JP2011104564A - Method and equipment for treating organic wastewater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide equipment for treating organic wastewater, which allows a denitrification reaction occurring in an anaerobic environment to proceed in an aeration tank as an aerobic environment without interfering with the function of decomposing organic matter, which is the function inherent in the organic wastewater treatment using activated sludge. <P>SOLUTION: In the equipment for treating organic wastewater using a biological treatment method, which includes the aeration tank 2 where the organic wastewater 9, together with the activated sludge, is subjected to aeration treatment, the equipment further includes a container 21 of a sealed structure provided with a nonporous membrane 22 in at least a portion thereof and filled with an electron donor substance 23, and a carrier 31 capable of carrying microorganisms thereon. The carrier 31 is arranged at least around the nonporous membrane 22 of the container 21, and the electron donor substance 23 gradually released through the region of the nonporous membrane 22 of the container 21 is supplied to the carrier 31. At least the carrier 31 is accommodated in such a position as to come into contact with the organic wastewater 9 in the aeration tank 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a method for treating organic wastewater and a treatment facility. More specifically, the present invention
The present invention relates to an organic wastewater treatment method and treatment equipment suitable for reducing the concentration of nitrogen components contained in organic wastewater.

  The activated sludge method is known as a typical purification method for organic wastewater. This method is performed as follows. That is, the organic waste water that has finished the primary treatment (screen, sand settling basin, first settling pond) continuously flows into the aeration tank 102 and is mixed with the activated sludge in the aeration tank 102. Air is forcibly blown into the aeration tank 102 from a blower (blower) or the like, the dissolved oxygen concentration in the organic wastewater in the aeration tank 102 is maintained at a high concentration, and organic matter (BOD component) in the organic wastewater is contained. It is oxidatively decomposed by the action of aerobic microorganisms present in the activated sludge. After the organic waste water is retained in the aeration tank 2 for a certain period of time, the mixed liquid in the aeration tank 102 is allowed to flow into the precipitation tank 103 as it is, and is allowed to stand to form a floc in the microorganism group (activated sludge) and settle. . The supernatant is discharged as treated water as it is or sent to the next step as necessary. The activated sludge settled in the settling tank 103 is returned to the aeration tank 102 as a return sludge, and is again subjected to organic matter decomposition work. On the other hand, the activated sludge corresponding to the grown microorganisms is recovered as excess sludge (see FIG. 16, p53-54 of Non-Patent Document 1, Non-Patent Document 2).

By the way, in recent years, the problem of eutrophication has become apparent in closed waters such as lakes and inland seas. In order to solve the eutrophication problem, it is important to prevent the inflow of nutrients such as nitrogen and phosphorus components into closed water bodies. Thus, as a modified method of the activated sludge method, a nitrification denitrification method for removing nitrogen, an anaerobic aerobic method for removing phosphorus, an anaerobic anaerobic anaerobic method for removing nitrogen and phosphorus simultaneously, and the like are used.

  For example, as shown in FIG. 18, the nitrification denitrification method is performed in a facility in which a denitrification tank 105 is provided upstream of the aeration tank 102. Specifically, ammonia nitrogen contained in the organic wastewater flows into the aeration tank 102 without any change in the denitrification tank 105. In the aeration tank 102, ammonia nitrogen is oxidized to nitrite nitrogen and nitrate nitrogen, and then into a denitrification tank 105 in large quantities (usually 1 to 3 times the amount of inflowing wastewater) as a nitrification circulating liquid. Returned. In the denitrification tank 105, nitrite nitrogen and nitrate nitrogen are subjected to a denitrification reaction using organic substances contained in the inflowing organic wastewater, and the concentration of nitrogen in the organic wastewater is reduced. Further, when nitrite nitrogen and nitrate nitrogen are contained in the organic wastewater from the beginning, the concentration of the organic wastewater is reduced by receiving a denitrification reaction when the organic wastewater flows into the denitrification tank 105. . In addition to consumption by denitrifying bacteria in the aeration tank 105, the concentration of the organic matter in the organic wastewater is reduced by oxidative decomposition treatment in the aeration tank 102 (p60-61 of Non-Patent Document 1, Non-Patent Document 1). 2).

  The anaerobic aerobic method (AO method) is a method in which an anaerobic tank 104 is provided in front of the aeration tank 102 as shown in FIG. In activated sludge, there are bacteria (polyphosphate-accumulating bacteria) that release phosphorus while ingesting organic matter in an anaerobic environment and absorb more phosphorus than released under aerobic conditions. Yes. By the function of this bacterium, the concentration of phosphorus in organic wastewater can be reduced, and phosphorus can be accumulated in excess sludge and discharged out of the system (see Non-Patent Document 2).

The anaerobic anaerobic anaerobic activated sludge method (A ₂ O method) is also called a circulation type anaerobic aerobic method. For example, as shown in FIG. 19, a denitrification tank 105 is provided in front of the aeration tank 102. It is carried out in a facility provided with an anaerobic tank 104 in the previous stage. Specifically, the anaerobic tank 104 is provided as a phosphorus elution tank further before the nitrification denitrification method, thereby releasing phosphorus from the polyphosphate accumulating bacteria contained in the activated sludge returned to the anaerobic tank 104, and in the aeration tank 102. By causing polyphosphate-accumulating bacteria to overtake phosphorus, the concentration of phosphorus contained in organic wastewater is reduced, and ammonia nitrogen and further sublimation are reduced by the denitrification tank 105 and the aeration tank 102 in the same manner as the nitrification denitrification method. Reduction of nitrate nitrogen and nitrate nitrogen concentration can be achieved. The concentration of organic substances in the organic wastewater is reduced by consumption by denitrifying bacteria in the denitrification tank 105, consumption by polyphosphate-accumulating bacteria in the anaerobic tank 104 and denitrification tank 105, and oxidative decomposition in the aeration tank 102 (non-patented). (Refer to p61-62 of Document 1, Non-Patent Document 2)

Environmental microbiology (written by Shoshodo, Toshio Omori, etc., 5th edition) Various activated sludge methods, [online], March 30, 2007, Livestock Environmental Technology Research Institute, [November 17, 2009 search], Internet <URL: http://www.chikusan-kankyo.jp/ osuiss / kiso / 0046.htm> Anaerobic-anoxic-aerobic method, [online], August 28, 2008, Kyoto City Sewerage Bureau, [searched on November 17, 2009], Internet <URL: http://www.city.kyoto. lg.jp/suido/page/0000008844.html>

However, each of these existing processing schemes has significant drawbacks.

  First, the standard activated sludge method and the anaerobic aerobic method are produced by oxidation of ammonia nitrogen, although nitrifying bacteria contained in activated sludge can oxidize ammonia nitrogen in organic wastewater. Nitrite nitrogen and nitrate nitrogen, as well as nitrite nitrogen and nitrate nitrogen originally contained in organic wastewater cannot be converted into molecular nitrogen (denitrification treatment). Therefore, it is not possible to reduce the concentration of the nitrogen component derived from nitrate nitrogen which causes the problem of eutrophication in a closed water area. Moreover, in the case of the anaerobic aerobic method, the remaining nitrate nitrogen flows into the anaerobic tank along with the returned sludge. It will not be demonstrated.

  The nitrification denitrification method and the anaerobic anaerobic aerobic method convert not only ammonia nitrogen contained in organic wastewater but also nitrite nitrogen and nitrate nitrogen into molecular nitrogen (denitrification treatment) and its concentration. However, since the denitrification tank 105 for the denitrification treatment is separately provided, the introduction is difficult when the site area is limited, and the construction cost increases. Furthermore, since a large amount of return is required from the aeration tank to the denitrification tank, the operation cost of the pump is also increased.

  These problems are caused by advancing the denitrification reaction that occurs in an anaerobic environment in the aeration tank 102, which is an aerobic environment, without interfering with the organic matter decomposition ability, which is the original function of organic wastewater treatment using activated sludge. If you can, you can solve everything. That is, for the activated sludge method and the anaerobic aerobic method, if the denitrification treatment in the aeration tank 102 can be realized, the concentration of nitrite nitrogen and nitrate nitrogen in the organic wastewater can be reduced without providing a new treatment tank. Can be achieved. As for the nitrification denitrification method and the anaerobic anaerobic anaerobic method, if the denitrification process in the aeration tank 102 can be realized, the amount of nitrate nitrogen returned to the denitrification tank 105 can be reduced. Alternatively, the denitrification treatment process in the denitrification tank 105 can be completely shifted to the aeration tank 102, and the return process of the nitrification circulating liquid to the denitrification tank 105 can be eliminated to reduce the operating cost of the pump and the facility scale. It becomes.

  Therefore, the present invention allows a denitrification reaction that occurs in an anaerobic environment to proceed in an aerobic environment aeration tank without interfering with the organic substance decomposition treatment ability that is an essential function of organic wastewater treatment using activated sludge. It aims at providing the processing method and processing equipment of the organic waste water which can do.

  In order to solve such a problem, the inventors of the present application conducted extensive research. As a result, the denitrification reaction can be advanced even in the aeration tank in the activated sludge method exposed to extremely strong aerobic environment, and organic substance decomposition is an essential function of organic wastewater treatment using activated sludge. The present inventors have found a configuration that does not impede processing ability and have completed the present invention.

  That is, the organic wastewater treatment method of the present invention is a method for treating organic wastewater using a biological treatment method including a step of aeration treatment of organic wastewater with activated sludge in an aeration tank. A carrier capable of supporting microorganisms is disposed around at least the non-porous membrane of a sealed container filled with an electron donor material, and the electron donor material is gradually removed from the non-porous membrane portion of the container. The aeration is carried out while supplying the carrier to the carrier and at least bringing the carrier into contact with the organic waste water in the aeration tank.

  Further, the organic wastewater treatment facility of the present invention is an organic wastewater treatment facility using a biological treatment method having an aeration tank in which the organic wastewater is aerated together with activated sludge. And a container having a sealed structure filled with an electron donor substance, and a carrier capable of supporting microorganisms, the carrier being disposed around at least the non-porous membrane of the container, and the non-porous membrane portion of the container It is assumed that the electron donor substance that is slowly released from is supplied to the carrier, and at least the carrier is accommodated in a position in contact with the organic waste water in the aeration tank.

  Therefore, according to the organic wastewater treatment method and treatment facility of the present invention, denitrifying bacteria contained in the activated sludge adhere to the carrier. And an anaerobic environment is formed in a support | carrier by supplying an electron donor substance to a support | carrier, and the denitrifying bacteria placed in the anaerobic environment show denitrification processing ability. Moreover, even when alcohol such as ethanol that increases the organic matter concentration of organic wastewater is supplied as an electron donor substance, activated sludge is used because it is quickly consumed by denitrifying bacteria and activated sludge adhering to the carrier. The ability to decompose organic substances, which is the original function of organic wastewater treatment, is not hindered.

  Here, in the present invention, the biological treatment method is preferably a standard activated sludge method, an anaerobic aerobic method, an anaerobic anaerobic anaerobic method or a nitrification denitrification method.

  In the present invention, denitrifying bacteria may be previously supported on the carrier.

  According to the present invention, the denitrification treatment in the aeration tank in which the organic wastewater is aerated together with the activated sludge without interfering with the organic substance decomposition treatment ability, which is the original function of the organic wastewater treatment using the activated sludge. It becomes possible.

  Therefore, since a denitrification ability can be imparted to the conventional standard activated sludge method or anaerobic aerobic aeration tank without adding a new treatment tank (denitrification tank), a new treatment tank is provided. It is possible to carry out the treatment of organic wastewater with a compact facility without securing the facility cost and site area.

  In addition, by imparting denitrification ability to the conventional nitrification denitrification method or anaerobic anaerobic anaerobic aeration tank, a part or all of the denitrification process in the denitrification tank can be shifted to the aeration tank. . Therefore, since the return amount of the nitrification circulating liquid from the aeration tank to the denitrification tank can be reduced, or the return process of the nitrification circulating liquid can be eliminated, the wastewater treatment efficiency can be greatly improved as compared with the prior art.

In anaerobic aerobic and anaerobic anaerobic aerobic methods for biological phosphorus removal, nitrate nitrogen flowing into the anaerobic tank along with the return sludge is reduced by reducing the nitrate nitrogen concentration in the aeration tank. . Therefore, in an anaerobic tank, the consumption by the denitrifying bacteria of the organic substance contained in the organic wastewater is greatly reduced, and it is likely to be preferentially consumed by the polyphosphate accumulating bacteria contained in the returned sludge. Therefore, the polyphosphate-accumulating bacteria are easily grown and the proportion of the polyphosphate-accumulating bacteria exhibiting the phosphorus accumulating ability is increased. Thereby, the phosphorus density | concentration of organic wastewater can be reduced rather than before.

It is a figure which shows an example of the processing equipment of the organic waste water of this invention at the time of setting the biological treatment method to the activated sludge method. It is a figure which shows an example of the treatment facility of the organic waste water of this invention at the time of making a biological treatment method into the anaerobic / aerobic activated sludge method. It is a figure which shows an example of the processing equipment of the organic wastewater of this invention at the time of setting biological treatment method as biological denitrification method. It is a figure which shows an example of the processing equipment of the organic waste water of this invention at the time of setting a biological treatment method as the biological dephosphorization method. It is a figure which shows an example of a structure of the container used for this invention. It is a figure which shows the other example of a structure of the container used for this invention. It is a figure which shows the form which included the container in the bag-shaped carrier. It is a figure which shows an example of the accommodation form of the denitrification module to the aeration tank in this invention. It is a figure which shows the other example of the accommodation form of the denitrification module to the aeration tank in this invention. It is a figure which shows the further another example of the accommodation form of the denitrification module to the aeration tank in this invention. It is a figure which shows the processing equipment of the organic waste water used in the Example. It is a figure which shows the time-dependent change of the organic substance density | concentration in organic wastewater when the support | carrier which carry | supported denitrifying bacteria beforehand is used. It is a figure which shows a time-dependent change of the nitrate nitrogen density | concentration in organic wastewater when the support | carrier which carry | supported denitrifying bacteria beforehand is used. It is a figure which shows the time-dependent change of the organic substance density | concentration in organic wastewater when the support | carrier which is not carry | supporting denitrifying bacteria beforehand is used. It is a figure which shows the time-dependent change of the nitrate nitrogen density | concentration in organic wastewater when the support | carrier which is not carry | supporting denitrifying bacteria beforehand is used. It is a figure which shows an example of the treatment equipment of the conventional organic wastewater for implementing the activated sludge method. It is a figure which shows an example of the processing equipment of the conventional organic wastewater for implementing an anaerobic / aerobic activated sludge method. It is a figure which shows an example of the treatment facility of the conventional organic wastewater for implementing biological denitrification method. It is a figure which shows an example of the treatment equipment of the conventional organic wastewater for implementing biological dephosphorization method.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  The organic wastewater treatment method of the present invention is a method for treating organic wastewater using a biological treatment method including a step of aeration treatment of organic wastewater in an aeration tank together with activated sludge. In addition, a carrier capable of supporting microorganisms is disposed around at least the non-porous membrane of a sealed container filled with an electron donor material, so that the electron donor material is gradually released from the non-porous membrane portion of the container. Then, the aeration treatment is performed while at least the carrier is brought into contact with the organic waste water in the aeration tank. By this method, it is possible to perform a denitrification process in the aeration tank.

  The organic wastewater treatment method of the present invention is carried out, for example, in an organic wastewater treatment facility shown in FIGS. That is, in the organic wastewater treatment facility 1 using the biological treatment method having the aeration tank 2 in which the organic wastewater 9 is aerated with activated sludge, the electron donor substance is provided with at least a part of the nonporous membrane 22. 23 and a carrier 31 capable of supporting microorganisms, and the carrier 31 is disposed around at least the non-porous membrane 22 of the container 21 so that the non-porous membrane 22 of the container 21 is filled. The electron donor material 23 that is gradually released from the part is supplied to the carrier 31, and at least the carrier 31 is carried out in the treatment facility 1 accommodated in a position in contact with the organic waste water 9 in the aeration tank 2. Incidentally, reference numeral 11 in FIGS. 1 to 4 denotes a denitrification module in which a carrier 31 is arranged around the non-porous membrane 22 portion of the container 21.

  Hereinafter, after describing the configuration of the container 21, the configuration of the carrier 31, and the accommodation form of the denitrification module 11 in the aeration tank 2, the treatment facility for organic wastewater illustrated in FIGS. 1 to 4 will be described in detail. In addition, about the container 21 and the support | carrier 31 which comprise the denitrification module 11, the thing substantially the same as what was described in the international publication 2006/135028 for which this applicant applied previously can be used.

<Construction of container>
About the container 21 used for this invention, the thing similar to what was described in detail in the international publication 2006/135028 for which this applicant applied previously can be used. Hereinafter, an outline of the configuration of the container 21 will be described.

  FIG. 5 shows an example of the form of the container 21. The container 21 has a non-porous membrane 22 at least in part and is filled with an electron donor material 23 to form a sealed structure. With this configuration, the electron donor material 23 can be supplied from the portion of the non-porous membrane 22 of the container 21 to the periphery of the container 21 at a speed governed by the molecular permeation performance of the non-porous membrane 22. . In the form shown in FIG. 5, the container 21 is formed into a bag shape composed entirely of a non-porous film 22, and the electron donor substance is formed such that the periphery is welded by heat sealing or bonded with an adhesive. However, the shape and structure are not limited to this. For example, the container 21 may be formed in a tube shape or a sheet shape. In addition, the container 21 is not limited to the whole composed of the non-porous film 22, but only one side is composed of the non-porous film 22, or a part of one surface is composed of only the non-porous film 22. You may make it do. When the non-porous film 22 is partially used, a metal or plastic rigid frame may be used for the other parts, or a film or member that does not transmit the electron donor material 23 may be used.

  The container 21 may be a sealed structure having means for introducing the electron donor material 23 into the container 21 without being completely sealed and independent, and the electron donor material 23 may be replenished from the outside. For example, as shown in FIG. 6, a structure in which a supply part 25 for injecting an electron donor substance 23 is provided at a part of the edge of the container 21 and a nozzle or a pipe 27 is attached may be provided. A nozzle or a pipe 27 may be used. The nozzle or pipe 27 and the tank 26 for storing the liquid electron donor material 23 may be connected by a tube 28 or the like so that the electron donor material 23 can be replenished as necessary. In this case, since the tank 26 and the container 21 are communicated with each other via the tube 28, if the electron donor material 23 is stored in the tank 26, the electron donor material 23 in the container 21 is reduced. In addition, the electron donor substance 23 can be replenished to the container 21 using the pressure difference between the two ends of the tube using the principle of siphon. Alternatively, the electron donor material 23 can be replenished to the container 21 by gravity. In this case, since the container 21 is provided with the supply unit 25 or the nozzle 27, the container 21 is not strictly sealed. However, the supply nozzle 27 is filled with the electron donor material 3 supplied from the tank. In this state, the liquid level becomes a seal and the inside of the container 21 is practically sealed. For this reason, the liquid or gasified electron donor substance 23 does not leak out of the container 21 through the supply unit 25 and the nozzle 27. Here, the electron donor material 23 is not only supplied from the supply unit into the container 21, but is further provided with a discharge unit to be discharged from the discharge unit so that the electron donor material 23 in the container 21 can be replaced. Also good. Also in this case, the supply part 25 and the discharge part are filled with the electron donor substance 23, the inside of the container 21 is effectively sealed, and the liquid or gasified electron donor substance 23 is supplied to the supply part 25 and the discharge part. It does not leak out of the container 21 through.

  The non-porous film 22 is a film that gradually releases the electron donor material 23 by allowing the molecules to pass through little by little. This non-porous membrane 22 is an electron donor material that permeates per unit area depending on the film material, film thickness, molecular weight and properties of the encapsulated electron donor material 23, temperature, concentration, film density, and structure of the film constituent molecules. It is possible to control the amount of the three molecules. For example, if the film thickness is reduced, the amount of molecules of the electron donor material 23 that permeate per unit area increases, and conversely, the thickness increases. If the temperature of the electron donor material 23 is increased, the amount of molecules of the electron donor material 23 that permeate per unit area increases, and conversely, the amount decreases. Increasing the concentration of the electron donor material 23 increases the amount of molecules of the electron donor material 23 that permeate per unit area, and conversely decreases the amount. If the film density is lowered, the amount of molecules of the electron donor material 23 permeating per unit area is increased, and conversely, if the film density is increased, the amount is decreased.

  As the non-porous membrane 22, a hydrophobic membrane, a hydrophilic membrane, or a membrane having both hydrophilic and hydrophobic properties should be used according to the nature of the electron donor substance filled in the container. Can do.

  Examples of the hydrophobic non-porous membrane include polyethylene, polypropylene and other olefin-based membranes, and ethylene / vinyl acetate copolymer membranes. These membranes can satisfactorily partition the water region, the soil, the atmosphere, and other regions where microorganisms are active. Further, it has an appropriate substance permeability and thermoreversibility, and is flexible and easy to mold. Since the ethylene / vinyl acetate copolymer film has higher permeation performance of the electron donor material 23 than the polyethylene or polypropylene film having the same film thickness, the thickness of the non-porous film 22 is set to a sufficient strength. This is preferable in that the initial specification of the molecular permeation performance of the non-porous membrane 22 can be increased while the thickness can be secured. The molar ratio of ethylene and vinyl acetate, which is a molecule constituting the ethylene / vinyl acetate copolymer, is not particularly limited. For example, the molar ratio of ethylene and vinyl acetate is preferably 88:12. It is. However, the hydrophobic non-porous membrane is not limited to these.

  Examples of hydrophilic non-porous membranes include membranes having a hydrophilic group in the molecular structure, such as polyester, nylon (polyamide), polyvinyl alcohol, vinylon, cellophane, polyglutamic acid, etc., but are not limited thereto. is not.

  Examples of the membrane having both hydrophilic and hydrophobic properties include ethylene vinyl alcohol copolymer (EVOH), that is, a copolymer membrane having both a hydrophobic polyethylene structure and a hydrophilic polyvinyl alcohol structure. Although it is mentioned, it is not limited to this. A membrane having both hydrophilic and hydrophobic properties can be made more hydrophobic or more hydrophilic by changing the content ratio of hydrophobic polyethylene and hydrophilic polyvinyl alcohol.

  The electron donor material 23 is an electron donor material required by the denitrifying bacteria and a substance made of a molecule that is not toxic to the denitrifying bacteria, and has a property of not corroding the non-porous film 22. And what has the molecular weight and the property which can permeate | transmit the non-porous film | membrane 22 is selected suitably, The state may be gaseous or liquid.

  When a hydrophobic non-porous film is used, examples of the electron donor material 23 include gaseous compounds such as hydrogen, hydrogen sulfide, methane, and ethane. Examples of the liquid substance include alcohols such as methanol, ethanol and propanol, acetic acid and volatile organic acids such as propionic acid having a molecular weight greater than acetic acid and acetic acid, and volatile organic substances such as benzene, toluene and phenol. The use of ethanol is preferred. However, the electron donor material 23 is not limited to these. These electron donor materials 23 may be used alone or in combination of two or more. Even when alcohol is used as the electron donor material 23, it can be used as it is. When the container 21 is sealed with alcohol, the alcohol is slowly supplied from the non-porous membrane 22 to the denitrifying bacteria. Therefore, even if the alcohol stock solution is used, the alcohol concentration is reduced and supplied to the denitrifying bacteria, and the denitrifying bacteria die. Never reach. Note that the alcohol stock solution is not necessarily used. Even when the alcohol stock solution is diluted with water or when impurities are mixed, only alcohol molecules permeate the non-porous membrane. And is slowly supplied to the microorganisms.

  When a hydrophilic non-porous membrane is used, examples of the electron donor material 23 include alcohols such as methanol, ethanol and propanol, organic acids such as lactic acid, acetic acid and propionic acid, and sugars such as glucose and sucrose. The electron donor material 23 is not limited to these. In the case of using a hydrophilic non-porous film, if a substance having a large carbon number is used, the hydrophobicity of the substance becomes too strong and the substance does not permeate the non-porous film. Therefore, it is preferable to use those having 1 to 5 carbon atoms, and it is more preferable to use those having 1 to 3 carbon atoms.

  When using a non-porous membrane having both hydrophilic and hydrophobic properties, any of the above electron donor materials may be used. Further, the container 21 is composed of a hydrophobic non-porous film and a hydrophilic non-porous film, and only an electron donor substance that passes through only the hydrophobic non-porous film and a hydrophilic non-porous film. May be used in combination with an electron-donor substance that permeates.

  The permeation of the electron donor material 23 through the non-porous membrane 22 occurs when the material molecules dissolve in the membrane, and the dissolved molecules diffuse inside the membrane and reach the opposite side. Accordingly, catechin having a molecular weight that is so large that the film does not dissolve is difficult to permeate the non-porous film 22. In addition, since polyethylene, polypropylene, and the like are highly hydrophobic membranes that do not have a functional group compatible with water and have low polarity, water that is a polar molecule hardly dissolves in the membrane. Therefore, a cyanide compound, which is a highly polar substance that easily dissolves in water, can hardly pass through. In addition, since water has strong hydrogen bonds between water molecules, water hardly permeates the membrane at room temperature. Therefore, when a hydrophobic non-porous membrane is used, it is possible to use waste alcohol in which antibacterial molecules that are toxic to microorganisms such as catechin and cyanide are mixed in the alcohol. . In other words, the non-porous film 22 functions as a “molecular sieve” that allows a desired electron donor substance to permeate as a main component. In addition, the electron donor material 23 is placed outside the container 21 regardless of whether the container 21 is filled with gas, liquid, or vapor (generated by volatilization of a volatile substance). Released in the molecular state. In other words, the electron donor substance 23 permeates through the non-porous film 22 and is gradually released in a gas (gas) state that does not aggregate due to the attractive force between molecules like a liquid. Therefore, the non-porous membrane 22 can also be expressed as a gas permeable membrane. Further, the electron donor material 23 is gradually released from the non-porous film 22 regardless of whether the external environment of the container 21 is a gas phase or a liquid phase.

  The non-porous film 22 is permeated by dissolving the electron donor substance 23 in the film, and controls the amount of the electron donor substance passing through the size and number of pores like the porous film. It is not a thing. Therefore, there is no problem of hole clogging due to long-term use, and there is no need for regular backwashing. Therefore, it can be used without maintenance for a long time, and the running cost can be reduced.

<Configuration of carrier>
As the carrier 31 used in the present invention, those substantially the same as those described in detail in International Publication No. 2006/135028 filed earlier by the present applicant can be used. Hereinafter, an outline of the configuration of the carrier 31 will be described.

  As the carrier 31 capable of supporting microorganisms, when attaching denitrifying bacteria in activated sludge, microorganisms such as fibers and nonwoven fabrics made of various organic or inorganic materials, or porous materials such as activated carbon and sintered ceramics are used. A known or novel carrier capable of supporting the above can be used as appropriate. When denitrifying bacteria are immobilized in advance, for example, natural polymers such as collagen, fibrin, albumin, casein, cellulose fiber, cellulose triacetate, agar, calcium alginate, carrageenan, agarose, polyacrylamide, poly-2 -Synthesis of hydroxyethyl methacrylic acid, polyvinyl chloride, γ-methylpolyglutamic acid, polystyrene, polyvinylpyrrolidone, polydimethylacrylamide, polyurethane, photocurable resin (polyvinyl alcohol derivative, polyethylene glycol derivative, polypropylene glycol derivative, polybutadiene derivative, etc.) It is possible to use a polymer, a complex thereof, or a water-absorbing polymer. As the water-absorbing polymer, known polymers can be used, and specific examples include polyacrylic acid, polyaspartic acid, polyglutamic acid, modified products thereof, modified polyethylene glycol, and the like. The modified product referred to here is a product obtained by crosslinking a polymer having an ionic group to a part of the polymer. Moreover, you may use the support | carrier similar to the case where denitrifying bacteria in activated sludge are made to adhere. However, the carrier 31 is not limited to these.

<Accommodation form of denitrification module in aeration tank>
In the organic wastewater treatment facility of the present invention, the carrier 31 is disposed around at least the nonporous membrane 22 of the container 21 and the electron donor substance 23 that is slowly released from the nonporous membrane 22 portion of the container 21 is the carrier. 31, and at least the carrier 31 is accommodated in a position in contact with the organic waste water 9 in the aeration tank 2.

  First, the denitrification module 11 will be described. In the denitrification module 11, a carrier 31 is arranged around at least the nonporous membrane 22 of the container 21, and an electron donor substance 23 that is slowly released from the nonporous membrane 22 portion of the container 21 is supplied to the carrier 31. Is. The positional relationship between the non-porous membrane 22 and the carrier 31 of the container 21 is such that the electron donor substance 23 that is slowly released from the non-porous membrane 22 portion of the container 21 is sufficiently supplied to the carrier 31. Although not particularly limited, it is preferable to bring the non-porous membrane 22 of the container 21 and the carrier 31 close to, for example, about several centimeters, and the carrier 31 is brought into contact with the non-porous membrane 22 of the container 21. Is more preferred.

  The carrier 31 may be provided on the surface of the non-porous membrane 22 by, for example, adhesion, or may be integrated by heat-sealing together with the carrier when the periphery of the bag of the non-porous membrane 22 is heat-sealed. Further, the carrier 31 is made into a bag shape and the container 21 is enclosed therein, or as shown in FIG. 7, a part of the bag-like carrier 31 is opened, and the container 21 is placed in the inner space 33 of the bag. You may make it accommodate. In the case of forming the bag-shaped carrier 31, for example, a bag is formed with a nonwoven fabric 32 or the like for structural reinforcement, and is formed on the inside of the bag, the outside of the bag, or both sides of the bag (in FIG. 7, the inside of the bag). The carrier 31 may be applied and formed, or the film-like carrier 31 formed in advance may be bonded or welded to the nonwoven fabric 32. However, the present invention is not limited to this form, and the nonwoven fabric 32 itself functions as a carrier capable of supporting microorganisms. Therefore, a bag may be formed only from the nonwoven fabric 32 and used as a carrier. Alternatively, the bag may be formed using only the carrier 31 such as a polymer without using the nonwoven fabric 32. The non-porous membrane portion 22 of the container 21 is preferably completely covered with the carrier 31. In this case, the electron donor material 23 can be supplied to the carrier 31 without waste.

  The thickness of the carrier 31 is not particularly limited as long as a region capable of supporting microorganisms can be secured, but is preferably at least 0.3 mm, and more preferably at least 1 mm.

  In the aeration tank 2 in which the aeration apparatus 2a is accommodated, as shown in FIG. 8, the denitrification module 11 containing the container 21 in the bag-like carrier 31 may be submerged in the organic waste water 9, and FIG. As shown, the denitrification module 11 provided with the carrier 31 only on one surface of the container 21 by adhesion or the like may be floated on the organic waste water 9 so that the carrier 31 contacts the organic waste water 9. In this case, it is preferable to provide a barrier film or the like so that the electron donor substance is not gradually released from the other surface of the container 21. The denitrification module 11 can exhibit the denitrification ability without contacting the organic waste water 9 as a whole, as long as at least the carrier 31 is brought into contact with the organic waste water 9.

  Here, the denitrification module 11 is not limited to an independent one from the aeration tank 2. For example, as shown in FIG. 10, a through-hole 40 is provided in a part of the aeration tank 2 and is closed with a non-porous membrane 22, and a carrier 31 is placed on the inner surface of the aeration tank 2 of the non-porous film 22, for example. The container 21 is provided with an adhesive or the like, and a hole is provided in a part of the container 21 so as to communicate with the through hole 40, and the electron donor material 23 is supplied from the hole toward the through hole 40 of the aeration tank 2, so that the non-porous The electron donor material 23 may be transmitted through the film 22. In this case, the container 21 may be provided independently of the aeration tank 2 or may be integrated with the aeration tank 2.

  8 and 9, only one denitrification module 11 is accommodated, but a plurality of denitrification modules 11 may be accommodated. By accommodating a plurality of denitrification modules 11, the area capable of supporting denitrifying bacteria can be increased and the denitrification reaction can be promoted. The shape of the denitrification module 11 is not limited to that shown in FIGS. 8 and 9. For example, the denitrification module 11 may have a tube shape. The supported area may be further increased.

  When the carrier 31 is brought into contact with the organic waste water 9 in the aeration tank 2, denitrifying bacteria present in the activated sludge are gradually carried on the carrier 31. By supplying the electron donor material 23 to the carrier 31, an anaerobic environment is formed in the carrier 31, and the electron donor material 23 is given to the denitrifying bacteria carried on the carrier 31. A denitrifying bacterium to which the electron donor material 23 is given in an anaerobic environment exhibits a denitrifying ability. Therefore, it is possible to denitrify nitrate nitrogen and nitrite nitrogen in the aeration tank 2.

  Here, denitrifying bacteria may be supported on the carrier 31 in advance. As the denitrifying bacteria to be supported in advance, known or novel ones in the field of microbiology can be appropriately employed. Examples thereof include, but are not limited to, Paracoccus denitrificans, Alcaligenes eutrophus, Alcaligenes faecalis, Pseudomonas denitrificans, Paracoccus pantotrophus, Thiobacillus denitrificans. In addition, as a support | carrier used when carrying | supporting denitrifying bacteria previously, it is suitable to use gel-like things, such as said natural polymer, a synthetic polymer, these composites, and a water absorbing polymer. Moreover, as a support | carrier used when carrying out the denitrifying bacteria contained in activated sludge in the aeration tank 2, it is suitable to use a raw material with high porosity, such as a nonwoven fabric.

  As described above, according to the configuration of the present invention, the denitrification reaction for converting nitrate nitrogen and nitrite nitrogen into molecular nitrogen can proceed in the aerobic tank 2 which is strongly aerobic. Moreover, even if the electron donor material 23 that may increase the BOD of the organic wastewater is supplied, the BOD of the organic wastewater does not increase, and the original function of the organic wastewater treatment using activated sludge is not observed. The ability to decompose organic matter is not inhibited. That is, only the denitrification treatment ability can be imparted without interfering with the organic matter decomposition treatment ability of the conventional activated sludge method. In addition, ammonia nitrogen contained in organic wastewater is oxidized to nitrite nitrogen or nitrate nitrogen by ammonia oxidizing bacteria contained in activated sludge functioning in an aerobic atmosphere. And this nitrite nitrogen and nitrate nitrogen are converted into molecular nitrogen by the denitrification ability given to the aeration tank 2. Therefore, according to the present invention, not only organic substances contained in organic wastewater, but also nitrate nitrogen and nitrite nitrogen, and ammonia nitrogen is converted into molecular nitrogen to form harmless nitrogen gas from organic wastewater. It can be removed.

<Organic wastewater treatment equipment>
Hereinafter, the treatment facility for organic wastewater according to the present invention using the standard activated sludge method, the anaerobic aerobic method, the anaerobic anaerobic aerobic method, and the nitrification denitrification method will be described.

(1) Standard activated sludge method An example of the treatment equipment for organic wastewater of the present invention using the standard activated sludge method is shown in FIG. In this treatment facility 1a, the organic waste water 9 is introduced into the aeration tank 2 and aerated with the activated sludge, and the mixed liquid of the organic waste water and the activated sludge flows into the sedimentation tank 3 as it is. And in the sedimentation tank 3, the activated sludge contained in the liquid mixture which flowed in from the aeration tank 2 forms a floc and settles, and the supernatant liquid of the sedimentation tank 3 is obtained as treated water. The activated sludge settled in the settling tank 3 is returned to the aeration tank 2 as return sludge, and is again subjected to organic matter decomposition work. On the other hand, an amount of activated sludge commensurate with the grown microorganisms is recovered as excess sludge. And the denitrification module 11 is accommodated in the aeration tank 2 with the above-mentioned various forms.

  By treating organic wastewater with this treatment facility 1a, while maintaining the decomposition ability of organic matter, which is the original function of the activated sludge method, ammonia nitrogen, nitrate nitrogen, Nitrate nitrogen can be converted to molecular nitrogen to reduce its concentration. That is, a nitrogen removal function can be provided without newly providing a denitrification tank.

  1 uses a continuous activated sludge method, but the same effect can be obtained even if the denitrification module 11 is accommodated in the aeration tank 2 of the batch activated sludge method.

(2) Anaerobic aerobic method An example of the treatment equipment for organic wastewater of the present invention using the anaerobic aerobic method is shown in FIG. In this treatment facility 1b, treatment tanks are installed in the order of anaerobic tank 4, aeration tank 2, and precipitation tank 3, and organic waste water 9 is introduced in the order of anaerobic tank 4 → aeration tank 2 → precipitation tank 3. The activated sludge settled in the settling tank 3 returns to the aeration tank 2 via the anaerobic tank 4 as return sludge, and is again subjected to the organic matter decomposition operation. On the other hand, an amount of activated sludge commensurate with the grown microorganisms is recovered as excess sludge. And the denitrification module 11 is accommodated in the aeration tank 2 with the above-mentioned various forms.

  By treating organic wastewater with this treatment facility 1b, it is included in the organic wastewater while maintaining the organic substance decomposition treatment ability, bulking suppression ability and phosphorus concentration reduction ability, which are the original functions of the anaerobic aerobic method. Ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen can be converted to molecular nitrogen to reduce its concentration. Moreover, the nitrate nitrogen which flows into the anaerobic tank 4 with returned sludge decreases by reducing the nitrate nitrogen concentration of the aeration tank 2. Therefore, in the anaerobic tank 4, the amount of organic matter contained in the organic wastewater due to denitrifying bacteria is greatly reduced, and it is likely to be preferentially consumed by the polyphosphate accumulating bacteria contained in the returned sludge. Therefore, the polyphosphate-accumulating bacteria are easily grown and the proportion of the polyphosphate-accumulating bacteria exhibiting the phosphorus accumulating ability is increased. Thereby, the phosphorus density | concentration of organic wastewater can be reduced rather than before.

(3) Nitrification denitrification method An example of the organic wastewater treatment facility of the present invention using the nitrification denitrification method is shown in FIG. In this treatment facility 1c, treatment tanks are installed in the order of denitrification tank 5, aeration tank 2, and precipitation tank 3, and organic waste water 9 is introduced in the order of denitrification tank 5 → aeration tank 2 → precipitation tank 3. The activated sludge settled in the settling tank 3 returns to the aeration tank 2 via the denitrification tank 5 as return sludge, and is again subjected to the organic matter decomposition work. On the other hand, an amount of activated sludge commensurate with the grown microorganisms is recovered as excess sludge. In addition, after ammonia nitrogen is oxidized to nitrite nitrogen and nitrate nitrogen in the aeration tank 2, the organic waste water 9 (mixed liquid with activated sludge) in the aeration tank 2 is denitrified as a nitrification circulating liquid. It is returned to 5, is subjected to a denitrification reaction, converted to molecular nitrogen and removed. When the organic wastewater contains nitrite nitrogen and nitrate nitrogen from the beginning, the concentration of the organic wastewater is reduced by receiving a denitrification reaction when the organic wastewater flows into the denitrification tank 5.

  In this treatment facility 1c, a part of the denitrification process can be shifted from the denitrification tank 5 to the aeration tank 2, and the return amount of the nitrification circulating liquid from the aeration tank 2 to the denitrification tank 5 can be reduced. Therefore, the operating cost of the pump for return can be reduced. In other words, in the conventional organic wastewater treatment facility using the nitrification denitrification method, the problem that occurred as a result of increasing the return amount to the denitrification tank in order to increase the denitrification capacity, that is, the problem that the pump cost increases. The treatment facility of the present invention can greatly reduce the amount. In the treatment facility 1c, the nitrification circulating liquid is returned from the aeration tank 2 to the denitrification tank 5, but the denitrification treatment process is completely shifted from the denitrification tank 5 to the aeration tank 2, and the return process is performed. May be deleted completely. In this case, while maintaining the organic matter decomposition ability and the nitrogen component removal ability, the denitrification tank 5 can be eliminated to make the equipment compact.

(4) Anaerobic / Anaerobic / Aerobic Method FIG. 4 shows an example of the organic wastewater treatment facility of the present invention using the anaerobic / anoxic / aerobic method. In this treatment facility 1d, treatment tanks are installed in the order of anaerobic tank 4, denitrification tank 5, aeration tank 2, and precipitation tank 3, and organic waste water 9 is anaerobic tank 4 → denitrification tank 5 → aeration tank 2 → precipitation tank 3 In this order. The activated sludge settled in the settling tank 3 returns to the aeration tank 2 through the anaerobic tank 4 and the denitrification tank 5 as return sludge, and is again used for the organic matter decomposition work. On the other hand, an amount of activated sludge commensurate with the grown microorganisms is recovered as excess sludge. In addition, after ammonia nitrogen is oxidized to nitrite nitrogen and nitrate nitrogen in the aeration tank 2, the organic waste water 9 (mixed liquid with activated sludge) in the aeration tank 2 is denitrified as a nitrification circulating liquid. It is returned to 5, is subjected to a denitrification reaction, converted to molecular nitrogen and removed. Moreover, by providing the anaerobic tank 4 as a phosphorus elution tank, phosphorus is discharged from the polyphosphate accumulating bacteria contained in the activated sludge returned to the anaerobic tank 4, and the polyphosphate accumulating bacteria are excessively ingested in the aeration tank 2. Thereby, the phosphorus concentration contained in organic wastewater can be reduced. Furthermore, the denitrification tank 5 and the aeration tank 2 can reduce ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen concentration. In addition to the oxidative decomposition treatment in the aeration tank 2, the organic matter in the organic wastewater is consumed by the denitrifying bacteria in the denitrification tank 5 and the concentration thereof is reduced. Furthermore, it is consumed by the polyphosphate accumulating bacteria in the anaerobic tank 4 and the denitrification tank 5 to reduce its concentration.

  In this treatment facility 1d, a part of the denitrification process can be shifted from the denitrification tank 5 to the aeration tank 2, and the return amount of the nitrification circulating liquid from the aeration tank 2 to the denitrification tank 5 can be reduced. Therefore, the operating cost of the pump for return can be reduced. Moreover, the nitrate nitrogen which flows into the anaerobic tank 4 with returned sludge decreases by reducing the nitrate nitrogen concentration of the aeration tank 2. Therefore, in the anaerobic tank 4, the consumption amount of the organic matter contained in the organic wastewater by the denitrifying bacteria is greatly reduced, and it is preferentially consumed by the polyphosphate accumulating bacteria contained in the returned sludge. As a result, the polyphosphate-accumulating bacteria can easily grow and the ratio of the polyphosphate-accumulating bacteria exhibiting the phosphorus accumulating ability increases, so that the phosphorus concentration of organic waste water can be reduced as compared with the conventional case. In the treatment facility 1d, the nitrification circulating liquid is returned from the aeration tank 2 to the denitrification tank 5, but the denitrification treatment process is completely shifted from the denitrification tank 5 to the aeration tank 2, and the return process is performed. In addition, the denitrification tank 5 of the processing facility 1d may be deleted. In this case, the facility can be made compact while maintaining the organic matter decomposing ability, phosphorus removing ability and nitrogen component removing ability.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the standard activated sludge method, the anaerobic aerobic method, the anaerobic anaerobic aerobic method, and the nitrification denitrification method have been described as examples, but in addition to these methods, the organic wastewater is activated sludge. In addition, the present invention can be applied to any biological treatment method including a process of aeration in an aeration tank.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

  The effectiveness of the present invention was examined using an activated sludge reactor.

<Configuration of activated sludge reactor>
A continuous activated sludge reactor shown in FIG. 11 was constructed. Tap water 53 was supplied from a water storage tank 51 to a 2.9-liter aeration tank 2 by a liquid feed pump 52. To this tap water 53, inorganic salts were added. The aeration tank 2 was supplied with about 40 times the concentrated organic substrate 55 (hereinafter referred to as the concentrated substrate 55) sterilized by the substrate pump 54 simultaneously with tap water. The composition of inorganic salts and organic substances was as shown in Table 1. That is, the tap water 53 and the concentrated substrate 55 are simultaneously supplied to the aeration tank 2 to supply the organic waste water 9 to the aeration tank 2. The supply amount of the organic waste water 9 is 8.2 L / day, and this corresponds to a substrate concentration of TOC of 120 mg / L and TN of 36 mg N / L.

  The organic waste water 9 aerated by the aeration apparatus (air stone 2a, air pump 2b) of the aeration tank 2 is sent to the sedimentation basin 3 and the activated sludge suspended in the organic waste water 9 is precipitated and activated. The sludge was returned to the aeration tank 2 by the liquid feed pump 52.

  Two activated sludge reactors were prepared and the settling basin was shared. Therefore, the treatment capacity of activated sludge alone in the two reactors is common. Seed sludge was collected from an urban sewage treatment plant using the anaerobic aerobic method (AO method).

  The operating conditions were HRT (hydraulic residence time) of 8.5 hours, sludge return rate of 100%, and SRT (sludge retention time) of 11 days. Although the water temperature and pH of the organic waste water 9 in the aeration tank 2 were not particularly controlled, they were 21 ° C. to 25 ° C. and 7.5 to 8.0, respectively, during the experiment period, and large fluctuations were observed. There was no effect on water quality. Moreover, the dissolved oxygen concentration of the organic waste water 9 in the aeration tank 2 was always maintained at 4 mg / L or more.

<Configuration of denitrification module>
The denitrification module 11 was the same as that shown in FIG. 7 except that a non-woven fabric 32 was used to produce an outer bag and a carrier 31 was applied to the outer surface of the denitrification module 11. That is, the electron donor supply container 21 has a bag shape in which the entire surface of the container 21 is a non-porous film 22. Specifically, a 0.1 mm-thick low density polyethylene film (Mipolon film, manufactured by Mitsuwa Corporation) was used. This was cut into approximately 16 cm × 16 cm and heat-sealed to form a bag, and 70 mL of 99.5% ethanol was sealed in the bag. The ethanol transmission rate of this film was 0.8 mg COD / cm ² / day at 25 ° C.

Next, a 0.6 mm thick PET (polyethylene terephthalate) resin nonwoven fabric (G2260-1S, manufactured by Toray Industries, Inc.) was used to produce an outer bag slightly larger than the electron donor supply container. On the surface of the outer bag, a photocurable resin (PVA-SBQ, SPP-H-13, Toyo Gosei Co., Ltd.) was added with ammonia oxidizing bacteria (Nitrosomonas europaea NBRC14298), nitrite oxidizing bacteria (Nitrobacter winogradskyi NBRC14297) and denitrifying bacteria ( It was mixed with a phosphate buffer containing Paracoccus pantotrophus JCM6892) and applied in a thickness of 1 mm. Thereafter, the metal halide lamp was irradiated and cured for about 20 minutes per side. This outer bag was used as a carrier 31, and an electron donor supply container 21 was placed in the bag for use in experiments (denitrification module 11 in which ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, and denitrifying bacteria were fixed in advance on the carrier 31 ( Example 1)).

In the case where ammonia-oxidizing bacteria, nitrite-oxidizing bacteria and denitrifying bacteria are not previously supported on the carrier, a polyethylene airlaid nonwoven fabric (Venus Paper) with a 2 mm-thick void and many voids is used as a nonwoven fabric for attaching the denitrifying bacteria in the activated sludge. Manufactured, 40 g / m ² ) to produce an outer bag slightly larger than the electron donor supply container. This outer bag was used as a carrier 31, and an electron donor supply container 21 was put in this bag and used for the experiment (denitrification module 11 in which ammonia oxidizing bacteria, nitrite oxidizing bacteria and denitrifying bacteria were not fixed to the carrier 31. (Example 2)).

<Analysis method>
As an organic matter index, the supernatant (treated water) of the precipitation tank 3 was centrifuged and filtered (pore system 0.2 μm), and then the TOC was measured. In addition, ammonia nitrogen was measured by the indophenol method, and nitrite nitrogen and nitrate nitrogen were measured by ion chromatography. The sludge concentration was measured by centrifugation.

Example 1
Two denitrification modules 11 in which ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, and denitrifying bacteria were fixed in advance on the carrier 31 were accommodated in the aeration tank 2 of the activated sludge reactor, and a treatment test for organic wastewater was performed. The total area of the polyethylene film (that is, the effective area of the carrier 31) was about 1000 cm ² .

(Comparative Example 1)
An organic wastewater treatment test was conducted without accommodating the denitrification module 11 in the aeration tank 2 of the activated sludge reactor.

<Experimental result 1>
The concentrations of ammonia nitrogen and nitrite nitrogen were 0.3 mg N / L or less in both cases of Example 1 and Comparative Example 1, and it was confirmed that the concentrations were extremely low.

  Also, as shown in FIG. 12, there was almost no difference between Example 1 and Comparative Example 1 regarding the TOC concentration. From this, it became clear that the increase in the TOC concentration due to the permeation of the ethanol 23 enclosed in the electron donor supply container 21 constituting the denitrification module 11 from the polyethylene film 22 does not occur.

  Further, as shown in FIG. 13, it was found that the concentration of nitrate nitrogen was lower in Example 1 than in Comparative Example 1. From this, the microbial carrier 31 of the denitrification module 11 is accommodated even under conditions in which the denitrification module 11 is accommodated in the aeration tank 2 of the activated sludge reactor and the aeration tank 2 is aerated to increase the dissolved oxygen concentration. It was shown that the denitrification ability of the denitrifying bacteria can be exhibited under a part of the anaerobic conditions.

(Example 2)
The experiment was carried out in the same manner as in Example 1 except that a denitrification module 11 that does not fix ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, and denitrifying bacteria to the carrier 31 was used.

<Experimental result 2>
The concentration of ammonia nitrogen and nitrite nitrogen was 0.3 mg N / L or less in both cases of Example 2 and Comparative Example 1, and it was confirmed that the concentrations were extremely low.

  Further, as shown in FIG. 14, almost no difference was found between Example 2 and Comparative Example 1 with respect to the TOC concentration. From this, it became clear that the increase in the TOC concentration due to the permeation of the ethanol 23 enclosed in the electron donor supply container 21 constituting the denitrification module 11 from the polyethylene film 22 does not occur.

  Further, as shown in FIG. 15, it was revealed that the concentration of nitrate nitrogen was lower in Example 2 than in Comparative Example 1. Therefore, even when the denitrification module 11 in which the denitrifying bacteria are not supported on the carrier 31 is accommodated in the aeration tank 2 of the activated sludge reactor, the carrier 31 on which the denitrifying bacteria are previously supported on the carrier 31 is removed. It was revealed that denitrification treatment was possible, as in the case of containing the. For this reason, the denitrifying bacteria contained in the activated sludge are supported on the carrier 31 and the denitrifying ability of the denitrifying bacteria is exhibited while performing the aeration treatment without the carrier 31 previously supporting the denitrifying bacteria. It became clear that this is possible.

  From the above results, by supplying the electron donor material 23 in general to the carrier 31, an anaerobic environment can be formed in the carrier 31, and the electron donor material 23 is added to the denitrifying bacteria carried on the carrier 31. The denitrification ability can be exerted on the denitrifying bacteria and the denitrification ability can be imparted to the aeration tank 2 without interfering with the organic matter decomposition ability that is the original function of organic wastewater treatment using activated sludge. The possibility was led.

1 (1a, 1b, 1c, 1d) Organic wastewater treatment facility 2 Aeration tank 9 Organic wastewater 21 Container 22 Non-porous membrane 23 Electron donor substance 31 Carrier

Claims (6)

In a method for treating organic wastewater using a biological treatment method including a process of aeration treatment of organic wastewater with activated sludge in an aeration tank,
A non-porous membrane is provided at least in part and a carrier capable of supporting microorganisms is disposed around at least the non-porous membrane in a sealed container filled with an electron donor substance, and the non-porous membrane of the container is disposed. In the aeration tank, the electron donor substance is gradually released from a membrane portion and supplied to the carrier, and the aeration treatment is performed while at least the carrier is in contact with the organic waste water in the aeration tank. Organic wastewater treatment method that enables denitrification treatment. The organic wastewater treatment method according to claim 1, wherein the biological treatment method is a standard activated sludge method, an anaerobic aerobic method, an anaerobic anaerobic aerobic method, or a nitrification denitrification method. The method for treating organic wastewater according to claim 1, wherein the carrier is loaded with denitrifying bacteria in advance and then brought into contact with the organic wastewater. In an organic wastewater treatment facility using a biological treatment method having an aeration tank in which organic wastewater is aerated with activated sludge,
A container having a non-porous membrane at least in part and having a sealed structure filled with an electron donor substance, and a carrier capable of supporting microorganisms;
The carrier is disposed around at least the nonporous membrane of the container, and the electron donor substance that is slowly released from the nonporous membrane portion of the container is supplied to the carrier, and at least the carrier is aerated. An organic wastewater treatment facility capable of denitrification in an aeration tank, wherein the treatment equipment is housed in a position in contact with the organic wastewater in the tank. The organic wastewater treatment facility according to claim 4, wherein the biological treatment method is a standard activated sludge method, an anaerobic aerobic method, an anaerobic anaerobic aerobic method, or a nitrification denitrification method. The treatment equipment for organic wastewater according to claim 4, wherein denitrifying bacteria are supported on the carrier in advance.