JP4490848B2 - Waste water treatment apparatus and waste water treatment method - Google Patents

Description

  The present invention relates to a wastewater treatment apparatus and a wastewater treatment method, and as an example, as a measure for the regulation of the total amount of nitrogen by a partial revision of the Water Pollution Control Law, which came into effect from April 2004, The present invention relates to a wastewater treatment apparatus and a wastewater treatment method that are excellent in initial cost, running cost, and maintenance cost capable of treating microorganisms with high concentration nitrogen wastewater (for example, high concentration ammonia wastewater) without dilution.

  Conventionally, high-concentration nitrogen wastewater, specifically, high-concentration ammonia wastewater of about 3000 ppm, generally cannot be treated with microorganisms because ammonia has high microbial toxicity.

  In the case where the ammonia wastewater is treated with microorganisms, treatment with a low ammonia inflow concentration of several hundred ppm has been common.

  Therefore, high concentration ammonia waste water of 3000 ppm or more was concentrated to about 1/10 using an evaporator as a physical method, and the concentrated liquid was disposed as industrial waste.

  As another physicochemical method, recently, a method of vaporizing and separating ammonia and then catalytically decomposing it has been developed, and operation by an actual apparatus has been started.

  In the method of concentrating with an evaporator and discharging it from a factory as industrial waste, the concentrate corresponds to industrial waste. As a result, industrial waste from business establishments is increased, and the disposal method of concentrated liquid as industrial waste is generally incineration, which causes problems such as air pollution due to the use of fuel such as heavy oil. there were.

  On the other hand, in a method in which ammonia is vaporized and separated and then catalytically decomposed, when ammonia in wastewater is ammonia alone, the ammonia can be treated. However, when ammonia is mixed with nitrous acid or nitric acid, these nitrogen compounds have a drawback that they cannot be treated by the above catalytic decomposition method. Further, the method of vaporizing and separating and then catalytically decomposing has a problem that nitrogen oxides in exhaust gas increase.

  Further, the method of decomposing the evaporator and the catalyst has a problem that the initial cost, running cost, and maintenance cost are large because it consumes a large amount of energy and becomes a large plant facility.

  Further, as a biological treatment method as a conventional technique, there is one described in Patent Document 1 (Japanese Patent No. 3467671).

  In this method, the organic wastewater in the raw water tank is sent to the denitrification tank and the nitrification tank one after another by a liquid feed pump and circulated between both tanks, so that ammonia nitrogen contained in the organic wastewater is biologically Nitrification and denitrification, which is reduced to nitrogen gas using a chemical nitrification and denitrification reaction, and using a suction pump, the sludge and treated water are separated by a filtration membrane unit immersed in the wastewater in the nitrification tank Is the method.

  As a feature of this nitrification / denitrification method, the pipe that feeds from the denitrification tank to the nitrification tank is branched in the middle, the tip of the branch is opened in the denitrification tank, and a part of the organic wastewater sent from the denitrification tank to the nitrification tank is It is blown out into the organic waste water in the denitrification tank.

  As another conventional biological treatment method, there is one described in Patent Document 2 (Japanese Patent No. 3095620).

  The biological treatment method includes a denitrification tank into which raw water containing organic matter flows, a nitrification tank into which a denitrification tank mixed solution of the denitrification tank flows, and a nitrification liquid circulation channel for circulating the nitrification liquid in the nitrification tank to the denitrification tank. And a treatment method using a biological nitrogen removing apparatus including the nitrification tank aeration apparatus disposed in the nitrification tank.

  More specifically, in the biological nitrogen removing apparatus, a denitrifying bacterium immobilization carrier filling zone that captures and removes suspended substances in the raw water flowing into the denitrifying tank is provided in the denitrifying tank. In addition, the raw water introduction channel and the nitrification solution circulation channel are communicated with the lower position of the denitrifying bacteria immobilization support filling zone of the denitrification tank, and the suspended matter trapped and removed in the denitrification bacteria immobilization support filling zone at the bottom of the denitrification tank. A sludge hopper for depositing is provided, and a hopper air diffuser is provided in the sludge hopper.

  However, as described above, conventionally, high-concentration ammonia wastewater having a concentration of about 3000 ppm has been generally not treated with microorganisms because of its high biological toxicity. That is, because of high biological toxicity, high-concentration ammonia wastewater that cannot be treated with microorganisms has been treated by a concentration method or a vaporization separation method.

For this reason, the concentration method has a problem of a large amount of energy consumption and an increase in industrial waste due to the concentrated solution. In addition to the large amount of energy consumption, the vapor separation method cannot treat nitrous acid or nitric acid other than ammonia. There are also drawbacks.
Japanese Patent No. 3467671 Japanese Patent No. 3095620

  Then, the subject of this invention is providing the waste water treatment apparatus and waste water treatment method which can implement | achieve energy saving and the weight reduction of a waste while being able to process high concentration nitrogen waste water.

In order to solve the above-described problem, the wastewater treatment apparatus of the present invention is introduced with nitrogen wastewater containing a nitrogen-based compound, added with at least one of phosphorus, potassium, calcium, magnesium, and hydrogen. A first denitrification tank to which a donor is added;
A nitrification tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the first denitrification tank is introduced into the semi-anaerobic part,
A second denitrification tank into which treated water from the nitrification tank is introduced and a hydrogen donor is added;
A re-aeration tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the second denitrification tank introduced into the semi-anaerobic part;
The microbial concentration of the treated water in the first denitrification tank, the nitrification tank, the second denitrification tank, and the re-aeration tank is 10000 ppm or more.

  In the wastewater treatment apparatus of this invention, nitrogen wastewater containing a nitrogen-based compound is introduced into the first denitrification tank. This nitrogen waste water is high concentration nitrogen waste water containing, for example, about 3000 ppm of a nitrogen compound. Examples of the nitrogen compound include ammonia, nitric acid, calcium fluoride, and the like. In addition, at least one of phosphorus, potassium, calcium, and magnesium is added to the first denitrification tank. In addition, the nitrification tank and the re-aeration tank have a lower semi-anaerobic part and an upper aerobic part. And the microorganisms density | concentration in the said 1st denitrification tank, a nitrification tank, a 2nd denitrification tank, and a re-aeration tank shall be 10000 ppm or more. Thus, in the present invention, there is a high concentration of microorganisms and phosphorus, potassium, calcium, and magnesium as trace elements that enhance the activity of the microorganisms. In addition, in the present invention, a semi-anaerobic portion is provided between the anaerobic parts (first denitrification tank, second denitrification tank) and aerobic parts (aerobic part of nitrification tank, aerobic part of re-aeration tank). There are sex parts (semi-anaerobic part of nitrification tank, semi-anaerobic part of re-aeration tank). Therefore, according to the present invention, even when the number of circulations of the entire system is increased, environmental changes with respect to microorganisms can be eased, and high-concentration nitrogen wastewater such as high-concentration ammonia wastewater can be treated efficiently.

  Therefore, according to the present invention, it is possible to realize a wastewater treatment apparatus that can treat high-concentration nitrogen wastewater and save energy and reduce waste compared to conventional evaporators and catalytic decomposition methods.

Moreover, the wastewater treatment method of one embodiment adds at least one or more of phosphorus, potassium, calcium, and magnesium to a nitrogen wastewater containing a nitrogen-based compound and a hydrogen donor, A first denitrification step for denitrification treatment;
A nitrification step of treating the denitrified treated water in order in a semi-anaerobic part and an aerobic part;
A second denitrification step of adding a hydrogen donor to the treated water after the nitrification step and performing a denitrification treatment;
A re-aeration process for sequentially treating the treated water after the second denitrification process in a semi-anaerobic part and an aerobic part,
The microbial concentration of treated water in each of the above steps is 10000 ppm or more.

  Moreover, in the waste water treatment apparatus of one Embodiment, as for the said re-aeration tank, the said aerobic part of the upper part has a liquid film.

  According to the wastewater treatment apparatus of this embodiment, the microbial concentration of active microorganisms can be easily maintained at 10,000 ppm or more by the submerged membrane of the aerobic part of the re-aeration layer. In the case of a system using a submerged membrane, it is desirable to add a trace element such as potassium, calcium, magnesium, etc. as a trace mineral in addition to phosphorus to the first denitrification tank in order to stabilize the microbial treatment.

  Moreover, in the waste water treatment apparatus of one Embodiment, as for the said nitrification tank, the aerobic part of the upper part has a vinylidene chloride filling.

  According to the wastewater treatment apparatus of this embodiment, since the aerobic part at the top of the nitrification tank has the vinylidene chloride filling, it is possible to stably propagate aerobic microorganisms in the vinylidene chloride filling in the nitrification tank. It is effective in microbial oxidation of nitrogen-based compounds such as ammonia nitrogen to nitrate nitrogen efficiently.

  In one embodiment, the nitrification tank has the upper aerobic part having a vinylidene chloride filling, and the re-aeration tank has the upper aerobic part having a submerged membrane.

  In this embodiment, the submerged membrane of the aerobic layer of the re-aeration layer makes it easy to maintain the microbial concentration of active microorganisms at 10,000 ppm or more, and is aerobic to the vinylidene chloride filling in the nitrification tank. Microorganisms can be stably propagated, and nitrogenous compounds such as ammonia nitrogen can be efficiently oxidized to nitrate nitrogen.

  Moreover, in the waste water treatment apparatus of one Embodiment, it has a return part which returns microbial sludge to the said 1st denitrification tank 1 from the said re-aeration tank.

  In this embodiment, since the microbial sludge of the re-aeration tank having the semi-anaerobic part at the lower part is returned to the first denitrification tank 1, there is an effect of mitigating the environmental change between the anaerobic part and the aerobic part. Furthermore, for the microorganisms of the entire system, efficient circulation with little environmental change can be realized, and nitrogen-based compounds such as ammonia nitrogen can be efficiently reduced to nitrate nitrogen and subsequent nitrogen gas.

  Moreover, in the wastewater treatment apparatus according to an embodiment, the return unit removes the microbial sludge having a flow rate of at least twice the flow rate of the nitrogen drainage flowing into the first denitrification tank per unit time from the re-aeration tank. Return to denitrification tank.

  According to this embodiment, toxicity can be further reduced by diluting high concentration nitrogen wastewater such as toxic high concentration ammonia wastewater. Therefore, nitrogen-based compounds such as ammonia nitrogen can be efficiently reduced to nitrate nitrogen and subsequent nitrogen gas.

  Moreover, in the waste water treatment apparatus of one Embodiment, the said nitrification tank has a 2 or more types of vinylidene chloride filler.

  According to this embodiment, the nitrification tank can propagate and cultivate more types of microorganisms in the two or more types of vinylidene chloride packing, and as a result, the treatment capacity of high-concentration nitrogen wastewater can be further improved.

  Moreover, in the waste water treatment apparatus of one embodiment, at least one or more of phosphorus, potassium, calcium, and magnesium is introduced into the first denitrification tank by introducing treated water or domestic sludge from the joint septic tank into the first denitrification tank. Add to denitrification tank.

  According to this embodiment, phosphorus, potassium, calcium, magnesium, etc. contained in the treated water of the combined septic tank or domestic sludge can be effectively used as a trace element that enhances the activity of microorganisms, thus reducing the running cost of the wastewater treatment device. it can.

Moreover, the wastewater treatment apparatus of one embodiment includes a first denitrification tank into which nitrogen drainage containing a nitrogen-based compound is introduced and a hydrogen donor is added,
A nitrification tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the first denitrification tank is introduced into the semi-anaerobic part,
A second denitrification tank into which treated water from the nitrification tank is introduced and a hydrogen donor is added;
A re-aeration tank having a lower semi-anaerobic part and an upper aerobic part and where treated water from the second denitrification tank is introduced into the semi-anaerobic part;
A first air lift pump for circulating treated water from the nitrification tank to the first denitrification tank;
And a second air lift pump that circulates treated water from the re-aeration tank to the second denitrification tank.

  According to the wastewater treatment apparatus of this embodiment, treated water is circulated from the nitrification tank to the first denitrification tank by the first air lift pump, and the second aeration pump removes the second aeration tank from the re-aeration tank. 2 Circulate the treated water to the denitrification tank. Therefore, the energy required for circulation can be significantly reduced as compared with a circulation system using a normal pump.

Moreover, the waste water treatment method of one embodiment includes a first denitrification step of adding a hydrogen donor to nitrogen waste water containing a nitrogen-based compound and denitrifying the nitrogen waste water in a first denitrification tank;
A nitrification step of sequentially treating the treated water subjected to the denitrification treatment in a semi-anaerobic part and an aerobic part of the nitrification tank;
A second denitrification step of adding a hydrogen donor to the treated water after the nitrification step and denitrifying in a second denitrification tank;
A re-aeration process for sequentially treating the treated water after the second denitrification process in a semi-anaerobic part and an aerobic part of the re-aeration tank,
The treated water is circulated from the nitrification tank performing the nitrification process to the first denitrification tank by an air lift pump,
Treated water is circulated from the re-aeration tank to the second denitrification tank by an air lift pump.

  Moreover, the waste water treatment method of one embodiment adds at least one of the biologically treated treated water or the biologically treated sludge to the first denitrification tank.

  According to the wastewater treatment method of this embodiment, microorganisms can be activated by purchasing trace elements as chemicals by using trace elements contained in biologically treated water or biologically treated sludge. Therefore, the running cost can be reduced.

  Moreover, the waste water treatment method of one Embodiment adds the aminoethanol waste liquid as a hydrogen donor to the said 1st and 2nd denitrification tank.

  According to the wastewater treatment method of this embodiment, for example, aminoethanol waste liquid discharged from a semiconductor factory is used as a hydrogen donor as a substitute for methanol as a chemical, so that resources are effectively used and running costs can be reduced.

In one embodiment, the upper aerobic part of the re-aeration tank has a submerged membrane.
A pump-type piping that is connected to the submerged membrane and allows the treated water to flow out from the submerged membrane and a gravity piping that utilizes a water head difference are provided.

  According to the wastewater treatment apparatus of this embodiment, the pump type pipe and the gravity pipe can be selected and used. In other words, the gravity piping does not use power, so it can save energy compared to the pump-type piping. On the other hand, when the flow rate is reduced due to the clogging of the gravity pipe, the treated water can be forcibly secured by operating the pump system pipe.

  Moreover, the waste water treatment apparatus of one Embodiment filled the said 1st denitrification tank, the said nitrification tank, and the said 2nd denitrification tank with the vinylidene chloride filler.

  According to the waste water treatment apparatus of this embodiment, since the three tanks of the first denitrification tank, the nitrification tank, and the second denitrification tank are filled with the vinylidene chloride filler, not only can the microorganism concentration be maintained at a high concentration. Helps stabilize the treatment with microorganisms. In the nitrification tank, both anaerobic microorganisms inside the vinylidene chloride packing and aerobic microorganisms outside the vinylidene chloride packing can be made high in concentration. Moreover, in a 1st denitrification tank and a 2nd denitrification tank, an anaerobic microorganism can be made into high concentration and a treated water can be processed efficiently.

  Moreover, the waste water treatment apparatus of one Embodiment was provided with the return part which returns the sludge of the semi-anaerobic part of the lower part of the said re-aeration tank to the said 1st denitrification tank.

  According to the wastewater treatment apparatus of this embodiment, the return unit returns the sludge of the semi-anaerobic part at the lower part of the re-aeration tank to the first denitrification tank. Therefore, compared with the case where the sludge in the aerobic part of the re-aeration tank is returned to the first denitrification tank, the anaerobic state of the first denitrification tank can be reliably maintained and stabilized. Thereby, denitrification performance can be improved.

  Moreover, the waste water treatment method of one Embodiment introduce | transduces a development waste liquid into the said 1st denitrification tank with the said nitrogen waste_water | drain.

  According to the wastewater treatment method of this embodiment, it becomes possible to treat the developing waste liquid with a single wastewater treatment apparatus in addition to high-concentration nitrogen wastewater, so that construction costs can be reduced.

  Moreover, the waste water treatment method of one Embodiment introduce | transduces a dimethylformamide waste liquid into the said 1st denitrification tank with the said nitrogen waste_water | drain.

  According to the wastewater treatment method of this embodiment, in addition to high-concentration nitrogen wastewater, dimethylformamide waste liquid can be treated with one wastewater treatment device, so that construction costs can be reduced.

Moreover, the wastewater treatment apparatus of one embodiment includes a raw water tank into which nitrogen wastewater containing a nitrogen-based compound is introduced,
A first denitrification tank into which the waste water from the raw water tank is introduced and a hydrogen donor is added;
A first nitrification tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the first denitrification tank introduced into the semi-anaerobic part;
A second denitrification tank into which treated water from the first nitrification tank is introduced and a hydrogen donor is added;
A second nitrification tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the second denitrification tank introduced into the semi-anaerobic part;
A third denitrification tank into which treated water from the second nitrification tank is introduced and a hydrogen donor is added;
A re-aeration tank having a lower semi-anaerobic part and an upper aerobic part and into which treated water from the third denitrification tank is introduced into the semi-anaerobic part;
A contact oxidation tank into which treated water from the re-aeration tank is introduced;
A settling tank into which treated water from the contact oxidation tank is introduced;
A first air lift pump for circulating treated water from the first nitrification tank to the first denitrification tank;
A second air lift pump for circulating treated water from the second nitrification tank to the second denitrification tank;
A third air lift pump for circulating treated water from the re-aeration tank to the third denitrification tank;
A return unit that returns sludge containing minerals such as calcium from the settling tank to the raw water tank.

  According to the wastewater treatment apparatus of this embodiment, the first to third denitrification tanks, the first to second nitrification tanks, and the re-aeration tank are provided. Since this re-aeration tank can be regarded as a nitrification tank, this embodiment has three combinations of a denitrification tank and a nitrification tank. Therefore, the high concentration nitrogen waste water (ammonia waste water) can be effectively treated to a low concentration by the three sets of denitrification tank and nitrification tank. Further, since the denitrification tank can be regarded as an anaerobic tank and the nitrification tank has a semi-anaerobic part, according to this embodiment, the generated sludge is substantially eliminated by the three sets of the anaerobic tank and the semi-anaerobic part. (Zero generation of sludge) becomes possible.

  Moreover, in this embodiment, since the circulation system by the 1st-3rd air lift pump is employ | adopted, compared with the circulation system by a normal pump, energy consumption can be reduced markedly. In this embodiment, since sludge containing minerals such as calcium from the precipitation tank is returned to the raw water tank, various microorganisms can be activated to efficiently treat high-concentration nitrogen wastewater (ammonia wastewater as an example). .

Moreover, the wastewater treatment method of one embodiment includes a first denitrification step of introducing nitrogen wastewater containing a nitrogen-based compound from a raw water tank to a first denitrification tank to which a hydrogen donor is added, and performing a denitrification process;
A first nitrification step of sequentially treating the denitrified treated water in a semi-anaerobic part and an aerobic part of the first nitrification tank;
A second denitrification step of adding a hydrogen donor to the treated water after the first nitrification step and denitrifying in a second denitrification tank;
A second nitrification step of sequentially treating the treated water after the second denitrification step in a semi-anaerobic portion and an aerobic portion of the second nitrification tank;
A re-aeration step for sequentially treating the treated water after the second nitrification step in a semi-anaerobic portion and an aerobic portion of the re-aeration tank;
A contact oxidation step of treating the treated water after the re-aeration step in a contact oxidation tank;
A precipitation step of introducing treated water after the contact oxidation step into a precipitation tank,
Circulating treated water from the first nitrification tank performing the first nitrification step to the first denitrification tank by a first air lift pump,
Circulating treated water from the second nitrification tank to the second denitrification tank by a second air lift pump,
The treated water is circulated from the re-aeration tank to the third denitrification tank by a third air lift pump,
Sludge containing minerals such as calcium from the settling tank is returned to the raw water tank.

  Moreover, the wastewater treatment method of one embodiment adds at least one of biologically treated treated water or biologically treated sludge to the first denitrification tank.

  In this embodiment, microorganisms can be activated by trace elements contained in biologically treated water or biologically treated sludge. In addition, since biologically treated water or biologically treated sludge is used, it is not necessary to purchase trace elements as chemicals, and running costs can be reduced.

  Moreover, the waste water treatment method of one Embodiment adds an aminoethanol waste liquid to the said 1st denitrification tank, a 2nd denitrification tank, and a 3rd denitrification tank.

  In the wastewater treatment method of this embodiment, the aminoethanol waste liquid is used as an alternative to methanol as a chemical, so that the running cost can be reduced. This aminoethanol waste liquid is discharged from a semiconductor factory as an example.

  Moreover, in the waste water treatment apparatus of one embodiment, the re-aeration tank has a submerged film in an upper aerobic part, and is introduced from the submerged film of the aerobic part of the re-aeration tank into the contact oxidation tank. The piping section has a pump-type piping and a gravity-type piping.

  According to this embodiment, since there are two types of piping, pump type piping and gravity type piping, there is an energy saving effect if the gravity type piping is selected and operated. In addition, since pump-type piping is also incorporated in the system, there is an effect of increasing the stability of the system. For example, when the gravity-type piping is clogged and the ability to discharge the treated water is reduced, the treated water can be forcibly secured by the pump-type piping.

  Moreover, in the waste water treatment apparatus of one embodiment, at least one of the first and second nitrification tanks, or the vinylidene chloride filler filled in at least one of the first to third denitrification tanks. Having at least one of the filled vinylidene chloride fillings.

  According to this embodiment, the above-mentioned vinylidene chloride filling can increase the microorganism concentration, and at the same time, because of the high concentration, it is possible to stabilize the microorganism treatment and improve the quality of the treated water. . For example, in each nitrification tank, both anaerobic microorganisms inside the vinylidene chloride packing and aerobic microorganisms outside the vinylidene chloride packing can be made high, and in each denitrification tank, the anaerobic microorganisms can be made high. The treated water can be efficiently treated with microorganisms.

  Moreover, in the waste water treatment apparatus of one Embodiment, it has a return part which returns sludge to the said 1st denitrification tank from the semi-anaerobic part of the lower part of the said re-aeration tank.

  According to this embodiment, the sludge of the semi-anaerobic part at the lower part of the re-aeration tank is returned to the first denitrification tank by the return part. Therefore, compared with the case where the sludge of the aerobic tank is returned to the first denitrification tank, the anaerobic state of the first denitrification tank can be stabilized. And denitrification performance can be improved because the anaerobic state of this 1st denitrification tank is stabilized.

  Moreover, in the waste water treatment method of one embodiment, the nitrogen waste water and the developing waste liquid are introduced into the raw water tank.

  In this embodiment, since it is possible to process two treatment objects of high-concentration nitrogen wastewater and developer wastewater with one wastewater treatment device, the construction cost of the wastewater treatment device can be reduced, and maintenance costs can be reduced. Can be reduced. As an example, a general semiconductor factory discharges high-concentration nitrogen wastewater and development waste liquid. In this embodiment, these two processing objects can be processed efficiently.

  Moreover, in the waste water treatment method of one embodiment, the nitrogen waste water and the dimethylformamide waste liquid are introduced into the raw water tank.

  According to this embodiment, since the two treatment objects of the high concentration nitrogen waste water and the dimethylformamide waste liquid can be treated with one waste water treatment device, the waste water treatment is performed as compared with the case where the two treatment objects are treated separately. Equipment construction costs can be reduced.

  In the wastewater treatment apparatus of this invention, nitrogen wastewater containing a nitrogen-based compound is introduced into the first denitrification tank. This nitrogen waste water is high concentration nitrogen waste water containing, for example, about 3000 ppm of a nitrogen compound. Examples of the nitrogen compound include ammonia, nitric acid, calcium fluoride, and the like. In addition, at least one of phosphorus, potassium, calcium, and magnesium is added to the first denitrification tank. In addition, the nitrification tank and the re-aeration tank have a lower semi-anaerobic part and an upper aerobic part. And the microorganisms density | concentration in a 1st denitrification tank, a nitrification tank, a 2nd denitrification tank, and a re-aeration tank shall be 10000 ppm or more. Thus, in the present invention, in addition to the presence of high-concentration microorganisms and trace elements that increase the activity of the microorganisms, phosphorus, potassium, calcium, and magnesium, anaerobic parts (first denitrification tank, second Semi-anaerobic part (semi-anaerobic part of nitrification tank, semi-anaerobic part of re-aeration tank) between aerobic part (aerobic part of nitrification tank, aerobic part of re-aeration tank) Exists. Therefore, according to the present invention, even when the number of circulations of the entire system is increased, environmental changes with respect to microorganisms can be eased, and high-concentration nitrogen wastewater such as high-concentration ammonia wastewater can be treated efficiently.

  Therefore, according to the present invention, it is possible to realize a wastewater treatment apparatus that can treat high-concentration nitrogen wastewater and save energy and reduce waste compared to conventional evaporators and catalytic decomposition methods.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a diagram schematically showing a first embodiment of the waste water treatment apparatus of the present invention. The waste water treatment apparatus includes a first denitrification tank 1, a nitrification tank 3, a second denitrification tank 7, a re-aeration tank 8, and a methanol tank 14. As shown in FIG. 1, at least one or more of trace elements such as phosphorus, potassium, calcium, and magnesium are added to the first denitrification tank 1.

  High concentration nitrogen wastewater containing a high concentration nitrogen-based compound is introduced into the lower portion 1A of the first denitrification tank 1. This high concentration nitrogen wastewater is, for example, a nitrogen wastewater containing about 3000 ppm of a nitrogen compound.

  The reason why this high concentration nitrogen drainage is introduced into the lower part 1A of the first denitrification tank 1 is that the lower 1A has a higher microorganism concentration due to gravity than the upper part 1B. In the lower part 1A, since the microbial concentration is high, the toxic high-concentration nitrogen drainage is less irritating to the microorganism and is suitable for microbial treatment. In addition, as said high concentration nitrogen waste_water | drain, the high concentration ammonia waste_water | drain discharged | emitted from a semiconductor factory corresponds, for example.

  The first denitrification tank 1 is provided with a stirrer 2 for efficiently mixing anaerobic microorganisms and high-concentration nitrogen drainage. The agitator 2 may be an underwater agitator installed in water, instead of a normal agitator, as long as it can efficiently mix anaerobic microorganisms and high-concentration nitrogen wastewater. Further, return sludge containing microorganisms from the re-aeration tank 9 is introduced into the first denitrification tank 1 from the return pipe L1 by the return sludge pump 10. The return sludge pump 10 and the return pipe L1 constitute a return part.

  In the re-aeration tank 9, the submerged film 11 is installed in the aerobic part 19 of the upper part 9B. Due to the submerged membrane 11, the microorganisms remain in the re-aeration tank 9. Alternatively, the microorganism is returned to the first denitrification tank 1 by the return sludge pump 10 and the return pipe L1.

  The microbial sludge returned to the first denitrification tank 1 then returns again to the re-aeration tank 9 via the nitrification tank 3 and the second denitrification tank. Thereby, the microbial sludge circulates in each first denitrification tank 1, nitrification tank 3, second denitrification tank 7, and re-aeration tank 9. In this way, the microbial sludge circulates in each of the tanks 1, 3, 7, and 9, whereby the microbial concentration of the treated water in each tank is maintained at a substantially similar concentration.

  The microorganism concentration is maintained at 10000 ppm or higher with MLSS (mixed liquor suspended solid). The first denitrification tank 1 and the second denitrification tank 7 are provided with an oxidation-reduction potentiometer (not shown) in order to measure the anaerobic degree.

  In the first denitrification tank 1, nitrate nitrogen in the treated water introduced by the return sludge pump 10 and the return pipe L1 is reduced to nitrogen gas by anaerobic microorganisms in the presence of hydrogen donor methanol. . An appropriate amount of this methanol is added from the methanol tank 14 to the first denitrification tank 1 by the methanol pump 15. Further, organic substances other than nitrogen in the high concentration nitrogen wastewater are biologically decomposed by anaerobic microorganisms.

  Next, the to-be-processed water which flowed out from the 1st denitrification tank 1 is introduce | transduced into the lower part of the nitrification tank 3 which has the semi-anaerobic part 16. FIG.

  Here, the anaerobic part is defined as a part where there is no dissolved oxygen, the aerobic part is defined as a state where the dissolved oxygen is maintained at several ppm, and the semi-anaerobic part is 0 ppm dissolved oxygen. Even if dissolved oxygen is present, it is defined as about 0.5 ppm.

  The nitrification tank 3 has an aerobic part 17 that forms an upper part and a semi-anaerobic part 16 that forms a lower part. A separation wall 5 for separating the aerobic part 17 and the semi-anaerobic part 16 is provided in the nitrification tank 3. It is installed on the inner side wall. A diffuser tube 6 is disposed in the aerobic portion 17. The air diffuser 6 is connected to the blower 13. The blower 13 and the air diffuser 6 constitute an aeration unit.

  The separation wall 5 may be constructed of concrete or made of steel. That is, the material of the separation wall 5 is not limited, but when it is made of steel, it must be firmly coated to prevent corrosion when used for a long time.

  In this nitrification tank 3, a semi-anaerobic part 16 is provided at the lower part, and the water to be treated from the first denitrification tank 1 is introduced into the semi-anaerobic part 16. Thereby, in the circulation system by the return sludge pump 10 and the return piping L1 between the 1st denitrification tank 1 and the re-aeration tank 9, it moves with the treated water processed by the anaerobic microorganism in the 1st denitrification tank 1. Anaerobic microorganisms are introduced into the aerobic part 17 through the semi-anaerobic part 16 of the nitrification tank 3. Thereby, compared with the case where the anaerobic microorganisms are directly introduced from the first denitrification tank 1 to the aerobic part 17 of the nitrification tank 3, the stress on the anaerobic microorganisms moving to the aerobic part 17 is reduced. Increases efficiency when processing nitrogen.

  When the treated water treated with anaerobic microorganisms in the first denitrification tank 1 and the moving anaerobic microorganisms are directly introduced into the aerobic part 17, the anaerobic part moves to the aerobic part 17. The stress on microorganisms increases.

  In addition, in the semi-anaerobic part 16 at the lower part of the nitrification tank 3 and the semi-anaerobic part 18 at the lower part of the re-aeration tank 9, specific microorganisms propagate and propagate not only in anaerobic microorganisms and aerobic microorganisms but also in the semi-anaerobic part. The treated water can be treated with various microorganisms that improve the overall treatment efficiency.

  The treated water from the aerobic part 17 at the upper part of the nitrification tank 3 is introduced into the lower part of the second denitrification tank 7. Since dissolved oxygen decreases slowly in the second denitrification tank 7, there is little stress on the aerobic microorganisms contained in the water to be treated moving to the lower part of the second denitrification tank 7.

  In the semi-anaerobic part 16 of the nitrification tank 3 and the semi-anaerobic part 18 of the re-aeration tank 9 to be described later, although aeration equipment is not installed, the aerobic part 17 and the aerobic part 19 flow in the upper part. As a result, the dissolved oxygen, which is a semi-anaerobic part condition, is 0 ppm, or even if dissolved oxygen is present, it is about 0.5 ppm. Thereby, semi-anaerobic property can be maintained in the semi-anaerobic part 16 and the semi-anaerobic part 18.

  Further, in the aerobic portion 17 that forms the upper part of the nitrification tank 3, a vinylidene chloride filler 4 as a filler for effectively propagating microorganisms is disposed, and a diffuser tube 6 is disposed under the vinylidene chloride filler 4. Is installed. The air diffuser 6 is connected to the blower 13.

  In this wastewater treatment apparatus, microorganisms propagate on the vinylidene chloride filling 4 with the passage of time from the trial operation. The microbial concentration on the surface of the vinylidene chloride filler 4 becomes 30000 ppm or more, which leads to an improvement in treatment efficiency. The material of the vinylidene chloride filler 4 is vinylidene chloride that is strong and not affected by chemical substances, and can be used semipermanently. The vinylidene chloride filler 4 includes products such as biocodes, ring laces, biomulti-leafs, biomodules, etc., and may be selected according to the properties of the waste water.

  In this nitrification tank 3, ammonia nitrogen in the high concentration nitrogen wastewater is oxidized by aerobic microorganisms to become nitrate nitrogen or nitrite nitrogen. Below the vinylidene chloride filler 4, air generated from the blower 13 is discharged from the air diffuser 6. Ascending water flow is generated in the aerobic part 17 by the air discharged from the air diffuser 6, and the aerobic part 17 can maintain aerobic properties and at the same time is agitated with air.

  As described above, the treated water from the nitrification tank 3 is introduced into the second denitrification tank 7 from below. The second denitrification tank 7 is provided with a stirrer 8 for stirring the treated water and anaerobic microorganisms to promote the nitrogen gas reaction of nitrate nitrogen in the treated water. In addition, methanol as a hydrogen donor is added to the second denitrification tank 7 by a methanol pump 15 from a methanol tank 14. In the second denitrification tank 7, by adding methanol as a hydrogen donor, nitrate nitrogen is reduced to become nitrogen gas and diffused into the air. In general, methanol is added as a hydrogen donor during denitrification treatment as nitrogen gas.

  Next, the to-be-processed water which flowed out from the 2nd denitrification tank 7 is introduce | transduced into the semi-anaerobic part 18 which makes the lower part of the re-aeration tank 9. FIG. In the re-aeration tank 9, a separation wall 5 for separating the upper aerobic part 19 and the lower semi-anaerobic part 18 of the re-aeration tank 9 is installed on the side inner wall of the re-aeration tank 9. An aeration tube 6 is installed in the aerobic part 19 of the re-aeration tank 9, and the aeration tube 6 is connected to the blower 13. The air diffuser 6 and the blower 13 constitute an aeration unit.

  In the re-aeration tank 9, a lower semi-anaerobic part 18 is provided, and the treated water from the second denitrification tank 7 is introduced into the lower semi-anaerobic part 18. Thereby, in the circulation system by the return sludge pump 10 and the return piping L1 between the 1st denitrification tank 1 and the re-aeration tank 9, it moves with the to-be-processed water processed by the anaerobic microorganism in the 2nd denitrification tank 7. The stress to the anaerobic microorganisms that come can be reduced. That is, when the anaerobic microorganisms that move with the treated water treated by the anaerobic microorganisms in the second denitrification tank 7 are directly introduced into the aerobic part 19, the stress on the anaerobic microorganisms increases.

  On the other hand, in the first denitrification tank 1, due to the slow decrease in dissolved oxygen, the object to be processed that moves from the aerobic part 19 of the re-aeration tank 9 to the first denitrification tank 1 through the return pipe L <b> 1. Less stress on water and aerobic microorganisms.

  Further, in the aerobic part 19 that forms the upper part of the re-aeration tank 9, a submerged film 11 and an air diffuser 6 for cleaning the submerged film 11 with air are installed below the submerged film 11. The air diffuser 6 is connected to the blower 13. As the submerged membrane, two types, a flat membrane type and a hollow fiber membrane, are commercially available.

  And the to-be-processed water in the aerobic part 19 of the re-aeration tank 9 is ensured from the submerged membrane 11 by operating the submerged membrane pump 12 connected to the pipe connected to the submerged membrane 11. Is done. In addition, what is necessary is just to wash | clean the submerged membrane 11 with sodium hypochlorite etc., when the amount of permeated water of the submerged membrane 11 falls, ie, the amount of treated water falls.

(Second embodiment)
Next, FIG. 2 shows a second embodiment of the waste water treatment apparatus of the present invention. The second embodiment is different from the first embodiment in the following point (i). Therefore, in this 2nd Embodiment, the same code | symbol is attached | subjected about the same part as 1st Embodiment, detailed description is abbreviate | omitted, and a different part from 1st Embodiment is demonstrated.

  (i) In place of the return sludge pump 10 and the return pipe L1, the return sludge pump 10A and the return pipe L2 are provided as a return unit, and the return sludge containing the treated water is supplied to the first denitrification tank 1 from the upper part of the re-aeration tank 9. The point that it can be returned to both nitrification tanks 3.

  The return pipe L <b> 2 extends from the aerobic part 19 at the top of the re-aeration tank 9 to the upper side of the first denitrification tank 1 via the return sludge pump 10 </ b> A. This return pipe L2 introduces the return sludge containing the water to be treated from the upper part of the re-aeration tank 9 into the first denitrification tank 1 from above through the pipe L2a having the valve 20a. Moreover, this return piping L2 has piping L2b which has the valve 20b, and the return sludge containing the treated water from the upper part of the re-aeration tank 9 is introduce | transduced into the nitrification tank 3 from upper direction from this piping L2b.

  In the second embodiment, the discharge amount (discharge amount per unit time) of the return sludge pump 10A is twice the discharge amount of the return sludge pump 10 in the first embodiment. Thereby, the return sludge containing the to-be-treated water from the upper part of the re-aeration tank 9 can be introduced not only in the first denitrification tank 1 but also in the nitrification tank 3.

  Thereby, in this 2nd Embodiment, compared with 1st Embodiment, the frequency | count of the circulation of the to-be-processed water contained in the return sludge in all the water tanks 1, 3, 7, 9 can be increased, and nitrogen in a treated water The removal rate can be improved. That is, the nitrogen treatment efficiency in the high-concentration nitrogen drainage increases the removal rate of nitrogen in the treated water as the number of circulations of the treated water contained in the return sludge in all the water tanks increases.

  In addition, the return amount of the return sludge containing the treated water returned to each of the first denitrification tank 1 and the nitrification tank 3 can be adjusted to a desired distribution by adjusting the opening / closing amounts of the valves 20a and 20b.

(Third embodiment)
Next, FIG. 3 shows a third embodiment of the waste water treatment apparatus of the present invention. The third embodiment is different from the second embodiment in the following point (i). Therefore, in the third embodiment, the same portions as those of the second embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and portions different from those of the second embodiment are described.

  (i) In place of the return sludge pump 10A and the return pipe L2, the return sludge pump 10B and the return pipe L3 are provided as a return section, and the return sludge containing the water to be treated is fed from the upper part of the re-aeration tank 9 to the first denitrification tank 1. And the point which enabled it to return to 3 tanks of the nitrification tank 3 and the 2nd denitrification tank 7.

  The return pipe L3 extends from the aerobic part 19 at the upper part of the re-aeration tank 9 to the upper side of the first denitrification tank 1 via the return sludge pump 10B. This return pipe L3 introduces the return sludge containing the water to be treated from the upper part of the re-aeration tank 9 into the first denitrification tank 1 from above through the pipe L3a having the valve 20a. Moreover, this return piping L3 has the piping L3b which has the valve 20b, and the return sludge containing the to-be-processed water from the upper part of the re-aeration tank 9 is introduce | transduced into the nitrification tank 3 from upper direction from this piping L3b. Moreover, this return piping L3 has the piping L3c which has the valve 20c, and introduce | transduces the return sludge containing the to-be-processed water from the upper part of the reaeration tank 9 into the 2nd denitrification tank 7 from this upper direction.

  In the third embodiment, the discharge amount (discharge amount per unit time) of the return sludge pump 10B is 1.5 times that of the return sludge pump 10A of the second embodiment (that is, the return sludge pump 10 of the first embodiment). 3 times). Thereby, in addition to the 1st denitrification tank 1 and the nitrification tank 3, the return sludge containing the to-be-processed water from the upper part of the re-aeration tank 9 can be introduce | transduced also into the 2nd denitrification tank 7. FIG.

  Thereby, in this 3rd Embodiment, compared with 2nd Embodiment, the frequency | count of the circulation of the to-be-processed water contained in the return sludge in all the water tanks 1, 3, 7, 9 can be increased, Nitrogen removal rate can be improved. That is, the nitrogen treatment efficiency in the high-concentration nitrogen drainage increases the removal rate of nitrogen in the water to be treated as the number of circulations of the water to be treated contained in the return sludge in all the water tanks increases.

  The return amount of the return sludge containing the treated water to be returned to each of the first denitrification tank 1, the nitrification tank 3 and the second denitrification tank 7 is distributed to a desired distribution by adjusting the opening / closing amounts of the valves 20a, 20b and 20c. Can be adjusted.

(First experiment example)
An experimental apparatus having the configuration of the waste water treatment apparatus of the first embodiment shown in FIG. 1 was manufactured. In this experimental apparatus, the capacity of the first denitrification tank 1 is 100 liters, the capacity of the nitrification tank 3 is 200 liters, the capacity of the second denitrification tank 7 is 100 liters, and the capacity of the re-aeration tank 9 is 100 liters.

  In this experimental apparatus, after the microbial training for about two months is completed, the treated water with a nitrogen concentration of 2860 ppm drained from the factory production apparatus is collected at a microorganism concentration of 16500 ppm and continuously in the first denitrification tank 1. Introduced. Then, after waiting for one month to elapse and the water quality to stabilize, the nitrogen concentration of the treated water was measured and found to be 22 ppm.

  FIG. 4A shows a time chart showing an example of the residence time in each tank in the first to third embodiments when the nitrogen concentration of the high-concentration nitrogen wastewater introduced into the first denitrification tank 1 is 3000 ppm. . Moreover, in FIG. 4B, the time chart which shows an example of the residence time in each tank in the said 1st-3rd embodiment in case the nitrogen concentration of the high concentration nitrogen waste_water | drain introduce | transduced into the 1st denitrification tank 1 is 6000 ppm is shown. .

  In addition, in the said 1st-3rd embodiment, when the vinylidene chloride packing 4 which the aerobic part 17 of the nitrification tank 3 has two or more types of vinylidene chloride packing, it propagates more various microorganisms, As a result, the treatment capacity of the high concentration nitrogen waste water can be further improved. Moreover, in the said 1st-3rd embodiment, by introduce | transducing the treated water or domestic sludge of a joint septic tank into the said 1st denitrification tank 1, at least 1 or more of phosphorus, potassium, calcium, and magnesium is said. You may make it add to the 1st denitrification tank 1. FIG. In this case, phosphorus, potassium, calcium, magnesium, etc. contained in the treated water of the combined septic tank or domestic sludge can be effectively used as trace elements that enhance the activity of microorganisms, and the running cost of the waste water treatment apparatus can be reduced. Moreover, in the said 1st-3rd embodiment, the return part sends the microorganism sludge of the flow more than twice the flow volume of the said high concentration nitrogen waste_water | drain flowing into the said 1st denitrification tank 1 per unit time from the said re-aeration tank 9. It is desirable to return to the first denitrification tank 1. In this case, since high-concentration nitrogen wastewater such as toxic high-concentration ammonia wastewater can be diluted to further reduce toxicity, nitrogenous compounds such as ammoniacal nitrogen can be efficiently removed from nitrate nitrogen and the subsequent Nitrogen gas can be reduced.

(Fourth embodiment)
FIG. 5 is a diagram schematically showing a fourth embodiment of the waste water treatment apparatus of the present invention. The fourth embodiment includes a first denitrification tank 41, a nitrification tank 43, a second denitrification tank 47, a re-aeration tank 49, and an aminoethanol tank 54.

  As shown in FIG. 5, the high-concentration nitrogen drainage containing the high-concentration nitrogen-based compound is introduced into the lower part of the first denitrification tank 41. The reason why this high-concentration nitrogen drainage is introduced into the lower part of the first denitrification tank 41 is that the lower part has a higher microorganism concentration due to gravity than the upper part. In the lower part of the first denitrification tank 41, since the microbial concentration is high, the toxic high-concentration nitrogen drainage is less irritating to the microorganism and is suitable for microbial treatment. In addition, this high concentration nitrogen wastewater is nitrogen wastewater containing about 3000 ppm of nitrogen compounds, for example. As an example of this high concentration nitrogen waste water, high concentration ammonia waste water discharged from a semiconductor factory corresponds.

  In the first denitrification tank 41, biologically treated water or sludge generated during biological treatment is introduced. Thereby, trace elements, such as phosphorus, potassium, calcium, magnesium contained in this biologically treated water or biologically treated sludge, promote the activity of microorganisms in all the tanks 41, 43, 47, 49. Will do.

  In the first denitrification tank 41, a stirrer 42 capable of efficiently mixing anaerobic microorganisms and high-concentration nitrogen wastewater is installed. In addition, as long as it is possible to mix anaerobic microorganisms and high-concentration nitrogen wastewater efficiently, an underwater stirrer installed in water may be used instead of a normal stirrer. Moreover, the return sludge including the microorganisms from the aerobic part 59 forming the upper part of the re-aeration tank 49 is introduced into the first denitrification tank 41 by the return part constituted by the return sludge pump 50 and the return pipe L41.

  A submerged film 51 is installed in the aerobic part 59 of the re-aeration tank 49. Due to the presence of the submerged film 51, the microorganisms remain in the re-aeration tank 49 or are returned to the first denitrification tank 41 by the return sludge pump 50. The aerobic part 59 is provided with a diffuser tube 46 that forms an aeration part. The air diffuser 46 is connected to the blower 53.

  This waste water treatment apparatus has a first air lift pump 61, and this first air lift pump 61 removes sludge containing treated water from the anaerobic part 56 forming the lower part of the nitrification tank 43 to the first denitrification tank 41. Return it. The transfer of sludge by the first air lift pump 61 is a transfer method using air, and a large amount of sludge can be transferred with less power. In general, a pump system can secure a large lift, but requires more power than an air lift system. This first air lift pump 61 is in the form of a pipe and can move the water to be treated by introducing air from the blower 53 and performing bubbling. The aerobic portion 57 is provided with a diffuser tube 46 that forms an aeration unit, and the diffuser tube 46 is connected to the blower 53.

  The sludge returned from the re-aeration tank 49 to the first denitrification tank 41 is microbial sludge containing microorganisms. The microbial sludge is sequentially supplied from the first denitrification tank 41 to the nitrification tank 43 and the second denitrification tank 47. Then, it is returned to the re-aeration tank 49 again. That is, the microbial sludge circulates in each tank 41, 43, 47, 49. As the microbial sludge circulates in each tank, the microbial concentration in each tank is maintained at substantially the same concentration. The microorganism concentration in each of the tanks 41, 43, 47, and 49 is maintained at 10,000 ppm or more with MLSS (mixed liquor suspended solid). In addition, in the 1st denitrification tank 41 and the 2nd denitrification tank 47, in order to measure the anaerobic degree, the oxidation-reduction potentiometer (not shown) is installed.

  An appropriate amount of aminoethanol from the aminoethanol tank 54 is added into the first denitrification tank 41 by an aminoethanol pump 55. In the first denitrification tank 41, nitrate nitrogen in the water to be treated introduced by the return sludge pump 50 and the return pipe L41 is present in the presence of aminoethanol which is an alternative to the hydrogen donor methanol by anaerobic microorganisms. Thus, reduction treatment is performed up to nitrogen gas.

  In the first denitrification tank 41, organic substances other than nitrogen in the high-concentration nitrogen wastewater are biologically decomposed by anaerobic microorganisms.

  Next, the to-be-processed water which flowed out from the 1st denitrification tank 41 is introduce | transduced into the lower part of the nitrification tank 43 which has the semi-anaerobic part 56. FIG. Here, the anaerobic part is a state where there is no dissolved oxygen, the aerobic part is a state where the dissolved oxygen is maintained at several ppm, and the semi-anaerobic part is 0 ppm of dissolved oxygen or there is dissolved oxygen. However, it is defined as about 0.5 ppm.

  In the nitrification tank 43, a separation wall 45 for separating the aerobic part 57 that forms the upper part of the nitrification tank 43 and the semi-anaerobic part 56 that forms the lower part is installed on the inner wall of the side surface. The separation wall 45 may be constructed of concrete or made of steel. That is, the material of the separation wall 45 is not limited, but when it is made of steel, it is desirable that the anti-corrosion coating is firmly used when used for a long time.

  In the separation wall 45, a water flow is generated by the air discharged from the diffuser tube 46 in the aerobic portion 57 that forms the upper part of the nitrification tank 43, but the water flow has some influence on the lower semi-anaerobic portion 56. However, it is installed for the purpose of not affecting more.

  In this embodiment, in the circulation system between the first denitrification tank 41 and the re-aeration tank 49 by the return part formed by the return sludge pump 50 and the return pipe L41, the semi-anaerobic part 16 is provided below the nitrification tank 43. Provided. Thereby, the to-be-processed water and the anaerobic microorganisms which were processed by the anaerobic microorganisms in the first denitrification tank 41 are introduced through the semi-anaerobic part 56. Thereby, compared with the case where the said treated water and anaerobic microorganisms are directly introduced into the aerobic part 57 of the upper part of the nitrification tank 43, the stress with respect to the anaerobic microorganisms which move to the nitrification tank 43 can be decreased, and a nitrification tank The nitrogen treatment efficiency at 43 can be improved.

  Further, in the semi-anaerobic part 56 of the nitrification tank 43 and the semi-anaerobic part 58 of the re-aeration tank 49, various microorganisms propagate and not only anaerobic microorganisms and aerobic microorganisms but also various semi-anaerobic parts 56 and 58. By treating the water to be treated with microorganisms, the overall treatment efficiency can be improved.

  Water to be treated and aerobic microorganisms are introduced from the aerobic part 57 of the nitrification tank 43 to the lower part of the second denitrification tank 47. In the 2nd denitrification tank 47, since dissolved oxygen reduces slowly, there is little stress with respect to treated water and an aerobic microorganism.

  Moreover, as a reason which can maintain semi-anaerobic property in the semi-anaerobic part 56 of the nitrification tank 43 and the semi-anaerobic part 58 of the re-aeration tank 49 demonstrated later, in the semi-anaerobic part 56 and the semi-anaerobic part 58, aeration equipment Is not installed and may not be aerated. For this reason, even if the semi-anaerobic parts 56 and 58 are affected by some water flow from the upper aerobic parts 57 and 59, the dissolved oxygen which is the condition of the semi-anaerobic part is 0 ppm or dissolved oxygen exists. Even if it becomes about 0.5 ppm.

  The aerobic part 57 that forms the upper part of the nitrification tank 43 is provided with a vinylidene chloride filler 44 as a filler for effectively propagating microorganisms, and a diffuser tube 46 is provided below the vinylidene chloride filler 44. Is installed. In this wastewater treatment apparatus, microorganisms propagate in the vinylidene chloride filling 44 with the passage of time from the trial run. The microbial concentration on the surface of the vinylidene chloride filling 44 becomes 30000 ppm or more, which leads to an improvement in treatment efficiency. The material of the vinylidene chloride filler 44 is vinylidene chloride which is strong and is not affected by chemical substances, and can be used semipermanently. The vinylidene chloride filling 44 includes products such as biocodes, ring laces, biomulti-leafs, biomodules, etc., and may be selected according to the properties of the waste water.

  In the nitrification tank 43, ammonia nitrogen in the high concentration nitrogen waste water is oxidized by aerobic microorganisms to become nitrate nitrogen or nitrite nitrogen. Below the vinylidene chloride filling 44 in the aerobic part 57 of the nitrification tank 43, the air generated in the blower 53 is discharged from the aeration tube 46. Ascending water flow is generated in the aerobic part 57 by the air discharged from the air diffuser 46, and the aerobic part 57 can maintain aerobic properties and at the same time is agitated with air.

  The anaerobic part 56 is provided with the first air lift pump 61 as described above. In the first air lift pump 61, when the air discharged from the blower 53 ascends inside the pipe 61A installed vertically, the return sludge also rises and is transferred at the same time. The air lift pump 61 can secure a lower head than the power pump, but can transfer a large amount of return sludge to the first denitrification tank 41 with less power.

  Next, the water to be treated in the nitrification tank 43 is introduced into the lower part of the second denitrification tank 47 through a pipe disposed in the upper part of the aerobic part 57 of the nitrification tank 43. The second denitrification tank 47 is provided with a stirrer 48, which stirs the water to be treated and anaerobic microorganisms to promote the nitrogen gas reaction of nitrate nitrogen in the water to be treated. In addition, aminoethanol as a hydrogen donor is added to the second denitrification tank 47 by an aminoethanol pump 55 from an aminoethanol tank 54. By adding aminoethanol as a hydrogen donor to the second denitrification tank 47, nitrate nitrogen is reduced to nitrogen gas and diffused into the air. Thus, when nitrate nitrogen is denitrified as nitrogen gas, it is common to add methanol as a hydrogen donor. In this embodiment, aminoethanol is used as a substitute for methanol. used. The aminoethanol may be aminoethanol waste liquid. In this case, for example, aminoethanol waste liquid discharged from a semiconductor factory can be used as a hydrogen donor as an alternative to methanol as a chemical, so that resources can be effectively used and running costs can be reduced.

  Next, the treated water flowing out from the second denitrification tank 47 is introduced into the lower part of the re-aeration tank 49 having the semi-anaerobic part 58. In the re-aeration tank 49, a separation wall 45 for separating the upper part (aerobic part 59) and the lower part (semi-anaerobic part 58) is installed on the inner side wall. Further, due to the presence of the semi-anaerobic part 58 in the re-aeration tank 49, the treated water and anaerobic microorganisms treated by the anaerobic microorganisms in the second denitrification tank 47 are introduced into the aerobic part 59 through the semi-anaerobic part 58. Thus, the stress on the anaerobic microorganisms is reduced. Therefore, in the circulation system of the four water tanks by the return sludge pump 50 and the return pipe L41 between the first denitrification tank 41 and the re-aeration tank 49, the stress on the anaerobic microorganisms is reduced and the microorganism treatment by the anaerobic microorganisms is performed. Can promote. On the other hand, when the treated water treated with the anaerobic microorganisms in the second denitrification tank 47 and the anaerobic microorganisms are directly introduced into the aerobic part 59, the stress on the anaerobic microorganisms increases.

  A second air lift pump 62 is installed in the re-aeration tank 49. In the second air lift pump 62, the vertical pipe 62 </ b> A extending vertically is located in the anaerobic part 58 of the re-aeration tank 49, and the treated water is circulated from the anaerobic part 58 to the second denitrification tank 47. As with the first air lift pump 61, air is supplied from the blower 53 to the vertical pipe 62 </ b> A of the second air lift pump 62.

  In addition, since dissolved oxygen slowly decreases in the first denitrification tank 41, there is little stress on the water to be treated and the aerobic microorganisms moving from the anaerobic part 58 of the re-aeration tank 49 to the first denitrification tank 41. The aerobic part 59 of the re-aeration tank 49 includes a submerged film 51 and a diffuser tube 46 disposed below the submerged film 51 to clean the submerged film 51 with air. As the submerged membrane 51, two types, a flat membrane type and a hollow fiber membrane, are commercially available.

  In the re-aeration tank 49, treated water naturally flows out from the gravity pipe 63 connected to the submerged film 51 by the action of gravity. The gravity pipe 63 is for draining treated water due to a water head difference between the water surface in the re-aeration tank 49 and the lower end of the gravity pipe 63. Since the outflow method using the gravity pipe does not require electric power, an energy saving operation is possible. Further, when the submerged film 51 is blocked and the discharge amount from the gravity pipe 63 is decreased, the treated water is discharged by operating the submerged film pump 52 connected to the submerged film 51 by the pipe. Can be secured. Alternatively, both of the two types of piping, that is, the gravity piping 63 and the piping connected to the submerged membrane pump 52, may be simultaneously used to secure treated water by taking advantage of each piping. When the amount of permeated water of the submerged membrane 51 is reduced (that is, when the amount of treated water is reduced), the submerged membrane 51 is washed with sodium hypochlorite or the like.

(Fifth embodiment)
Next, FIG. 6 shows a fifth embodiment of the waste water treatment apparatus of the present invention. This fifth embodiment is different from the above-described fourth embodiment only in that the first denitrification tank 41 is filled with the vinylidene chloride filling 44-1. Therefore, the same parts as those in the above-described fourth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, this 5th Embodiment can improve the nitrogen treatment efficiency with respect to high concentration nitrogen waste_water | drain by filling the 1st denitrification tank 41 with the vinylidene chloride filling material 44-1 as a filler. By filling the first denitrification tank 41 with the vinylidene chloride filling 44-1 as in the fifth embodiment, not only the microorganism concentration in the first denitrification tank 41 becomes higher but also the vinylidene chloride filling. Microorganisms adhere to and proliferate on the object 44, and the microorganisms are more stabilized and the nitrogen treatment capacity is improved as compared with a state where there is no packing. In order to make the microbial concentration high throughout the tank 41, it is preferable to dispose the vinylidene chloride filling 44-1 throughout the water tank 41. As in the fifth embodiment, the presence of the vinylidene chloride filler 44-1 in the first denitrification tank 41 increases the anaerobic degree (measured by the oxidation-reduction potential) and can promote the denitrification reaction. .

(Sixth embodiment)
Next, FIG. 7 shows a sixth embodiment of the present invention. The sixth embodiment is different from the fifth embodiment described above in that not only the first denitrification tank 41 but also the second denitrification tank 47 is filled with the vinylidene chloride filler 44-1. Therefore, in the sixth embodiment, the same parts as those in the above-described fifth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, in the sixth embodiment, the second denitrification tank 47 is filled with the vinylidene chloride filler 44-1 as the filler, so that the nitrogen treatment efficiency for the high concentration nitrogen waste water can be improved. In the sixth embodiment, since the second denitrification tank 47 is also filled with the vinylidene chloride filler 44-1, not only the microbial concentration in the second denitrification tank 47 becomes higher, but also the vinylidene chloride filler. Compared to the state where microorganisms adhere to and propagate on 44-1, and there is no packing, the microorganisms are more stabilized and the treatment capacity of nitrogen is improved. In order to make the microbial concentration high throughout the tank 47, it is preferable to dispose the vinylidene chloride filler 44-1 throughout the water tank. In the sixth embodiment, since the vinylidene chloride filling 44-1 as the filler exists in the second denitrification tank 47, the anaerobic degree (measured by the oxidation-reduction potential) is increased, and the denitrification reaction can be promoted.

(Seventh embodiment)
Next, FIG. 8 shows a seventh embodiment of the present invention. The seventh embodiment is different from the above-described fourth embodiment in that high-concentration nitrogen drainage and developing waste liquid are introduced into the lower portion of the first denitrification tank 41. Therefore, in the seventh embodiment, the same portions as those in the above-described fourth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the seventh embodiment, not only the high-concentration nitrogen drainage but also the development waste liquid is introduced into the lower portion of the first denitrification tank 41, so that the development waste liquid that is a waste liquid containing organic matter can be treated. Examples of the developing waste liquid that is a waste liquid containing organic substances include a developing waste liquid discharged from a semiconductor factory. The main component of this developing waste liquid is tetramethylammonium hydroxide.

  In the seventh embodiment, as in the above-described fourth embodiment, the submerged membrane 51 is used as a method for wastewater treatment, and the microbial concentration is increased to 10000 ppm or more to drain both anaerobic microorganisms and aerobic microorganisms. Since it is processed, it is also possible to treat a developing waste liquid that is a waste liquid containing the organic matter.

(Eighth embodiment)
Next, FIG. 9 shows an eighth embodiment of the present invention. The eighth embodiment is different from the above-described fourth embodiment in that both high-concentration nitrogen waste water and dimethylformamide waste liquid are introduced into the lower portion of the first denitrification tank 41. Therefore, in the eighth embodiment, the same portions as those in the above-described fourth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the eighth embodiment, not only the high-concentration nitrogen wastewater but also the dimethylformamide waste liquid is introduced into the lower part of the first denitrification tank 41, so that the development waste liquid that is a waste liquid containing organic matter can be treated. The dimethylformamide waste liquid which is a waste liquid containing organic substances is discharged from, for example, a semiconductor factory.

  In the eighth embodiment, as in the fourth embodiment described above, the submerged membrane 51 is used as a method for wastewater treatment, and the microbial concentration is increased to 10,000 ppm or more to drain both anaerobic microorganisms and aerobic microorganisms. Since it processes, the dimethylformamide waste liquid which is a waste liquid containing the said organic substance can also be processed. Dimethylformamide contained in the dimethylformamide waste liquid is a harmful substance.

(Example 2)
An experimental apparatus having the configuration of the waste water treatment apparatus of the fourth embodiment shown in FIG. 5 was produced. In this experimental apparatus, the capacity of the first denitrification tank 41 is 100 liters, the capacity of the nitrification tank 43 is 200 liters, the capacity of the second denitrification tank 47 is 100 liters, and the capacity of the re-aeration tank 49 is 100 liters.

  In this experimental apparatus, after the microbial training for about two months is completed, treated water with a nitrogen concentration of 2640 ppm drained from the factory production equipment is collected at a microorganism concentration of 18500 ppm and continuously in the first denitrification tank 41. Introduced. Then, after waiting for one month to elapse and the water quality to stabilize, the nitrogen concentration of the treated water was measured and found to be 20 ppm.

  In addition, in FIG. 10A, the time chart which shows an example of the residence time in each tank in the said 4th-8th embodiment in case the nitrogen concentration of the high concentration nitrogen waste_water | drain introduce | transduced into the 1st denitrification tank 41 is 3000 ppm is shown. . FIG. 10B shows a time chart showing an example of the residence time in each tank in the fourth to eighth embodiments when the nitrogen concentration of the high-concentration nitrogen wastewater introduced into the first denitrification tank 41 is 6000 ppm. .

  In addition, in the said 4th-8th embodiment, you may provide the return part which returns the sludge of the semi-anaerobic part 58 of the lower part of the reaeration tank 49 to the 1st denitrification tank 41. FIG. In this case, the anaerobic state of the first denitrification tank 41 can be reliably maintained and stabilized as compared with the case where the sludge of the aerobic part 59 of the re-aeration tank 49 is returned to the first denitrification tank 41. Thereby, denitrification performance can be improved.

(Ninth embodiment)
Next, FIG. 11 shows a ninth embodiment of the waste water treatment apparatus of the present invention. The ninth embodiment includes a raw water tank 71, a first denitrification tank 73, a first nitrification tank 77, a second denitrification tank 82, a second nitrification tank 104, a third denitrification tank 88, and a re-aeration tank. 90, a contact oxidation tank 98 and a precipitation tank 100.

  The raw water tank 71 is introduced with high-concentration nitrogen drainage containing nitrogen-based compounds from above. The raw water tank 71 can be adjusted to some extent with respect to the amount and quality of the drainage water, although there are differences in the degree depending on the capacity of the raw water tank 71.

  The high-concentration nitrogen wastewater introduced into the raw water tank 71 is introduced into the lower part of the first denitrification tank 73 by the raw water tank pump 72. The first denitrification tank 73 is supplied with aminoethanol from an aminoethanol tank 83 by an aminoethanol pump 84.

  In this 1st denitrification tank 73, the said high concentration nitrogen waste_water | drain is introduce | transduced into the lower part where the microorganisms concentration is high concentration compared with the upper part, and the irritation | stimulation which a toxic high concentration nitrogen waste water gives to microorganisms can be reduced. . In addition, this high concentration nitrogen waste water is high concentration nitrogen waste water containing about 3000 ppm of nitrogen compounds, for example. As this high concentration nitrogen waste water, high concentration ammonia waste water discharged from a semiconductor factory corresponds.

  The first denitrification tank 73 is treated with biologically treated water or sludge generated when biologically treated. Microbial treatment can be promoted by the trace elements such as phosphorus, potassium, calcium, and magnesium contained in the biologically treated water or sludge generated during the biological treatment promoting the activity of microorganisms in all the tanks.

  The first denitrification tank 73 is provided with a stirrer 74. This stirrer 74 can efficiently mix anaerobic microorganisms and high-concentration nitrogen wastewater. The stirrer 74 may be an underwater stirrer installed in water instead of a normal stirrer. In addition, the return sludge containing microorganisms from the re-aeration tank 90 is returned to and introduced into the first denitrification tank 73 by a return section constituted by the return sludge pump 96 and the return pipe L96.

  The re-aeration tank 90 has a lower semi-anaerobic part 91 and an upper aerobic part 92, and a submerged film 93 is installed in the upper aerobic part 92. A diffuser tube 81 is disposed below the submerged film 93. The air diffuser 81 is connected to the blower 97. The air diffuser 81 and the blower 97 constitute an aeration unit. In the re-aeration tank 90, the microorganisms remain in the re-aeration tank 90 by the submerged film 93 of the aerobic part 92 or are returned to the first denitrification tank 73 by the return sludge pump 96.

  The first air lift pump 75 circulates the microbial sludge containing the water to be treated from the anaerobic part 78 below the first nitrification tank 77 to the first denitrification tank 73. The first air lift pump 75 operates when air is supplied from the blower 97, and can transfer a large amount of return sludge with less power. Although a general pump system can secure a large lift, it requires a lot of power compared to an air lift system. That is, according to the air lift pump 75, energy saving can be achieved.

  The microbial sludge returned to the first denitrification tank 73 from the return unit and the air lift pump 75 is sequentially supplied to the first nitrification tank 77, the second denitrification tank 82, the second nitrification tank 104, and the third denitrification tank 88. Then, it returns to the re-aeration tank 90 again and circulates through the tanks 73, 77, 82, 104, 88, 90. By circulating the microbial sludge through each tank, the microbial concentration in each tank is maintained at substantially the same concentration. The microorganism concentration in each tank is maintained at 10000 ppm or more by MLSS (Mixed Liquor Suspended Solid).

  The treated water returned from the re-aeration tank 90 to the first denitrification tank 73 sequentially passes through the first nitrification tank 77, the second denitrification tank 82, the second nitrification tank 104, and the third denitrification tank 88. Then, it returns to the re-aeration tank (which can be regarded as a third nitrification tank) 90 again. Thereby, the said to-be-processed water will circulate an anaerobic tank and an aerobic tank 3 steps or more (3 steps from 1st to 3rd), and substantially zero generated sludge is achieved. . The anaerobic tanks are the three tanks of the first denitrification tank 73, the second denitrification tank 82, and the third denitrification tank 88, and the aerobic tanks are the first nitrification tank 77 and the second nitrification tank. A nitrification tank 104 and a re-aeration tank 90.

  In addition, in the 1st denitrification tank 73, the 2nd denitrification tank 82, and the 3rd denitrification tank 88, in order to measure the anaerobic degree, the oxidation-reduction potentiometer (not shown) is installed.

  In the first denitrification tank 73, nitrate nitrogen in the water to be treated introduced from the return sludge pump 96 is reduced to nitrogen gas by anaerobic microorganisms in the presence of aminoethanol which is a substitute for hydrogen donor methanol. It is processed. An appropriate amount of this aminoethanol is added from the aminoethanol tank 83 to the first denitrification tank 73 by the aminoethanol pump 84. Naturally, as a hydrogen donor, it goes without saying that general alcohols such as methanol may be selected in place of aminoethanol. The aminoethanol may be aminoethanol waste liquid. In this case, for example, aminoethanol waste liquid discharged from a semiconductor factory can be used as a hydrogen donor as an alternative to methanol as a chemical, so that resources can be effectively used and running costs can be reduced.

  In the first denitrification tank 73, organic substances other than nitrogen in the high concentration nitrogen waste water are biologically decomposed by anaerobic microorganisms.

  Next, the water to be treated that has flowed out of the first denitrification tank 73 is introduced into the semi-anaerobic part 78 at the lower part of the first nitrification tank 77. The first nitrification tank 77 has a lower semi-aerobic part 78 and an upper aerobic part 79, and the aerobic part 79 is disposed below the vinylidene chloride filling 80 and the vinylidene chloride filling 80. And an air diffuser 81. The air diffuser 81 is connected to the blower 97. The blower 97 and the air diffuser 81 constitute an aeration unit.

  Here, the anaerobic part is a state where there is no dissolved oxygen, the aerobic part is a state where the dissolved oxygen is maintained at several ppm, and the semi-anaerobic part is 0 ppm of dissolved oxygen or there is dissolved oxygen. However, it is defined as about 0.5 ppm.

  In the first nitrification tank 77, a separation wall 76 for separating the upper part (aerobic part 79) and the lower part (semi-anaerobic part 78) of the first nitrification tank 77 is installed on the side inner wall of the first nitrification tank 77. Yes. The separation wall 76 may be constructed of concrete or made of steel. In other words, the material of the separation wall 76 is not limited, but it is desirable that the separation wall 76 be made of steel, and if it is used for a long period of time, it should be firmly coated for corrosion. A water flow is generated by the air discharged from the air diffuser 81 in the aerobic portion 79 in the upper part of the first nitrification tank 77, but this water flow has some influence on the lower semi-anaerobic part 78 due to the presence of the separation wall 76. However, many will not be affected.

  Moreover, in this embodiment, in the circulation system by the return part (return sludge pump 96, return piping L96) formed between the 1st denitrification tank 73 and the re-aeration tank 90, the said 1st nitrification tank 77 is half in the lower part. It has an anaerobic part 78. In this way, the anaerobic microorganisms that move together with the water to be treated treated with the anaerobic microorganisms in the first denitrification tank 73 are not directly (straightly) introduced into the aerobic part 79, but are semi-anaerobic parts. After 78, it is introduced into the aerobic part 79. Thereby, the environmental stress with respect to the anaerobic microorganisms which move to the 1st nitrification tank 77 from the 1st denitrification tank 73 can be decreased. Since there is little environmental stress with respect to anaerobic microorganisms, the efficiency at the time of processing nitrogen can be improved.

  In addition, microorganisms specific to the semi-anaerobic part 78 of the first nitrification tank 77 are propagated, and the treated water is microbially treated not only by anaerobic microorganisms and aerobic microorganisms but also by various microorganisms that propagate in the semi-anaerobic part 78. Therefore, overall processing efficiency can be improved.

  Similarly to the first nitrification tank 77, a second nitrification tank 104 and a re-aeration tank 90 described later also have a semi-anaerobic part 86 and a semi-anaerobic part 91 in the lower part. It was discovered that the microorganisms that propagate in these semi-anaerobic parts 78, 86, 91 are useful for reducing the volume of sludge. That is, in this embodiment, the sludge can be significantly reduced by the three-stage semi-anaerobic portions 78, 86, 91, and the substantial sludge elimination can be achieved.

  Next, the water to be treated and the aerobic microorganisms move from the aerobic part 79 of the first nitrification tank 77 to the lower part of the second denitrification tank 82. In the 2nd denitrification tank 82, since dissolved oxygen reduces slowly, there is little stress with respect to the said treated water and an aerobic microorganism.

  In the semi-anaerobic part 78 of the first nitrification tank 77 described above, the semi-anaerobic part 86, and the semi-anaerobic part 91 described later, aeration equipment is not installed in the semi-anaerobic part 78, the semi-anaerobic part 86, and the semi-anaerobic part 91. So it is not aerated. The semi-anaerobic part 78, the semi-anaerobic part 86, and the semi-anaerobic part 91 are affected by some water flow from the upper aerobic part 79, aerobic part 87, and aerobic part 92. Even if dissolved oxygen, which is a condition, is 0 ppm or dissolved oxygen is present, it becomes about 0.5 ppm, and semi-anaerobic properties can be maintained.

  Also, a vinylidene chloride filler 80 as a filler for effectively propagating microorganisms is installed in the aerobic portion 79 at the upper part of the first nitrification tank 77, and an air diffuser tube is provided under the vinylidene chloride filler 80. 81 is installed. Microorganisms propagate in the vinylidene chloride filling 80 with the passage of time from the trial operation of the wastewater treatment apparatus. The microbial concentration on the surface of the vinylidene chloride filler 80 becomes 30000 ppm or more, which leads to an increase in processing efficiency. The material of the vinylidene chloride filler 80 is vinylidene chloride that is strong and not affected by chemical substances, and can be used semipermanently. The vinylidene chloride filling 80 includes products such as biocodes, ring laces, biomulti-leafs, biomodules, etc., and may be selected according to the properties of the waste water.

  In the first nitrification tank 77, ammonia nitrogen in the high concentration nitrogen waste water is oxidized by aerobic microorganisms to become nitrate nitrogen or nitrite nitrogen. In addition, air generated in the blower 97 is discharged from the air diffuser 81 to the lower part of the vinylidene chloride filling 80. The air discharged from the air diffuser 81 generates an ascending water flow in the aerobic part 79, and the aerobic part 79 can maintain aerobic properties and at the same time be agitated with air.

  The aerobic portion 79 is provided with a first air lift pump 75. In the first air lift pump 75, when the air discharged from the blower 97 rises inside the pipe 75A provided vertically, the return sludge is also lifted and transferred simultaneously. Although this air lift pump 75 can secure only a small head, a large amount of return sludge can be transferred from the first nitrification tank 77 to the first denitrification tank 73 with less power.

  Next, the water to be treated from the first nitrification tank 77 is introduced into the lower part of the second denitrification tank 82 through a pipe disposed in the upper part of the aerobic part 79 of the first nitrification tank 77. The second denitrification tank 82 is provided with a stirrer 74, which stirs the treated water and anaerobic microorganisms and promotes the nitrogen gas reaction of nitrate nitrogen in the treated water. . In addition, aminoethanol as a hydrogen donor is added to the second denitrification tank 82 by an aminoethanol pump 84 from an aminoethanol tank 83. By adding aminoethanol as a hydrogen donor to the second denitrification tank 82, nitrate nitrogen is reduced to form nitrogen gas and diffused into the air. In a denitrification tank, when nitrate nitrogen is denitrified as nitrogen gas, it is common to add methanol as a hydrogen donor. In this embodiment, aminoethanol is used as a substitute for methanol. .

  Next, the to-be-processed water which flowed out from the 2nd denitrification tank 82 is introduce | transduced into the semi-anaerobic part 86 of the lower part of the 2nd nitrification tank 104. FIG. In the second nitrification tank 104, a separation wall 76 for separating the upper part (aerobic part 87) and the lower part (semi-anaerobic part 86) of the second nitrification tank 104 is installed on the inner side wall of the second nitrification tank 104. ing.

  In a circulation system of six water tanks by a return part (return sludge pump 96, return pipe L96) arranged between the first denitrification tank 73 and the re-aeration tank 90, the second nitrification tank 104 is a semi-anaerobic part at the bottom. 86. Thereby, the anaerobic microorganisms that move together with the water to be treated treated by the anaerobic microorganisms in the second denitrification tank 82 are not directly (straightly) introduced into the aerobic part 87 but are semi-anaerobic part 86. It can introduce into the aerobic part 87 via. Thereby, the stress with respect to anaerobic microorganisms can be decreased.

  Moreover, by providing the semi-anaerobic part 86, as described above, microorganisms that propagate in the three semi-anaerobic parts of the semi-anaerobic part 78, the semi-anaerobic part 86, and the semi-anaerobic part 91 are useful for reducing sludge volume. I found And the substantial zeroization of sludge can be achieved by constructing microbial treatment of three steps or more by the three semi-anaerobic parts.

  In addition, this waste water treatment apparatus has a second air lift pump 85-1 that circulates water to be treated from the anaerobic part 86 at the lower part of the second nitrification tank 104 to the second denitrification tank 82. The second air lift pump 85-1 can simultaneously transfer the return sludge contained in the water to be treated when the air discharged from the blower 97 rises inside the vertical pipe 85-1A. The second air lift pump 85-1 can transfer a large amount of return sludge from the second nitrification tank 104 to the second denitrification tank 82 with a small amount of electric power.

  Next, the treated water from the second nitrification tank 104 is introduced into the third denitrification tank 88 through a pipe disposed on the upper part of the aerobic part 87 of the second nitrification tank 104. In this third denitrification tank 88, the dissolved oxygen decreases slowly, so that there is little stress on the water to be treated and the aerobic microorganisms moving from the aerobic part 87 of the second nitrification tank 104 to the third denitrification tank 88. .

  The third denitrification tank 88 is provided with a stirrer 89, which stirs the water to be treated and anaerobic microorganisms and promotes the nitrogen gas reaction of nitrate nitrogen in the treated water. . In addition, aminoethanol as a hydrogen donor is added to the third denitrification tank 88 from an aminoethanol tank 83 by an aminoethanol pump 84. By adding aminoethanol as a hydrogen donor to the third denitrification tank 88, nitrate nitrogen is reduced to nitrogen gas and diffused into the air. As described above, when nitrate nitrogen is reduced and denitrified as nitrogen gas, it is common that methanol is added as a hydrogen donor. Ethanol was used.

  Next, the treated water flowing out from the third denitrification tank 88 is introduced into the lower part of the re-aeration tank 90 having the semi-anaerobic part 91. The re-aeration tank 90 has a separation wall 76 for separating the upper part (aerobic part 92) and the lower part (semi-anaerobic part 91) of the re-aeration tank 90. The separation wall 76 is installed on the inner side wall of the re-aeration tank 90. Further, by providing the semi-anaerobic part 21 in the re-aeration tank 90, it is introduced from the denitrification tank for the same reason as providing the semi-anaerobic parts 78 and 86 in the first nitrification tank 73 and the second nitrification tank 104. The stress on the anaerobic microorganisms can be reduced.

  Further, in the aerobic portion 92 at the upper portion of the re-aeration tank 90, a submerged film 93 and a diffuser tube 81 disposed below the submerged film 93 are installed. The air diffuser 81 is connected to a blower 97, and air discharged from the blower 97 is supplied. The blower 97 and the air diffuser 81 constitute an aeration unit. As the submerged membrane 93, two types, a flat membrane type and a hollow fiber membrane, are commercially available.

  The treated water in the re-aeration tank 90 naturally flows out from the gravity pipe 95 connected to the submerged film 93 by the action of gravity. That is, the gravity pipe 95 uses the difference (water head difference) between the water surface in the re-aeration tank 90 and the lower end of the gravity pipe 95, and does not require electric power to discharge the treated water. Is possible.

  In addition, when the submerged membrane 93 is blocked and the discharge amount from the gravity pipe 95 is reduced, the treated water is surely treated by operating the submerged membrane pump 94 connected to the submerged membrane 93 by the pipe. Can be secured. Further, the submerged membrane 23 is connected to both a gravity pipe 95 that obtains treated water by a gravity method and a submerged membrane pump 94 that forcibly obtains treated water using electric power. It is more preferable from the viewpoint of safe driving to secure treated water by utilizing the above. When the amount of permeated water of the submerged membrane 93 decreases, that is, when the amount of treated water decreases, the submerged membrane 93 is washed with sodium hypochlorite or the like.

  Moreover, in this embodiment, it has the 3rd air lift pump 85-2 which circulates to-be-processed water from the anaerobic part 91 of the lower part of the re-aeration tank 90 to the 3rd denitrification tank 88. FIG. The third air lift pump 85-2 can simultaneously transfer the return sludge contained in the treated water when the air discharged from the blower 97 rises inside the vertical pipe 85-2A. Therefore, the third air lift pump 85-2 can transfer a large amount of return sludge from the re-aeration tank 90 to the third denitrification tank 88 with a small amount of electric power.

  Next, the water to be treated from the re-aeration tank 90 is introduced into the contact oxidation tank 98 via the gravity pipe 95 or the submerged membrane pump 94. In the contact oxidation tank 98, a small amount of organic matter remaining in the water to be treated is biologically treated by the biofilm generated in the kakiga (oyster shell) 99. Moreover, in this re-aeration tank 90, when the pH of to-be-processed water has fallen to about 6 or less, the to-be-processed water is neutralized by the said scraper 99 melt | dissolving. The contact oxidation tank 98 is provided with an air diffuser 81 for aeration inside the tank. The air discharged from the blower 97 is supplied to the air diffuser 81.

  Next, the water to be treated from the contact oxidation tank 98 is introduced into the precipitation tank 100 having the rake 101 and separated into sludge containing a mineral such as calcium as a precipitate and a supernatant. This supernatant is discharged into a river or the like, or processed again and recycled in the factory. Since the sedimentation tank 100 has the scraper 99, sludge containing minerals such as calcium is generated. In other words, kakigara 99 is natural, and is composed of various minerals with calcium carbonate as a main component. When kakigara 99 comes into contact with acidic treated water, the components are dissolved and finally Sludge containing minerals such as calcium is generated. In addition, the reason why acidic water to be treated is generated in the sedimentation tank 100 is that nitrogen in the high-concentration nitrogen wastewater is oxidized to produce nitrate nitrogen, and the pH of the treated water is lowered. And the sludge containing minerals, such as calcium precipitated in the sedimentation tank 100, moves in the mineral sludge piping 103 by the pump 102, is introduced into the raw water tank 71, and is mixed with the high concentration nitrogen waste water.

  In each of the first denitrification tank 73, the first nitrification tank 77, the second denitrification tank 82, the second nitrification tank 104, the third denitrification tank 88, and the re-aeration tank 90, the microorganism concentration is maintained at a high concentration, When processing high concentration nitrogen wastewater, which is a toxic substance, if the water to be treated contains minerals such as calcium, the microorganisms are more activated and the treatment can be performed efficiently.

(Tenth embodiment)
Next, FIG. 12 shows a tenth embodiment of the waste water treatment apparatus of the present invention. In the tenth embodiment, the first denitrification tank 73N is filled with a vinylidene chloride filler 180 as a filler, the second denitrification tank 82N is filled with a vinylidene chloride filler 181 as a filler, and the third denitrification tank 88N is filled. A vinylidene chloride filler 182 is filled as a material. In other respects, the tenth embodiment is the same as the ninth embodiment. Therefore, in the tenth embodiment, the same portions as those in the ninth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the tenth embodiment, the first denitrification tank 73N, the second denitrification tank 82N, and the third denitrification tank 88N were filled with vinylidene chloride fillers 180, 181, and 182 as fillers. Thereby, each microorganism concentration in the 1st denitrification tank 73N, the 2nd denitrification tank 82N, and the 3rd denitrification tank 88N can be made high. Therefore, in the tenth embodiment, when the entire tank is averaged, the microorganism concentration is higher than that in the case where there is no packing. In addition, microorganisms adhere to and propagate on the vinylidene chloride filler 180 to 182, and the microorganisms are more stabilized and the nitrogen treatment capacity can be improved compared to the case where the filler is not present.

  In addition, the said vinylidene chloride filling 180-182 arrange | positions to the whole water tank 73N, 82N, 88N, and a microorganism will propagate to high concentration in each whole tank, and is preferable. When this vinylidene chloride filling 180-182 exists, compared with the case where there is no said filling, in each tank, the anaerobic degree measured by oxidation-reduction potential increases more, and a denitrification reaction can be accelerated | stimulated.

(Eleventh embodiment)
Next, an eleventh embodiment of the waste water treatment apparatus of the present invention is shown in FIG. The eleventh embodiment is different from the ninth embodiment in that both high-concentration nitrogen drainage and developing waste liquid are introduced into the raw water tank 71. Therefore, in the eleventh embodiment, the same portions as those in the ninth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the eleventh embodiment, similarly to the ninth embodiment, high-concentration nitrogen drainage can be treated, but the submerged membrane 93 disposed in the aerobic part 92 of the re-aeration tank 90 is used to reduce the microbial concentration. High concentration nitrogen wastewater is treated with both anaerobic microorganisms and aerobic microorganisms by raising the concentration to 10,000 ppm or more. Therefore, in the eleventh embodiment, development waste liquid containing other organic substances can be treated with both the anaerobic microorganisms and the aerobic microorganisms propagated at the high concentration. The development waste liquid corresponds to, for example, a development waste liquid discharged from a semiconductor factory that is an organic waste liquid. The main component of this developing waste liquid is tetramethylammonium hydroxide.

  According to the eleventh embodiment, since two types of wastewater can be treated with one wastewater treatment device, the initial cost and running cost can be reduced.

(Twelfth embodiment)
Next, FIG. 14 shows a twelfth embodiment of the waste water treatment apparatus of the present invention. The twelfth embodiment differs from the ninth embodiment described above in that both high-concentration nitrogen drainage and dimethylformamide waste liquid are introduced into the raw water tank 71. Therefore, in the twelfth embodiment, the same parts as those in the twelfth embodiment described above are denoted by the same reference numerals and detailed description thereof is omitted.

  In the twelfth embodiment, similarly to the ninth embodiment, high-concentration nitrogen waste water can be treated, but the submerged membrane 93 disposed in the aerobic part 92 of the re-aeration tank 90 is used to reduce the microbial concentration. High concentration nitrogen wastewater is treated with both anaerobic microorganisms and aerobic microorganisms by raising the concentration to 10,000 ppm or more. Therefore, in the twelfth embodiment, waste liquids containing other organic substances can be treated with both the anaerobic microorganisms and the aerobic microorganisms propagated at the high concentration. That is, in the twelfth embodiment, for example, dimethylformamide waste liquid discharged from a semiconductor factory, which is an organic waste liquid, can be treated.

  In the twelfth embodiment, as described above, since the microorganism concentration is 10,000 ppm or more, dimethylformamide, which is a harmful substance contained in the dimethylformamide waste liquid, can be treated. As in the twelfth embodiment, the initial cost and the running cost can be reduced by treating two types of wastewater with one wastewater treatment device.

(Third experimental example)
An experimental apparatus having the configuration of the waste water treatment apparatus of the ninth embodiment shown in FIG. 11 was produced. The capacity of the raw water tank 71 in this experimental apparatus was 50 liters, and the capacity of the first denitrification tank 73, the second denitrification tank 82, and the third denitrification tank 88 was 100 liters. Moreover, the capacity | capacitance of the 1st nitrification tank 77, the 2nd nitrification tank 104, and the re-aeration tank 90 was 200 liters, respectively. The capacity of the contact oxidation tank 98 was 200 liters, and the capacity of the precipitation tank 100 was 50 liters.

  In this experimental apparatus, after the microbial training for about two months is completed, treated water with a nitrogen concentration of 2660 ppm discharged from the factory production equipment is collected and continuously introduced into the raw water tank 71 with a microorganism concentration of 18600 ppm. did. Then, after waiting for one month to elapse and the water quality to stabilize, the nitrogen concentration of the treated water was measured and found to be 15 ppm.

  In addition, in FIG. 15, the time chart which shows an example of the residence time in each tank in the said 9th-12th embodiment in case the nitrogen concentration of the high concentration nitrogen waste_water | drain introduce | transduced into the raw | natural water tank 71 is 3000 ppm is shown. FIG. 16 is a time chart showing an example of the residence time in each tank in the ninth to twelfth embodiments when the nitrogen concentration of the high-concentration nitrogen wastewater introduced into the raw water tank 71 is 6000 ppm.

  In the ninth to twelfth embodiments, a return unit that returns sludge to the first denitrification tank 73 from the semi-anaerobic part 91 below the re-aeration tank 90 may be provided. In this case, the anaerobic state of the first denitrification tank 73 can be stabilized as compared with the case where the sludge in the aerobic section 92 of the re-aeration tank 90 is returned to the first denitrification tank 73. Thereby, denitrification performance can be improved.

It is a figure which shows typically 1st Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 2nd Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 3rd Embodiment of the waste water treatment equipment of this invention. It is an example (when nitrogen concentration is 3000 ppm) in the time chart in the said 1st-3rd embodiment. It is an example (when nitrogen concentration is 6000 ppm) in the time chart in the said 1st-3rd embodiment. It is a figure which shows typically 4th Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 5th Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 6th Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 7th Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 8th Embodiment of the waste water treatment equipment of this invention. It is an example (when nitrogen concentration is 3000 ppm) in the time chart in the said 4th-8th embodiment. It is an example (when nitrogen concentration is 6000 ppm) in the time chart in the said 4th-8th embodiment. It is a figure which shows typically 9th Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 10th Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 11th Embodiment of the waste water treatment equipment of this invention. It is a figure which shows typically 12th Embodiment of the waste water treatment equipment of this invention. It is an example (when nitrogen concentration is 3000 ppm) in the time chart in the said 9th-12th embodiment. It is an example (when nitrogen concentration is 6000 ppm) in the time chart in the said 9th-12th embodiment.

Explanation of symbols

1, 41, 73, 73N First denitrification tank 2, 42, 74 Stirrer 3, 43 Nitrification tank 4, 44, 80, 180, 181, 182 Vinylidene chloride filler 5, 45, 76 Separation wall 6, 46, 81 Air diffuser 7, 47, 82, 82N Second denitrification tank 8, 48, 74, 89 Stirrer 9, 49, 90 Re-aeration tank 10, 10A, 10B, 50, 96 Return sludge pump 11, 51, 93 Submerged membrane 12, 52, 94 Submerged membrane pump 13, 53, 97 Blower 14 Methanol tank 15 Methanol pump 16, 18, 56, 58, 78, 86, 91 Semi-anaerobic part 17, 19, 57, 59, 79, 87, 92 Aerobic part
20a-20c Valves L1-L3, L41 Return piping 54, 83 Aminoethanol tank 61, 75 First air lift pump 62 Second air lift pump 63, 95 Gravity piping 71 Raw water tank 72 Raw water tank pump 77 First nitrification tank 85-1 Second air lift pump 85-2 Third air lift pump 88, 88N Third denitrification tank L96 Return piping 98 Contact oxidation tank 100 Precipitation tank 104 Second nitrification tank

Claims (27)

A first denitrification tank into which nitrogen drainage containing a nitrogen-based compound is introduced, at least one of phosphorus, potassium, calcium, and magnesium is added, and a hydrogen donor is added;
A nitrification tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the first denitrification tank is introduced into the semi-anaerobic part,
A second denitrification tank into which treated water from the nitrification tank is introduced and a hydrogen donor is added;
A re-aeration tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the second denitrification tank introduced into the semi-anaerobic part;
A wastewater treatment apparatus characterized in that the microbial concentration of treated water in the first denitrification tank, nitrification tank, second denitrification tank, and re-aeration tank is 10,000 ppm or more. A first denitrification step in which at least one of phosphorus, potassium, calcium, and magnesium and a hydrogen donor are added to a nitrogen wastewater containing a nitrogen-based compound to denitrify the nitrogen wastewater;
A nitrification step of treating the denitrified treated water in order in a semi-anaerobic part and an aerobic part;
A second denitrification step of adding a hydrogen donor to the treated water after the nitrification step and performing a denitrification treatment;
A re-aeration process for sequentially treating the treated water after the second denitrification process in a semi-anaerobic part and an aerobic part,
A wastewater treatment method characterized in that the microbial concentration of treated water in each of the above steps is 10,000 ppm or more. The waste water treatment apparatus according to claim 1,
The re-aeration tank is characterized in that the upper aerobic part has a submerged membrane. The waste water treatment apparatus according to claim 1,
The nitrification tank is characterized in that the upper aerobic part has a vinylidene chloride filling. The waste water treatment apparatus according to claim 1,
In the nitrification tank, the upper aerobic part has a vinylidene chloride filling,
The re-aeration tank is characterized in that the upper aerobic part has a submerged membrane. The waste water treatment apparatus according to claim 5,
A wastewater treatment apparatus comprising a return section for returning microbial sludge from the re-aeration tank to the first denitrification tank. The waste water treatment apparatus according to claim 6,
The return part
A wastewater treatment apparatus, wherein microbial sludge having a flow rate of at least twice the flow rate of the nitrogen drainage flowing into the first denitrification tank per unit time is returned from the re-aeration tank to the first denitrification tank. The waste water treatment apparatus according to claim 5,
The said nitrification tank has a 2 or more types of vinylidene chloride filling, The waste water treatment equipment characterized by the above-mentioned. The waste water treatment apparatus according to claim 4,
Wastewater characterized by adding at least one of phosphorus, potassium, calcium, and magnesium to the first denitrification tank by introducing treated water or sludge from the joint septic tank into the first denitrification tank. Processing equipment. A first denitrification tank into which nitrogen drainage containing a nitrogen-based compound is introduced and a hydrogen donor is added;
A nitrification tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the first denitrification tank is introduced into the semi-anaerobic part,
A second denitrification tank into which treated water from the nitrification tank is introduced and a hydrogen donor is added;
A re-aeration tank having a lower semi-anaerobic part and an upper aerobic part and where treated water from the second denitrification tank is introduced into the semi-anaerobic part;
A first air lift pump for circulating treated water from the nitrification tank to the first denitrification tank;
A wastewater treatment apparatus comprising: a second air lift pump that circulates treated water from the re-aeration tank to the second denitrification tank. A first denitrification step of adding a hydrogen donor to nitrogen wastewater containing a nitrogen-based compound and denitrifying the nitrogen wastewater in a first denitrification tank;
A nitrification step of sequentially treating the treated water subjected to the denitrification treatment in a semi-anaerobic part and an aerobic part of the nitrification tank;
A second denitrification step of adding a hydrogen donor to the treated water after the nitrification step and denitrifying in a second denitrification tank;
A re-aeration process for sequentially treating the treated water after the second denitrification process in a semi-anaerobic part and an aerobic part of the re-aeration tank,
The treated water is circulated from the nitrification tank performing the nitrification process to the first denitrification tank by an air lift pump,
A wastewater treatment method characterized by circulating treated water from the re-aeration tank to the second denitrification tank by an air lift pump. The waste water treatment method according to claim 11,
A wastewater treatment method comprising adding at least one of biologically treated water or biologically treated sludge to the first denitrification tank. The waste water treatment method according to claim 11,
A wastewater treatment method comprising adding aminoethanol waste liquid as a hydrogen donor to the first and second denitrification tanks. The waste water treatment apparatus according to claim 10,
The upper aerobic part of the re-aeration tank has a submerged membrane,
A wastewater treatment apparatus comprising: a pump-type pipe that is connected to the submerged film and causes treated water from the submerged film to flow out; and a gravity pipe that uses a water head difference. The waste water treatment apparatus according to claim 10,
A wastewater treatment apparatus, wherein the first denitrification tank, the nitrification tank, and the second denitrification tank are filled with a vinylidene chloride filler. The waste water treatment apparatus according to claim 10,
A wastewater treatment apparatus comprising a return unit that returns the sludge of the semi-anaerobic part at the bottom of the re-aeration tank to the first denitrification tank. The waste water treatment method according to claim 11,
A wastewater treatment method, wherein a developing waste liquid is introduced into the first denitrification tank together with the nitrogen wastewater. The waste water treatment method according to claim 11,
A waste water treatment method, wherein a dimethylformamide waste liquid is introduced into the first denitrification tank together with the nitrogen waste water. A raw water tank into which nitrogen drainage containing nitrogen compounds is introduced;
A first denitrification tank into which the waste water from the raw water tank is introduced and a hydrogen donor is added;
A first nitrification tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the first denitrification tank introduced into the semi-anaerobic part;
A second denitrification tank into which treated water from the first nitrification tank is introduced and a hydrogen donor is added;
A second nitrification tank having a lower semi-anaerobic part and an upper aerobic part and treated water from the second denitrification tank introduced into the semi-anaerobic part;
A third denitrification tank into which treated water from the second nitrification tank is introduced and a hydrogen donor is added;
A re-aeration tank having a lower semi-anaerobic part and an upper aerobic part and into which treated water from the third denitrification tank is introduced into the semi-anaerobic part;
A contact oxidation tank into which treated water from the re-aeration tank is introduced;
A settling tank into which treated water from the contact oxidation tank is introduced;
A first air lift pump for circulating treated water from the first nitrification tank to the first denitrification tank;
A second air lift pump for circulating treated water from the second nitrification tank to the second denitrification tank;
A third air lift pump for circulating treated water from the re-aeration tank to the third denitrification tank;
A wastewater treatment apparatus comprising: a return unit that returns sludge containing minerals such as calcium from the settling tank to the raw water tank. A first denitrification step of introducing a nitrogen wastewater containing a nitrogen-based compound from a raw water tank to a first denitrification tank to which a hydrogen donor is added, and denitrifying;
A first nitrification step of sequentially treating the denitrified treated water in a semi-anaerobic part and an aerobic part of the first nitrification tank;
A second denitrification step of adding a hydrogen donor to the treated water after the first nitrification step and denitrifying in a second denitrification tank;
A second nitrification step of sequentially treating the treated water after the second denitrification step in a semi-anaerobic portion and an aerobic portion of the second nitrification tank;
A re-aeration step for sequentially treating the treated water after the second nitrification step in a semi-anaerobic portion and an aerobic portion of the re-aeration tank;
A contact oxidation step of treating the treated water after the re-aeration step in a contact oxidation tank;
A precipitation step of introducing treated water after the contact oxidation step into a precipitation tank,
Circulating treated water from the first nitrification tank performing the first nitrification step to the first denitrification tank by a first air lift pump,
Circulating treated water from the second nitrification tank to the second denitrification tank by a second air lift pump,
The treated water is circulated from the re-aeration tank to the third denitrification tank by a third air lift pump,
A wastewater treatment method, wherein sludge containing minerals such as calcium from the settling tank is returned to the raw water tank. The waste water treatment method according to claim 20,
A wastewater treatment method comprising adding at least one of biologically treated water or biologically treated sludge to the first denitrification tank. The waste water treatment method according to claim 20,
A wastewater treatment method, wherein an aminoethanol waste liquid is added to the first denitrification tank, the second denitrification tank, and the third denitrification tank. The waste water treatment apparatus according to claim 19,
The re-aeration tank has a submerged membrane in the upper aerobic part,
The waste water treatment apparatus, wherein the pipe part introduced from the submerged film of the aerobic part of the re-aeration tank into the contact oxidation tank has a pump-type pipe and a gravity-type pipe. The waste water treatment apparatus according to claim 19,
At least one of the vinylidene chloride fillers filled in at least one of the first to third denitrification tanks, or at least one of the vinylidene chloride fillers filled in at least one of the first and second nitrification tanks. A waste water treatment apparatus having one side. The waste water treatment apparatus according to claim 19,
A wastewater treatment apparatus comprising a return section for returning sludge from the semi-anaerobic section at the bottom of the re-aeration tank to the first denitrification tank. The waste water treatment method according to claim 20,
A wastewater treatment method, wherein the nitrogen drainage and the developing waste liquid are introduced into the raw water tank. The waste water treatment method according to claim 20,
A wastewater treatment method comprising introducing the nitrogen wastewater and dimethylformamide waste liquid into the raw water tank.

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