operation 3) Maintenance of stable treated water quality

It is a systematic diagram which shows embodiment of the biological treatment method and apparatus of the organic waste water of 1st invention. It is a systematic diagram which shows other embodiment of the biological treatment method and apparatus of the organic waste water of 1st invention. It is a systematic diagram which shows other embodiment of the biological treatment method and apparatus of the organic waste water of 1st invention. It is a systematic diagram which shows other embodiment of the biological treatment method and apparatus of the organic waste water of 1st invention. It is a systematic diagram which shows other embodiment of the biological treatment method and apparatus of the organic waste water of 1st invention. It is a systematic diagram which shows embodiment of the biological treatment method and apparatus of the organic waste water of 2nd invention. It is a systematic diagram which shows other embodiment of the biological treatment method and apparatus of the organic waste water of 2nd invention. It is a systematic diagram which shows other embodiment of the biological treatment method and apparatus of the organic waste water of 2nd invention.

Embodiments of the organic wastewater biological treatment method and apparatus according to the present invention will be described below in detail with reference to the drawings.

[First invention]
1 to 5 are system diagrams showing an embodiment of a biological treatment method and apparatus for organic wastewater according to the first invention.
1 to 5, 1 is a first biological treatment tank, 2 is a second biological treatment tank, 3 is a sedimentation tank, 4 is an oxygen-free tank, 5 is a membrane separator, 11 and 21 are air diffusers, and 22 is a micro animal. A holding carrier, 41 is a stirring means, and 42 is a carrier, and members having the same functions in FIGS.

In the embodiment of FIG. 1, raw water (organic wastewater) is introduced into the first biological treatment tank 1, and 70% or more, desirably 80% of the organic component (soluble BOD) is obtained by dispersible bacteria (non-aggregating bacteria). More preferably, 90% or more is oxidatively decomposed. The pH of the first biological treatment tank 1 is 6 or more, preferably 8 or less. However, when the raw water contains a large amount of oil, the pH may be 8 or more.

Further, the water flow to the first biological treatment tank 1 is usually a transient type, and the BOD volume load of the first biological treatment tank 1 is 1 kg / m ³ / d or more, for example, 1 to 20 kg / m ³ / d, By setting the HRT (raw water retention time) to 24 h or less, preferably 8 h or less, for example 0.5 to 8 h, treated water dominated by dispersible bacteria can be obtained, and by shortening the HRT, Wastewater with a low BOD concentration can be treated with a high load.

By returning a part of the sludge from the subsequent biological treatment tank to the first biological treatment tank 1, making the first biological treatment tank 1 a multistage configuration of two or more tanks, or adding a carrier , High load processing with a BOD volumetric load of 5 kg / m ³ / d or more is also possible.

When a carrier is added to the first biological treatment tank 1, the shape of the carrier is arbitrary such as a spherical shape, a pellet shape, a hollow cylindrical shape, a thread shape, a plate shape, etc., and the size is also arbitrary within a diameter of about 0.1 to 10 mm. is there. Further, the material of the carrier is any material such as a natural material, an inorganic material, and a polymer material, and a gel material may be used. Moreover, when the filling rate of the support | carrier added to the 1st biological treatment tank 1 is high, a dispersal microbe does not produce | generate but bacteria adheres to a support | carrier or a filamentous bacterium grows. Therefore, by setting the filling rate of the carrier added to the first biological treatment tank 1 to 10% or less, desirably 5% or less, it is possible to produce dispersed bacteria that are not affected by the concentration fluctuation and are easy to prey.

Further, the first biological treatment tank 1 may suppress the growth of filamentous bacteria by setting the dissolved oxygen (DO) concentration to 1 mg / L or less, preferably 0.5 mg / L or less.
In addition, when dissolved organic matter is completely decomposed in the first biological treatment tank 1, flocs are not formed in the second biological treatment tank 2, and nutrients for microanimal growth are insufficient, and sludge with low compactness is used. Only becomes the dominant biological treatment tank. Therefore, it is preferable that the decomposition rate of the organic component in the first biological treatment tank 1 is not 100% but 95% or less, desirably 85 to 90%.

The treated water in the first biological treatment tank 1 (first biological treated water) is passed through the second biological treatment tank 2 in the subsequent stage, where the remaining organic components are oxidatively decomposed and the dispersible bacteria are self-degraded. Reduce excess sludge through predation of micro-animals.

In the second biological treatment tank 2, it is necessary to use an operation condition and a treatment apparatus that allow the microanimal and the bacteria to remain in the system in order to use the action of the microanimal having a slower growth rate than the bacteria and the self-degradation of the bacteria. . Therefore, it is desirable to use the activated sludge method or the membrane separation activated sludge method for returning the sludge to the second biological treatment tank 2. Moreover, this 2nd biological treatment tank 2 is good also as a multistage structure of two or more tanks.

In the first invention, by providing the micro animal holding carrier 22 in the second biological treatment tank 2, the holding amount of the micro animal in the tank is increased.
In the case of a fluidized bed, the shape of the carrier 22 provided in the second biological treatment tank 2 is arbitrary, such as a spherical shape, a pellet shape, a hollow cylindrical shape, and a thread shape, and the size may be about 0.1 to 10 mm. A fixed bed may be used, and the shape of the carrier 22 in that case is arbitrary, such as a thread shape or a plate shape. The material of the carrier 22 is arbitrary such as a natural material, an inorganic material, or a polymer material, and a gel material may be used.
In the second biological treatment tank 2, a large amount of scaffolding for maintaining micro-animals is required, so the filling rate of the carrier to be added varies depending on the type and material of the fluidized bed and fixed bed. It is desirable to make it 40%.

In addition, as described above, in the second biological treatment tank 2, not only the filtration and predation type micro animals that prey on the dispersed cells, but also the aggregate predation type micro animals that can prey on the floc sludge. Since the latter prey on flocs while swimming, if prioritized, sludge is eaten and becomes sludge in which fine floc pieces are scattered. The floc pieces increase the concentration of treated water SS in sedimentation basin type activated sludge, and membrane clogging occurs in membrane activated sludge. Therefore, in the first invention, an oxygen-free tank 4 is provided, and sludge extracted from the second biological treatment tank 2 is retained in the oxygen-free tank 4 for a predetermined time, thereby inhibiting the growth of the swimming micro-animals. Stabilize biota. In this case, the second biological treatment tank 2 is provided with a micro-animal holding carrier 22, and the filtered predatory micro-animal is fixed on the carrier 22 side. , So that the growth of filtered predatory microanimals is not inhibited. The sludge extracted from the second biological treatment tank 2 and treated in the anoxic tank 4 is returned to the second biological treatment tank 2.

The amount of sludge withdrawn from the second biological treatment tank 2 to the oxygen-free tank 4 and the sludge residence time in the oxygen-free tank 4 are appropriately determined according to the treatment status. 1/30 times the amount / day or more, and the sludge residence time in the oxygen-free tank 4 is preferably 0.5 hours or more.

In the first invention, in the anaerobic tank 4, the ORP needs to be 0 mV or less in order to inhibit the growth of minute animals. Therefore, it is desirable not to perform aeration in the oxygen-free tank 4 but only to mechanical stirring. Moreover, in order to accelerate | stimulate the fall of ORP, 1st biological treatment water and raw | natural water may be passed, and you may make it lower ORP by an acid production | generation reaction or a denitrification reaction.

Further, a carrier may be added to the oxygen-free tank 4 in order to stably advance the ORP reduction (denitrification reaction, acid generation reaction) in the oxygen-free tank 4. If the ORP in the anaerobic tank 4 is low, the decrease in the activity of the swimming micro-animal is promoted, so the residence time of the second biological treatment tank sludge in the anoxic tank 4 can be shortened, and the anaerobic tank 4 can be downsized. can do. In the case of a fluidized bed, the shape of the carrier to be added is arbitrary such as a spherical shape, a pellet shape, a hollow cylindrical shape, and a thread shape, and the size is arbitrary with a diameter of about 0.1 to 10 mm. A fixed bed may be used, and the shape of the carrier 22 in that case is arbitrary, such as a thread shape or a plate shape. Further, the material may be a natural material, an inorganic material, a polymer material or the like, and a gel material may be used.
When a carrier is added to the anaerobic tank 4, the filling rate varies depending on the type of fluidized bed and fixed bed and the material, but is preferably 0.5 to 40%.

In the second biological treatment tank 2, the tank sludge is periodically replaced, that is, in order to thin out minute animals and feces, the SRT (solid content retention time) is 60 days or less, preferably 45 days or less, and more preferably It is desirable to control it within a range from 10 days to 45 days. However, when the sludge concentration (MLSS) in the second biological treatment tank 2 is 2000 mg / L or less, SRT> 60 days may be set. Here, SRT = (sludge concentration in tank × aeration tank volume) ÷ (drawn sludge concentration × amount drawn per day), and sludge concentration in tank (MLSS) indicates the concentration of floating sludge, exclude.

In the first invention, when a large amount of organic matter remains in the first biological treatment water charged into the second biological treatment tank 2, the oxidative decomposition is performed in the subsequent treatment tank. It is known that when oxidative degradation of organic matter by bacteria occurs in the second biological treatment tank 2 where a large amount of micro animals are present, as a countermeasure to escape from predation of micro animals, it grows in a form that is difficult to be predated. The bacterial group thus grown is not preyed on by the micro-animals, and their decomposition depends only on autolysis, and the effect of reducing the amount of sludge generated is reduced. Therefore, as described above, in the first biological treatment tank, it is necessary to decompose most of the organic matter, that is, 70% or more of the raw water BOD, desirably 80% or more, and convert it into cells. Therefore, it is desirable to operate at 0.25 to 0.50 kg-BOD / kg-MLSS / d in terms of sludge load due to soluble BOD in the latter biological treatment tank. Again, MLSS refers to the concentration of suspended sludge and does not include sludge for carrier adhesion.

In FIG. 1, the treated water from the second biological treatment tank 2 is then solid-liquid separated into sludge and treated water in the settling tank 3, the separated water is taken out as treated water, and a part of the separated sludge is returned to the sludge. To the second biological treatment tank 2 and the remainder is discharged out of the system as excess sludge.

It should be noted that a membrane separation device may be used as a solid-liquid separation means instead of the precipitation tank 3. Conventionally, in membrane separation treatment of activated sludge, reduction of flux due to clogging of the membrane and chemical cleaning have been problems, but according to the present invention, sudden dispersion of sludge can be prevented, Operation management of the separation device can be facilitated.

In the embodiment shown in FIG. 2, a part of the first biological treatment tank treated water from the first biological treatment tank 1, for example, about 10 to 20% is introduced into the anoxic tank 4, and the remaining part is supplied to the second biological treatment tank 2. The point of introduction is different from that shown in FIG. As described above, by introducing a part of the first biological treatment tank water into the anoxic tank 4 as described above, the ORP of the anoxic tank 4 is lowered, and the growth inhibition effect of the minute animals in the anoxic tank 4 is reduced. Can be increased.

The embodiment shown in FIG. 3 is different from the embodiment shown in FIG. 1 in that a part of raw water, for example, about 10 to 20% is directly introduced into the anoxic tank 4 and the remainder is introduced into the first biological treatment tank 1. Have the same configuration. As described above, by introducing a part of the raw water into the anoxic tank 4 as described above, the ORP of the anoxic tank 4 can be lowered and the effect of inhibiting the growth of micro animals in the anoxic tank 4 can be enhanced. .

The embodiment shown in FIG. 4 uses a membrane separation device 5 in place of the sedimentation tank 3, takes out the permeated water of the membrane separation apparatus 5 as treated water, returns the concentrated water to the second biological treatment tank 2, and removes excess sludge. The point which was made to pull out directly from the 2nd biological treatment tank 2 differs from the aspect shown in FIG. 1, and others are set as the same structure. As described above, when the membrane separation device 5 is used as the solid-liquid separation means, according to the first invention, since the growth of the aggregate predation type micro-animal is suppressed, as in the conventional activated sludge membrane separation process. The problem of clogging of the membrane is reduced, the membrane flux is stabilized, and the frequency of chemical cleaning can be reduced.

5 differs from the embodiment shown in FIG. 1 in that the carrier 42 is added to the anaerobic tank 4, and the other configuration is the same. As described above, by adding the carrier to the oxygen-free tank 4 in this manner, the ORP of the oxygen-free tank 4 can be reduced, and the effect of inhibiting the growth of micro animals in the oxygen-free tank 4 can be enhanced.

1 to 5 show an example of an embodiment of the first invention, and the first invention is not limited to the one shown in the drawings. For example, the first biological treatment tank and the second biological treatment tank may have a multi-stage configuration with two or more stages as described above. Therefore, in the first invention, the biological treatment tank may be provided in three or more stages.
Moreover, as a solid-liquid separation means, a sedimentation tank, a membrane separation apparatus, a flotation separation tank, or the like may be used. As the treatment tank, a membrane separation type aerobic treatment may be performed.

In any aspect, according to the first invention, the biological treatment tank after the second biological treatment tank is provided with the micro animal holding carrier, and the biological treatment tank sludge after the second biological treatment tank is treated in the anoxic tank. Thereby, the priority of the aggregate predation type | mold animal can be suppressed, and sludge reduction and the improvement of a treated water quality can be made compatible.

[Second invention]
6 to 8 are system diagrams showing an embodiment of the biological treatment method and apparatus for organic waste water of the second invention.
6 to 8, 1 is a first biological treatment tank, 2 is a second biological treatment tank, 4 is an oxygen-free tank, 5 is a membrane separation device, 11 and 21 are air diffusers, 22 is a micro-animal holding carrier, 41 is Members that are stirring means and have the same function in FIGS. 6 to 8 are given the same reference numerals.

In the embodiment of FIG. 6, raw water (organic wastewater) is introduced into the first biological treatment tank 1, and 70% or more, preferably 80% of the organic component (soluble BOD) is obtained by dispersible bacteria (non-aggregating bacteria). More preferably, 90% or more is oxidatively decomposed. The pH of the first biological treatment tank 1 is 6 or more, preferably 8 or less. However, when the raw water contains a large amount of oil, the pH may be 8 or more.

When a carrier is added to the first biological treatment tank 1, the shape of the carrier is arbitrary such as a spherical shape, a pellet shape, a hollow cylindrical shape, a thread shape, a plate shape, etc., and the size is also arbitrary within a diameter of about 0.1 to 10 mm. is there. Further, the material of the carrier is any material such as a natural material, an inorganic material, and a polymer material, and a gel material may be used. Moreover, when the filling rate of the support | carrier added to the 1st biological treatment tank 1 is high, a dispersal microbe does not produce | generate but bacteria adheres to a support | carrier or a filamentous bacterium grows. Therefore, by setting the filling rate of the carrier added to the first biological treatment tank 1 to 20% or less, desirably 10% or less, it is possible to generate disperse bacteria that are easy to prey without being affected by concentration fluctuations.

The treated water in the first biological treatment tank 1 (first biological treated water) is passed through the second biological treatment tank 2 in the subsequent stage, where the remaining organic components are oxidatively decomposed and the dispersible bacteria are self-degraded. And reduce excess sludge by predation of micro-animals.

In the second biological treatment tank 2, it is necessary to use an operation condition and a treatment apparatus that allow the microanimal and the bacteria to remain in the system in order to use the action of the microanimal having a slower growth rate than the bacteria and the autolysis of the bacteria. . Therefore, it is desirable to use the activated sludge method or the membrane activated sludge method for returning the sludge to the second biological treatment tank 2. Moreover, this 2nd biological treatment tank 2 is good also as a multistage structure of two or more tanks. In the case of the membrane activated sludge method, the membrane separation device may be either a tank internal type or a tank external type, but by using the tank external type, clogging of the membrane by dispersal bacteria whose predation was delayed at high loads is prevented. be able to.

In the second aspect of the invention, by providing the micro-animal holding carrier 22 in the second biological treatment tank 2, the micro-animals, particularly the dispersal bacteria, can be efficiently eaten to contribute to the solid-liquid separation of sludge and the quality of the treated water. Increase the amount of filterable predatory microanimals that can be retained in the tank.

That is, in the second biological treatment tank 2, not only the filtration and predation type micro animals that prey on the dispersed cells, but also the aggregate predation type micro animals that can prey on the floc sludge. Since the latter prey on flocs while swimming, if prioritized, sludge is eaten and becomes sludge in which fine floc pieces are scattered. The floc pieces cause membrane clogging in the membrane activated sludge method. Therefore, in the second invention, in this second biological treatment tank 2, the tank sludge is periodically replaced, that is, in order to thin out minute animals and feces, the SRT (solid content retention time) is desirably 60 days or less, and more desirably. Is controlled to be constant within a range of 45 days or less, more desirably 10 days or more and 45 days or less. However, when the sludge concentration (MLSS) in the second biological treatment tank 2 is 2000 mg / L or less, SRT> 60 days may be set. Here, SRT = (tank sludge concentration × aeration tank volume) ÷ (drawn sludge concentration × amount drawn per day), and the sludge concentration in the tank (MLSS) indicates the concentration of floating sludge. exclude.
In addition, a micro-animal holding carrier 22 is provided in the second biological treatment tank 2 in order to maintain the filtration predation type micro-animal that prey on the dispersed cells in the second biological treatment tank 2. That is, this kind of micro animal is fixed to the sludge floc and maintained in the system, but since the sludge is drawn out of the system with a certain residence time, it is necessary to provide a supply source in the system. At this time, if the carrier is a granular or square fluidized bed, the shearing force for fluidization not only prevents stable retention at high concentrations, but also organic substances are completely processed in the fluidized bed, and sludge flocs are refined. This leads to membrane occlusion.
Therefore, in the second invention, the carrier provided in the second biological treatment tank 2 is not a fluid carrier, but at least a part of the carrier is fixed to any one of the bottom surface, the side surface, the upper part and the like of the second biological treatment tank 2. A fixed carrier is preferred. In this case, the shape of the carrier 22 is arbitrary such as a thread shape, a plate shape, or a strip shape. The material of the carrier 22 is arbitrary such as a natural material, an inorganic material, or a polymer material, and a gel material may be used. A porous urethane foam is desirable, for example, a plate shape or a strip shape with a thickness of 100 to 400 cm × 50 to 200 cm × 0.5 to 5 cm, and it is desirable to install it where aeration air does not contact.

In the second biological treatment tank 2, a large amount of scaffolding for maintaining micro-animals is required. However, if the filling rate of the carrier is excessively high, mixing in the tank, sludge decay, etc. may occur. The filling rate is preferably about 0.1 to 20%.

In the second invention, when a large amount of organic matter remains in the first biological treatment water charged into the second biological treatment tank 2, the oxidative decomposition is performed in a subsequent treatment tank. It is known that when oxidative degradation of organic matter by bacteria occurs in the second biological treatment tank 2 where a large amount of micro animals are present, as a countermeasure to escape from predation of micro animals, it grows in a form that is difficult to be predated. The bacterial group thus grown is not preyed on by the micro-animals, and their decomposition depends only on autolysis, and the effect of reducing the amount of sludge generated is reduced. Therefore, as described above, in the first biological treatment tank, it is necessary to decompose most of the organic matter, that is, 70% or more of the raw water BOD, desirably 80% or more, and convert it into cells. Therefore, it is desirable to operate at 0.25 to 0.50 kg-BOD / kg-MLSS / d in terms of sludge load due to soluble BOD in the latter biological treatment tank. Again, MLSS refers to the concentration of suspended sludge and does not include sludge for carrier adhesion.

In FIG. 6, the treated water from the second biological treatment tank 2 is fed to the outside membrane separation device 5, and the permeated water of the membrane separation device 5 is taken out as treated water, and the concentrated water is treated with the second biological treatment. It returns to the upstream of the tank 2, and the excess sludge is extracted directly from the second biological treatment tank 2. Thus, when the membrane separation apparatus 5 is used as the solid-liquid separation means, according to the second invention, since the growth of the aggregate predation type micro-animal is suppressed, Membrane clogging problems are alleviated, membrane flux can be stabilized and chemical cleaning frequency can be reduced, and sudden sludge dispersion can be prevented, facilitating operation management of membrane separation equipment. be able to.

There is no restriction | limiting in particular as the membrane separation apparatus 5 outside a tank, An ultrafiltration (UF) membrane separation apparatus, a microfiltration (MF) membrane separation apparatus, etc. can be used.

The embodiment shown in FIG. 7 is different from the embodiment shown in FIG. 6 in that a part of raw water, for example, about 5 to 50% is introduced directly into the second biological treatment tank 2 without passing through the first biological treatment tank 1. The other configurations are the same. In this way, by introducing a part of the raw water directly into the second biological treatment tank 2, an effect of avoiding the load shortage of the second biological treatment tank when the raw water fluctuates (when the load is reduced) is achieved.

In the embodiment shown in FIG. 8, by extracting a part of the sludge in the second biological treatment tank 2 holding the micro animals and treating it in the anoxic tank 4, the micro animal holding biological treatment tank 2 The growth of the aggregate predation type micro-animal is further suppressed to preferentially proliferate the filtration predation type micro-animal, and the other configuration is the same as that of the embodiment of FIG.

That is, by providing the oxygen-free tank 4 and retaining the sludge extracted from the second biological treatment tank 2 in the oxygen-free tank 4 for a predetermined time, the growth of the swimming micro-animals is inhibited. Stabilize biota. In this case, the second biological treatment tank 2 is provided with a micro-animal holding carrier 22, and since a certain amount of the filter predation type micro animal is held on the carrier 22 side, the growth of the filter predation type micro animal is inhibited. Never happen. The sludge extracted from the second biological treatment tank 2 and treated in the anoxic tank 4 is returned to the second biological treatment tank 2.

The amount of sludge withdrawn from the second biological treatment tank 2 to the oxygen-free tank 4 and the sludge residence time in the oxygen-free tank 4 are appropriately determined according to the treatment status. It is preferable that the sludge residence time in the anaerobic tank 4 is 0.5 hour or more.

In the second invention, in the anaerobic tank 4, the ORP needs to be 0 mV or less in order to inhibit the growth of minute animals. Therefore, it is desirable not to perform aeration in the oxygen-free tank 4 but only to mechanical stirring. Moreover, in order to accelerate | stimulate the fall of ORP, a part of 1st biological treatment water and raw | natural water may be passed, and you may make it lower ORP by an acid production | generation reaction or a denitrification reaction.

6 to 8 show an example of the embodiment of the second invention, and the second invention is not limited to the illustrated one. For example, the first biological treatment tank and the second biological treatment tank may have a multi-stage configuration with two or more stages as described above. Therefore, in the second invention, the biological treatment tank may be provided in three or more stages.

In any aspect, according to the second invention, by providing a micro-animal holding carrier in the biological treatment tanks subsequent to the second biological treatment tank, the priority of the aggregate predation type micro-animal is suppressed, so that sludge It is possible to achieve both weight loss and improvement of the quality of treated water, and by separating the biologically treated water after this second biological treatment tank by solid-liquid separation with a membrane separator, it prevents the membrane of the membrane separator from being blocked, Stable and high-load processing is possible.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

[Examples and Comparative Examples of the First Invention]
[Example I-1]
As shown in FIG. 1, a first biological treatment tank 1 with a capacity of 3.6 L, a second biological treatment tank 2 with a capacity of 15 L, an anoxic tank 4 with a capacity of 5 L, and a precipitation tank 3 with a capacity of 5 L The organic waste water according to the present invention was treated using an experimental apparatus in which the two were connected. The raw water contains artificial substrates of COD _Cr : 1000 mg / L, BOD: 640 mg / L.
The treatment conditions for each biological treatment tank were as follows.

<First biological treatment tank>
DO: 0.5 mg / L
BOD volumetric load: 3.85 kg-BOD / m ³ / d
HRT: 4h
pH: 7.0
<Second biological treatment tank>
DO: 4 mg / L
Carrier filling rate: 2%
HRT: 17h
SRT: 30 days pH: 7.0
<Anoxic tank>
ORP: -100 mV
HRT (= SRT): 12h

In addition, a plate-like polyurethane foam was used as the carrier 12 of the second biological treatment tank 2.
Further, the BOD volumetric load in the entire apparatus was 0.75 kg-BOD / m ³ / d, and the HRT in the entire apparatus was 21 h.

As a result, the sludge floc in the second biological treatment tank 2 and the filter-precipitating microanimals (Villus elegans, scallop) are prioritized on the carrier, and the sludge conversion rate is 0.1 kg-MLSS / kg-COD _Cr. It was. The quality of the treated water (solid-liquid separated water in the precipitation tank 4) was always in good condition throughout the test period, with an SS concentration of less than 10 mg / L and a soluble COD _Cr concentration of less than 30 mg / L.

[Example I-2]
The treatment was performed under the same conditions as in Example I-1, except that a UF membrane was used as the membrane separation device instead of the precipitation tank, and the experimental device shown in FIG. 4 was used. The quality of the raw water, the treatment conditions of the first and second biological treatment tanks and anoxic tanks, and the overall BOD volumetric load and HRT are the same as in Example I-1.

As a result, the sludge floc in the second biological treatment tank and the fixed filter predation type micro-animals (Villus elegans, Hirata rotifer) were prioritized and the sludge conversion rate was 0.075 kg-MLSS / kg-COD _Cr . .
The quality of the treated water (permeated water of the membrane separation apparatus) was always in good condition during the test period, with a soluble COD _Cr concentration of less than 20 mg / L. Moreover, there was almost no increase in transmembrane pressure, and a stable flux could be maintained without chemical cleaning for one month or longer.

[Comparative Example I-1]
The treatment was performed under the same conditions as in Example I-1, except that the anoxic tank was omitted and no carrier was provided in the second biological treatment tank.
The quality of the raw water, the treatment conditions of the first and second biological treatment tanks, the overall BOD volumetric load and the HRT are the same as in Example I-1.
As a result, the sludge conversion rate was 0.13 kg-MLSS / kg-COD _Cr . However, every other month, aggregate predation type micro-animals (Hole worms) were prioritized, during which time the treated water SS concentration increased to 80 mg / L and the soluble COD _Cr increased to 150 mg / L.

[Comparative Example I-2]
The treatment was performed under the same conditions as in Example I-2 except that the anoxic tank was omitted and no carrier was provided in the second biological treatment tank.
The quality of the raw water, the treatment conditions of the first and second biological treatment tanks, the overall BOD volumetric load and the HRT are the same as in Example I-1.
As a result, the sludge conversion rate was 0.12 kg-MLSS / kg-COD _Cr . However, every two months, aggregate predation type micro-animals (Hole worms) are prioritized, and during that time, transmembrane pressure increases frequently, and chemical cleaning of membranes is required once every two weeks throughout the test period. It became.

[Examples and Comparative Examples of the Second Invention]
[Example II-1]
As shown in FIG. 6, the present invention uses an experimental apparatus in which a first biological treatment tank 1 having a capacity of 3.6 L, a second biological treatment tank 2 having a capacity of 15 L, and a UF membrane separation device 5 are connected. Treatment of organic wastewater by The raw water contains artificial substrates of COD _Cr : 1000 mg / L, BOD: 640 mg / L.
The treatment conditions for each biological treatment tank were as follows.

<First biological treatment tank>
DO: 0.5 mg / L
BOD volumetric load: 3.85 kg-BOD / m ³ / d
HRT: 4h
pH: 7.0
<Second biological treatment tank>
DO: 4 mg / L
Carrier filling rate: 2%
HRT: 17h
SRT: 30 days pH: 7.0

In addition, plate-like polyurethane foam (15 mm × 300 mm × 50 mm / 1 sheet) is used as the carrier 12 of the second biological treatment tank 2, and it is in a position symmetrical to the air diffusion tube 21 with respect to the vertical plane at the center of the tank. The bottom and the left and right sides were fixed to the tank wall surface.
Further, the BOD volumetric load in the entire apparatus was 0.75 kg-BOD / m ³ / d, and the HRT in the entire apparatus was 21 h.

As a result, the sludge floc in the second biological treatment tank 2 and the filter-precipitating microanimals (Villus elegans, scallop) are prioritized on the carrier, and the sludge conversion rate is 0.1 kg-MLSS / kg-COD _Cr. It was.
The quality of the treated water (permeated water of the membrane separation device 5) was always in good condition throughout the test period, with a soluble COD _Cr concentration of less than 20 mg / L.
Further, there was almost no increase in the transmembrane pressure difference of the membrane separation device 5, and a stable flux could be maintained without chemical cleaning for one month or longer.

[Comparative Example II-1]
The treatment was performed under the same conditions as in Example II-1 except that the first biological treatment tank was omitted, the capacity of the second biological treatment tank was 18.6 L, and no carrier was provided in the second biological treatment tank. .
Raw water quality, DO and pH of the second biological treatment tank, overall BOD volumetric load and HRT are the same as in Example II-1.
As a result, the sludge conversion rate was 0.20 kg-MLSS / kg-COD _Cr . However, every other month, the aggregate predatory microanimals (Holeoptera) prevailed, and during that time, the transmembrane pressure difference increased, requiring chemical cleaning of the membrane once every two weeks. In addition, the process water is also worse, soluble _{COD Cr} concentration was increased to more than 70 mg / L.

[Example II-2]
As shown in FIG. 8, an anoxic tank 4 having a capacity of 5 L is provided, and after sludge in the second biological treatment tank 2 is extracted and treated in the anoxic tank 4, it is returned to the second biological treatment tank 2. Except for this, the treatment was performed under the same conditions as in Example II-1. The quality of raw water, the treatment conditions of the first and second biological treatment tanks, and the overall BOD volumetric load and HRT are the same as in Example II-1.
The processing conditions of the anoxic tank 4 were as follows.
<Anoxic tank>
ORP: -100 mV
HRT (= SRT): 12h

As a result, the sludge floc in the second biological treatment tank and the fixed filter predation type micro-animals (Villus elegans, Hirata rotifer) were prioritized and the sludge conversion rate was 0.075 kg-MLSS / kg-COD _Cr . .
The quality of the treated water was always in good condition during the test period with a soluble COD _Cr concentration of less than 20 mg / L. Moreover, there was almost no increase in transmembrane pressure, and a stable flux could be maintained without chemical cleaning for one month or longer.

The biological treatment method and apparatus for organic wastewater of the present invention can be used for treatment of organic wastewater in a wide concentration range including domestic wastewater, sewage, food factories and pulp factories.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
The present application includes a Japanese patent application filed on March 31, 2010 (Japanese Patent Application No. 2010-083136), a Japanese patent application filed on July 21, 2010 (Japanese Patent Application No. 2010-164087), 2011. Based on the Japanese patent application filed on March 2 (Japanese Patent Application No. 2011-044797) and the Japanese patent application filed on March 2, 2011 (Japanese Patent Application No. 2011-044798), which are incorporated by reference in their entirety. Is done.

DESCRIPTION OF SYMBOLS 1 1st biological treatment tank 2 2nd biological treatment tank 3 Precipitation tank 4 Anoxic tank 5 Membrane separation device

Claims

The first organism containing the dispersed bacteria from the first biological treatment tank by introducing organic wastewater into the first biological treatment tank of the aerobic biological treatment tank provided in two or more stages and biologically treating with bacteria In the biological treatment method for organic wastewater, the treated water is passed through a biological treatment tank after the second biological treatment tank and biologically treated.
The biological treatment tank after the second biological treatment tank is provided with a carrier for holding micro-animals, and a part of the sludge in the biological treatment tank after the second biological treatment tank is extracted and treated in an oxygen-free tank. A biological treatment method for organic wastewater, which is returned to a biological treatment tank after the second biological treatment tank.
2. The biological treatment of organic wastewater according to claim 1, wherein at least part of the first biological treatment water is passed through the anoxic tank to a biological treatment tank after the second biological treatment tank. Method.
3. The biological treatment method for organic wastewater according to claim 1 or 2, wherein a part of the organic wastewater is introduced into the anoxic tank and the remainder is introduced into the first biological treatment tank.
The biological treatment method for organic wastewater according to any one of claims 1 to 3, wherein the anoxic tank holds a carrier.
The biological treatment method for organic wastewater according to any one of claims 1 to 4, wherein a carrier for holding a micro animal is provided in the biological treatment tank after the second biological treatment tank.
The organic waste water according to any one of claims 1 to 5, wherein sludge is extracted so that an SRT (solid content retention time) of the biological treatment tanks after the second biological treatment tank is 60 days or less. Biological treatment method.
The biological treatment tank according to any one of claims 1 to 6, wherein the treated water in the biological treatment tank after the second biological treatment tank is subjected to solid-liquid separation, and at least a part of the separated sludge is removed from the second biological treatment tank. A method for biological treatment of organic wastewater, which is returned to the factory.
The aerobic biological treatment tank is provided in two or more stages, the organic wastewater is introduced into the first biological treatment tank and biologically treated with bacteria, and the dispersed bacteria from the first biological treatment tank are contained. In a biological treatment apparatus for organic wastewater that is biologically treated by passing one biological treatment water through a biological treatment tank after the second biological treatment tank,
The biological treatment tank after the second biological treatment tank is provided with a carrier for holding micro-animals, and after removing a part of the sludge in the biological treatment tank after the second biological treatment tank and treating it, the second An organic wastewater biological treatment apparatus comprising an oxygen-free tank that is returned to a biological treatment tank after the biological treatment tank.
9. The organic waste water according to claim 8, further comprising means for passing at least a part of the first biological treatment water to the biological treatment tank after the second biological treatment tank through the anoxic tank. Biological treatment equipment.
10. The organic material according to claim 8, further comprising: means for introducing a part of the organic wastewater into the oxygen-free tank; and means for introducing the remainder of the organic wastewater into the first biological treatment tank. Biological wastewater treatment equipment.
The biological treatment apparatus for organic wastewater according to any one of claims 8 to 10, wherein a carrier is held in the oxygen-free tank.
The biological treatment apparatus for organic wastewater according to any one of claims 8 to 11, wherein a carrier for holding a micro animal is provided in the biological treatment tank after the second biological treatment tank.
The organic property according to any one of claims 8 to 12, wherein the sludge is drawn out so that the SRT (solid content retention time) of the biological treatment tank after the second biological treatment tank is 60 days or less. Wastewater biological treatment equipment.
The biological treatment tank according to any one of claims 8 to 13, wherein the treated water in the biological treatment tank after the second biological treatment tank is subjected to solid-liquid separation, and at least a part of the separated sludge is removed from the second biological treatment tank. A biological treatment apparatus for organic wastewater, characterized by having means for returning to the waste water.
The first organism containing the dispersed bacteria from the first biological treatment tank by introducing organic wastewater into the first biological treatment tank of the aerobic biological treatment tank provided in two or more stages and biologically treating with bacteria In the biological treatment method of organic waste water, the treated water is passed through a biological treatment tank after the second biological treatment tank to be biologically treated, and the treated water in the biological treatment tank after the second biological treatment tank is solid-liquid separated.
A biological treatment tank after the second biological treatment tank is provided with a carrier for holding a micro animal,
A biological treatment method for organic wastewater, wherein solid-liquid separation of treated water in biological treatment tanks after the second biological treatment tank is performed by membrane separation treatment.
16. The biological treatment method for organic wastewater according to claim 15, wherein the membrane separation treatment is performed by an outside-membrane type membrane separation apparatus.
The biological treatment method for organic wastewater according to claim 15 or 16, wherein the carrier provided in the biological treatment tank after the second biological treatment tank is a carrier fixed to the biological treatment tank.
18. The organic material according to claim 15, wherein a part of the organic waste water is introduced into a biological treatment tank after the second biological treatment tank without passing through the first biological treatment tank. Biological treatment method for effluent.
The organic waste water according to any one of claims 15 to 18, wherein sludge is drawn out so that an SRT (solid content retention time) of the biological treatment tanks after the second biological treatment tank is 60 days or less. Biological treatment method.
20. The biological treatment tank according to claim 15, wherein a part of the sludge in the biological treatment tank after the second biological treatment tank is extracted and treated in an oxygen-free tank, and then the biological treatment tank after the second biological treatment tank. A method for biological treatment of organic wastewater, which is returned to the factory.
The aerobic biological treatment tank is provided in two or more stages, the organic wastewater is introduced into the first biological treatment tank and biologically treated with bacteria, and the dispersed bacteria from the first biological treatment tank are contained. Organic wastewater characterized in that one biologically treated water is passed through a biological treatment tank after the second biological treatment tank for biological treatment, and the treated water in the biological treatment tank after the second biological treatment tank is solid-liquid separated. In the biological treatment equipment of
A carrier for holding micro animals is provided in the biological treatment tank after the second biological treatment tank,
An organic wastewater biological treatment apparatus comprising a membrane separation treatment device as a solid-liquid separation means for treated water in biological treatment tanks after the second biological treatment tank.
23. The biological treatment apparatus for organic waste water according to claim 21, wherein the membrane separation apparatus is an outside tank type membrane separation apparatus.
The biological treatment apparatus for organic wastewater according to claim 21 or 22, wherein the carrier provided in the biological treatment tank after the second biological treatment tank is a carrier fixed to the biological treatment tank.
24. In any one of Claims 21 thru | or 23, It has a means to introduce | transduce a part of said organic waste water into the biological treatment tank after the said 2nd biological treatment tank, without passing through said 1st biological treatment tank. Biological treatment equipment for organic wastewater.
25. The organic material according to any one of claims 21 to 24, wherein the sludge is drawn out so that an SRT (solid content residence time) of the biological treatment tank after the second biological treatment tank is 60 days or less. Wastewater biological treatment equipment.
In any one of Claims 21 thru | or 25, after extracting and processing a part of sludge in the biological treatment tank after the said 2nd biological treatment tank, it does not return to the biological treatment tank after this 2nd biological treatment tank. An organic wastewater biological treatment apparatus characterized by providing an oxygen tank.