JP4291975B2 - Method for producing microbial preparation and microbial preparation - Google Patents

Description

【００４０】
＜培養液中のMLSS濃度に対するMLVSS濃度の好適範囲の決定＞
培養液中の任意のMLSS濃度に対するMLVSS濃度比（MLVSS/MLSS）範囲におけるMLSS濃度（χ軸）と菌培養槽の単位MLSSに対する単位時間あたりの窒素処理能力（単位容積あたりの窒素処理能力をMLSS濃度で除したもの；ｙ軸）との関係を求めた。その結果を図３及び図４に示す。
培養液中のMLSS濃度の好適範囲として決定した約15000mg/L〜約40000mg/LにあてはまらないMLSS濃度のデータであっても、例外的に菌培養槽内の流動性が確保できたと観察されたものは敢えて考慮に入れている。図３はMLVSS/MLSSが20〜30％の場合で、両軸には良い相関が見られる。一方、図４はMLVSS/MLSSが30〜40％の場合で、図３に比較して相関性が低い。図４の場合のように、MLSS濃度の変動に窒素処理能力が対応しないことは、バイオマスの過剰によって基質が微生物に十分に行き渡らなかったり、基質処理に寄与しない、無駄な微生物が菌培養槽内に留まっている可能性を示している。
様々なMLVSS/MLSS範囲においてMLSS濃度と菌培養槽の単位MLSSに対する単位時間あたりの窒素処理能力との相関係数（ｒ自乗値）を測定した。その結果を図５に示す。図５によれば、比較的高い相関係数（0.7以上）が得られるのはMLVSS/MLSSが約35％までであった。以上より、培養液中のMLSS濃度に対するMLVSS濃度の好適範囲を約35％以下と決定した。
【００４１】
＜微生物製剤の製造＞
MLSS濃度14960mg/L、MLVSS/MLSS比が59％となった硝化細菌の培養液について、前記全浮遊固形物濃度に対するバイオマス濃度の好適範囲上限値である約35％を上回ったため培養液総容量の約33％を菌培養槽外に取り出した。この結果、菌培養槽の容積に対するMLSS濃度は約10000mg/L、MLSS濃度に対するMLVSS濃度の比は59％のままなのでMLVSS濃度は約6000mg/Lとなった。
培養液を取り出した後、石炭焼却灰フライアッシュを菌培養槽に添加して、MLVSS/MLSS比を前記MLSS濃度に対するMLVSS濃度の好適範囲である約22％（菌培養槽の容積に対するMLSS濃度27000mg/L、MLVSS濃度6000mg/L）として、培養を継続し、以後、これに準じて固形物すなわち微生物製剤の菌培養槽外への取り出しと石炭焼却灰フライアッシュの添加を適宜行いながら約100日間にわたり微生物製剤の生産を行った。
なお、石炭焼却灰フライアッシュの菌培養槽内への定着性を高める目的で、これを菌培養槽に添加する前に0.2w/v％濃度のカチオン性高分子凝集剤（住友化学工業製スミフロックFC-185N）溶液、次いで0.1w/v％濃度のカチオン性高分子凝集剤（住友化学工業製スミフロックFA-30）溶液内に分散させてから使用した。
菌培養槽から取り出した硝化細菌を主成分とする微生物製剤は、約481.5kg-窒素/L・hrの窒素処理能力を有していた。さらに、本微生物製剤を30分以上自然沈降させ、上澄み液をオーバーフローさせることによって得た濃縮微生物製剤は、約1000mg-窒素/L・hrの窒素処理能力を有していた。ちなみに、一般の下水処理場の窒素処理能力は、この100分の1〜1000分の1程度である。
【００４２】
【発明の効果】
本発明により、無機微粒子固体を用いて微生物を凝集造粒化させてから培養し、菌培養槽内のバイオマス濃度があらかじめ決定した好適範囲を超えた培養液を菌培養槽外に取り出して微生物製剤を得、さらに菌培養槽内のMLSS濃度があらかじめ決定した好適範囲内の値になるように無機微粒子固体を追加して培養を続行するという簡単かつ安価な操作によって、すぐに使用でき、かつ自然環境に悪影響を与えない微生物製剤を提供することができる。
【図面の簡単な説明】
【図１】菌培養槽として使用される気泡塔反応器の概略縦断面図である。
【図２】菌培養槽として使用される他の気泡塔反応器の概略縦断面図である。
【図３】菌培養槽内のMLSS濃度に対するMLVSS濃度が20〜30％の範囲におけるMLSS濃度（χ軸）と菌培養槽の単位MLSS、時間あたりの窒素処理能力（ｙ軸）との関係を示すグラフである。
【図４】菌培養槽内のMLSS濃度に対するMLVSS濃度が30〜40％の範囲におけるMLSS濃度（χ軸）と菌培養槽の単位MLSS、時間あたりの窒素処理能力（ｙ軸）との関係を示すグラフである。
【図５】菌培養槽内のMLSS濃度に対するMLVSS濃度の様々の範囲（χ軸）に対してMLSS濃度と菌培養槽の単位MLSSと時間あたりの窒素処理能力との相関係数ｒ自乗値（ｙ軸）を示すグラフである。
【符号の説明】
１：隔壁、２：外塔、３：ドラフトチューブ、４：スロープ、５：酸素供給口、６：沈降部、７：反応部、８：排出口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a microbial preparation and a microbial preparation.
[0002]
[Prior art]
In order to eliminate various troubles that often occur in biological treatment equipment such as wastewater by the activated sludge method, various materials, that is, so-called microbial preparations having a specific function, have been developed and used. For example, this applies to microbial preparations used for the purpose of enhancing the organic matter treatment capacity, promoting the treatment of difficult-to-treat components such as oil, and promoting the nitrification function for nitrogen removal. Also, in the technology of decomposing organic waste using a fermentation treatment apparatus, composting or composting, and returning to farmland, a microbial preparation may be used to promote fermentation. Furthermore, in recent years, in order to promote the purification of soil and groundwater contaminated with heavy oil, chemical substances, heavy metals, etc., the development of microbial preparations with microorganisms having a function of decomposing them as the dominant species has been promoted and put to practical use. It is being done.
[0003]
Thus, it is expected that microbial preparations will be widely and rapidly spread in the near future mainly in fields related to environmental purification. Therefore, development of a means for continuously producing large quantities of microorganism preparations at a lowest possible cost with a simple operation is awaited. Many of the microbial preparations that have been put to practical use so far are obtained by culturing the target microorganism in a culture tank in batch, semi-batch, or chemostat, etc., and then collecting the cells by centrifugation or filtration. Or the manufacturing method of drying and pulverizing has been employ | adopted.
However, such a production method has a problem in that it requires a large-capacity culture vessel and separation / concentration equipment with respect to the yield of bacterial cells, which increases the cost.
[0004]
As a proposal to solve the above-mentioned problems, Japanese Patent Application Laid-Open No. 5-308957 discloses that microorganisms are entrapped and immobilized in a gel, and this is cultured in waste water, sewage, a synthetic culture solution or a natural culture solution, There is disclosed a method for producing a microbial preparation by crushing immobilized microorganisms to obtain an emulsion containing microorganisms at a high concentration.
[0005]
However, even with such a technique, a high-speed rotating machine such as a homogenizer is still necessary for gel crushing, and it may be a factor that increases costs when the production scale reaches a certain level. Further, according to the publication, the microbial preparation is accompanied by a gel component composed of an organic polymer. For this reason, when the density | concentration of a gel component becomes high, for example, reaches to 15 weight%, there also exists a concern that this may become a pollution source as an organic substance in the activated sludge and soil which are the main application points as a microorganism preparation.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a microbial preparation and a microbial preparation that can be produced at low cost by simple operations and do not adversely affect the natural environment.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have cultivated and granulated microorganisms using a predetermined inorganic fine particle solid, and the biomass concentration in the fungus culture tank exceeded a predetermined range. Occasionally, the culture solution is taken out of the fungus culture tank to obtain a microbial preparation, and the cultivation is continued by adding inorganic fine particle solids so that the total suspended solid concentration in the fungus culture tank is within a predetermined range. In this case, the present inventors have found a new fact that a microorganism preparation can be produced easily and inexpensively, and a microorganism preparation production method and microorganism preparation that do not adversely affect the natural environment can be provided, thereby completing the present invention. It came to.
[0008]
That is, the method for producing a microorganism preparation and the microorganism preparation of the present invention have the following constitution.
(1) It is obtained by aggregating and granulating microorganisms using an inorganic fine particle solid having a central particle diameter of 100 μm or less, and then culturing by adding a substrate (culture medium) specific to the target microorganism. And a mixture of the above-mentioned inorganic fine particle solid and a biomass mainly composed of a target microbial cell (hereinafter referred to as “MLVSS”, where the biomass is an acronym of “Mixed liquor Volatile Suspended Solid”) A method for producing a microbial preparation comprising:
Cultivate in the range of MLSS concentration in the culture solution determined in advance so that the uniformity of all suspended solids in the fungal culture tank (hereinafter referred to as “MLSS” by the acronym of Mixed liquor Suspended Solid) is maintained. Done
When the ratio of MLVSS concentration to MLSS concentration reaches or exceeds the upper limit of the range where it is recognized that there is a correlation between MLSS concentration and substrate processing capacity per unit time for unit MLSS ,
A method for producing a microbial preparation, wherein a part of the culture solution is taken out from the fungus culture tank as a microbial preparation.
[0009]
(2) In the method for producing a microbial preparation according to the above (1), after the microbial preparation is taken out of the bacterial culture tank, an inorganic fine particle solid having a central particle size of 100 μm or less and water containing water or a substrate are contained. A method for producing a microorganism preparation, which is added to a fungus culture tank, adjusted so that the MLSS concentration and MLVSS concentration are within the respective ranges described in (1) above, and the cultivation is continued again.
[0010]
(3) The method for producing a microbial preparation according to the above (1) or (2), wherein the inorganic fine particle solid is coal incineration ash.
(4) The method for producing a microbial preparation according to any one of (1) to (3), wherein the microorganism is a nitrifying bacterium.
(5) The method for producing a microbial preparation according to any one of (1) to (4) above, wherein the substrate for specific growth of the target microorganism is sewage or wastewater.
(6) The method for producing a microorganism preparation according to any one of (1) to (5) above, wherein the culture solution taken out of the fungus culture tank is concentrated or dried.
[0011]
(7) The inorganic fine particle solid obtained by aggregating and granulating microorganisms on an inorganic fine particle solid having a center particle size of 100 μm or less, and adding a substrate for growth specific to the target microorganism and culturing; , A microbial preparation comprising a mixture of biomass mainly composed of the target microbial cells,
A culture solution in which the ratio of biomass concentration to total suspended solids exceeds the range where it is recognized that there is a correlation between the total suspended solids concentration and the substrate processing capacity per unit time for all suspended solids or A microbial preparation comprising the concentrate or dried product.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
In the present invention, the inorganic fine particle solid is a material that contains a metal and its inorganic salts, oxides, or carbon, but is chemically classified as an inorganic substance, or has an organic carbon content. A pure substance or mixture of less than about 1%. Specifically, incineration ash and thermal power generation of organic waste such as industrial products such as alumina (aluminum oxide) and hydroxyapatite (calcium phosphate hydroxide) (including non-standard products, by-products and waste products) and activated sludge Examples include coal incineration ash, which is a compost for coke ovens. The specific gravity is not particularly limited, but is preferably about 1.2 to 3.5.
[0013]
The center particle diameter of the inorganic fine particle solid is preferably 100 μm or less. When the inorganic fine particle solid of this fraction is mixed with a suspension of microorganisms, for example, activated sludge which is an aggregate of microorganisms having various functions, both of them are mixed. Aggregation and granulation occur, and can be an effective microorganism-immobilized carrier.
[0014]
As an inorganic fine particle solid, especially coal incineration ash is most preferable, as described in Japanese Patent Application Laid-Open No. 9-131178, because the expression of the activity of microorganisms occurs in a short period of time at a very low cost with a simple operation. In particular, the fraction called fly ash is obtained by capturing a fine-grained fraction of coal husk contained in the exhaust gas of coke oven boilers at thermal power plants and steelworks with an electrostatic precipitator, etc. This is particularly suitable because the central particle diameter is 100 μm or less without the above measures.
[0015]
Fly ash has some variations in the elemental composition, central particle size, and specific gravity of the main component depending on the origin and age of coking coal, the performance of the dust collector, etc. (Tanozaki Takao et al., Chichibu Onoda Research Report Vol. 46, Volume 1 No. 129, pages 104-125, 1995), such differences are not a problem for use in the practice of the present invention. In addition, the coarse-grained fraction collected after falling under a boiler among coal ash burning husks is called clinker ash, and has an elemental composition equivalent to fly ash. If clinker ash is pulverized, it is possible to obtain almost the same as fly ash, which can also be used in the present invention.
[0016]
In the present invention, the target microorganism is predominately cultured, prepared in a large amount, and formulated into a microbial preparation to compensate for a lack of biological function or enzyme activity at a certain application point. The thing which has the specific function used in order to activate is pointed out. Specifically, for example, nitrifying bacteria having characteristics of being easily deactivated or killed in spite of playing an important role in nitrogen removal in biological treatment equipment of wastewater, causes of contamination of soil and groundwater Examples of the microorganisms that decompose and purify organochlorine compounds such as trichlorethylene, and various microorganisms that promote fermentation decomposition or composting of organic waste. These may of course be pure bacteria, but for the purpose of use in a natural environment, for example, it may be a dominant species, that is, the main component in the presence of other microorganisms.
[0017]
In the present invention, as already described, the inorganic fine particle solid and the microorganism are present in the form of agglomerated granules in the suspension, and the culture is performed by adding a substrate specific to the target microorganism. Thus, only the target microorganism can be propagated or become the dominant species. As a culture method, any of batch, semi-batch, and continuous methods can be applied. However, in order to efficiently prepare a microorganism having a slow growth and a low cell yield, such as nitrifying bacteria, it is particularly preferable to use As described in Japanese Patent No. 187272, a continuous culture method is effective in which the amount of ammonia (culture medium) supplied to a container for culturing microorganisms (hereinafter referred to as a fungus culture tank) is increased logarithmically with the passage of culture time. As a culture medium, natural or artificial culture medium as well as sewage and wastewater can be used.
[0018]
In the present invention, the specification of the bacteria culture tank is not particularly limited, and conventionally used culture tanks, activated sludge treatment tanks, and the like can be used as they are. When the target microorganism is an aerobic microorganism, the culture as shown in FIG. 1 is performed for the purpose of efficiently cultivating the microorganism by accumulating it at a high concentration with low operation costs and easy operation management. It is preferable to employ a tank to culture aerobic microorganisms.
[0019]
That is, the culture tank shown in FIG. 1 is composed of a cylindrical bubble column reactor. This reactor has a triple structure in which a cylindrical partition wall 1 and a draft tube 3 are incorporated in the outer column 2, and the region inside the partition wall 1 is sandwiched between the reaction portion 7, the partition wall 1 and the outer column 2. It is a sedimentation part 6. The bottom of the outer tower 2 has a tapered slope 4, and solids descending along the slope are caused by the upward flow of air or high oxygen partial pressure gas flowing in from the oxygen supply port 5 (intake port) at the bottom. The inside of the draft tube 3 rises, contacts and mixes with the inflowing water above the reaction portion 7, and forms a circulation flow that descends outside the draft tube 3 and reaches the bottom slope 4.
[0020]
In the sedimentation part 6, solids and clarified water are separated by gravity, the solids travel along the slope 4 and return to the reaction part 7, and the clarified water is discharged from the outlet 8 as treated water. A synthetic medium or a chemical fertilizer manufacturing factory waste water is supplied as inflow water flowing from above the water surface of the reaction portion 6 to perform culture. The supply of influent water may be either continuous or intermittent.
[0021]
In the culture tank shown in FIG. 1, an inorganic fine particle solid (microorganism immobilization support) is flowed in the culture tank, and aerobic microorganisms are accumulated and cultured in this. In culturing, raw water is supplied to the culture tank, air or high oxygen partial pressure gas is supplied from the oxygen supply port 5, and the inorganic fine particle solid flows while circulating the culture liquid containing the inorganic fine particle solid in the reaction portion 7. And accumulate microorganisms on the inorganic fine particle solid. In this way, aerobic microorganisms can be accumulated at a high concentration and efficiently cultured with low operating costs and easy operation management, and the utilization efficiency of oxygen supplied into the tank is high. Driving becomes possible.
[0022]
Further, the same effect can be obtained by culturing aerobic microorganisms using a culture apparatus as shown in FIG. 2 instead of the culture tank shown in FIG. That is, as shown in FIG. 2, the culture tank 10 is provided with a raw water introduction pipe 18, a treatment liquid discharge pipe 17, and a treatment liquid discharge port 19, and the culture tank 10 is partitioned by a partition plate 12. An upward flow path 20 and a downward flow path 21, and communication flow paths 22 and 23 provided above and below the upward flow path 20 and the downward flow path 21 are formed, and a lower portion of the downward flow path 21 is inclined. The bottom wall 14 is provided at the upper part of the descending flow path 21 with a rectifying plate 13 inclined in the direction opposite to the inclined bottom wall 14. The upward flow path 20 and the downward flow path 21 are provided with air aeration means 15 and high oxygen partial pressure gas diffusion means 16 as oxygen supply means. The treatment liquid discharge port 19 may be an overflow weir, and the treated water overflowing from this overflow weir is discharged out of the tank through the treated water discharge pipe 17. The partition plate 12 forms a circulation channel for the culture solution in the culture tank 10.
[0023]
The raw water supply pipe 18 is installed at, for example, the upper part of the upward flow path 20 or the middle stage or the lower stage in the culture tank 10 so that the culture liquid does not flow through the treatment liquid discharge pipe 17 through a short path. Further, the processing liquid discharge port 19 is preferably installed on the wall surface of the tank 10 facing the partition plate 12 from above the lower end of the rectifying plate 13, so that the high oxygen content is set. The rectifying tank is such that bubbles of the high oxygen partial pressure gas supplied from the pressure gas diffusion means 16 flow out of the culture tank from the processing liquid discharge port 19 through the processing liquid discharge pipe 17 along with the discharge liquid. 13 can prevent it.
[0024]
The inclined bottom wall 14 is inclined so that the liquid depth gradually increases from the wall surface of the tank 10 facing the partition plate 12 in the descending flow path 21 toward the upward flow path 20. As a result, it is possible to prevent the microorganism immobilization carrier or the accumulation of microorganisms from accumulating on the bottom of the culture tank 10 to reduce the culture efficiency of the microorganisms, and to smoothly form a circulation flow.
[0025]
The rectifying plate 13 is provided on the upper part of the descending flow path 21 so as to be inclined downward (that is, inclined in the direction opposite to the inclined bottom wall 14) from the partition plate 12 toward the wall surface of the tank 1 facing the partition plate 12. ing. As a result, an upward flow of the culture solution is formed by the air lift effect of the air supplied from the oxygen supply means 15 provided in the lower part of the upward flow path 20, and then the rectifying plate 13 via the communication flow path 22. A suitable circulation flow is formed in the culture tank 10 and oxygen bubbles supplied from the high oxygen partial pressure gas diffuser 16 flow out of the treated water discharge port 19 to the outside of the tank. It is preventing. The rectifying plate 13 is installed so that the upper part protrudes from the liquid surface of the culture tank 10 so that the circulating liquid does not flow out from the treatment liquid discharge pipe 17. The rectifying plate 13 does not have to be inclined as a whole, and at least the lower portion may be inclined.
[0026]
In the present invention, when a substrate specific to the target microorganism is added to the aggregated granulated body of the inorganic fine particle solid and the microorganism and cultured, only the target microorganism grows or becomes a dominant species, and then the fungus culture tank The MLVSS concentration in the inside increases. On the other hand, the inorganic fine particle solid concentration in the fungus culture tank may not increase or may decrease by leaking out of the fungus culture tank in the case of the continuous culture method. Therefore, the ratio of the MLVSS concentration to the MLSS concentration in the fungus culture tank usually increases with the passage of the culture time. When the ratio of the MLVSS concentration to the MLSS concentration becomes excessively large, problems such as deterioration of the agglomeration and granulating properties of microorganisms and the substrate not sufficiently reaching the target microorganisms due to the consolidation of the biofilm may occur. Even if such a failure does not occur, it is not preferable that a great deal of energy is consumed in order to maintain culture of microorganisms more than necessary. However, from the viewpoint of a microbial preparation, it is generally preferable that the amount of impurities other than microorganisms, that is, the amount of inorganic fine particle solids is small. Of course, it is not impossible to separate and remove contaminants when commercialized as a microbial preparation, but it is not preferable to add such a separation and purification step in terms of cost.
[0027]
Therefore, in the present invention, a suitable range of the MLSS concentration in the fungus culture tank and a suitable range of the ratio of the MLVSS concentration to the MLSS concentration in the fungus culture tank in this range are determined in advance, and the MLVSS concentration is the upper limit value. Is exceeded, the culture solution is taken out of the fungus culture tank and used as a microorganism preparation. In other words, the microorganism preparation of the present invention is obtained by removing excessive biomass from the fungus culture tank in the form of agglomerated granules with inorganic fine particle solids.
Such a microbial preparation of the present invention is suitable for commercialization as a microbial preparation because the ratio of the MLVSS concentration to the MLSS concentration is higher than that in the culture tank and the amount of the inorganic fine particle solid is small.
[0028]
The preferred range of MLSS concentration in the bacterial culture tank set in advance in the present invention is a range in which the uniformity of MLSS in the bacterial culture tank is maintained, that is, MLSS does not flow out of the bacterial culture tank. The range that can flow uniformly without adhering or depositing at any point.
[0029]
The preferred range of the ratio of MLVSS concentration to MLSS concentration corresponds to the range where MLSS concentration is recognized as having a correlation between the MLSS concentration and the substrate treatment capacity per unit time per unit MLSS, that is, the MLSS concentration in the culture tank. This refers to a range where the substrate treatment performance is exhibited and grows more than necessary and does not contribute to the substrate treatment. Regarding the criteria for determining that there is a correlation, for example, graphing a plurality of actual measurement results of MLSS concentration and substrate processing capacity per unit MLSS / time, and obtaining a correlation coefficient between them, for example, a correlation coefficient of 0.7 or more It can be determined, for example, as having a correlation.
[0030]
If the MLSS concentration and MLVSS concentration in the fungus culture tank are within these preferable ranges, the material circulation and fluidity in the fungus culture tank can be maintained, and while maintaining the energy cost and the cost of the culture medium appropriately, Production can be done.
[0031]
When the culture solution is extracted as a microbial preparation outside the bacterial culture tank by the method of the present invention, the ratio of the MLVSS concentration to the MLSS concentration in the bacterial culture tank does not change, but the MLSS concentration value itself decreases. If a new substrate is supplied in such a situation, only the MLVSS concentration will increase, so that the biofilm will be consolidated, and waste microorganisms that do not contribute to the substrate treatment as described above will be retained in the bacterial culture tank. It becomes easy to do.
Therefore, the inorganic fine particle solids whose residual amount in the fungus culture tank has been reduced by being taken out of the fungus culture tank accompanying the biomass is less than the upper limit of the ratio of the MLVSS concentration to the MLSS concentration in the preset culture solution. If the culture is continued and added, the inorganic fine particle solids are properly mixed in the biofilm to prevent the biofilm from being consolidated, so that the culture condition is good until the MLVSS concentration reaches or exceeds the upper limit again. Can be maintained.
[0032]
Thereafter, the microbial preparation can be continuously produced by continuing the culture. Of course, the MLSS concentration, MLVSS concentration and the ratio of both in the fungus culture tank are constantly monitored, and while maintaining these within the above-mentioned preferred range, the culture solution is extracted and the inorganic particulate solid is continuously added. It is also included in the scope of the method of the present invention to be a continuous production method of a microorganism preparation such as a kind of chemostat culture.
[0033]
In the present invention, the culture solution taken out of the system is itself a microbial preparation, but it may be concentrated or dried by removing water in the same manner as many other existing microbial preparations. Since the microorganisms are agglomerated and granulated as a feature of the present invention, the microorganism preparation is concentrated by separating, discarding and concentrating the supernatant liquid by gravity sedimentation without relying on relatively high energy consumption processes such as centrifugation and filtration. Can be obtained. Further, when the microorganism preparation of the present invention is stored or stored, if it is an aerobic microorganism, it is preferably treated in advance with a high oxygen partial pressure gas as described in JP-A-2000-354484.
[0034]
【Example】
Next, examples of the present invention using nitrifying bacteria as target microorganisms will be shown, but the present invention is not limited to the following examples.
The MLSS concentration and the MLVSS concentration were measured according to the Japan Sewerage Association, edited by the Sewerage Test Method 1997 edition (first volume), pages 269-271.
[0035]
<Aggregation, granulation and culture of microorganisms by inorganic fine particle solid>
As an inorganic fine particle solid for agglomerating and granulating microorganisms, fly ash was used from coal incineration ash of a thermal power plant. Its elemental composition and the like are as described in Japanese Patent Application Laid-Open No. 9-131178, and the main component is a metal oxide such as silica, alumina, and iron oxide, the center particle size is 9.12 μm, and the specific gravity is 2.29. Agglomeration and continuous culture of microorganisms were performed using activated sludge from a chemical factory as a seed source for fly ash and nitrifying bacteria.
[0036]
That is, 110 g of coal incineration ash was added to a 0.2% cationic polymer flocculant solution (0.35 g of “Sumiflock” FC-185N manufactured by Sumitomo Chemical Co., Ltd.) dissolved in 176 mL of water, and then 0.1% An anionic polymer flocculant solution (manufactured by Sumitomo Chemical Co., Ltd., “Sumiflock” FA-30 0.132 g dissolved in 132 mL of water) was added and further stirred for 30 minutes or more. This was mixed with 11g of activated sludge from a chemical plant as MLSS, and a synthetic medium (ammonium sulfate 0.71g / L (final concentration, the same shall apply hereinafter), disodium phosphate 0.57g / L, potassium chloride 0.11g / L, magnesium sulfate hemihydrate Japanese 0.085g / L, Iron (II) sulfate heptahydrate 0.0085g / L, Calcium chloride dihydrate 0.005g / L, Manganese sulfate tetrahydrate 0.002g / L, Sodium molybdate dihydrate 0.05 mg / L, zinc sulfate heptahydrate 0.1 mg / L, copper sulfate pentahydrate 0.1 mg / L, cobalt chloride hexahydrate 0.001 mg / L) and water to 3.4 L, It put into the cylindrical bubble column reactor shown in FIG. The main structural parts of this reactor are all made of acrylic resin, and have a triple structure in which a partition 1 having an inner diameter of 80 mm and a draft tube 3 having an inner diameter of 30 mm are incorporated in an outer tower 2 having an inner diameter of 100 mm. In this culture tank, the solid matter descending along the tapered slope 4 at the bottom of the outer tower 2 rises in the draft tube 3 by the upward flow of air or high oxygen partial pressure gas flowing in from the oxygen supply port 5, and reacts. It is brought into contact with and mixed with the incoming water above the portion 7 to form a circulating flow that descends outside the draft tube 3 and reaches the slope 4 at the bottom. Solids and clarified water are separated by gravity in the sedimentation part 6, the solids return to the reaction part 7 through the slope 4, and the clarified water is discharged from the outlet 8 as treated water. The height of the outer tower 2 from the oxygen supply port 5 is about 470 mm, and the height of the draft tube 3 is also about 370 mm. The effective volume of the reaction part 7 is about 2.2L, and that of the sedimentation part is about 1.2L.
Batch culture was performed by supplying air from the bottom of the reactor overnight while automatically adjusting the pH of the microbial suspension in the reactor to about 7.5 with a pH controller. The culture temperature was room temperature (about 25 ° C.). On the next day, the partition wall 1 and the draft tube 3 were inserted into the reactor, and a three-phase fluidized bed bubble column reactor having an effective reaction section volume of 2.2 L was obtained. The concentrations of fly ash and activated sludge in the fungus culture tank at this time are 5% [w / v] and 0.5% [w / v], that is, 50000 mg / L and 5000 mg-MLSS / L, respectively. A synthetic medium was continuously cultured at room temperature under a pH of about 7.5 while adjusting the ammonia concentration logarithmically over time and adjusting the phosphorus concentration to be 10% of the nitrogen concentration. .
[0037]
Synthetic medium (containing about 150 mg / L to about 2000 mg / L as ammonia nitrogen) or chemical fertilizer manufacturing plant wastewater (about 100 mg / L as ammonia nitrogen) from the space above the water surface of reaction part 6 containing ammonium sulfate as inflow water About 1500 mg / L) was supplied continuously while appropriately changing the ammonia nitrogen concentration and flow rate (hereinafter collectively referred to as ammonia load), and culture specific to nitrifying bacteria was performed. In order to maintain the pH in the fungus culture tank at 7.5, a 10% sodium carbonate aqueous solution was automatically dropped by a pH controller (manufactured by Takumina Seisakusho). Nitrogen treatment capacity per unit volume of the fungus culture tank was measured as needed as an immediate confirmation of nitrifying bacteria growth.
[0038]
<Determination of the suitable range of MLSS concentration in the culture medium>
While continuously culturing while changing the ammonia load, the relationship between the MLSS concentration and the homogeneity of the fungus culture tank was investigated. As criteria for determining whether the solids are uniform or not, the outflow of solids to the sedimentation part 6 and the discharge port 8 of the fungus culture tank, the adhesion of solids to the inner surface of the partition wall 1, the solid matter at the bottom of the fungus culture tank A four-stage determination was made based on the degree of occurrence of a failure such as partial or complete deposition. Table 1 summarizes the observation results under a certain condition in which the ratio of the MLVSS concentration to the MLSS concentration in the fungus culture tank is about 25% to about 30%. Judgment results of observation findings were represented by symbols ◎ (very good), ○ (good), Δ (somewhat poor), and × (bad). According to Table 1, the MLSS concentration range in which the fluidity in the bacterial culture tank can be stably maintained is considered to be about 15000 mg / L to about 40,000 mg / L, and this was determined as a suitable range for the MLSS concentration in the culture solution.
[0039]
[Table 1]

[0040]
<Determination of the preferred range of MLVSS concentration relative to MLSS concentration in the culture medium>
MLSS concentration (χ axis) in the range of MLVSS concentration ratio (MLVSS / MLSS) to any MLSS concentration in the culture solution and nitrogen treatment capacity per unit time for the unit MLSS of the fungal culture tank (nitrogen treatment capacity per unit volume MLSS The relationship with the value divided by the concentration (y-axis) was determined. The results are shown in FIGS.
Even in the case of MLSS concentration data that does not fall within the range of about 15000 mg / L to about 40000 mg / L determined as the preferred range of MLSS concentration in the culture solution, it was observed that the fluidity in the bacterial culture tank was exceptionally secured. Things are taken into consideration. FIG. 3 shows a case where MLVSS / MLSS is 20 to 30%, and a good correlation is seen between both axes. On the other hand, FIG. 4 shows a case where MLVSS / MLSS is 30 to 40%, and the correlation is low compared to FIG. As in the case of FIG. 4, the fact that the nitrogen treatment capacity does not correspond to fluctuations in the MLSS concentration means that the substrate is not sufficiently distributed to the microorganisms due to the excess of biomass, or the wasteful microorganisms that do not contribute to the substrate treatment are in the bacteria culture tank. The possibility of staying in is shown.
In various MLVSS / MLSS ranges, the correlation coefficient (r-square value) between the MLSS concentration and the nitrogen treatment capacity per unit time for the unit MLSS of the fungus culture tank was measured. The result is shown in FIG. According to FIG. 5, a relatively high correlation coefficient (0.7 or more) was obtained for MLVSS / MLSS up to about 35%. From the above, it was determined that the preferred range of MLVSS concentration relative to the MLSS concentration in the culture solution was about 35% or less.
[0041]
<Manufacture of microbial preparations>
The culture solution of nitrifying bacteria with an MLSS concentration of 14960 mg / L and an MLVSS / MLSS ratio of 59% exceeded the upper limit of about 35%, which is the preferred upper limit of the biomass concentration relative to the total suspended solids concentration. About 33% was taken out of the fungus culture tank. As a result, the MLSS concentration was about 10000 mg / L with respect to the volume of the bacterial culture tank, and the ratio of the MLVSS concentration to the MLSS concentration was still 59%, so the MLVSS concentration was about 6000 mg / L.
After removing the culture broth, coal incineration ash fly ash is added to the fungus culture tank, and the MLVSS / MLSS ratio is about 22%, which is a suitable range of MLVSS concentration relative to the MLSS concentration (MLSS concentration with respect to the volume of the fungus culture tank is 27000 mg) / L, MLVSS concentration 6000mg / L), and continued culture for about 100 days, taking out solid substances, that is, microbial products outside the cell culture tank and adding coal incineration ash fly ash accordingly. Microbial preparations were produced throughout.
In addition, in order to improve the fixability of coal incineration ash fly ash in the fungus culture tank, before adding it to the fungus culture tank, a 0.2w / v% concentration cationic polymer flocculant (Sumifloc manufactured by Sumitomo Chemical Co., Ltd.) FC-185N) solution, and then dispersed in a 0.1 w / v% cationic polymer flocculant solution (Sumiflock FA-30 manufactured by Sumitomo Chemical Co., Ltd.) before use.
The microbial preparation mainly composed of nitrifying bacteria removed from the fungus culture tank had a nitrogen treatment capacity of about 481.5 kg-nitrogen / L · hr. Furthermore, the concentrated microorganism preparation obtained by allowing the microorganism preparation to spontaneously settle for 30 minutes or more and overflowing the supernatant liquid had a nitrogen treatment capacity of about 1000 mg-nitrogen / L · hr. Incidentally, the nitrogen treatment capacity of a general sewage treatment plant is about 1 / 100th to 1 / 1000th of this.
[0042]
【The invention's effect】
According to the present invention, microorganisms are agglomerated and granulated using an inorganic fine particle solid and cultured, and a culture solution in which the biomass concentration in the fungus culture tank exceeds a pre-determined preferred range is taken out of the fungus culture tank to obtain a microorganism preparation In addition, it can be used immediately and easily by simple and inexpensive operation of adding the inorganic fine particle solid so that the MLSS concentration in the fungus culture tank becomes a value within a predetermined preferable range. A microorganism preparation that does not adversely affect the environment can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view of a bubble column reactor used as a fungus culture tank.
FIG. 2 is a schematic longitudinal sectional view of another bubble column reactor used as a fungus culture tank.
[Figure 3] The relationship between MLSS concentration (χ axis) in the range of MLVSS concentration to 20-30%, MLSS concentration in fungus culture tank, unit MLSS of bacteria culture tank, and nitrogen treatment capacity per hour (y axis) It is a graph to show.
[Figure 4] Figure 4 shows the relationship between MLSS concentration (χ axis) in the range of MLVSS concentration in the cell culture tank from 30 to 40%, unit MLSS of bacteria culture tank, and nitrogen treatment capacity per hour (y axis). It is a graph to show.
FIG. 5 is a correlation coefficient r-square value between MLSS concentration, unit MLSS of a bacterial culture tank, and nitrogen treatment capacity per hour for various ranges (χ axis) of MLVSS concentration with respect to MLSS concentration in the bacterial culture tank. It is a graph which shows a y-axis.
[Explanation of symbols]
1: partition wall, 2: outer tower, 3: draft tube, 4: slope, 5: oxygen supply port, 6: settling section, 7: reaction section, 8: discharge port

Claims (3)

The nitrifying bacteria are aggregated granulated median particle size using the following coal ash 100 [mu] m, obtained by performing the cultivation by adding a substrate for the specific growth nitrifying bacteria of interest, the coal ash And a method for producing a microbial preparation comprising a mixture of a target nitrifying bacterial cell as a main component,
Cultivate in the range of the total suspended solids concentration in the culture solution determined in advance so that the uniformity of all suspended solids in the fungus culture tank is maintained,
The ratio of biomass concentration to total suspended solids reaches the upper limit of the range where the correlation coefficient between the total suspended solids concentration and the substrate processing capacity per unit time for all unit suspended solids is 0.7 or more. Or when this upper limit is exceeded,
Remove a part of the culture solution from the fungus culture tank as a microorganism preparation,
Thereafter, coal incineration ash with a central particle size of 100 μm or less and water containing water or substrate are added to the fungus culture tank, and adjusted so that the total suspended solids concentration and biomass concentration are within the above ranges. The method for producing a microorganism preparation, characterized in that the culture is continued again. Substrates for specific proliferation in nitrifying bacteria of interest The method for producing a microbial preparation according to claim 1, wherein the sewage or waste water. The method for producing a microbial preparation according to claim 1 or 2, wherein the culture solution taken out of the fungus culture tank is concentrated or dried.

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