WO2012169381A1 - Method and apparatus for biological treatment of organic wastewater - Google Patents

Method and apparatus for biological treatment of organic wastewater Download PDF

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Publication number
WO2012169381A1
WO2012169381A1 PCT/JP2012/063599 JP2012063599W WO2012169381A1 WO 2012169381 A1 WO2012169381 A1 WO 2012169381A1 JP 2012063599 W JP2012063599 W JP 2012063599W WO 2012169381 A1 WO2012169381 A1 WO 2012169381A1
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biological treatment
treatment tank
tank
carrier
organic wastewater
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PCT/JP2012/063599
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French (fr)
Japanese (ja)
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繁樹 藤島
太郎 飯泉
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栗田工業株式会社
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/12—Activated sludge processes
    • C02F3/1205—Particular type of activated sludge processes
    • C02F3/121—Multistep treatment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/08—Aerobic processes using moving contact bodies
    • C02F3/085—Fluidized beds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

  • the present invention relates to a biological treatment method and apparatus for organic wastewater that can be used for treatment of organic wastewater in a wide concentration range including domestic wastewater, sewage, food factories and pulp factories.
  • the present invention relates to a biological treatment method and apparatus for organic wastewater that can improve the treatment efficiency and reduce the amount of excess sludge generation without deteriorating water quality.
  • the activated sludge method used when biologically treating organic wastewater is widely used for sewage treatment, industrial wastewater treatment, and the like because of its advantages such as good treated water quality and easy maintenance.
  • the BOD volume load in the activated sludge method is about 0.5 to 0.8 kg / m 3 / d, a large site area is required.
  • 20% of the decomposed BOD is converted into bacterial cells, that is, sludge, a large amount of excess sludge treatment is also a problem.
  • Japanese Patent Application Laid-Open No. 2000-210692 proposes a countermeasure for deterioration in processing performance due to fluctuations in the quality of raw water, which is a problem in the processing method of Japanese Patent Application Laid-Open No. 55-20649.
  • “adjust BOD fluctuation of treated water to within 50% from median average concentration”, “measure water quality in first treatment tank and first treated water over time”, Methods such as “add seed sludge or microbial preparation to the first treatment tank when the quality of the first treated water deteriorates” have been proposed.
  • the multi-stage activated sludge method using the predatory action of such minute animals is actually used for organic wastewater treatment.
  • the treatment efficiency is improved and the amount of generated sludge is reduced by about 50%. Is possible.
  • Microanimals that contribute to sludge reduction in the multistage activated sludge process that uses the predatory action of microanimals include a filter predation type and an aggregate predation type.
  • aggregate predation type micro-animals can also prey while gnawing flocked sludge, so if this predominates, the quality of treated water will deteriorate. For this reason, in order to maintain the treated water quality, it is desirable to dominate the filtration predation type micro-animal rather than the aggregate predation type micro-animal. No control method has been proposed to make it dominant. For this reason, depending on the operating conditions, the problem of unexpectedly deteriorated treated water quality may occur due to the predominance of aggregate predatory microanimals.
  • the membrane activated sludge method for membrane separation treatment of biologically treated water eliminates the need for sludge management in the sedimentation basin and provides high quality treated water quality, but the membrane activated sludge method is subject to membrane clogging. Even in low-load operation, there was a problem that fine SS was generated by sludge dismantling and the membrane was blocked. In addition, if the aggregate predation type micro-animals that prey on flocs in activated sludge increase due to water temperature, load, and SRT, refinement of sludge is promoted and the quality of treated water deteriorates. There were also problems that made management difficult.
  • an object of the present invention is to provide a biological treatment method and apparatus for organic wastewater that reduces sludge and obtains good treated water quality.
  • the present inventors hold micro-animals in order to predominate the fixed filtration predation-type micro-animals that prey on the dispersal bacteria in the subsequent biological treatment tank.
  • the carrier is a fluidized bed carrier so that the fixed filtration predation type micro-animal can efficiently eat the dispersal bacteria, and the fluidized bed carrier by controlling the amount of aeration It has been found that by controlling the dropout of microanimals from the plant, the predation type microanimals can be made dominant.
  • the present invention has been achieved on the basis of such knowledge, and the gist thereof is as follows.
  • Organic wastewater is introduced into the first biological treatment tank of the aerobic biological treatment tank provided in two or more stages and biologically treated with bacteria, including dispersed bacteria from the first biological treatment tank
  • the first biological treatment water is passed through the biological treatment tank in the latter stage to biologically treat
  • the biological treatment water in the last stage biological treatment tank is solid-liquid separated into sludge and treated water.
  • a fluidized bed carrier for holding micro-animals is provided in the subsequent biological treatment tank, and the amount of aeration in the biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom area / h or less.
  • a biological treatment method for organic wastewater is 50 m 3 -air / m 2 -bottom area / h or less.
  • the latter biological treatment tank is composed of biological treatment tanks provided in two or more stages, and the fluidized bed carrier is placed in at least one of the biological treatment tanks provided in the multiple stages.
  • a biological treatment method for organic wastewater characterized in that the aeration amount of a biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom area / h or less.
  • [3] A biological treatment method for organic wastewater according to [1] or [2], wherein the solid-liquid separation is performed by membrane separation.
  • An aerobic biological treatment tank provided in two or more stages, and solid-liquid separation means for solid-liquid separation of the biological treatment water of the last biological treatment tank into sludge and treated water
  • the biological treatment tank is a tank for biologically treating organic wastewater with bacteria
  • the latter biological treatment tank is a tank for biologically treating the first biologically treated water containing dispersed bacteria introduced from the first biological treatment tank.
  • the biological treatment tank in the subsequent stage is provided with a fluidized bed carrier for holding micro-animals, and the aeration amount of the biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom bottom
  • An organic wastewater biological treatment apparatus characterized by having an area / h or less.
  • the latter biological treatment tank is composed of two or more stages of biological treatment tanks, and the fluidized bed carrier is provided in at least one of the biological treatment tanks provided in the multiple stages.
  • An organic wastewater biological treatment apparatus wherein the biological treatment tank provided with the fluidized bed carrier has an aeration amount of 50 m 3 -air / m 2 -bottom area / h or less.
  • the fixed type filter predation type micro animal in the multi-stage activated sludge method utilizing the predatory action of a micro animal, by providing a carrier in a biological treatment tank in the subsequent stage that holds the micro animal, the fixed type filter predation type micro animal can be stably placed on this carrier. Can be retained and propagated. That is, since the filtration predation type micro-animal is a fixed type, a scaffold is required to predominate the filtration predation type micro-animal. Filtered predation type micro-animals can be adhered to the sludge floc in the tank, but since sludge is drawn out of the system with a certain residence time, the carrier as a scaffold for adhering the filtration predation type micro-animals Is provided.
  • the carrier is a fluidized bed carrier
  • the micro-animal on the carrier can efficiently prey on the dispersal bacteria flowing together with the carrier and flowing into the tank.
  • the carrier is a fluidized bed carrier
  • the minute animals can be detached from the carrier and dropped off due to the shearing force due to aeration in the tank, and the minute animals cannot be stably held at a high concentration on the carrier. .
  • the flow of the carrier is suppressed to some extent, It is possible to prevent the micro-animal from falling off and to predominate the filtration and predation-type micro-animal in the biological treatment tank and to maintain this predominance state stably (above [1] and [4]). .
  • two or more biological treatment tanks may be provided in multiple stages as subsequent biological treatment tanks.
  • a fluidized bed carrier is provided in at least one of the biological treatment tanks provided in multiple stages.
  • the aeration amount of the biological treatment tank provided with the fluidized bed carrier is preferably 50 m 3 -air / m 2 -tank bottom area / h or less (the above [2], [5]).
  • solid-liquid separation of biological treatment water at the last stage may be performed by membrane separation.
  • the growth of aggregate predation type micro-animals that cause blockage of the membrane is suppressed, which contributes to improvement of treated water quality.
  • By preferentially filtering predatory type micro-animals it is possible to prevent clogging of the membrane due to the generation of fine SS due to sludge refinement, and the frequency of chemical cleaning is reduced to maintain stable operation over a long period of time. ([3], [6] above).
  • 1 to 3 are system diagrams showing an embodiment of a biological treatment method and apparatus for organic wastewater according to the present invention.
  • 1 is a first biological treatment tank
  • 2 is a second biological treatment tank
  • 3 is a sedimentation tank
  • 4 is a third biological treatment tank
  • 5 is a membrane separator
  • 2A is a fluidized bed carrier
  • 1B, 2B , 4B are air diffusers, and members having the same functions are denoted by the same reference numerals.
  • raw water organic wastewater
  • first biological treatment tank 1 a first biological treatment tank 1
  • 70% or more, desirably 80% or more, more desirably 90% of the organic component (soluble BOD) by dispersible bacteria. % Or more is oxidatively decomposed.
  • the pH of the first biological treatment tank 1 is 6 or more, preferably 8 or less. However, when the raw water contains a large amount of oil, the pH may be 8 or more in order to increase the decomposition rate.
  • the flow of raw water to the first biological treatment tank 1 is made transient
  • the BOD volumetric load is 1 kg / m 3 / d or more, for example, 1 to 20 kg / m 3 / d
  • the HRT raw water retention time
  • Low waste water can be treated with high load, which is preferable.
  • the dissolved oxygen (DO) concentration in the first biological treatment tank 1 is preferably controlled to 1 mg / L or less, particularly 0.5 mg / L or less, for example 0.05 to 0.5 mg / L. While the growth of filamentous bacteria is suppressed, dispersal bacteria having a size of about 1 to 5 ⁇ m dominate, and these are rapidly preyed in the second biological treatment tank 2.
  • the first biological treatment tank In this first biological treatment tank, a part of the sludge from the latter biological treatment tank is returned, the first biological treatment tank is composed of two or more stages, or a carrier is added to the first biological treatment tank. As a result, high load processing with a BOD volumetric load of 5 kg / m 3 / d or more becomes possible.
  • the shape of the carrier to be used is arbitrary such as a spherical shape, a pellet shape, a hollow cylindrical shape, a thread shape, and a plate shape, and the size may be about 0.1 to 10 mm.
  • the material of the carrier is arbitrary such as a natural material, an inorganic material, or a polymer material, and a gel material may be used.
  • the carrier filling rate (the volume ratio of the carrier with respect to the tank volume) is preferably 10% or less, and preferably 5% or less.
  • the HRT of the first biological treatment tank 1 is longer than the optimum value, it will lead to the predominance of filamentous bacteria and the formation of flocs, and bacteria that are difficult to prey in the second biological treatment tank 2 will be generated. End up. Therefore, it is necessary to control the HRT of the first biological treatment tank 1 to be constant. Since this optimum HRT varies depending on the quality of raw water, it is necessary to obtain an HRT capable of removing 70 to 90% of organic components from a desktop test or the like. As a method of maintaining the HRT at the optimum value, when the raw water amount is reduced, a part of the treated water is returned, the amount of water flowing into the first biological treatment tank 1 is made constant, and the HRT of the first biological treatment tank 1 is stabilized.
  • the width for stabilizing the HRT of the first biological treatment tank 1 is desirably within the range of 0.75 to 1.5 times the optimum HRT obtained by the desktop test.
  • the decomposition rate of the organic component in the first biological treatment tank 1 is not 100% but 95% or less.
  • the treated water (first biological treated water) in the first biological treatment tank 1 is passed through the second biological treatment tank 2 in the subsequent stage, where the remaining organic components are oxidatively decomposed and the self of dispersible bacteria. Reduce excess sludge by decomposition and predation of micro-animals.
  • the second biological treatment tank 2 is an aeration tank in which a carrier 2A is added to the tank to form a fluidized bed, thereby increasing the amount of filtration predation type micro-animal retained in the tank.
  • the shape of the carrier 2A added to the second biological treatment tank 2 may be any shape such as a spherical shape, a pellet shape, a hollow cylindrical shape, a thread shape, a plate shape, and the size may be about 0.1 to 10 mm.
  • the material of the carrier 2A is arbitrary such as a natural material, an inorganic material, or a polymer material, and a gel material may be used.
  • the filling rate of the carrier 2A in the second biological treatment tank 2 is preferably 50% or less, particularly 5 to 50%.
  • the second biological treatment tank 2 has an aeration amount of 50 m 3 ⁇ in order to prevent the filtration predation type micro-animal adhering to the carrier 2A from being peeled off and dropped out by the shearing force caused by the flow of the carrier. Air / m 2 ⁇ Bath bottom area / h or less. When the aeration amount exceeds 50 m 3 -air / m 2 -tank bottom area / h, the filtration predation type micro-animal is preferentially placed in the second biological treatment tank 2 by dropping and outflow of the filtration predation type micro animal from the carrier. It will not be possible to divide.
  • the amount of aeration is 1 to 40 m 3 -air / m. 2 - tank bottom area / h, in particular 1 ⁇ 20m 3 -air / m 2 - is preferably a tank bottom area / h.
  • the biological treatment tank at the subsequent stage not only the filtration predation type micro animals that prey on the dispersed cells, but also the aggregate predation type micro animals that can prey on the floc sludge. Since the latter prey on flocs while swimming, if this predominates, the sludge is eaten and becomes sludge in which fine floc pieces are scattered. Due to the floc pieces, the quality of treated water is deteriorated, and membrane clogging occurs in the membrane activated sludge method.
  • the SRT (sludge retention time) of the second biological treatment tank 2 is controlled to be constant within a range of 60 days or less, particularly 45 days or less, especially 10 days or more and 30 days or less. It is desirable.
  • SRT at this time shows the residence time of floating sludge and does not include a carrier adhesion part.
  • the treated water from the second biological treatment tank 2 is then solid-liquid separated into sludge and treated water in the sedimentation tank 3, a part of the separated sludge is returned as return sludge, and the remainder as extra sludge. Discharged.
  • the biological treatment tank in the subsequent stage has a multistage configuration of the second biological treatment tank 2 and the third biological treatment tank 4, and the carrier 2A is added to the second biological treatment tank 2 so that the aeration amount is as described above.
  • 50 m 3 -air / m 2 -tank bottom area / h or less, preferably 1 to 40 m 3 -air / m 2 -tank bottom area / h, particularly preferably 1-20 m 3 -air / m 2 -tank bottom area / h 1 is different from the embodiment shown in FIG. 1, and the other points are the same as the embodiment shown in FIG.
  • the carrier may be added to the third biological treatment tank 4, or the carrier may be added only to the third biological treatment tank 4 without adding the carrier to the second biological treatment tank 2.
  • the aeration amount of the biological treatment tank to which the carrier is added is set to 50 m 3 -air / m 2 -tank bottom area / h or less as described above.
  • the biological treatment tank in the subsequent stage may have a multi-stage configuration of three or more stages, and even in that case, the biological treatment tank to which the carrier is added may be one tank, two tanks or more, or all tanks.
  • the number of tanks and the positions of the tanks are arbitrary, but it is necessary to adjust the position and number of biological treatment tanks to which the carrier is added so that the inside of the tanks does not become anaerobic due to excessive aeration.
  • the embodiment shown in FIG. 3 is a membrane activated sludge system so that micro-animals and bacteria stay in the system.
  • a membrane separation device 5 is provided instead of the sedimentation tank 3, and the permeation of the membrane separation device 5 is performed. The difference is that water is extracted as treated water, the concentrated water is returned to the second biological treatment tank 2 and excess sludge is extracted from the second biological treatment tank 2, and the others are the same as the embodiment shown in FIG.
  • the pH in order to promote predation by the microanimals, it is preferable to set the pH to 7 or less, for example, pH 5.5 to 6.5 in the biological treatment tank subsequent to the second biological treatment tank 2.
  • the DO concentration in the biological treatment tank 2 in the subsequent stage is preferably about 1 to 4 mg / L.
  • a nutrient is added to the second biological treatment tank after the second biological treatment tank 2, in particular, the second biological treatment tank 2 to stably maintain the micro-animal, thereby stabilizing the sludge reduction effect. You may do it. Moreover, you may accelerate
  • nutrients include phospholipids, free fatty acids, lysophospholipids, sterols and lecithins containing these, liquid sugar, rice bran, beer pomace, vegetable oil pomace, soybean extract, sugar beet koji, Nutrients effective in promoting the growth of metazoans such as shellfish powder, eggshell, vegetable extract, fish meat extract, various amino acids and various vitamins can be used. These may be used alone or in combination of two or more. When these nutrients are added, the amount added is preferably about 0.5 to 10% of the amount of organic matter in the raw water.
  • 1 to 3 show an example of an embodiment of the present invention, and the present invention is not limited to the illustrated method unless it exceeds the gist.
  • a floating separation tank or the like may be used in addition to the precipitation tank and the membrane separation device.
  • the oxidative decomposition is performed in the second biological treatment tank 2.
  • the bacteria grow in a form that is difficult to be predated as a countermeasure to escape from predation of the micro animals.
  • the bacteria that have grown in this way are not preyed on by the micro-animals, and their decomposition depends only on autolysis, which reduces the effect of reducing the amount of sludge generated.
  • the second biological treatment tank 2 in the latter stage is desirably operated at 0.025 to 0.05 kg-BOD / kg-MLSS / d in terms of sludge load due to the soluble BOD.
  • latter stage by bypassing a raw
  • MLSS shows the sludge density
  • Example 1 As shown in FIG. 1, a first biological treatment tank (capacity sludge return) 1 having a capacity of 3.6 L, a second biological treatment tank (capacity sludge return) 2 having a capacity of 15 L, and a sedimentation tank 3 having a capacity of 5 L
  • the organic waste water according to the present invention was treated using an experimental apparatus in which the two were connected.
  • COD Cr 2000 mg / L and BOD 1280 mg / L artificial substrates were used, and the treatment conditions of each biological treatment tank were as follows.
  • the BOD volumetric load of the entire apparatus was 1.5 kg-BOD / m 3 / d, and the HRT of the entire apparatus was 21 h.
  • the sludge floc in the second biological treatment tank 2 and the filter-precipitating microanimals that are sticking to the carrier (Teleganus elegans) are sludge conversion rates of 0.10 kg-MLSS / kg-COD Cr. It was.
  • the treated water quality was always in good condition during the test period with COD Cr concentration ⁇ 30 mg / L and SS ⁇ 10 mg / L.
  • Example 2 The raw water was treated under the same conditions as in Example 1 except that the amount of aeration in the second biological treatment tank was 20 L / min (40 m 3 -air / m 2 -tank bottom area / h). As a result, the sludge flocs in the second biological treatment tank, filtered predatory miniature animals to the carrier is excellent Uranaika, sludge conversion rate was 0.10kg-MLSS / kg-COD Cr . The treated water quality was always in good condition throughout the test period with COD Cr concentration ⁇ 50 mg / L and SS ⁇ 20 mg / L.
  • Example 1 A comparative experiment was conducted using an experimental apparatus in which a biological treatment tank (with no carrier) having a capacity of 18.6 L and a 5 L sedimentation basin were connected.
  • the treated raw water, the BOD volumetric load of the entire apparatus, and the HRT are the same as those in Example 1.
  • the sludge conversion rate was 0.30 kg-MLSS / kg-COD Cr .
  • a large amount of filamentous bacteria were generated, making it difficult to separate solid and liquid in the sedimentation basin.
  • Example 2 Raw water was treated under the same conditions as in Example 1 except that no carrier was added to the second biological treatment tank. As a result, the sludge conversion rate was 0.10kg-MLSS / kg-COD Cr . However, since the aggregate predation type micro-animals prevailed in the second biological treatment tank, the quality of the treated water deteriorated, and the COD Cr concentration of the treated water was 80 mg / L or more and the SS concentration was 50 mg / L throughout the test period. That was bad.
  • Example 3 Raw water was treated under the same conditions as in Example 1 except that the amount of aeration in the second biological treatment tank was 30 L / min (60 m 3 -air / m 2 -tank bottom area / h). As a result, the sludge conversion rate was 0.10kg-MLSS / kg-COD Cr . However, treated water by aggregate predatory miniature animals in the second biological treatment tank has excellent Uranaika worsened, throughout the study, COD Cr concentration in the treated water 50 mg / L or more, SS concentration 20 mg / L or more It was worse than Example 1.
  • the biological treatment method for organic wastewater of the present invention can be used for treatment of organic wastewater in a wide concentration range including domestic wastewater, sewage, food factories and pulp factories.

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Abstract

A multi-step activated sludge method utilizing the feeding activity of a micro animal, in which the amount of sludge can be reduced and good quality can be imparted to treated water by inhibiting the proliferation of an aggregate-feeding micro animal and prioritizing a filter-feeding micro animal. A method for biologically treating organic wastewater, comprising: introducing the organic wastewater into a first biological treatment vessel (1) in a multi-stage aerobic biological treatment tank that is composed of at least two biological treatment vessels to thereby biologically treat the organic wastewater with bacteria; allowing a first biologically treated water that is obtained from the first biological treatment vessel (1) and contains the bacteria dispersed therein to pass through a subsequent-stage biological treatment vessel (2) to thereby biologically treat the first biologically treated water; and performing the solid-liquid separation of biologically treated water that is obtained from a final-stage biological treatment vessel (2) into sludge and treated water. In the method, a fluidized bed carrier (2A) having the micro animal carried thereon is provided in the subsequent-stage biological treatment vessel (2) and the amount of aeration in the biological treatment vessel (2) is set at 50 m3-air/m2-(vessel bottom surface area)/h or less.

Description

有機性排水の生物処理方法および装置Biological treatment method and apparatus for organic wastewater
　本発明は、生活排水、下水、食品工場やパルプ工場をはじめとした広い濃度範囲の有機性排水の処理に利用することができる有機性排水の生物処理方法および装置に関するものであり、特に、処理水質を悪化させることなく、処理効率を向上させ、かつ、余剰汚泥発生量の低減が可能な有機性排水の生物処理方法および装置に関する。 The present invention relates to a biological treatment method and apparatus for organic wastewater that can be used for treatment of organic wastewater in a wide concentration range including domestic wastewater, sewage, food factories and pulp factories. The present invention relates to a biological treatment method and apparatus for organic wastewater that can improve the treatment efficiency and reduce the amount of excess sludge generation without deteriorating water quality.
　有機性排水を生物処理する場合に用いられる活性汚泥法は、処理水質が良好で、メンテナンスが容易であるなどの利点から、下水処理や産業廃水処理等に広く用いられている。しかしながら、活性汚泥法におけるＢＯＤ容積負荷は０．５～０．８ｋｇ／ｍ３／ｄ程度であるため、広い敷地面積が必要となる。また、分解したＢＯＤの２０％が菌体、即ち汚泥へと変換されるため、大量の余剰汚泥処理も問題となる。 The activated sludge method used when biologically treating organic wastewater is widely used for sewage treatment, industrial wastewater treatment, and the like because of its advantages such as good treated water quality and easy maintenance. However, since the BOD volume load in the activated sludge method is about 0.5 to 0.8 kg / m 3 / d, a large site area is required. Moreover, since 20% of the decomposed BOD is converted into bacterial cells, that is, sludge, a large amount of excess sludge treatment is also a problem.
　有機性排水の高負荷処理に関しては、担体を添加した流動床法が知られている。この方法を用いた場合、３ｋｇ／ｍ３／ｄ以上のＢＯＤ容積負荷で運転することが可能となる。しかしながら、この方法では発生汚泥量は分解したＢＯＤの３０％程度で、通常の活性汚泥法より高くなることが欠点となっている。 For high load treatment of organic waste water, a fluidized bed method with a carrier added is known. When this method is used, it is possible to operate with a BOD volume load of 3 kg / m 3 / d or more. However, this method has a disadvantage that the amount of generated sludge is about 30% of the decomposed BOD, which is higher than the normal activated sludge method.
　特開昭５５－２０６４９号公報には、有機性排水をまず、第一処理槽で細菌により処理し、排水に含まれる有機物を酸化分解して非凝集性の細菌の菌体に変換した後、第二処理槽で固着性原生動物に捕食除去させることで余剰汚泥の減量化が可能になることが記載されている。さらに、この方法では高負荷運転が可能となり、活性汚泥法の処理効率も向上するとされている。 In Japanese Patent Laid-Open No. 55-20649, organic wastewater is first treated with bacteria in a first treatment tank, and organic matter contained in the wastewater is oxidatively decomposed and converted into non-aggregating bacterial cells. It is described that excess sludge can be reduced by precipitating and removing the sticking protozoa in the second treatment tank. Further, this method enables high-load operation and improves the processing efficiency of the activated sludge method.
　このように細菌の高位に位置する原生動物や後生動物の捕食を利用した廃水処理方法は、多数提案されている。 A number of wastewater treatment methods using protozoa and metazoan predation located at high levels of bacteria have been proposed.
　例えば、特開２０００－２１０６９２号公報では、特開昭５５－２０６４９号公報の処理方法で問題となる、原水の水質変動による処理性能悪化の対策が提案されている。具体的な方法としては、「被処理水のＢＯＤ変動を平均濃度の中央値から５０％以内に調整する」、「第一処理槽内および第一処理水の水質を経時的に測定する」、「第一処理水の水質悪化時には種汚泥又は微生物製剤を第一処理槽に添加する」等の方法が提案されている。 For example, Japanese Patent Application Laid-Open No. 2000-210692 proposes a countermeasure for deterioration in processing performance due to fluctuations in the quality of raw water, which is a problem in the processing method of Japanese Patent Application Laid-Open No. 55-20649. As specific methods, “adjust BOD fluctuation of treated water to within 50% from median average concentration”, “measure water quality in first treatment tank and first treated water over time”, Methods such as “add seed sludge or microbial preparation to the first treatment tank when the quality of the first treated water deteriorates” have been proposed.
　特公昭６０－２３８３２号公報では、細菌、酵母、放線菌、藻類、カビ類や廃水処理の初沈汚泥や余剰汚泥を、原生動物や後生動物に捕食させる際に、超音波処理または機械攪拌により、これらの餌のフロックサイズを動物の口より小さくさせる方法を提案している。 In Japanese Examined Patent Publication No. 60-23832, bacteria, yeasts, actinomycetes, algae, molds, wastewater treatment primary sludge and surplus sludge are precipitated by protozoa and metazoans by ultrasonic treatment or mechanical stirring. Have proposed a method for making these foods smaller in size than the animal's mouth.
　また、流動床と活性汚泥法の多段処理に関する発明としては、特許第３４１０６９９号公報に記載のものがある。この方法では、後段の活性汚泥法をＢＯＤ汚泥負荷０．１ｋｇ－ＢＯＤ／ｋｇ－ＭＬＳＳ／ｄの低負荷で運転することで、汚泥を自己酸化させ、汚泥引き抜き量を大幅に低減できるとしている。
特開昭５５－２０６４９号公報 特開２０００－２１０６９２号公報 特公昭６０－２３８３２号公報 特許第３４１０６９９号公報 Moreover, as invention regarding the multistage process of a fluidized bed and an activated sludge method, there exists a thing as described in patent 3410699 gazette. In this method, the latter activated sludge method is operated at a low load of BOD sludge load 0.1 kg-BOD / kg-MLSS / d, so that the sludge can be self-oxidized and the amount of sludge extraction can be greatly reduced.
JP-A-55-20649 JP 2000-210692 A Japanese Patent Publication No. 60-23832 Japanese Patent No. 3410699
　このような微小動物の捕食作用を利用した多段活性汚泥法は、実際に有機性廃水処理に用いられており、対象とする排水によっては、処理効率の向上、５０％程度の発生汚泥量の減量化が可能となっている。 The multi-stage activated sludge method using the predatory action of such minute animals is actually used for organic wastewater treatment. Depending on the target wastewater, the treatment efficiency is improved and the amount of generated sludge is reduced by about 50%. Is possible.
　この微小動物の捕食作用を利用した多段活性汚泥法における汚泥減量に寄与する微小動物には、濾過捕食型のものと凝集体捕食型のものがある。このうち、凝集体捕食型の微小動物は、フロック化した汚泥をかじりながら捕食することも可能であるため、こちらが優占化した場合、処理水質は悪化してしまう。
　このため、処理水質の維持のためには、凝集体捕食型の微小動物よりも濾過捕食型の微小動物を優占化させることが望ましいが、現時点では、両者の微小動物のうちの一方を確実に優占化させる制御方法は提案されていない。このため、運転条件によっては、凝集体捕食型微小動物が優占化することにより、予期しない処理水質悪化の問題が発生することがあった。 Microanimals that contribute to sludge reduction in the multistage activated sludge process that uses the predatory action of microanimals include a filter predation type and an aggregate predation type. Among these, aggregate predation type micro-animals can also prey while gnawing flocked sludge, so if this predominates, the quality of treated water will deteriorate.
For this reason, in order to maintain the treated water quality, it is desirable to dominate the filtration predation type micro-animal rather than the aggregate predation type micro-animal. No control method has been proposed to make it dominant. For this reason, depending on the operating conditions, the problem of unexpectedly deteriorated treated water quality may occur due to the predominance of aggregate predatory microanimals.
　また、生物処理水を膜分離処理する膜式活性汚泥法であれば、沈殿池での汚泥管理が不要で、良質な処理水質が得られるが、膜式活性汚泥法では、膜の閉塞が課題となっており、低負荷運転であっても、汚泥の解体で微細なＳＳが発生して膜を閉塞させる問題があった。また、水温、負荷、ＳＲＴにより、活性汚泥内でフロックを捕食する凝集体捕食型の微小動物が急増すると、汚泥の微細化が促進されて処理水質の悪化につながり、膜式活性汚泥法の運転管理が困難となる問題もあった。 In addition, the membrane activated sludge method for membrane separation treatment of biologically treated water eliminates the need for sludge management in the sedimentation basin and provides high quality treated water quality, but the membrane activated sludge method is subject to membrane clogging. Even in low-load operation, there was a problem that fine SS was generated by sludge dismantling and the membrane was blocked. In addition, if the aggregate predation type micro-animals that prey on flocs in activated sludge increase due to water temperature, load, and SRT, refinement of sludge is promoted and the quality of treated water deteriorates. There were also problems that made management difficult.
　本発明は上記従来の問題点を解決し、微小動物の捕食作用を利用した多段活性汚泥法において、凝集体捕食型の微小動物の増殖を抑制し、濾過捕食型の微小動物を優占化させて、汚泥を減量すると共に良好な処理水質を得る有機性排水の生物処理方法および装置を提供することを課題とする。 The present invention solves the above-mentioned conventional problems, and in the multistage activated sludge method utilizing the predatory action of micro animals, suppresses the growth of aggregate predatory type micro animals, and predominates the filter predatory type micro animals. Thus, an object of the present invention is to provide a biological treatment method and apparatus for organic wastewater that reduces sludge and obtains good treated water quality.
　本発明者らは、上記課題を解決するべく鋭意検討を行った結果、後段の生物処理槽に分散菌を捕食する固着性の濾過捕食型微小動物を優占化させるべく、微小動物を保持する担体を設けること、この際、固着型の濾過捕食型微小動物が分散菌を効率的に捕食することができるように担体を流動床担体とすること、そして曝気量を制御することにより流動床担体からの微小動物の脱落を抑制すること、により、濾過捕食型の微小動物を優占化させることができることを見出した。 As a result of intensive studies to solve the above-mentioned problems, the present inventors hold micro-animals in order to predominate the fixed filtration predation-type micro-animals that prey on the dispersal bacteria in the subsequent biological treatment tank. In this case, the carrier is a fluidized bed carrier so that the fixed filtration predation type micro-animal can efficiently eat the dispersal bacteria, and the fluidized bed carrier by controlling the amount of aeration It has been found that by controlling the dropout of microanimals from the plant, the predation type microanimals can be made dominant.
　本発明は、このような知見に基いて達成されたものであり、以下を要旨とする。 The present invention has been achieved on the basis of such knowledge, and the gist thereof is as follows.
［１］　二段以上の多段に設けられた好気性生物処理槽の第一生物処理槽に有機性排水を導入して細菌により生物処理し、第一生物処理槽からの分散状態の細菌を含む第一生物処理水を後段の生物処理槽に通水して生物処理し、最後段の生物処理槽の生物処理水を汚泥と処理水とに固液分離する有機性排水の生物処理方法において、該後段の生物処理槽に微小動物を保持する流動床担体を設けると共に、該流動床担体を設けた生物処理槽の曝気量を５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下とすることを特徴とする有機性排水の生物処理方法。 [1] Organic wastewater is introduced into the first biological treatment tank of the aerobic biological treatment tank provided in two or more stages and biologically treated with bacteria, including dispersed bacteria from the first biological treatment tank In the biological treatment method of organic wastewater, the first biological treatment water is passed through the biological treatment tank in the latter stage to biologically treat, and the biological treatment water in the last stage biological treatment tank is solid-liquid separated into sludge and treated water. A fluidized bed carrier for holding micro-animals is provided in the subsequent biological treatment tank, and the amount of aeration in the biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom area / h or less. A biological treatment method for organic wastewater.
［２］　［１］において、前記後段の生物処理槽が、二段以上の多段に設けられた生物処理槽よりなり、該多段に設けられた生物処理槽の少なくとも一槽に前記流動床担体を設けると共に、該流動床担体を設けた生物処理槽の曝気量を５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下とすることを特徴とする有機性排水の生物処理方法。 [2] In [1], the latter biological treatment tank is composed of biological treatment tanks provided in two or more stages, and the fluidized bed carrier is placed in at least one of the biological treatment tanks provided in the multiple stages. A biological treatment method for organic wastewater, characterized in that the aeration amount of a biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom area / h or less.
［３］　［１］又は［２］において、前記固液分離を膜分離により行うことを特徴とする有機性排水の生物処理方法。 [3] A biological treatment method for organic wastewater according to [1] or [2], wherein the solid-liquid separation is performed by membrane separation.
［４］　二段以上の多段に設けられた好気性生物処理槽と、最後段の生物処理槽の生物処理水を汚泥と処理水とに固液分離する固液分離手段とを備え、第一生物処理槽は、有機性排水を細菌により生物処理する槽であり、後段の生物処理槽は、第一生物処理槽から導入される分散状態の細菌を含む第一生物処理水を生物処理する槽であり、該後段の生物処理槽に微小動物を保持する流動床担体が設けられていると共に、該流動床担体が設けられた生物処理槽の曝気量が５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下であることを特徴とする有機性排水の生物処理装置。 [4] An aerobic biological treatment tank provided in two or more stages, and solid-liquid separation means for solid-liquid separation of the biological treatment water of the last biological treatment tank into sludge and treated water, The biological treatment tank is a tank for biologically treating organic wastewater with bacteria, and the latter biological treatment tank is a tank for biologically treating the first biologically treated water containing dispersed bacteria introduced from the first biological treatment tank. The biological treatment tank in the subsequent stage is provided with a fluidized bed carrier for holding micro-animals, and the aeration amount of the biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom bottom An organic wastewater biological treatment apparatus characterized by having an area / h or less.
［５］　［４］において、前記後段の生物処理槽は、二段以上の多段に設けられた生物処理槽よりなり、該多段に設けられた生物処理槽の少なくとも一槽に前記流動床担体が設けられていると共に、該流動床担体が設けられた生物処理槽の曝気量が５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下であることを特徴とする有機性排水の生物処理装置。
［６］　［４］又は［５］において、前記固液分離手段が膜分離手段であることを特徴とする有機性排水の生物処理装置。 [5] In [4], the latter biological treatment tank is composed of two or more stages of biological treatment tanks, and the fluidized bed carrier is provided in at least one of the biological treatment tanks provided in the multiple stages. An organic wastewater biological treatment apparatus, wherein the biological treatment tank provided with the fluidized bed carrier has an aeration amount of 50 m 3 -air / m 2 -bottom area / h or less.
[6] The biological treatment apparatus for organic wastewater according to [4] or [5], wherein the solid-liquid separation means is a membrane separation means.
　本発明では、微小動物の捕食作用を利用した多段活性汚泥法において、微小動物を保持する後段の生物処理槽に担体を設けることにより、固着型の濾過捕食型微小動物をこの担体上に安定に保持して増殖させることができる。即ち、濾過捕食型微小動物は固着型であるため、濾過捕食型微小動物を優占化させるためにはその足場が必要となる。濾過捕食型微小動物は、槽内の汚泥フロックに固着することも可能であるが、汚泥は一定の滞留時間で系外へ引き抜かれるため、濾過捕食型微小動物が固着するための足場としての担体を設ける。本発明において、この担体は流動床担体であるため、担体上の微小動物は、担体と共に流動して槽内に流入してきた分散菌を効率的に捕食することができる。
　しかし、担体が流動床担体であると、槽内の曝気による流動のための剪断力で、微小動物が担体から剥離、脱落し、担体上に微小動物を高濃度で安定に保持することができない。本発明では、流動床担体を設けた生物処理槽の曝気量を５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下と小さくすることにより、担体の流動をある程度抑制し、流動床担体からの微小動物の脱落を防止して、生物処理槽内で濾過捕食型の微小動物を優占化させると共に、この優占化状態を安定に維持することができる（上記［１］，［４］）。 In the present invention, in the multi-stage activated sludge method utilizing the predatory action of a micro animal, by providing a carrier in a biological treatment tank in the subsequent stage that holds the micro animal, the fixed type filter predation type micro animal can be stably placed on this carrier. Can be retained and propagated. That is, since the filtration predation type micro-animal is a fixed type, a scaffold is required to predominate the filtration predation type micro-animal. Filtered predation type micro-animals can be adhered to the sludge floc in the tank, but since sludge is drawn out of the system with a certain residence time, the carrier as a scaffold for adhering the filtration predation type micro-animals Is provided. In the present invention, since the carrier is a fluidized bed carrier, the micro-animal on the carrier can efficiently prey on the dispersal bacteria flowing together with the carrier and flowing into the tank.
However, if the carrier is a fluidized bed carrier, the minute animals can be detached from the carrier and dropped off due to the shearing force due to aeration in the tank, and the minute animals cannot be stably held at a high concentration on the carrier. . In the present invention, by reducing the aeration amount of the biological treatment tank provided with the fluidized bed carrier to 50 m 3 -air / m 2 -tank bottom area / h or less, the flow of the carrier is suppressed to some extent, It is possible to prevent the micro-animal from falling off and to predominate the filtration and predation-type micro-animal in the biological treatment tank and to maintain this predominance state stably (above [1] and [4]). .
　本発明においては、後段の生物処理槽として二槽以上の生物処理槽を多段に設けてもよく、その場合において、多段に設けた生物処理槽の少なくとも一槽に流動床担体を設けると共に、この流動床担体を設けた生物処理槽の曝気量を５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下とすることが好ましい（上記［２］，［５］）。 In the present invention, two or more biological treatment tanks may be provided in multiple stages as subsequent biological treatment tanks. In that case, a fluidized bed carrier is provided in at least one of the biological treatment tanks provided in multiple stages. The aeration amount of the biological treatment tank provided with the fluidized bed carrier is preferably 50 m 3 -air / m 2 -tank bottom area / h or less (the above [2], [5]).
　また、最後段の生物処理水の固液分離を膜分離により行ってもよく、その場合には、膜の閉塞を引き起こす凝集体捕食型微小動物の増殖を抑制し、処理水質の向上に寄与する濾過捕食型微小動物を優先化させることにより、汚泥の微細化で微細なＳＳが発生することによる膜の閉塞を防止することができ、薬品洗浄頻度を低減して長期に亘り安定運転を維持することができる（上記［３］，［６］）。 In addition, solid-liquid separation of biological treatment water at the last stage may be performed by membrane separation. In this case, the growth of aggregate predation type micro-animals that cause blockage of the membrane is suppressed, which contributes to improvement of treated water quality. By preferentially filtering predatory type micro-animals, it is possible to prevent clogging of the membrane due to the generation of fine SS due to sludge refinement, and the frequency of chemical cleaning is reduced to maintain stable operation over a long period of time. ([3], [6] above).
　このようなことから、本発明によれば、有機性排水の効率的な生物処理が可能になり、以下のような効果が奏される。
１）排水処理時に発生する汚泥の大幅な減量化
２）高負荷運転による処理効率の向上
３）安定した処理水質の維持 Therefore, according to the present invention, efficient biological treatment of organic wastewater is possible, and the following effects are exhibited.
1) Significant reduction of sludge generated during wastewater treatment 2) Improvement of treatment efficiency by high load operation 3) Maintenance of stable treated water quality
本発明の有機性排水の生物処理方法および装置の実施の形態を示す系統図である。It is a systematic diagram which shows embodiment of the biological treatment method and apparatus of the organic waste water of this invention. 本発明の有機性排水の生物処理方法および装置の他の実施の形態を示す系統図である。It is a systematic diagram which shows other embodiment of the biological treatment method and apparatus of the organic waste water of this invention. 本発明の有機性排水の生物処理方法および装置の他の実施の形態を示す系統図である。It is a systematic diagram which shows other embodiment of the biological treatment method and apparatus of the organic waste water of this invention.
　以下に図面を参照して本発明の有機性排水の生物処理方法および装置の実施の形態を詳細に説明する。 Embodiments of the organic wastewater biological treatment method and apparatus according to the present invention will be described below in detail with reference to the drawings.
　図１～３は本発明の有機性排水の生物処理方法および装置の実施の形態を示す系統図である。
　図１～３において、１は第一生物処理槽、２は第二生物処理槽、３は沈殿槽、４は第三生物処理槽、５は膜分離装置、２Ａは流動床担体、１Ｂ，２Ｂ，４Ｂは散気管であり、同一機能を奏する部材には同一符号を付してある。 1 to 3 are system diagrams showing an embodiment of a biological treatment method and apparatus for organic wastewater according to the present invention.
1 to 3, 1 is a first biological treatment tank, 2 is a second biological treatment tank, 3 is a sedimentation tank, 4 is a third biological treatment tank, 5 is a membrane separator, 2A is a fluidized bed carrier, 1B, 2B , 4B are air diffusers, and members having the same functions are denoted by the same reference numerals.
　図１の態様では、原水（有機性排水）は第一生物処理槽１に導入され、分散性細菌により、有機成分(溶解性ＢＯＤ)の７０％以上、望ましくは８０％以上、さらに望ましくは９０％以上が酸化分解される。この第一生物処理槽１のｐＨは６以上、望ましくは８以下とする。ただし、原水中に油分を多く含む場合には、分解速度を上げるためにｐＨを８以上としても良い。 In the embodiment of FIG. 1, raw water (organic wastewater) is introduced into the first biological treatment tank 1, and 70% or more, desirably 80% or more, more desirably 90% of the organic component (soluble BOD) by dispersible bacteria. % Or more is oxidatively decomposed. The pH of the first biological treatment tank 1 is 6 or more, preferably 8 or less. However, when the raw water contains a large amount of oil, the pH may be 8 or more in order to increase the decomposition rate.
　また、第一生物処理槽１への原水の通水は一過式とし、ＢＯＤ容積負荷は１ｋｇ／ｍ３／ｄ以上、例えば１～２０ｋｇ／ｍ３／ｄ、ＨＲＴ（原水滞留時間）は２４ｈ以下、特に８ｈ以下、例えば０．５～８ｈとすることで、分散性細菌（非凝集性細菌）が優占化した処理水を得ることができ、また、ＨＲＴを短くすることでＢＯＤ濃度の低い排水を高負荷で処理することができ、好ましい。 In addition, the flow of raw water to the first biological treatment tank 1 is made transient, the BOD volumetric load is 1 kg / m 3 / d or more, for example, 1 to 20 kg / m 3 / d, and the HRT (raw water retention time) is 24 h. In the following, it is possible to obtain treated water in which dispersible bacteria (non-aggregating bacteria) predominate, particularly by setting it to 8 h or less, for example, 0.5 to 8 h, and shortening the HRT can reduce the BOD concentration. Low waste water can be treated with high load, which is preferable.
　また、この第一生物処理槽１の溶存酸素（ＤＯ）濃度は１ｍｇ／Ｌ以下、特に０．５ｍｇ／Ｌ以下、例えば０．０５～０．５ｍｇ／Ｌに制御することが好ましく、これにより、糸状性細菌の増殖が抑制される一方で、１～５μｍ程度の大きさの分散菌が優占化し、これらは第二生物処理槽２で速やかに捕食される。 The dissolved oxygen (DO) concentration in the first biological treatment tank 1 is preferably controlled to 1 mg / L or less, particularly 0.5 mg / L or less, for example 0.05 to 0.5 mg / L. While the growth of filamentous bacteria is suppressed, dispersal bacteria having a size of about 1 to 5 μm dominate, and these are rapidly preyed in the second biological treatment tank 2.
　この第一生物処理槽には、後段生物処理槽からの汚泥の一部を返送したり、第一生物処理槽を二槽以上の多段構成としたり、第一生物処理槽に担体を添加してもよく、これによりＢＯＤ容積負荷５ｋｇ／ｍ３／ｄ以上の高負荷処理も可能となる。 In this first biological treatment tank, a part of the sludge from the latter biological treatment tank is returned, the first biological treatment tank is composed of two or more stages, or a carrier is added to the first biological treatment tank. As a result, high load processing with a BOD volumetric load of 5 kg / m 3 / d or more becomes possible.
　第一生物処理槽に担体を添加する場合、用いる担体の形状は、球状、ペレット状、中空筒状、糸状、板状等任意であり、大きさも０．１～１０ｍｍ程度の径で良い。また、担体の材料は天然素材、無機素材、高分子素材等任意であり、ゲル状物質を用いても良い。 When the carrier is added to the first biological treatment tank, the shape of the carrier to be used is arbitrary such as a spherical shape, a pellet shape, a hollow cylindrical shape, a thread shape, and a plate shape, and the size may be about 0.1 to 10 mm. The material of the carrier is arbitrary such as a natural material, an inorganic material, or a polymer material, and a gel material may be used.
　また、第一生物処理槽における担体の充填率が高い場合、分散菌は生成せず、細菌は担体に付着するか、糸状性細菌が増殖するので、第一生物処理槽に担体を添加する場合、担体の充填率（槽容積に対する担体の容積率）は１０％以下、望ましくは５％以下とすることが好ましく、このように担体の充填率を小さくすることにより、濃度変化に影響されず、捕食しやすい分散菌の生成が可能となる。 In addition, when the filling rate of the carrier in the first biological treatment tank is high, dispersal bacteria will not be generated, and bacteria will adhere to the carrier or filamentous bacteria will grow, so when adding a carrier to the first biological treatment tank The carrier filling rate (the volume ratio of the carrier with respect to the tank volume) is preferably 10% or less, and preferably 5% or less. By reducing the carrier filling rate in this way, the change in concentration is not affected, Dispersed bacteria that are easy to prey can be generated.
　なお、第一生物処理槽１のＨＲＴが最適値に比べて長くなると、糸状性細菌の優占化やフロックの形成につながり、後段の第二生物処理槽２で捕食されにくい細菌が生成してしまう。そこで、第一生物処理槽１のＨＲＴを一定に制御する必要がある。この最適ＨＲＴは原水の水質により異なるため、机上試験などから、有機成分の７０～９０％を除去できるＨＲＴを求める必要がある。ＨＲＴを最適値に維持する方法としては、原水量減少時に、処理水の一部を返送して、第一生物処理槽１に流入する水量を一定にし、第一生物処理槽１のＨＲＴを安定させる方法や、原水量の変動に合わせて第一生物処理槽１の水位を変動させる方法がある。第一生物処理槽１のＨＲＴを安定させる幅は、机上試験で求めた最適ＨＲＴの０．７５～１．５倍の範囲内に納めることが望ましい。 If the HRT of the first biological treatment tank 1 is longer than the optimum value, it will lead to the predominance of filamentous bacteria and the formation of flocs, and bacteria that are difficult to prey in the second biological treatment tank 2 will be generated. End up. Therefore, it is necessary to control the HRT of the first biological treatment tank 1 to be constant. Since this optimum HRT varies depending on the quality of raw water, it is necessary to obtain an HRT capable of removing 70 to 90% of organic components from a desktop test or the like. As a method of maintaining the HRT at the optimum value, when the raw water amount is reduced, a part of the treated water is returned, the amount of water flowing into the first biological treatment tank 1 is made constant, and the HRT of the first biological treatment tank 1 is stabilized. And a method of changing the water level of the first biological treatment tank 1 in accordance with the fluctuation of the amount of raw water. The width for stabilizing the HRT of the first biological treatment tank 1 is desirably within the range of 0.75 to 1.5 times the optimum HRT obtained by the desktop test.
　なお、第一生物処理槽１で溶解性有機物を完全に分解した場合、第二生物処理槽２ではフロックが形成されず、また、微小動物増殖のための栄養も不足し、圧密性の低い汚泥のみが優占化した生物処理槽となる。従って、第一生物処理槽１での有機成分の分解率は１００％ではなく、９５％以下となるようにすることが好ましい。 In addition, when dissolved organic matter is completely decomposed in the first biological treatment tank 1, flocs are not formed in the second biological treatment tank 2, and nutrients for microanimal growth are insufficient, and sludge with low compactness is used. Only becomes the dominant biological treatment tank. Therefore, it is preferable that the decomposition rate of the organic component in the first biological treatment tank 1 is not 100% but 95% or less.
　第一生物処理槽１の処理水（第一生物処理水）は、後段の第二生物処理槽２に通水して、ここで、残存している有機成分の酸化分解、分散性細菌の自己分解および微小動物の捕食による余剰汚泥の減量化を行う。 The treated water (first biological treated water) in the first biological treatment tank 1 is passed through the second biological treatment tank 2 in the subsequent stage, where the remaining organic components are oxidatively decomposed and the self of dispersible bacteria. Reduce excess sludge by decomposition and predation of micro-animals.
　第二生物処理槽２では、細菌に比べ増殖速度の遅い微小動物の働きと細菌の自己分解を利用するため、微小動物と細菌が系内に留まるような運転条件および処理装置を用いる必要がある。
　本発明では、第二生物処理槽２は、槽内に担体２Ａを添加して流動床を形成した曝気槽とすることにより、濾過捕食型の微小動物の槽内保持量を高める。 In the second biological treatment tank 2, it is necessary to use an operation condition and a treatment apparatus that allow the microanimal and the bacteria to remain in the system in order to use the action of the microanimal having a slower growth rate than the bacteria and the self-degradation of the bacteria. .
In the present invention, the second biological treatment tank 2 is an aeration tank in which a carrier 2A is added to the tank to form a fluidized bed, thereby increasing the amount of filtration predation type micro-animal retained in the tank.
　第二生物処理槽２に添加する担体２Ａの形状は、球状、ペレット状、中空筒状、糸状、板状等任意であり、大きさも０．１～１０ｍｍ程度の径で良い。また、担体２Ａの材料は天然素材、無機素材、高分子素材等任意であり、ゲル状物質を用いても良い。 The shape of the carrier 2A added to the second biological treatment tank 2 may be any shape such as a spherical shape, a pellet shape, a hollow cylindrical shape, a thread shape, a plate shape, and the size may be about 0.1 to 10 mm. The material of the carrier 2A is arbitrary such as a natural material, an inorganic material, or a polymer material, and a gel material may be used.
　第二生物処理槽２内の担体２Ａの充填率（槽容積に対する担体の容積率）が少な過ぎると濾過捕食型微小動物を十分に保持することができないが、多過ぎると汚泥が解体することから、第二生物処理槽２内の担体２Ａの充填率は５０％以下、特に５～５０％とすることが好ましい。 If the filling rate of the carrier 2A in the second biological treatment tank 2 (the volume ratio of the carrier with respect to the tank volume) is too small, the filtered predation type micro-animal cannot be sufficiently retained, but if too much, the sludge is dismantled. The filling rate of the carrier 2A in the second biological treatment tank 2 is preferably 50% or less, particularly 5 to 50%.
　また、この第二生物処理槽２は、前述の如く、担体の流動による剪断力で担体２Ａに固着した濾過捕食型微小動物が剥離、脱落することを防止するために、曝気量を５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下とする。この曝気量が５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈを超えると、担体からの濾過捕食型微小動物の脱落、流出で、第二生物処理槽２内に濾過捕食型微小動物を優占化させることができなくなる。
　ただし、曝気量が過度に少ないと担体が流動し難くなり、担体上の濾過捕食型微小動物が槽内に流入した分散菌を捕食しにくくなるため、曝気量は１～４０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ、特に１～２０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈとすることが好ましい。 In addition, as described above, the second biological treatment tank 2 has an aeration amount of 50 m 3 − in order to prevent the filtration predation type micro-animal adhering to the carrier 2A from being peeled off and dropped out by the shearing force caused by the flow of the carrier. Air / m 2 −Bath bottom area / h or less. When the aeration amount exceeds 50 m 3 -air / m 2 -tank bottom area / h, the filtration predation type micro-animal is preferentially placed in the second biological treatment tank 2 by dropping and outflow of the filtration predation type micro animal from the carrier. It will not be possible to divide.
However, if the amount of aeration is too small, the carrier becomes difficult to flow, and it becomes difficult for the filtered predatory microanimal on the carrier to prey on the dispersal bacteria that have flowed into the tank, so the amount of aeration is 1 to 40 m 3 -air / m. 2 - tank bottom area / h, in particular 1 ~ 20m 3 -air / m 2 - is preferably a tank bottom area / h.
　また、後段の生物処理槽では、分散状態の菌体を捕食する濾過捕食型微小動物だけでなく、フロック化した汚泥を捕食できる凝集体捕食型微小動物も増殖する。後者は遊泳しながら、フロックを捕食するため、これが優占化した場合、汚泥は食い荒らされ、微細化したフロック片が散在する汚泥となる。このフロック片により、処理水質が悪化すると共に、膜式活性汚泥法では、膜の目詰まりが発生する。
　そこで、凝集体捕食型微小動物を間引くため、第二生物処理槽２のＳＲＴ（汚泥滞留時間）は６０日以下、特に４５日以下、とりわけ１０日以上３０日以下の範囲内で一定に制御することが望ましい。なお、このときのＳＲＴは浮遊汚泥の滞留時間を示し、担体付着分は含めない。 Further, in the biological treatment tank at the subsequent stage, not only the filtration predation type micro animals that prey on the dispersed cells, but also the aggregate predation type micro animals that can prey on the floc sludge. Since the latter prey on flocs while swimming, if this predominates, the sludge is eaten and becomes sludge in which fine floc pieces are scattered. Due to the floc pieces, the quality of treated water is deteriorated, and membrane clogging occurs in the membrane activated sludge method.
Therefore, in order to thin out the aggregate predation type micro-animal, the SRT (sludge retention time) of the second biological treatment tank 2 is controlled to be constant within a range of 60 days or less, particularly 45 days or less, especially 10 days or more and 30 days or less. It is desirable. In addition, SRT at this time shows the residence time of floating sludge and does not include a carrier adhesion part.
　この第二生物処理槽２からの処理水は、次いで、沈殿槽３で汚泥と処理水とに固液分離され、分離汚泥の一部が返送汚泥として返送され、残部が余剰汚泥として系外へ排出される。 The treated water from the second biological treatment tank 2 is then solid-liquid separated into sludge and treated water in the sedimentation tank 3, a part of the separated sludge is returned as return sludge, and the remainder as extra sludge. Discharged.
　図２に示す態様は、後段の生物処理槽を第二生物処理槽２と第三生物処理槽４の多段構成とし、第二生物処理槽２に担体２Ａを添加して曝気量を前述の如く５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下、好ましくは１～４０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ、特に好ましくは１～２０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈとした点が図１に示す態様とは異なり、その他は図１に示す態様と同様である。 In the embodiment shown in FIG. 2, the biological treatment tank in the subsequent stage has a multistage configuration of the second biological treatment tank 2 and the third biological treatment tank 4, and the carrier 2A is added to the second biological treatment tank 2 so that the aeration amount is as described above. 50 m 3 -air / m 2 -tank bottom area / h or less, preferably 1 to 40 m 3 -air / m 2 -tank bottom area / h, particularly preferably 1-20 m 3 -air / m 2 -tank bottom area / h 1 is different from the embodiment shown in FIG. 1, and the other points are the same as the embodiment shown in FIG.
　図２に示す態様において、第三生物処理槽４にも担体を添加してもよく、第二生物処理槽２に担体を添加せずに第三生物処理槽４のみに担体を添加してもよい。いずれの場合であっても担体を添加した生物処理槽の曝気量を上述の如く５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下とする。 In the embodiment shown in FIG. 2, the carrier may be added to the third biological treatment tank 4, or the carrier may be added only to the third biological treatment tank 4 without adding the carrier to the second biological treatment tank 2. Good. In any case, the aeration amount of the biological treatment tank to which the carrier is added is set to 50 m 3 -air / m 2 -tank bottom area / h or less as described above.
　また、後段の生物処理槽は三段以上の多段構成としてもよく、その場合においても担体を添加する生物処理槽は１槽であってもよく、２槽以上、或いはすべての槽であってもよく、その槽数も槽の位置も任意であるが、過少曝気により槽内が嫌気性とならないように担体を添加する生物処理槽の位置と槽数を調整する必要がある。 Further, the biological treatment tank in the subsequent stage may have a multi-stage configuration of three or more stages, and even in that case, the biological treatment tank to which the carrier is added may be one tank, two tanks or more, or all tanks. Well, the number of tanks and the positions of the tanks are arbitrary, but it is necessary to adjust the position and number of biological treatment tanks to which the carrier is added so that the inside of the tanks does not become anaerobic due to excessive aeration.
　図３に示す態様は、微小動物と細菌が系内に留まるように膜式活性汚泥方式とし、図１の態様において、沈殿槽３の代りに膜分離装置５を設け、膜分離装置５の透過水を処理水として抜き出し、濃縮水を第二生物処理槽２に返送して余剰汚泥を第二生物処理槽２から抜き出す点が異なり、その他は図１に示す態様と同様である。 The embodiment shown in FIG. 3 is a membrane activated sludge system so that micro-animals and bacteria stay in the system. In the embodiment of FIG. 1, a membrane separation device 5 is provided instead of the sedimentation tank 3, and the permeation of the membrane separation device 5 is performed. The difference is that water is extracted as treated water, the concentrated water is returned to the second biological treatment tank 2 and excess sludge is extracted from the second biological treatment tank 2, and the others are the same as the embodiment shown in FIG.
　本発明においては、微小動物による捕食を促進させるために、第二生物処理槽２以降の後段の生物処理槽においてはｐＨを７以下、例えばｐＨ５．５～６．５の条件にすることが好ましい。また、後段の生物処理槽２のＤＯ濃度は１～４ｍｇ／Ｌ程度とすることが好ましい。 In the present invention, in order to promote predation by the microanimals, it is preferable to set the pH to 7 or less, for example, pH 5.5 to 6.5 in the biological treatment tank subsequent to the second biological treatment tank 2. . Further, the DO concentration in the biological treatment tank 2 in the subsequent stage is preferably about 1 to 4 mg / L.
　また、運転条件を微小動物の増殖に適したものに設定しても、原水中に微小動物の増殖に必須な成分が含まれていなければ、微小動物は増殖せず、汚泥減量効果も向上しない。そこで、第二生物処理槽２以降の後段の生物処理槽、特に、第二生物処理槽２に栄養剤を添加して、微小動物を安定して維持させ、これにより汚泥減量の効果を安定させるようにしても良い。また、第三生物処理槽４に栄養剤を添加することで、減量効果を促進しても良い。この場合、栄養剤としてはリン脂質、遊離脂肪酸、リゾリン脂質、ステロールやこれらを含むレシチン、その他、液糖、米糠、ビールの絞り粕、植物性油の絞り粕、大豆抽出物、甜菜粕、貝殻粉、卵殻、野菜エキス、魚肉エキス、各種アミノ酸、各種ビタミン等の後生動物の増殖促進に効果のある栄養剤を用いることができる。これらは１種を単独で用いても良く、２種以上を混合して用いても良い。
　これらの栄養剤を添加する場合、その添加量は原水中の有機物量の０．５～１０％程度とすることが好ましい。 In addition, even if the operating conditions are set to be suitable for the growth of micro-animals, the micro-animals will not proliferate and the sludge reduction effect will not improve unless the raw water contains essential ingredients for the micro-animal growth. . Therefore, a nutrient is added to the second biological treatment tank after the second biological treatment tank 2, in particular, the second biological treatment tank 2 to stably maintain the micro-animal, thereby stabilizing the sludge reduction effect. You may do it. Moreover, you may accelerate | stimulate the weight loss effect by adding a nutrient to the 3rd biological treatment tank 4. FIG. In this case, nutrients include phospholipids, free fatty acids, lysophospholipids, sterols and lecithins containing these, liquid sugar, rice bran, beer pomace, vegetable oil pomace, soybean extract, sugar beet koji, Nutrients effective in promoting the growth of metazoans such as shellfish powder, eggshell, vegetable extract, fish meat extract, various amino acids and various vitamins can be used. These may be used alone or in combination of two or more.
When these nutrients are added, the amount added is preferably about 0.5 to 10% of the amount of organic matter in the raw water.
　図１～３の態様は本発明の実施の形態の一例を示すものであり、本発明はその要旨を超えない限り、何ら図示の方法に限定されるものではない。 1 to 3 show an example of an embodiment of the present invention, and the present invention is not limited to the illustrated method unless it exceeds the gist.
　例えば、後段の生物処理槽の生物処理水の固液分離手段としては、沈殿槽や膜分離装置の他、浮上分離槽等を用いても良い。また、生物処理槽と固液分離手段とを兼ねる膜浸漬型生物処理槽を用いて膜分離式好気処理を行ってもよい。 For example, as the solid-liquid separation means of the biologically treated water in the biological treatment tank at the subsequent stage, a floating separation tank or the like may be used in addition to the precipitation tank and the membrane separation device. Moreover, you may perform a membrane separation type aerobic process using the membrane immersion type biological treatment tank which serves as a biological treatment tank and a solid-liquid separation means.
　また、本発明において、第二生物処理槽２に導入する第一生物処理水中に有機物が多量に残存した場合、その酸化分解は第二生物処理槽２で行われることになる。しかし、微小動物が多量に存在する第二生物処理槽２で細菌による有機物の酸化分解が起こると、微小動物の捕食から逃れるための対策として、細菌は捕食されにくい形態で増殖することが知られており、このように増殖した細菌群は微小動物により捕食されず、これらの分解は自己消化のみに頼ることとなり、汚泥発生量低減の効果が下がってしまう。
　そこで、前述の如く、第一生物処理槽１では原水中の有機成分の大部分、すなわち原水ＢＯＤの７０％以上、望ましくは８０％以上、さらに望ましくは９０％以上を分解し、菌体へと安定して変換しておく必要がある。
　このため、後段の第二生物処理槽２は、溶解性ＢＯＤによる汚泥負荷で表わすと０．０２５～０．０５ｋｇ－ＢＯＤ／ｋｇ－ＭＬＳＳ／ｄで運転することが望ましい。このような負荷に調整するために、原水の一部を原水を第一生物処理槽をバイパスして、後段の第二生物処理槽に直接導入してもよい。なお、このとき、ＭＬＳＳは浮遊汚泥の汚泥濃度を示し、担体付着分は含めない。 In the present invention, when a large amount of organic matter remains in the first biological treatment water introduced into the second biological treatment tank 2, the oxidative decomposition is performed in the second biological treatment tank 2. However, when oxidative degradation of organic matter by bacteria occurs in the second biological treatment tank 2 in which a large amount of micro animals are present, it is known that the bacteria grow in a form that is difficult to be predated as a countermeasure to escape from predation of the micro animals. Thus, the bacteria that have grown in this way are not preyed on by the micro-animals, and their decomposition depends only on autolysis, which reduces the effect of reducing the amount of sludge generated.
Therefore, as described above, in the first biological treatment tank 1, most of the organic components in the raw water, that is, 70% or more, preferably 80% or more, more preferably 90% or more of the raw water BOD, is decomposed into cells. It is necessary to convert stably.
For this reason, the second biological treatment tank 2 in the latter stage is desirably operated at 0.025 to 0.05 kg-BOD / kg-MLSS / d in terms of sludge load due to the soluble BOD. In order to adjust to such a load, you may introduce | transduce a part of raw | natural water directly to a 2nd biological treatment tank of a back | latter stage by bypassing a raw | natural water for a 1st biological treatment tank. In addition, MLSS shows the sludge density | concentration of floating sludge at this time, and a carrier adhesion part is not included.
　以下に実施例及び比較例を挙げて本発明をより具体的に説明する。 Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
［実施例１］
　図１に示す如く、容量が３．６Ｌの第一生物処理槽(汚泥返送なし)１と、容量が１５Ｌの第二生物処理槽(汚泥返送あり)２と、容量が５Ｌの沈殿槽３とを連結させた実験装置を用いて、本発明による有機性排水の処理を行った。
　原水には、ＣＯＤＣｒ２０００ｍｇ／Ｌ、ＢＯＤ１２８０ｍｇ／Ｌの人工基質を用い、各生物処理槽の処理条件は次の通りとした。 [Example 1]
As shown in FIG. 1, a first biological treatment tank (capacity sludge return) 1 having a capacity of 3.6 L, a second biological treatment tank (capacity sludge return) 2 having a capacity of 15 L, and a sedimentation tank 3 having a capacity of 5 L The organic waste water according to the present invention was treated using an experimental apparatus in which the two were connected.
For raw water, COD Cr 2000 mg / L and BOD 1280 mg / L artificial substrates were used, and the treatment conditions of each biological treatment tank were as follows.
＜第一生物処理槽＞
　ＤＯ：０．０１ｍｇ／Ｌ
　溶解性ＢＯＤ容積負荷：７．７ｋｇ－ＢＯＤ／ｍ３／ｄ
　ＨＲＴ：４ｈ
　ｐＨ：７
＜第二生物処理槽＞
　ＤＯ：２～３ｍｇ／Ｌ
　担体：ポリウレタンフォームの立方体型流動床担体（５ｍｍ×５ｍｍ×５ｍｍ）
　担体充填率：１０％
　曝気量：１０Ｌ／ｍｉｎ（２０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ）
　ＨＲＴ：１７ｈ
　ＳＲＴ：２５日
　溶解性ＢＯＤ容積負荷：０．０４０ｋｇ－ＢＯＤ／ｋｇ－ＭＬＳＳ／ｄ
　ｐＨ：６．５ <First biological treatment tank>
DO: 0.01 mg / L
Soluble BOD volume loading: 7.7 kg-BOD / m 3 / d
HRT: 4h
pH: 7
<Second biological treatment tank>
DO: 2-3 mg / L
Carrier: Polyurethane foam cubic fluid bed carrier (5 mm x 5 mm x 5 mm)
Carrier filling rate: 10%
Aeration amount: 10 L / min (20 m 3 -air / m 2 -tank bottom area / h)
HRT: 17h
SRT: 25 days Soluble BOD volumetric load: 0.040 kg-BOD / kg-MLSS / d
pH: 6.5
　装置全体でのＢＯＤ容積負荷は１．５ｋｇ－ＢＯＤ／ｍ３／ｄであり、装置全体でのＨＲＴは２１ｈであった。
　その結果、第二生物処理槽２の汚泥フロック、担体には固着性の濾過捕食型微小動物（ツリガネムシ、ヒルガタワムシ）が優占化し、汚泥転換率は０．１０ｋｇ－ＭＬＳＳ／ｋｇ－ＣＯＤＣｒとなった。処理水質は、ＣＯＤＣｒ濃度＜３０ｍｇ／Ｌ、ＳＳ＜１０ｍｇ／Ｌと、試験期間中、常時良好な状態を維持していた。 The BOD volumetric load of the entire apparatus was 1.5 kg-BOD / m 3 / d, and the HRT of the entire apparatus was 21 h.
As a result, the sludge floc in the second biological treatment tank 2 and the filter-precipitating microanimals that are sticking to the carrier (Teleganus elegans) are sludge conversion rates of 0.10 kg-MLSS / kg-COD Cr. It was. The treated water quality was always in good condition during the test period with COD Cr concentration <30 mg / L and SS <10 mg / L.
［実施例２］
　第二生物処理槽の曝気量を２０Ｌ／ｍｉｎ（４０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ）としたこと以外は実施例１と同条件で原水の処理を行った。その結果、第二生物処理槽の汚泥フロック、担体には濾過捕食型微小動物が優占化し、汚泥転換率は０．１０ｋｇ－ＭＬＳＳ／ｋｇ－ＣＯＤＣｒとなった。処理水質は、ＣＯＤＣｒ濃度＜５０ｍｇ／Ｌ、ＳＳ＜２０ｍｇ／Ｌと、試験期間中、常時良好な状態を維持していた。 [Example 2]
The raw water was treated under the same conditions as in Example 1 except that the amount of aeration in the second biological treatment tank was 20 L / min (40 m 3 -air / m 2 -tank bottom area / h). As a result, the sludge flocs in the second biological treatment tank, filtered predatory miniature animals to the carrier is excellent Uranaika, sludge conversion rate was 0.10kg-MLSS / kg-COD Cr . The treated water quality was always in good condition throughout the test period with COD Cr concentration <50 mg / L and SS <20 mg / L.
［比較例１］
　容量が１８．６Ｌの生物処理槽（担体無し）と５Ｌの沈殿池を連結させた実験装置を用いて比較実験を実施した。処理した原水、装置全体でのＢＯＤ容積負荷、ＨＲＴは実施例１と同一である。
　その結果、汚泥転換率は０．３０ｋｇ－ＭＬＳＳ／ｋｇ－ＣＯＤＣｒとなった。また、糸状性細菌が大量に発生し、沈殿池での固液分離が困難となった。 [Comparative Example 1]
A comparative experiment was conducted using an experimental apparatus in which a biological treatment tank (with no carrier) having a capacity of 18.6 L and a 5 L sedimentation basin were connected. The treated raw water, the BOD volumetric load of the entire apparatus, and the HRT are the same as those in Example 1.
As a result, the sludge conversion rate was 0.30 kg-MLSS / kg-COD Cr . In addition, a large amount of filamentous bacteria were generated, making it difficult to separate solid and liquid in the sedimentation basin.
［比較例２］
　第二生物処理槽に担体を添加しなかったこと以外は実施例１と同条件で原水の処理を行った。その結果、汚泥転換率は０．１０ｋｇ－ＭＬＳＳ／ｋｇ－ＣＯＤＣｒとなった。しかしながら、第二生物処理槽で凝集体捕食型微小動物が優占化したことで、処理水質は悪化し、試験期間を通じて、処理水のＣＯＤＣｒ濃度は８０ｍｇ／Ｌ以上、ＳＳ濃度は５０ｍｇ／Ｌ以上と悪かった。 [Comparative Example 2]
Raw water was treated under the same conditions as in Example 1 except that no carrier was added to the second biological treatment tank. As a result, the sludge conversion rate was 0.10kg-MLSS / kg-COD Cr . However, since the aggregate predation type micro-animals prevailed in the second biological treatment tank, the quality of the treated water deteriorated, and the COD Cr concentration of the treated water was 80 mg / L or more and the SS concentration was 50 mg / L throughout the test period. That was bad.
［比較例３］
　第二生物処理槽の曝気量を３０Ｌ／ｍｉｎ（６０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ）としたこと以外は実施例１と同条件で原水の処理を行った。その結果、汚泥転換率は０．１０ｋｇ－ＭＬＳＳ／ｋｇ－ＣＯＤＣｒとなった。しかしながら、第二生物処理槽で凝集体捕食型微小動物が優占化したことで処理水質は悪化し、試験期間を通じて、処理水のＣＯＤＣｒ濃度は５０ｍｇ／Ｌ以上、ＳＳ濃度は２０ｍｇ／Ｌ以上と実施例１に比べ悪かった。 [Comparative Example 3]
Raw water was treated under the same conditions as in Example 1 except that the amount of aeration in the second biological treatment tank was 30 L / min (60 m 3 -air / m 2 -tank bottom area / h). As a result, the sludge conversion rate was 0.10kg-MLSS / kg-COD Cr . However, treated water by aggregate predatory miniature animals in the second biological treatment tank has excellent Uranaika worsened, throughout the study, COD Cr concentration in the treated water 50 mg / L or more, SS concentration 20 mg / L or more It was worse than Example 1.
　本発明の有機性排水の生物処理方法は、生活排水、下水、食品工場やパルプ工場をはじめとした広い濃度範囲の有機性排水の処理に利用することができる。 The biological treatment method for organic wastewater of the present invention can be used for treatment of organic wastewater in a wide concentration range including domestic wastewater, sewage, food factories and pulp factories.
　本発明を特定の態様を用いて詳細に説明したが、本発明の意図と範囲を離れることなく様々な変更が可能であることは当業者に明らかである。
　なお、本出願は、２０１１年６月９日付で出願された日本特許出願（特願２０１１－１２９２５９）に基づいており、その全体が引用により援用される。 Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on June 9, 2011 (Japanese Patent Application No. 2011-129259), which is incorporated by reference in its entirety.

Claims (12)

  1. 　二段以上の多段に設けられた好気性生物処理槽の第一生物処理槽に有機性排水を導入して細菌により生物処理し、第一生物処理槽からの分散状態の細菌を含む第一生物処理水を後段の生物処理槽に通水して生物処理し、最後段の生物処理槽の生物処理水を汚泥と処理水とに固液分離する有機性排水の生物処理方法において、
    　該後段の生物処理槽に微小動物を保持する流動床担体を設けると共に、該流動床担体を設けた生物処理槽の曝気量を５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下とすることを特徴とする有機性排水の生物処理方法。     The first organism containing the dispersed bacteria from the first biological treatment tank by introducing organic wastewater into the first biological treatment tank of the aerobic biological treatment tank provided in two or more stages and biologically treating with bacteria In the biological treatment method for organic wastewater, the treated water is passed through a biological treatment tank at the latter stage to biologically treat, and the biologically treated water in the last stage biological treatment tank is separated into sludge and treated water.
    A fluidized bed carrier for holding micro-animals is provided in the subsequent biological treatment tank, and the amount of aeration in the biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom area / h or less. A biological treatment method for organic wastewater.
  2. 　請求項１において、前記後段の生物処理槽が、二段以上の多段に設けられた生物処理槽よりなり、該多段に設けられた生物処理槽の少なくとも一槽に前記流動床担体を設けると共に、該流動床担体を設けた生物処理槽の曝気量を５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下とすることを特徴とする有機性排水の生物処理方法。 In Claim 1, the latter biological treatment tank is composed of biological treatment tanks provided in two or more stages, and the fluidized bed carrier is provided in at least one of the biological treatment tanks provided in the multiple stages, A biological treatment method for organic waste water, wherein the aeration amount of a biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom area / h or less.
  3. 　請求項１において、第一生物処理槽と第二生物処理槽とを備えており、第二生物処理槽が最後段の生物処理槽であることを特徴とする有機性排水の生物処理方法。 2. The organic wastewater biological treatment method according to claim 1, further comprising a first biological treatment tank and a second biological treatment tank, wherein the second biological treatment tank is the last biological treatment tank.
  4. 　請求項２において、第一生物処理槽、第二生物処理槽及び第三生物処理槽とを備えており、第二生物処理槽に前記流動床担体が設けられており、第三生物処理槽に流動床担体が設けられていないことを特徴とする有機性排水の生物処理方法。 In Claim 2, It comprises a 1st biological treatment tank, a 2nd biological treatment tank, and a 3rd biological treatment tank, The said fluidized bed support | carrier is provided in the 2nd biological treatment tank, A biological treatment method for organic wastewater, wherein no fluid bed carrier is provided.
  5. 　請求項１ないし４のいずれか１項において、前記曝気量が１～４０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈであることを特徴とする有機性排水の生物処理方法。 The biological treatment method for organic waste water according to any one of claims 1 to 4, wherein the aeration amount is 1 to 40 m 3 -air / m 2 -tank bottom area / h.
  6. 　請求項１ないし４のいずれか１項において、前記固液分離を膜分離により行うことを特徴とする有機性排水の生物処理方法。 The biological treatment method for organic wastewater according to any one of claims 1 to 4, wherein the solid-liquid separation is performed by membrane separation.
  7. 　二段以上の多段に設けられた好気性生物処理槽と、最後段の生物処理槽の生物処理水を汚泥と処理水とに固液分離する固液分離手段とを備え、
    　第一生物処理槽は、有機性排水を細菌により生物処理する槽であり、
    　後段の生物処理槽は、第一生物処理槽から導入される分散状態の細菌を含む第一生物処理水を生物処理する槽であり、
    　該後段の生物処理槽に微小動物を保持する流動床担体が設けられていると共に、該流動床担体が設けられた生物処理槽の曝気量が５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下であることを特徴とする有機性排水の生物処理装置。     Aerobic biological treatment tank provided in two or more stages, and solid-liquid separation means for solid-liquid separation of biological treatment water of the last biological treatment tank into sludge and treated water,
    The first biological treatment tank is a tank that biologically treats organic wastewater with bacteria.
    The latter biological treatment tank is a tank for biologically treating the first biological treatment water containing the dispersed bacteria introduced from the first biological treatment tank.
    The latter biological treatment tank is provided with a fluidized bed carrier for holding micro-animals, and the aeration amount of the biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -tank bottom area / h A biological treatment apparatus for organic wastewater characterized by:
  8. 　請求項７において、前記後段の生物処理槽は、二段以上の多段に設けられた生物処理槽よりなり、該多段に設けられた生物処理槽の少なくとも一槽に前記流動床担体が設けられていると共に、該流動床担体が設けられた生物処理槽の曝気量が５０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈ以下であることを特徴とする有機性排水の生物処理装置。 In Claim 7, the said biological treatment tank of a back | latter stage consists of the biological treatment tank provided in the multistage of two or more steps, and the said fluidized bed support | carrier is provided in at least 1 tank of the biological treatment tank provided in this multistage. And an aeration amount of the biological treatment tank provided with the fluidized bed carrier is 50 m 3 -air / m 2 -bottom area / h or less.
  9. 　請求項７において、第一生物処理槽と第二生物処理槽とを備えており、第二生物処理槽が最後段の生物処理槽であることを特徴とする有機性排水の生物処理装置。 8. The biological treatment apparatus for organic wastewater according to claim 7, comprising a first biological treatment tank and a second biological treatment tank, wherein the second biological treatment tank is the last biological treatment tank.
  10. 　請求項８において、第一生物処理槽、第二生物処理槽及び第三生物処理槽とを備えており、第二生物処理槽に前記流動床担体が設けられており、第三生物処理槽に流動床担体が設けられていないことを特徴とする有機性排水の生物処理装置。 In Claim 8, It is equipped with the 1st biological treatment tank, the 2nd biological treatment tank, and the 3rd biological treatment tank, The said fluidized bed support | carrier is provided in the 2nd biological treatment tank, A biological treatment apparatus for organic waste water, characterized in that no fluid bed carrier is provided.
  11. 　請求項７ないし１０のいずれか１項において、前記曝気量が１～４０ｍ３－ａｉｒ／ｍ２－槽底面積／ｈであることを特徴とする有機性排水の生物処理装置。 The biological treatment apparatus for organic wastewater according to any one of claims 7 to 10, wherein the aeration amount is 1 to 40 m 3 -air / m 2 -tank bottom area / h.
  12. 　請求項７ないし１０のいずれか１項において、前記固液分離手段が膜分離手段であることを特徴とする有機性排水の生物処理装置。 11. A biological treatment apparatus for organic wastewater according to claim 7, wherein the solid-liquid separation means is a membrane separation means.
PCT/JP2012/063599 2011-06-09 2012-05-28 Method and apparatus for biological treatment of organic wastewater WO2012169381A1 (en)

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