JP2013123706A - System and method for treating waste water containing suspended organic matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a more efficient treatment system for waste water containing a suspended organic matter reducing the leak of nitric acid even in waste water containing suspended organic matter in high concentration.SOLUTION: This suspended organic matter-containing waste water treatment system includes a suspended organic matter separator 10 for separating the suspended organic matter from water to be treated containing the suspended organic matter, a sludge anaerobic digestion apparatus 20 for anaerobically digesting the separated suspended organic matter, a nitrification apparatus 30 for oxidizing ammonia contained in the digested solution to nitrous acid under an aerobic condition, a denitrification apparatus 40 for performing denitrification treatment in which the treated solution is treated with autotrophic denitrification bacteria under an anaerobic condition to convert not only ammonia nitrogen to an electron donor but also nitrous nitrogen to an electron acceptor to perform anaerobic ammonia oxidation treatment and denitrification treatment in which nitrous nitrogen and nitric nitrogen are reduced to nitrogen molecules by heterotrophic bacteria, and a first transfer route R1 for supplying the separated solution from which the suspended organic matter is removed by the suspended organic matter separator 10 to the denitrification apparatus 40.

Description

  The present invention relates to a treatment system and a treatment method for suspending organic substance-containing wastewater, and particularly to a treatment system and treatment method suitable for wastewater containing a high concentration of suspending organic matter.

  Conventionally, waste water containing a high concentration of suspending organic substances has been employed in which the suspending organic substances are first removed and then the separated liquid is treated in a biological treatment process such as nitrification denitrification. The removed suspended organic matter is dehydrated as it is, or disposed of after anaerobic digestion for the purpose of weight reduction and methane gas recovery. Then, the dehydrated filtrate and digestive juice generated at this time are returned to the biological treatment process of the separated liquid and processed.

  The nitrification denitrification method is a nitrification process in which ammonia nitrogen in wastewater is oxidized to nitrite nitrogen by ammonia oxidizing bacteria, and nitrite nitrogen is oxidized to nitrate nitrogen by nitrite oxidizing bacteria, This is a method of decomposing ammonium nitrogen in waste water into nitrogen molecules through a denitrification step of decomposing nitrate nitrogen into nitrogen molecules by heterotrophic denitrifying bacteria.

  However, in such a conventional biological nitrification denitrification method, a large amount of oxygen is required in the nitrification process, and the power cost required for a blower fan for aeration increases, and a large amount of organic carbon source in the denitrification process. Running costs, such as the problem of increased chemical costs for the addition of methanol, etc., and the problem of increased sludge generation due to the use of heterotrophic denitrifying microorganisms, resulting in increased processing costs for excess sludge. There was a problem that increased.

  Therefore, Patent Document 1 discloses that a target treatment liquid containing SS organic substances and ammonia nitrogen is subjected to anaerobic digestion of separated sludge obtained by solid-liquid separation, and then the nitrite nitrification nitrification solution and the target treatment liquid are solidified. A biological nitrogen removal system has been proposed in which the separated liquid is denitrified by anaerobic ammonia oxidation treatment with autotrophic denitrifying microorganisms using nitrite nitrogen as an electron acceptor and ammonia nitrogen as an electron donor. ing.

The biological nitrogen removal system performs anaerobic treatment on solid-liquid separation means for solid-liquid separation of a target treatment liquid containing SS organic substances and ammonia nitrogen, and separation sludge separated by the solid-liquid separation means. Biological denitrification by mixing an anaerobic digestion tank, a nitritation tank for nitrating the treatment liquid of the anaerobic digestion tank, a treated liquid of the nitritation tank and a separation liquid of the solid-liquid separation means A biological denitrification tank is provided.

Japanese Patent Laid-Open No. 2003-245687

Anaerobic ammonia oxidation treatment is an anaerobic ammonia oxidation treatment using anaerobic denitrifying microorganisms (autotrophic denitrifying bacteria) using anaerobic nitrogen as an electron donor and nitrite nitrogen as an electron acceptor under anaerobic conditions. Thus, as represented by the following formula, 1 equivalent of ammonia nitrogen and 1.32 equivalent of nitrite nitrogen are converted into nitrogen molecules by denitrification reaction. At this time, 0.26 equivalent of nitric acid is produced.
NH ₄ ⁺ + 1.32NO ₂ ⁻ + 0.066HCO ₃ ⁻ + 0.13H ⁺ →
1.02N ₂ + 0.26NO ₃ ⁻ + 0.066CH ₂ O _0.5 N _0.15 + 2.03H ₂ O

  When the method described in Patent Document 1 is adopted for wastewater containing a high concentration of suspended organic matter, high concentration of ammonia is generated by anaerobic digestion treatment. About 57% of this ammonia is nitritized in a nitritation tank and denitrified in the biological denitrification tank together with the remaining ammonia. At this time, as shown in the above formula, 0.26 equivalent of nitric acid is generated with respect to 1.0 equivalent of ammonia. That is, about 11% of the ammonia contained in the digestive juice is converted to nitric acid and discharged out of the treatment system. Normally, this is not a problem because it is diluted with the separation liquid, but if the dilution effect cannot be sufficiently obtained with wastewater with a small amount of the separation liquid, a large amount of ammonia that cannot be reduced sufficiently by dilution is anaerobic digestion. If this occurs, the treatment method cannot be used if the concentration is reduced by dilution but the total nitrogen limit cannot be cleared.

  In addition, it is described that an aerobic treatment may be performed prior to the denitrification process when there is a soluble organic substance in the separation liquid, but the power cost required for the blower for aeration increases.

  In view of the above-described problems, the object of the present invention is to enable more efficient treatment than the prior art, and further reduce the leakage of nitric acid even in wastewater containing a high concentration of suspended organic matter. It is in the point which provides the processing system and processing method of an efficient suspending organic substance containing wastewater.

  In order to achieve the above-mentioned object, the first characteristic configuration of the treatment system for waste water containing suspended organic matter according to the present invention contains the suspended organic matter as described in claim 1 of the claims. Suspended organic matter separator for separating suspended organic matter from water to be treated, sludge anaerobic digester for anaerobically digesting suspended organic matter separated by the suspended organic matter separator, and sludge anaerobic Suspended organic substance-containing wastewater having a nitrification apparatus that oxidizes ammonia contained in the digestion liquid of the digestion apparatus to nitrous acid under aerobic conditions, and a denitrification apparatus that denitrifies the treatment liquid of the nitritation apparatus The denitrification apparatus is a denitrification apparatus which performs anaerobic ammonia oxidation treatment using ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor by an autotrophic denitrification microorganism under anaerobic conditions. Processing and subordination A denitrification treatment for reducing nitrite nitrogen and nitrate nitrogen to nitrogen molecules by a neutral denitrifying microorganism, wherein the separation liquid from which the suspended organic matter has been removed by the suspension organic matter separation device is dehydrated. A first transfer path for supplying to the nitrogenation apparatus is provided.

  According to the above-described configuration, the suspended organic matter is separated from the water to be treated by the suspended organic matter separation device provided in the previous stage of the autotrophic denitrification device. Then, the sludge anaerobic digester performs anaerobic digestion of the suspended organic matter separated by the suspended organic matter separator, and the digested liquid containing ammonia is introduced into the nitritation device. In the nitrification apparatus, ammonia contained in the digestive juice is oxidized to nitrous acid under aerobic conditions.

  In the denitrification device, anaerobic ammonia oxidation using ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor by an autotrophic denitrification microorganism under anaerobic conditions with respect to the treatment solution of the nitritation device. A denitrification treatment to be performed and a denitrification treatment to reduce nitrite nitrogen and nitrate nitrogen to nitrogen molecules by heterotrophic denitrification microorganisms are performed. At the same time, denitrification by heterotrophic denitrification microorganisms using nitric acid produced by anaerobic ammonia oxidation treatment as an electron acceptor and organic matter dissolved in the separation liquid as an electron donor occurs. The amount of nitric acid and organic matter discharged out of the system can be reduced.

In the second feature configuration, as described in claim 2, in addition to the first feature configuration described above, the second transfer for supplying the suspending organic substance separation device separation liquid to the nitritation device It is characterized by having a route.

  According to the above configuration, the nitrite concentration (free nitrous acid concentration) in the nitritation apparatus can be adjusted to a concentration suitable for nitritation, so that the reaction efficiency can be improved. As a result, temperature and pH control becomes unnecessary, and power costs and chemical costs can be saved.

  In addition to the first or second feature configuration described above, the third feature configuration is an organic matter reduction device that reduces organic matter contained in the digestive liquid of the sludge anaerobic digester as described in claim 3. Is provided in the previous stage of the nitritation apparatus.

  If the water to be treated supplied to the nitritation device contains a large amount of organic matter, the oxygen required for the nitritation treatment will be spent on the decomposition treatment of the organic matter, which will prevent the nitritation treatment. According to the above configuration, the organic matter reducing device provided in the previous stage of the nitritation device reduces the organic matter contained in the digested liquid of the sludge anaerobic digestion device and supplies it to the nitritation device. Therefore, the power cost can be reduced.

  In the organic matter reducing device, the organic matter contained in the digestive juice is reduced by, for example, aerobic digestion treatment, membrane separation treatment, and aggregation treatment.

  In the fourth feature configuration, in addition to any of the first to third feature configurations described above, the treatment liquid of the denitrification device is supplied to the nitritation device, as described in claim 4. A third transfer path is provided.

  According to the above configuration, by returning a part of the treatment liquid of the denitrification apparatus to the nitritation apparatus, excess ammonia contained in the treatment liquid of the denitrification apparatus can be nitrified. The amount of ammonia discharged out of the system from the denitrification device can be reduced.

  The first characteristic configuration of the method for treating suspending organic substance-containing wastewater according to the present invention is the suspending property for separating the suspending organic substance from the water to be treated containing the suspending organic substance as described in claim 5. Organic matter separation treatment, sludge anaerobic digestion treatment for anaerobically digesting suspended organic matter separated by the suspension organic matter separation treatment, and ammonia contained in the digested liquid by the sludge anaerobic digestion treatment under aerobic conditions A nitritation treatment that oxidizes to nitrous acid at a nitrite treatment method, and a treatment method for suspending organic matter-containing wastewater that denitrifies a treatment solution by the nitritation treatment, wherein the denitrification treatment is performed under anaerobic conditions. Denitrification treatment by anaerobic ammonia oxidation with autotrophic denitrifying microorganisms using ammonia nitrogen as electron donor and nitrite nitrogen as electron acceptor, and nitrite nitrogen and nitrate nitrogen by heterotrophic denitrifying microorganisms Into nitrogen molecules And a denitrification process for the original, there separation liquid suspension of organic matter has been removed by the suspension of organic matter separation in that and supplying to the denitrification.

  In the second feature configuration, as described in claim 6, in addition to the first feature configuration described above, the denitrification is performed on the separation liquid from which the suspended organic matter has been removed by the suspension organic matter separation treatment. It is characterized by being distributed and supplied to the treatment and the nitritation treatment.

  In addition to the first or second feature configuration described above, the third feature configuration is an organic matter reduction treatment that reduces organic matter contained in the digested liquid by the sludge anaerobic digestion treatment as described in claim 7. The nitrite treatment is performed after the above.

  In the fourth feature configuration, as described in claim 8, in addition to any of the first to third feature configurations described above, a treatment liquid by the denitrification treatment is supplied to the nitritation treatment. This is a feature.

  As described above, according to the present invention, more efficient treatment than the prior art is possible, and moreover, even in wastewater containing a high concentration of suspended organic matter, the leakage of nitric acid can be reduced more efficiently. It has become possible to provide a treatment system and a treatment method for waste water containing suspending organic substances.

Explanatory drawing of the 1st aspect of the processing system by this invention Explanatory drawing of the 2nd aspect of the processing system by this invention Explanatory drawing of the 3rd aspect of the processing system by this invention. Explanatory drawing of the 4th aspect of the processing system by this invention. Explanatory drawing of the 5th aspect of the processing system by this invention.

Hereinafter, an embodiment of a processing system and a processing method for waste water containing suspended organic matter according to the present invention will be described.
FIG. 1 shows a treatment system for suspending organic substance-containing wastewater according to the first embodiment. The said processing system is a system which purifies the to-be-processed water containing a suspending organic substance, the suspending organic substance separation apparatus 10 which isolate | separates the suspending organic substance contained in a to-be-processed water, and a suspending organic substance separation apparatus A sludge anaerobic digester 20 for anaerobically digesting the suspended organic matter separated in 10 and a nitritation device 30 for oxidizing ammonia contained in the digested liquid of the sludge anaerobic digester 20 to nitrous acid under aerobic conditions. And a denitrification device 40 for denitrifying the treatment liquid of the nitritation device 30 and a first transfer path for supplying the denitrification device 40 with the separation liquid from which the suspended organic substances have been removed by the suspension organic matter separation device 10 R1 is provided.

  The suspension organic matter separation device 10 can be configured by any of a precipitation device, a coagulation precipitation device, a flotation separation device, a screen device, a membrane separation device, a cyclone device, a mechanical separation device such as a screw press or a decanter, A combination of these plural devices is also possible.

  The suspending organic matter separated from the water to be treated by the suspending organic matter separating device 10 is anaerobically digested by the sludge anaerobic digesting device 20 to obtain a digested liquid containing ammonia nitrogen.

  In the nitritation apparatus 30, ammonia nitrogen is added to the digested liquid of the sludge anaerobic digestion apparatus 20 containing ammonia nitrogen by an autotrophic denitrifying microorganism (autotrophic nitrite) under aerobic conditions. A nitritation treatment is performed to oxidize nitrite to nitrite nitrogen.

  In the denitrification apparatus 40, anaerobic ammonia oxidation is performed on the treatment liquid of the nitritation apparatus 30 by using autotrophic denitrification microorganisms under anaerobic conditions using ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. A denitrification treatment to be performed and a denitrification treatment to reduce nitrite nitrogen and nitrate nitrogen to nitrogen molecules by heterotrophic denitrification microorganisms are performed.

  As described above, in the denitrification apparatus 40, anaerobic ammonia oxidation treatment is performed, and further, nitrate nitrogen generated by the anaerobic ammonia oxidation treatment is used as an electron acceptor, and organic substances and the like dissolved in the separation liquid are donated by electrons. By proceeding with the denitrification reaction by the heterotrophic denitrifying microorganisms as a body, the amount of nitric acid and organic matter discharged from the denitrification device 40 to the outside of the system can be reduced.

  The denitrification apparatus 40 is charged with autotrophic denitrification microorganisms and heterotrophic denitrification microorganisms, and is maintained in an anaerobic atmosphere.

  As a denitrification microorganism 40 retention form in the denitrification apparatus 40, it can be retained in the form of airborne bacteria in the denitrification apparatus 40, or a biofilm in which the denitrification microorganisms are attached to the filler, or denitrification. It can also be held as an immobilization carrier in which microorganisms are immobilized on an immobilization material.

  When the autotrophic denitrification microorganisms and heterotrophic denitrification microorganisms are held as biofilms, the filling amount into the denitrification apparatus 40 is preferably 20 to 80% by volume in the case of the fixed bed type. As the filler, materials such as a nonwoven fabric, a plastic material, a sponge material, and porous ceramics can be used, and various shapes such as a plate shape, a granular shape, and a cylindrical shape can be used.

  For immobilization on the carrier, two methods of adhesion immobilization and entrapping immobilization can be used. In the case of adhesion fixation, it is preferable to use a carrier having a rough shape, such as a spherical or cylindrical carrier, a string-like material, a gel-like material, or a non-woven fabric material, because microorganisms are easily attached. As a method for entrapping immobilization, a method is generally used in which microorganisms to be immobilized and a monomer or prepolymer as a carrier are mixed and then polymerized to entrap and immobilize the microorganisms. As the monomer material, acrylamide, methylenebisacrylamide, triacryl formal and the like are preferable, and as the prepolymer material, polyethylene glycol diacrylate and polyethylene glycol methacrylate are preferable. As in the case of adhesion and fixation, the shape with many irregularities has good contact efficiency with the water to be treated, and the denitrification ability is improved.

  It is ideal that the molar ratio of ammonia and nitrous acid is adjusted to 1: 1.32 in the nitritation apparatus 30, but the nitrite remaining due to the anaerobic ammonia oxidation reaction in the denitrification apparatus 40 in the subsequent stage Can be denitrified by heterotrophic denitrifying microorganisms, and therefore, the nitritation apparatus 30 may be adjusted so that the nitrous acid is larger than the molar ratio of 1.32 with ammonia. In some cases, nitrification may proceed to nitric acid. However, in order to increase the efficiency of denitrification and reduce the amount of oxygen required for nitrification, it is desirable that ammonia: nitrous acid be adjusted to about 1: 1.32 to 1.5 in the nitritation apparatus 30.

  That is, the suspension organic matter separation process for separating the suspension organic substance from the water to be treated containing the suspension organic substance, and the sludge anaerobic digestion of the suspension organic substance separated by the suspension organic matter separation process Suspension for denitrifying the treatment solution by oxidizing treatment, oxidizing the ammonia contained in the digested solution by the sludge anaerobic digestion to nitrous acid under aerobic conditions, and treating the solution by the nitrite treatment A method for treating wastewater containing organic substances, wherein the denitrification treatment is performed by anaerobic ammonia using an autotrophic denitrifying microorganism under anaerobic conditions using ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. It includes denitrification treatment for oxidation treatment and denitrification treatment for reducing nitrite nitrogen and nitrate nitrogen to nitrogen molecules by heterotrophic denitrification microorganisms. Suspended organic matter is removed by the suspension organic matter separation treatment. Was Processing method suspendable organic wastewater containing and supplying syneresis in the denitrification process is performed.

  FIG. 2 shows a processing system according to the second embodiment. In addition to the processing system of the first aspect described above, the processing system includes a second transfer path R2 that supplies the separated liquid of the suspending organic matter separation device 10 to the nitritation device 30. .

  According to the above configuration, the nitrite concentration in the nitritation apparatus 30 can be adjusted to a concentration suitable for nitritation, so that the reaction efficiency can be improved. As a result, temperature and pH control becomes unnecessary, and power costs and chemical costs can be saved.

  That is, in addition to the above-described method for treating suspending organic substance-containing wastewater, the separated liquid from which the suspending organic substance has been removed by the suspending organic substance separation treatment is distributed and supplied to the denitrification treatment and the nitritation treatment. A method for treating wastewater containing suspending organic matter is characterized.

In nitrification, it is said that all nitrifying bacteria are inhibited when the free nitrite concentration (FNA) is 0.2 ppm or more. According to the calculation formula of Anthonisen et al., The free nitrous acid concentration (FNA) is expressed by the following formula. That is, the free nitrous acid concentration (FNA) is determined by the nitrous acid concentration, temperature, and pH.

  Table 1 shows the free nitrous acid concentration calculated based on the above equation when the nitrite was added so that the ammonia concentration and the nitrous acid concentration of the anaerobic digestive fluid were 1: 1.32. When the ammonia concentration of the anaerobic digestion liquid is 1000 ppm, the nitrite is oxidized so that the nitrous acid concentration becomes 570 ppm. At this time, if the pH is 7.4 and the water temperature is 30 ° C., the free nitrous acid concentration is 0.151 ppm and there is no problem in nitritation. However, when the pH is lowered to 7.2, the concentration of free nitrous acid becomes 0.239 ppm, which is a concentration that hinders nitritation. Conventionally, an alkali agent has been added to raise the pH, but according to the treatment system of the second aspect, the separation liquid is supplied from the second transfer path R2 to dilute the nitrous acid concentration to about 470 ppm. Thus, the free nitrite concentration can be set to a level that does not hinder nitritation. When the water temperature becomes 15 ° C., the free nitrous acid concentration becomes 0.224 ppm, but it can be diluted to a nitrous acid concentration of about 500 ppm without increasing the water temperature, and a good state for nitritation can be maintained. When the ammonia concentration of the anaerobic digestion solution reaches 2000 ppm, the free nitrous acid concentration becomes 0.302 ppm at a pH of 7.4 and a water temperature of 30 ° C. At this time, when the pH is adjusted to 7.6 or the water temperature is adjusted to 48 ° C., the concentration of free nitrous acid becomes less than 0.2 ppm, but a large amount of alkaline agent and enormous energy for heating are required. However, according to the treatment system of the second aspect, the free nitrous acid concentration can be brought to a level that does not hinder nitritation by diluting the nitrous acid concentration to about 740 ppm.

  FIG. 3 shows the processing system of the third aspect. The said processing system is equipped with the organic substance reduction apparatus 50 which reduces the organic substance contained in the digestive liquid of the sludge anaerobic digester 20 in the front | former stage of the nitritation apparatus 30 in addition to the processing system of the above-mentioned 2nd aspect. It is characterized by. Note that the second transfer path R2 is not necessarily provided.

  If the water to be treated supplied to the nitritation apparatus 30 contains a large amount of soluble organic matter, the oxygen required for the nitritation treatment is consumed in the decomposition treatment of the soluble organic matter, preventing the nitritation treatment. However, according to the above-described configuration, the organic matter reducing device 50 provided in the previous stage of the nitrifying device 30 reduces the organic matter contained in the digested liquid of the sludge anaerobic digesting device 20, and the nitrifying device. Therefore, the power cost for aeration can be reduced.

  In addition, in the organic substance reduction apparatus 50, the organic substance contained in a digestive liquid is reduced by an aerobic digestion process, a membrane separation process, and a coagulation process, for example.

  That is, in addition to the suspending organic matter-containing wastewater treatment method of the first or second aspect described above, the nitrous acid is subjected to the organic matter reduction treatment for reducing the organic matter contained in the digested liquid by the sludge anaerobic digestion treatment. The processing method of the waste water containing a suspending organic substance characterized by performing a chemical conversion treatment is realized.

  FIG. 4 shows a processing system according to the fourth aspect. In addition to the processing system of the second aspect described above, the processing system includes a third transfer path R3 that supplies the processing liquid of the denitrification apparatus 40 to the nitritation apparatus 30. Note that the second transfer path R2 is not necessarily provided. Moreover, you may equip the front | former stage of the nitritation apparatus 30 with the organic substance reduction apparatus 50 which reduces the organic substance contained in the digestive liquid of the sludge anaerobic digester 20 like the processing system of a 3rd aspect.

  By returning a part of the treatment liquid of the denitrification apparatus 40 to the nitritation apparatus 30 via the third transfer path R3, surplus ammonia contained in the treatment liquid of the denitrification apparatus 40 is nitrified. Therefore, the amount of ammonia discharged out of the system from the denitrification apparatus 40 can be reduced.

  That is, in addition to the treatment method according to any one of the first to third aspects described above, the treatment liquid by the denitrification treatment is supplied to the nitritation treatment. The method is executed.

  FIG. 5 shows a suspending organic substance-containing wastewater treatment system according to a fifth aspect. The said processing system is a system which purifies the to-be-processed water containing a suspending organic substance, the suspending organic substance separation apparatus 10 which isolate | separates the suspending organic substance contained in a to-be-processed water, and a suspending organic substance separation apparatus The sludge anaerobic digester 20 for anaerobically digesting the suspended organic matter separated in 10 and the nitritation device 30 for oxidizing ammonia contained in the digested liquid of the sludge anaerobic digester 20 to nitrous acid under aerobic conditions. Anaerobic ammonia oxidation using an autotrophic denitrifying microorganism using nitrite nitrogen contained in the treatment liquid of the nitritation apparatus 30 as an electron acceptor and ammonia nitrogen as an electron donor. Apparatus 40A, heterotrophic denitrification apparatus 40B for denitrifying nitrous acid contained in the treatment liquid of anaerobic ammonia oxidation apparatus 40A by heterotrophic denitrifying microorganisms, and suspension organic matter separation The separated liquid suspension of organic matter has been removed by the location 10, and a second transport path R2 supplied to the first transfer path R1 nitrite apparatus 30 supplies the heterotrophic denitrifying device 40B.

  In this way, the denitrification apparatus 40 is not composed of one tank, but is composed of two tanks in series, an anaerobic ammonia oxidation apparatus 40A and a heterotrophic denitrification apparatus 40B. In each tank, anaerobic ammonia oxidation treatment and heterotrophic nutrition are performed. It can comprise so that the denitrification process by a characteristic denitrification microorganism may be performed.

  According to the above-described configuration, the nitrate nitrogen generated by the anaerobic ammonia oxidation apparatus 40A is used as an electron acceptor, and the organic matter contained in the separated liquid from which the suspended organic matter is removed by the suspension organic matter separation apparatus 10 is the electron. Since the nitric acid and organic matter can be removed by the denitrification reaction by the heterotrophic denitrifying microorganism used as the donor, the amount of nitric acid discharged out of the processing system is the same as in the processing system of the first aspect. The amount of organic matter can be reduced.

  Furthermore, since the nitrite concentration in the nitritation apparatus 30 can be adjusted to a concentration suitable for nitritation as in the treatment system of the second aspect, the reaction efficiency can be improved. As a result, temperature and pH control becomes unnecessary, and power costs and chemical costs can be saved.

  As shown in FIG. 5, the processing system of the fifth aspect may include a third transfer path R <b> 3 that supplies the processing liquid of the heterotrophic denitrification device 40 </ b> B to the nitritation device 30. By returning a part of the treatment liquid of the heterotrophic denitrification device 40B to the nitritation device 30 via the third transfer path R3, the heterotrophic denitrification is the same as in the treatment system of the fourth aspect. Since surplus ammonia contained in the treatment liquid of the apparatus 40B can be nitrified, the amount of ammonia discharged out of the system from the heterotrophic denitrification apparatus 40B can be reduced.

  Each of the above-described embodiments is an example of the present invention, and the present invention is not limited by the description. The specific configuration of each part can be appropriately designed within the range where the effects of the present invention are exhibited. Needless to say.

10: Suspended organic matter separation device 20: Sludge anaerobic digestion device 30: Nitrite device 40A: Anaerobic ammonia oxidation device 40B: Heterotrophic denitrification device 50: Organic matter reduction device R1: First transfer route R2: First 2 transfer route R3: third transfer route

Claims (8)

Suspended organic matter separation device for separating suspended organic matter from water to be treated containing suspended organic matter, and sludge anaerobic digestion for anaerobic digestion of suspended organic matter separated by the suspended organic matter separation device A denitrification apparatus for denitrifying the treatment liquid of the apparatus, the nitritation apparatus that oxidizes ammonia contained in the digestion liquid of the sludge anaerobic digestion apparatus to nitrous acid under aerobic conditions, and A suspending organic matter-containing wastewater treatment system comprising:
The denitrification apparatus comprises a denitrification treatment in which anaerobic denitrification microorganisms under anaerobic conditions are subjected to anaerobic ammonia oxidation treatment using ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. It is a device that performs denitrification treatment to reduce nitrite nitrogen and nitrate nitrogen to nitrogen molecules by nitrogenous microorganisms,
A treatment system for wastewater containing suspended organic matter, comprising a first transfer path for supplying the separation liquid from which suspended organic matter has been removed by the suspended organic matter separation device to the denitrification device.   The treatment system for wastewater containing suspended organic matter according to claim 1, further comprising a second transfer path for supplying a separation liquid of the suspended organic matter separation device to the nitritation device.   The suspended organic matter-containing wastewater according to claim 1 or 2, further comprising an organic substance reducing device for reducing organic substances contained in the digested liquid of the sludge anaerobic digester in a stage preceding the nitritation device. Processing system.   The suspending organic substance-containing wastewater treatment system according to any one of claims 1 to 3, further comprising a third transfer path for supplying a treatment liquid of the denitrification device to the nitritation device. Suspended organic matter separation treatment for separating suspended organic matter from water to be treated containing suspended organic matter, and sludge anaerobic digestion for anaerobically digesting suspended organic matter separated by the suspended organic matter separation treatment Suspended organic matter for treating, denitrifying the treatment liquid by nitritation, and oxidizing the ammonia contained in the digestion liquid by the sludge anaerobic digestion to nitrous acid under aerobic conditions A method for treating contained wastewater,
The denitrification treatment includes an anaerobic ammonia oxidation treatment using ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor by heterotrophic denitrification microorganisms under anaerobic conditions, and heterotrophic properties. A denitrification microorganism that reduces nitrite nitrogen and nitrate nitrogen to nitrogen molecules by a denitrifying microorganism,
A method for treating a suspending organic substance-containing wastewater, wherein a separation liquid from which the suspending organic substance has been removed by the suspending organic substance separation treatment is supplied to the denitrification treatment.   6. The suspending organic substance-containing wastewater according to claim 5, wherein the separation liquid from which the suspending organic substance has been removed by the suspending organic substance separation treatment is distributed and supplied to the denitrification treatment and the nitritation treatment. Processing method.   The suspending organic matter-containing wastewater treatment according to claim 5 or 6, wherein the nitrite treatment is performed after the organic matter reduction treatment for reducing the organic matter contained in the digested liquid by the sludge anaerobic digestion treatment. Method.   The method for treating suspended organic matter-containing wastewater according to any one of claims 5 to 7, wherein a treatment liquid obtained by the denitrification treatment is supplied to the nitritation treatment.