JP2009072739A - Method for biodegradation treatment of material to be treated - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for biodegradation treatment of a material to be treated which enables the biodegradation treatment of a hardly decomposable material to be treated, and can reduce the generation of surplus sludge. <P>SOLUTION: An inorganic substance for aggregating aerobic bacteria and anaerobic bacteria is mixed into water containing sludge containing both bacteria to prepare granular aggregate. Keeping of the aggregate in the environment with a dissolved oxygen of 2 mg/L or more further forms a granular material where aerobic bacteria exist mainly on the front side of the aggregate and anaerobic bacteria exist mainly in the inside (core side) of the aggregate. As a result, the granular material in which the aerobic bacteria and the anaerobic bacteria coexist is brought into contact with the material to be treated to enable the execution of the biodegradation treatment of the material to be treated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a biodegradation treatment method for a substance to be treated.

  Conventionally, a method for biodegrading a material to be treated using activated sludge containing aerobic bacteria is known.

For example, in the biodegradation treatment method for a substance to be treated disclosed in Patent Document 1, activated sludge containing aerobic bacteria and the substance to be treated are put into a treatment tank, and then the treatment is performed by aeration in the treatment tank. The amount of dissolved oxygen in the tank is controlled. Such an aerobic bacterium decomposes a pollutant (BOD, SS, etc.) in the material to be treated and stably decomposes and purifies the material to be treated.
JP-A-4-268000

  However, the biodegradation treatment method for a substance to be treated disclosed in Patent Document 1 has a problem that there are substances that cannot be biodegradable, such as plating factory effluent, β starch, and lignin. Moreover, since bacteria may adsorb pollutants (BOD, SS, etc.) without decomposing, a large amount of excess sludge is generated in the treatment tank. According to this, in order to set the sludge concentration in the treatment tank, which is a management index when continuously performing biodegradation treatment, to a predetermined value, it is necessary to frequently remove sludge in the treatment tank. there were.

  The present invention has been made in view of the above problems, and its purpose is to enable biodegradation treatment of a material to be treated that has been difficult to decompose by conventional biodegradation treatment, and It is providing the biodegradation processing method of the to-be-processed substance which can reduce generation | occurrence | production of excess sludge.

That is, the present invention
[1] A biodegradation treatment method for a substance to be treated, in which an aerobic bacterium and an anaerobic bacterium are aggregated in an inorganic substance, and the substance to be treated are brought into contact with each other under a condition of dissolved oxygen amount of 2 mg / L or more 2] A granular material obtained by aggregating an aerobic bacterium and an anaerobic bacterium into an inorganic substance in an environment having a dissolved oxygen amount of 2 mg / L or more.

  ADVANTAGE OF THE INVENTION According to this invention, there exists the outstanding effect that the biodegradation process of the to-be-processed substance which is hardly decomposable is possible, and generation | occurrence | production of excess sludge can be reduced.

  The biodegradation treatment method for a substance to be treated according to the present invention is a method in which a granular material in which aerobic bacteria and anaerobic bacteria are aggregated in an inorganic substance is brought into contact with the substance to be treated under a condition where the dissolved oxygen amount is 2 mg / L or more. is there.

  Further, the present invention is a granular material obtained by aggregating an aerobic bacterium and an anaerobic bacterium into an inorganic substance in an environment having a dissolved oxygen amount of 2 mg / L or more.

  In the present invention, the granular material can be prepared by mixing an inorganic substance that aggregates both bacteria in water containing sludge containing aerobic bacteria and anaerobic bacteria. Thereby, an aerobic bacterium and an anaerobic bacterium aggregate to an inorganic substance, and form an aggregate first. By placing this aggregate in an environment where the dissolved oxygen amount is 2 mg / L or more, there are mainly aerobic bacteria on the surface side of the aggregate and mainly anaerobic bacteria on the inside (center) side of the aggregate. A granular material is further formed. As a result, the granular material in the state where aerobic bacteria and anaerobic bacteria coexist can be brought into contact with the material to be treated, and biodegradation treatment of the material to be treated can be performed. In addition, the granular material said here means a thing with a diameter of about 1 mm-5 mm.

  In the present invention, the dissolved oxygen amount is 2 mg / L or more, and preferably 3 mg / L or more, from the viewpoint of forming a granular material. Moreover, since the dissolved oxygen amount beyond the formation of the granule is unnecessary, it is preferably 8 mg / L or less, more preferably 7 mg / L or less, and further 6 mg / L or less. preferable. The amount of dissolved oxygen can be measured using a DO meter OM12 (manufactured by Horiba, Ltd.) or the like, and can be easily controlled by adjusting the rotational speed of a fan that sends air into the treatment tank.

  The aerobic bacterium and the anaerobic bacterium used in the present invention are not particularly limited as long as they form an aggregate with an inorganic substance under a specific oxygen condition to form a granular body. As long as the substance to be treated is biodegradable by the above method.

  In addition, since the aerobic bacteria and anaerobic bacteria coexist in the granular material, it is possible to treat the treated material suitable for the degradation of the aerobic bacteria and the treated material suitable for the degradation of the anaerobic bacteria. Therefore, the types of substances that can be processed can be increased. In particular, it is also effective for decomposing nitrogen, phosphorus, etc. suitable for treatment with anaerobic bacteria.

  Furthermore, the odor at the time of decomposition | disassembly of the to-be-processed substance in a processing tank can be prevented. The reason why odor can be prevented is that odorous substances such as methane are usually generated during biodegradation treatment with anaerobic bacteria, but in the present invention, odorous substances generated by anaerobic bacteria at the center of the granular material are treated with anaerobic bacteria. Since the aerobic bacteria located around the oxidizer are oxidized, it is possible to prevent the release of odorous substances, and the fact that the inside of the treatment tank is aerobic greatly contributes to the prevention of odors.

  The present invention may be a method in which the substance to be treated is a waste liquid containing a substance to be treated, and the amount of dissolved oxygen in the treatment tank containing the granular material and the waste liquid may be controlled.

  In the present invention, the treatment tank is a treatment tank containing the granular material and the waste liquid, and refers to a tank that decomposes a material to be treated. Specifically, an aeration tank or the like is used as a treatment tank, but one or a plurality of aeration tanks may be used, or a raw water tank in which waste liquid is stored may be combined.

  The submerged membrane used in the treatment tank is not particularly limited, but a hollow fiber membrane or a flat membrane is preferable.

  In the present invention, after the aerobic bacteria and anaerobic bacteria are aggregated in an inorganic substance and the substance to be treated are brought into contact with each other under the condition that the dissolved oxygen amount is 2 mg / L or more, the submerged film in the treatment tank It may be filtered.

  In the present invention, since the treatment with aerobic bacteria and the treatment with anaerobic bacteria can be performed simultaneously in one treatment tank, the increase of the treatment tanks can be prevented, and the treatment equipment and treatment steps can be performed. Can be reduced.

  In the present invention, the amount of sludge suspended solids (MLSS) in the treatment tank is preferably 5000 to 100000 mg / L, more preferably 30000 to 60000 mg / L, from the viewpoint of the load applied to the membrane for filtration. May be an average value measured several times in the treatment tank. Here, the amount of sludge suspended solids (MLSS) is a value defined as a suspended substance defined in JIS K0102.

  Further, in the present invention, the amount of sludge organic suspended solids (MLVSS) in the treatment tank is preferably 1000 to 30000 mg / L, more preferably 5000 to 10000 mg / L from the viewpoint of the load applied to the membrane for filtration. These values may be average values obtained by measuring the inside of the treatment tank several times. Here, the amount of sludge organic suspended solids (MLVSS) is a value defined as an ignition loss defined in JIS K0102 among MLSS.

  In the present invention, the aerobic bacteria and the anaerobic bacteria are aggregated into an inorganic substance to form a granular material. Therefore, the amount of sludge suspended solids and the amount of sludge organic suspended solids can be made extremely large compared to general sludge. Therefore, it is possible to increase the contact opportunity between the substance to be treated and the granular material (aerobic bacteria and anaerobic bacteria), and it is also possible to biodegrade the substance to be treated which is hardly degradable.

  Further, in the biodegradation treatment using the granular material of the present invention, even if the MLSS value is high, the viscosity of the liquid can be lowered, so that the stirring effect in the treatment tank is enhanced and oxygen is spread all over. In particular, the action of aerobic bacteria can be activated.

  The present invention preferably includes a step of mixing a bacterial group including aerobic bacteria and anaerobic bacteria and an inorganic substance that aggregates the aerobic bacteria and the anaerobic bacteria.

  In the present invention, the proportion of the inorganic substance in the granular material is preferably 20% by weight or more, more preferably 30 to 60% by weight, from the viewpoint of sufficiently aggregating aerobic bacteria and anaerobic bacteria. More preferably, it is 40 to 50% by weight. The ratio of the inorganic substance can be calculated by using a composition analysis, specifically, a substance after removing organic components by drying, using fluorescent X-ray analysis or the like.

  The inorganic substance used in the present invention may be any substance that can form a space in which bacteria can be aggregated and retained, and is preferably calcium, aluminum, or magnesium. Further, calcium is more preferably calcite-type calcium carbonate from the viewpoint of forming a space for aggregating and holding bacteria.

  In addition, since inorganic substances agglutinate aerobic and anaerobic bacteria, it is possible to agglutinate and granulate bacteria that do not have self-aggregation performance, making them suitable for treated substances regardless of self-aggregation ability. Biodegradation can be performed using bacteria.

  In the present invention, the substance to be treated is preferably at least one selected from the group consisting of a surfactant-containing waste liquid, a lignin-containing waste liquid, a tofu-containing waste liquid, and a β-starch-containing waste liquid.

  In the present invention, as an additive for biodegradation treatment of a substance to be treated, a magnesium compound, a silicon compound, and a nutrient for bacterial culture may be used to activate bacteria in the granular material.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The waste liquid containing the processing target substance was processed in the processing plant shown in FIG. Hereinafter, the reference numerals of the respective members are based on FIG. Specifically, the waste liquid containing the substance to be treated was sequentially transferred to the raw water tank 1 composed of a 500 L capacity tank with the submersible pump 2 (trade name: submersible pump DWV6.15S, manufactured by Ebara Corporation). In the raw water tank 1, 350 L of lignin-containing waste liquid was stored. In the raw water tank 1, the pH is predetermined by adding 25% by weight sodium hydroxide or 18% by weight sulfuric acid to the waste liquid containing the treatment target substance while measuring with a pH meter (B-21) manufactured by HORIBA, Ltd. Adjusted to value.

  The waste liquid containing the substance to be treated was transferred from the raw water tank 1 to the 340 L aeration tank 3 (500 × 450 × 1600 mm, effective volume 340 L) with the submersible pump 2 while stirring under aeration. In the aeration tank 3, aerobic bacteria, anaerobic bacteria, and inorganic substances that aggregate these are introduced. The waste water is transferred from the raw water tank 1 to the aeration tank 3 by using a water level sensor 5 (electrode bar) provided in the aeration tank 3, and the residence time of the waste liquid containing the treatment target substance in the aeration tank 3 is a predetermined time. Was done.

The aeration tank 3 includes a hollow fiber membrane unit 4 composed of 10 hollow fiber membranes (1 m ² , manufactured by Toray Industries, Inc., trade name: SUR134) for filtering the treatment liquid, and an air diffuser 6 for aeration of air. Composed. The inside of the aeration tank 3 is kept at a dissolved oxygen amount of 2 mg / L or more by the air from the air diffuser 6. As a result, there are mainly aerobic bacteria on the surface side of the aggregate in which aerobic bacteria and anaerobic bacteria are aggregated on the inorganic substance, and particulates in which there are mainly anaerobic bacteria on the inside (center) side of the aggregate. It becomes. This granular material has a diameter of about 1 mm to 5 mm.

  In the present embodiment, the biodegradation process is performed by bringing the granular material and the waste liquid containing the processing target substance into contact with each other. This granular material is considered to be generated as follows. The production process of the granular material will be described with reference to FIG. First, calcium as an inorganic substance 103, more specifically calcite-type calcium carbonate, is put into a waste liquid containing aerobic bacteria 101 and anaerobic bacteria 102. Thereby, the aerobic bacteria 101 and the anaerobic bacteria 102 aggregate on the inorganic substance 103 to form an aggregate 110.

  Next, the aggregate 110 is treated with a dissolved oxygen amount of 2 mg / L or more. Thereby, the aerobic bacteria 101 mainly exists on the surface side of the aggregate, and the granular body 100 in which the anaerobic bacteria 102 mainly exists on the inside (center) side of the aggregate 110 is formed. That is, the granular body 100 in a state where the aerobic bacteria 101 and the anaerobic bacteria 102 coexist is formed.

  In the aeration tank 3, the hollow fiber membrane unit 4 is arranged in the center of the aeration tank 3 immediately above the aeration pipe 6, and is arranged so as to receive air aeration from the aeration pipe 6 sufficiently. The air diffusion pipe 6 is disposed at the lower part of the aeration tank 3 and can agitate the entire aeration tank 3 by air aeration. In the aeration tank 3, the air supplied from the diffuser pipe passes through the hollow fiber membrane unit 4, descends the wall surface of the aeration tank 3, and the granular material also convects in the same manner.

  The MLSS in the waste liquid treatment containing the substance to be treated in the aeration tank 3 is preferably 10,000 mg / L or more, more preferably 20000 mg / L or more as an average value measured several times in the aeration tank. Further, the average value of MLVSS is preferably 8000 mg / L or more, and more preferably 10,000 mg / L or more.

  Further, in the aeration tank 3, diatomaceous earth, magnesium sulfate, and neutron as a treating agent containing at least one of a magnesium compound, a silicon compound, Et-OH, and diammonium phosphate in a mixture of the granular material and the waste liquid containing the treatment target substance. Trient broth (manufactured by Kyokuto Pharmaceutical Co., Ltd .; gelatin partial hydrolyzate 5: contained in meat extract 3), Et-OH and diammonium phosphate were sequentially added. The amount of air supplied to the aeration tank 3 was 80 L / min, whereby the amount of dissolved oxygen (DO) in the mixture was maintained at 2 mg / L or more.

  Then, BOD, COD, etc. of the treated water that passed through the aeration tank 3 were measured. Each of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen and total phosphorus was measured. BOD measures the amount of dissolved oxygen in a sample after 5 days of culture and the amount of dissolved oxygen in the sample before culture using a trade name: DO meter OM12 (manufactured by Horiba, Ltd.) by a conventional method. And it calculated based on the numerical value of the amount of dissolved oxygen before and after the obtained culture | cultivation. COD was evaluated by measuring the amount of oxygen consumed chemically using potassium permanganate. TOC (total organic carbon) was measured using a total organic carbon meter TOC-4110 manufactured by Shimadzu Corporation.

  The total amount of nitrogen (TN) was determined by adding sodium hydroxide and potassium peroxodisulfate to the waste liquid containing the substance to be treated according to the ultraviolet absorption photometry, and heating the resulting mixture at 120 ° C. for 30 minutes. Hydrochloric acid was added to the product thus obtained, and the obtained product was evaluated by measuring the absorbance at 220 nm. The total phosphorus amount (TP) is determined by adding nitric acid to the waste liquid containing the substance to be treated, heating and concentrating according to the nitric acid monosulfate decomposition method, and adding nitric acid and sulfuric acid to the resulting product. Then, the phosphorus compound was changed to phosphate ion by heating, the organic substance was decomposed, and the phosphate ion in the obtained product was evaluated by measuring with molybdenum blue (asconolepinic acid reduction) spectrophotometry.

  Next, a plurality of examples of biodegradation treatment of a hardly decomposable substance as a treatment target substance are shown, and the results are shown in Tables 1 to 3.

Example 1
In this embodiment, the material to be treated is a plating factory effluent containing a surfactant. This plating factory waste liquid contains at least dipropylene glycol ether, alkylbenzimidazole, benzimidazole derivative, diethylene glycol monobutyl ether, monoethanolamine, polyoctylphenyl ether, isopropyl alcohol, ethylene glycol, N, N′-dimethylformamide and the like. It was.

  The pH in the raw water of the plating factory effluent was 7.0, BOD 5000 mg / L, COD 3300 mg / L, TOC 3400 mg / L, TN 790 mg / L, and TP 140 mg / L.

  An inorganic substance (calcium) that aggregates aerobic bacteria and anaerobic bacteria is introduced into a mixed liquid of the plating factory waste liquid and sludge containing aerobic bacteria and anaerobic bacteria, and the pH of the plating factory waste liquid is 7. The treatment conditions in the aeration tank 3 were controlled so that the amount of dissolved oxygen was 0 to 9.0, the amount of dissolved oxygen was 2.0 to 6.0 mg / L, and the residence time was 24 hours. Thereby, the granular material was formed. In addition, MLSS during the treatment averaged 42500 mg / L (amplitude 11000 to 130000 mg / L), and MLVSS averaged 10,000 mg / L (amplitude 2500 to 26000 mg / L).

  Further, in the aeration tank 3, diatomaceous earth, magnesium sulfate and nutritive broth (manufactured by Kyokuto Pharmaceutical; gelatin partial hydrolyzate 5: contained in meat extract 3), Et-OH and Diammonium phosphate was added sequentially. The amount of air supplied to the aeration tank 3 was 80 L / min, whereby the amount of dissolved oxygen (DO) in the mixture was maintained at 2 mg / L or more.

  Granules having a diameter of about 2 mm were observed in the aeration tank 3 of this example. When this granule was analyzed by microarray and gene information was analyzed, it was confirmed that aerobic bacteria and anaerobic bacteria existed. It was estimated that mainly aerobic bacteria existed on the surface of the granule and mainly anaerobic bacteria existed inside. Further, when the composition of the granular material is confirmed, C (organic substance) is 24.4% by weight, Ca is 43.6% by weight, and, in addition, Na, Mg, Al, Si, P, S, Cl, K, and Fe are several. % By weight to 0.1% by weight were confirmed. Here, it was possible to estimate that calcium was calcite-type calcium carbonate from the shape.

BOD, COD, etc. of the treated water that passed through the aeration tank 3 of Example 1 were measured. As a result, the BOD was 15 mg / L, the COD was 200 mg / L, the TOC was 140 mg / L, the total nitrogen amount (TN) was 130 mg / L, and the total phosphorus amount (TP) was 30 mg / L. BOD and the like were significantly reduced, and water quality suitable for discharge into sewage and public water areas could be obtained.
Here, the standard of “water quality suitable for being discharged into sewage and public water areas” may vary depending on the region and the like. For example, the sewage discharge standard [pH: 5. 0 to 9.0, BOD: (river discharge BOD + 2 × suspended suspended matter amount) 600 mg / L or less, total nitrogen amount 240 mg / L or less, total phosphorus amount 32 mg / L or less].

(Comparative Examples 1-3)
Sludge collected from two sewage treatment plants and sludge collected from a wastewater treatment plant of a chemical plant were introduced into the aeration tank 3 to treat the plating plant wastewater. At this time, the granular material could not be observed in the aeration tank 3. Moreover, when the amount of dissolved oxygen in the aeration tank 3 was approximately 2.0 mg / L or more, scum was generated and wastewater treatment could not be performed.

  Next, the composition of the sludge in the aeration tank 3 was observed. In any of the sludges of Comparative Examples 1 to 3, the ratio of Ca (an inorganic substance that agglomerates organic substances) was extremely low as compared with Example 1.

(Comparative Example 4)
Although it is the same processing method as Example 1, the amount of dissolved oxygen in the aeration tank 3 was 0.2 to 1.9 mg / L. Compared with Example 1, the values of BOD, COD, TOC, TN, and TP of the treated water were deteriorated.

(Example 2)
In this embodiment, the material to be treated is paper mill waste liquid. This paper mill effluent contained at least lignin. This paper mill effluent was diluted 20 to 25 times to obtain raw water.

  An inorganic substance (calcium) that aggregates aerobic bacteria and anaerobic bacteria was added to a mixed liquid of paper mill waste liquid and sludge containing aerobic bacteria and anaerobic bacteria. It was pH 7.0, BOD6429mg / L, COD7338mg / L, TOC4170mg / L, lignin amount 2100mg / L, TN237mg / L, TP305mg / L in raw water of paper mill waste liquid.

  The processing conditions in the aeration tank 3 were controlled so that the pH of this paper mill waste liquid was around 8.0, the dissolved oxygen amount was 5.0 mg / L, and the residence time was 144 hours. Thereby, the granular material was formed. When this granule was analyzed by microarray and gene information was analyzed, it was confirmed that aerobic bacteria and anaerobic bacteria existed. Moreover, the MLSS during processing averaged 42500 mg / L, and the MLVSS averaged 14250 mg / L.

  Further, in the aeration tank 3, diatomaceous earth, magnesium sulfate and nutritive broth (manufactured by Kyokuto Pharmaceutical; gelatin partial hydrolyzate 5: contained in the meat extract 3), Et-OH are added to the paper mill effluent containing the granulate and lignin. And diammonium phosphate were added sequentially. The amount of air supplied to the aeration tank 3 was 80 L / min, whereby the amount of dissolved oxygen (DO) in the mixture was maintained at 2 mg / L or more.

  Granules having a diameter of about 2 mm were also observed in the aeration tank 3 of this example. When this granule was observed in the same manner as in Example 1, it was estimated that mainly aerobic bacteria were present on the surface of the granule and that anaerobic bacteria were mainly present inside. Further, when the composition of the granular material is confirmed, 36.6% by weight of C (organic matter), 38.3% by weight of Ca, and other numbers of Na, Mg, Al, Si, P, S, Cl, K, and Fe % By weight to 0.1% by weight were confirmed. Here, it was possible to estimate that calcium was calcite-type calcium carbonate from the shape.

  The BOD, COD, etc. of the treated water that passed through the aeration tank 3 of Example 2 were measured. As a result, the BOD was 13 mg / L, the COD was 260 mg / L, the TOC was 118 mg / L, the lignin amount was 1 mg / L or less, the total nitrogen amount (TN) was 23 mg / L, and the total phosphorus amount (TP) was 104 mg / L. In treated water, the amount of BOD and lignin is remarkably reduced.

(Comparative Example 5)
In Example 2, the amount of dissolved oxygen was 0.2 mg / L. As a result, the amount of lignin in the treated water became 300 mg / L, and the treatment capacity of lignin decreased. Moreover, in the comparative example 5, the ratio of the calcium in a granular material was 17.1 weight%.

(Example 3)
In this embodiment, the substance to be treated is a β starch-containing waste liquid. The pH of this waste liquid in raw water was 6.4, BOD 96 mg / L, COD 4240 mg / L, TOC 4000 mg / L, TN 42 mg / L, and T-P 1 mg / L or less.

  The processing conditions in the aeration tank 3 were controlled such that the pH of this β-starch-containing waste liquid was 7.2 to 9.1, the dissolved oxygen amount was 2.0 to 6.6 mg / L, and the residence time was 48 hours. In addition, MLSS during the treatment averaged 30000 mg / L (amplitude 25,000 to 54000 mg / L), and MLVSS averaged 14667 mg / L (amplitude 11000 to 34000 mg / L).

  Furthermore, in the aeration tank 3, diatomaceous earth, magnesium sulfate and nutritive broth (manufactured by Kyokuto Pharmaceutical Co., Ltd .; gelatin partial hydrolyzate 5: contained in meat extract 3), Et are added to the mixture of granulate and paper mill effluent containing lignin. -OH and diammonium phosphate were added sequentially. The amount of air supplied to the aeration tank 3 was 80 L / min, whereby the amount of dissolved oxygen (DO) in the mixture was maintained at 2 mg / L or more.

  In addition, the granular material about 2 mm in diameter was observed also in the aeration tank 3 of a present Example. When this granule is analyzed with a microarray and gene information is analyzed, it can be confirmed that aerobic bacteria and anaerobic bacteria coexist in the granule, mainly aerobic bacteria are present on the surface of the granule, and mainly inside. It was estimated that anaerobic bacteria existed. Further, when the composition of the granular material is confirmed, C (organic matter) is 37.1% by weight, Ca is 32.6% by weight, and other numbers of Na, Mg, Al, Si, P, S, Cl, K, and Fe are several. % By weight to 0.1% by weight were confirmed. Here, it was possible to estimate that calcium was calcite-type calcium carbonate from the shape.

Example 4
In this embodiment, the substance to be treated is a tofu (soy milk whey) -containing waste liquid. The pH of the tofu-containing waste liquid in the raw water was 4.1, BOD 12250 mg / L, COD 9700 mg / L, TOC 7928 mg / L, TN 870 mg / L, TP 175 mg / L.

  An inorganic substance (calcium) that aggregates aerobic bacteria and anaerobic bacteria is added to a mixed liquid of the tofu-containing waste liquid and sludge containing aerobic bacteria and anaerobic bacteria, and has a pH of 7.9 to 8.5. The treatment conditions in the aeration tank 3 were controlled so that the dissolved oxygen amount was 2.7 to 6.2 mg / L and the residence time was 72 hours. Thereby, the granular material was formed. In addition, MLSS during the treatment averaged 21000 mg / L (amplitude 17000 to 25000 mg / L), and MLVSS averaged 8450 mg / L (amplitude 8000 to 9000 mg / L).

  Furthermore, in the aeration tank 3, diatomaceous earth, magnesium sulfate and nutrient broth [manufactured by Kyokuto Pharmaceutical; gelatin partial hydrolyzate 5: contained in the meat extract 3] are added to the mixture of the granular material and the waste liquid containing the treatment target substance. Silicic acid, magnesium sulfate, nutritive broth Et-OH and diammonium phosphate were added sequentially. The amount of air supplied to the aeration tank 3 was 80 L / min, whereby the amount of dissolved oxygen (DO) in the mixture was maintained at 2 mg / L or more.

  Granules having a diameter of about 2 mm were observed in the aeration tank 3 of this example. When this granule is analyzed with a microarray and gene information is analyzed, it can be confirmed that aerobic bacteria and anaerobic bacteria coexist in the granule, mainly aerobic bacteria are present on the surface of the granule, and mainly inside. It was estimated that anaerobic bacteria existed. Then, BOD, COD, etc. of the treated water that passed through the aeration tank 3 of Example 4 were measured. As a result, the BOD was 19 mg / L, the COD was 20 mg / L, the TOC was 8.7 mg / L, the total nitrogen amount (TN) was 110 mg / L, and the total phosphorus amount (TP) was 28 mg / L. BOD and the like were significantly reduced, and water quality suitable for discharge into sewage and public water bodies could be obtained. In Example 4, excess sludge was not generated.

(Comparative Example 6)
The raw water similar to that in Example 4 was used instead of granular material, and activated sludge was used. Further, the raw water was treated without addition of an inorganic substance (calcium). The MLSS during the treatment was 4000 to 8000 mg / L, and the MLVSS was 2000 to 6000 mg / L. However, the following treated water could not be obtained unless the treatment conditions in the aeration tank 3 were controlled so that the residence time was 185 hours.

BOD, COD, etc. of the treated water that passed through the aeration tank 3 of Comparative Example 6 were measured. As a result, the BOD was 50 mg / L and the COD was 300 mg / L. In this comparative example, surplus sludge was generated at 5.3 L / m ³ .

  Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to these embodiments, and can be applied to various embodiments without departing from the present invention.

(Other embodiments)
In embodiment mentioned above, the example which makes a granular material and a to-be-processed substance contact is shown in the processing tank 3 in which waste liquid is introduce | transduced. However, for example, by placing wood chips containing aerobic bacteria and anaerobic bacteria in the treatment tank, and further adding an inorganic substance, and adjusting the dissolved oxygen amount in the treatment tank to 2 mg / L or more by stirring, The effects described above can be exhibited. This embodiment can be used for a so-called biotoilet.

FIG. 1 is a schematic diagram illustrating a waste liquid treatment plant according to an embodiment. FIG. 2 is a diagram schematically showing a granule generation process of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw water tank 2 Submersible pump 3 Aeration tank 4 Hollow fiber membrane unit 5 Water level sensor 6 Aeration pipe 100 Granule 101 Aerobic bacteria 102 Anaerobic bacteria 103 Inorganic substance (calcium, calcite type calcium carbonate)
110 Aggregates

Claims (10)

  A biodegradation treatment method for a substance to be treated, which comprises contacting a granular material in which aerobic bacteria and anaerobic bacteria are aggregated into an inorganic substance and a substance to be treated under a condition where the dissolved oxygen amount is 2 mg / L or more.   The treatment method according to claim 1, wherein the substance to be treated is a waste liquid containing a substance to be treated, and the amount of dissolved oxygen in the treatment tank containing the granular material and the waste liquid is controlled.   The processing method of Claim 2 whose amount of sludge suspended solids (MLSS) in a processing tank is 5000-100000 mg / L.   The processing method of Claim 2 whose amount of sludge organic suspended solids (MLVSS) in a processing tank is 1000-30000 mg / L.   The processing method in any one of Claims 1-4 including the process of mixing the bacteria group containing aerobic bacteria and anaerobic bacteria, and the inorganic substance which aggregates aerobic bacteria and anaerobic bacteria.   The processing method in any one of Claims 1-5 whose ratio of the inorganic substance in a granular material is 20 weight% or more.   The processing method according to claim 1, wherein the inorganic substance is calcium.   The processing method according to claim 7, wherein the calcium is calcite-type calcium carbonate.   The processing method according to any one of claims 1 to 8, wherein the substance to be treated is at least one selected from the group consisting of a surfactant-containing waste liquid, a lignin-containing waste liquid, a tofu-containing waste liquid, and a β starch-containing waste liquid.   A granular material obtained by aggregating an aerobic bacterium and an anaerobic bacterium into an inorganic substance in an environment having a dissolved oxygen amount of 2 mg / L or more.

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