JP2016168564A - Sludge treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sludge treatment system that can highly efficiently treat a biological sludge.SOLUTION: A sludge treatment system according to an embodiment has a first biocatalyst culture tank, a first decomposition tank, a second biocatalyst culture tank, a second decomposition tank, and a digestion tank. The first biocatalyst culture tank cultures a first biocatalyst. The first decomposition tank decomposes the viscous material contained in a biological sludge by the first biocatalyst. The second biocatalyst culture tank cultures a second biocatalyst. The second decomposition tank decomposes microorganisms in the biological sludge by the second biocatalyst. The digestion tank anaerobic-digestion treats the biological sludge treated in the second decomposition tank, and converts to a biogas. The first biocatalyst is a catalyst for decomposing the constituent of a viscous material contained in a biological sludge, exhibited on the cell surface of a host organism. The second biocatalyst is a catalyst for decomposing the constituent of a microorganism in a biological sludge, exhibited on the cell surface of a host organism.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to a sludge treatment system.

  In the water treatment system, biological sludge containing microorganisms may be treated. However, with the conventional technology, there is room for study on improving the treatment efficiency of biological sludge.

JP 2005-169329 A JP 2001-327998 A JP 2008-264650 A JP 2004-8892 A

  The problem to be solved by the present invention is to provide a sludge treatment system capable of treating biological sludge with high efficiency.

  The sludge treatment system of the embodiment has a first biocatalyst culture tank, a first decomposition tank, a second biocatalyst culture tank, a second decomposition tank, and a digestion tank. The first biocatalyst culture tank cultures the first biocatalyst. A 1st decomposition tank decomposes | disassembles the structural component of the viscous substance contained in biological sludge with a said 1st biocatalyst. The second biocatalyst culture tank cultures the second biocatalyst. A 2nd decomposition tank is arrange | positioned in the back | latter stage of the said 1st decomposition tank, and decomposes | disassembles the component of the microorganisms in the biological sludge processed in the said 1st decomposition tank with a said 2nd biocatalyst. A digestion tank is arrange | positioned in the back | latter stage of the said 2nd decomposition tank, performs the anaerobic digestion process of the biological sludge processed in the said 2nd decomposition tank, and converts it into biogas. The first biocatalyst presents a catalyst that decomposes components of viscous substances contained in biological sludge on the cell surface of the host organism. The second biocatalyst presents a catalyst that decomposes the constituent components of microorganisms in the biological sludge on the cell surface of the host organism.

The figure which shows the structural example of the sludge treatment system in 1st Embodiment. The figure which shows the structural example of the sludge processing system in 2nd Embodiment. The figure which shows the structural example of the sludge processing system in 3rd Embodiment. The figure which shows the structural example of the sludge processing system in 4th Embodiment. The schematic diagram which shows an example of the structure of the floc contained in excess sludge. Explanatory drawing of the biocatalyst used suitably for embodiment.

  Hereinafter, the sludge treatment system of an embodiment is explained with reference to drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of a sludge treatment system 1 in the first embodiment. In the first embodiment, the sludge treatment system is referred to as “sludge treatment system 1a”. The sludge treatment system 1a is not limited to a specific facility as long as it is a facility that decomposes biological sludge containing microorganisms. The sludge treatment system 1a is, for example, a sewage treatment plant or a food factory. In the first embodiment, the sludge treatment system 1a is a sewage treatment plant as an example.

  In the first embodiment, decomposing biological sludge is to lower the molecular weight of at least part of the components of biological sludge.

  The sludge treatment system 1a includes a substrate tank 70, a first biocatalyst culture tank 10a, a viscous substance decomposition tank 10b (first decomposition tank), a second biocatalyst culture tank 20a, and a cell wall decomposition tank 20b ( A second decomposition tank), a third biocatalyst culture tank 30a, a cell membrane / cytoplasmic decomposition tank 30b (third decomposition tank), and a digestion tank 50. Each said tank may be connected with the pipe | tube.

The first biocatalyst culture tank 10a is a tank that performs culture production of the first biocatalyst. A 1st biocatalyst presents the catalyst which decomposes | disassembles the component of the viscous substance contained in biological sludge on the cell surface of a host organism, and the organism itself which produces this catalyst is mentioned.
Examples of the catalyst produced by a living body include proteins such as enzymes, and hydrolase, oxidoreductase, transferase, eliminase, isomerase, and synthase are preferable, and hydrolase is more preferable.

  In 1st Embodiment, a viscous substance is a viscous substance which comprises the floc contained in biological sludge, and what was secreted by the microorganisms contained in biological sludge is mentioned.

The first biocatalyst culture tank 10a includes means for suitably growing host cells. Examples of such means include temperature control means, pH control means, substrate concentration control means such as a turbidimeter, pressure control means, stirring means and the like.
As an example, when using yeast as a host cell, the 1st biocatalyst culture tank 10a is controlled so that the environment in a tank will be 20-30 degreeC and pH 4-7.

The substrate tank 70 stores a medium to be supplied to the first biocatalyst culture tank 10a, the second biocatalyst culture tank 20a, and the third biocatalyst culture tank 30a. The medium is not particularly limited as long as it can cultivate microorganisms and the like in the first biocatalyst culture tank 10a, the second biocatalyst culture tank 20a, and the third biocatalyst culture tank 30a. Those containing a nitrogen source, inorganic salts and the like are preferred. A medium is introduced into each biocatalyst culture tank by the adjusting unit 80. The adjustment unit 80 is, for example, a pump or a valve.
Examples of the carbon source include saccharides such as glucose, fructose, and sucrose; and carbohydrates such as starch or starch hydrolyzate.
Nitrogen sources include ammonia, ammonium salts of inorganic or organic acids such as ammonium chloride, ammonium sulfate, and ammonium acetate, peptone, meat extract, yeast extract, corn steep liquor, casein hydrolyzate, soybean meal, soybean meal hydrolyzate And various fermented bacterial cell digests.
Examples of inorganic salts include magnesium phosphate, magnesium sulfate, sodium chloride, monopotassium phosphate, dipotassium phosphate, ferrous sulfate, manganese sulfate, copper sulfate, calcium carbonate and the like.

  In the embodiment, the substrate tank 70 for supplying the culture medium to the biocatalyst culture tank is common to each biocatalyst culture tank, but the biocatalyst culture tank is introduced so that the substrate is introduced to each biocatalyst culture tank. Each substrate tank may be provided.

The viscous substance decomposition tank 10b is a tank that decomposes the constituents of the viscous substance contained in the excess sludge F with the first biocatalyst. Surplus sludge F (biological sludge) is introduced into the viscous substance decomposition tank 10b by the adjusting unit 10d. In addition, the first biocatalyst is introduced into the viscous substance decomposition tank 10b by the adjusting unit 10c and merges with the excess sludge F. The adjusting units 10d and 10c are pumps or valves as an example.
By reducing the molecular components of the viscous material contained in the excess sludge F by the first biocatalyst, the treatment in each subsequent decomposition tank and the anaerobic digestion treatment of the biological sludge in the digestion tank 50 can be performed. It becomes possible to carry out efficiently.

  In the embodiment, the biological sludge is surplus sludge F. The excess sludge F introduced into the viscous material decomposition tank 10b contains organic substances and microorganisms. Organic sludge, especially biological sludge such as surplus sludge, is mainly composed of microbial aggregates (floc). FIG. 5 is a diagram schematically showing the structure of floc contained in the excess sludge F. As shown in FIG. 5, the microorganism floc in the sludge is surrounded by a viscous substance secreted by the microorganism itself. These viscous substances protect microorganisms so that they surround them. For example, Zoulea bacteria secrete a viscous substance and have the habit of trapping themselves or other microorganisms in the viscous substance.

In order to convert biological sludge into biogas more efficiently, it is preferable to lower the molecular weight of the sludge so that it becomes a substrate for anaerobic digestion in the digestion tank 50. Even in the digestion tank 50, some components of sludge can be reduced in molecular weight by the action of anaerobic microorganisms such as acid-producing bacteria, but the decomposition reaction by anaerobic microorganisms basically requires time. Therefore, it is effective to reduce the molecular weight of the organic component contained in the microorganism in advance using a biocatalyst when reducing the molecular weight of the sludge. It is expected that the digestion reaction in the digester proceeds more smoothly by reducing the molecular weight of the component at a high reaction rate using a biocatalyst.
However, the blocking of the floc by the viscous substance makes it difficult for the catalyst to access the microorganism. In addition, the chemical resistance of viscous materials is very strong. As a method for decomposing a viscous substance, a physical method (for example, ultrasonic treatment, ozone treatment, heat treatment) is effective, but enormous energy is applied.
In the embodiment, the viscous material is decomposed by the catalyst capable of decomposing the constituent components of the viscous material, so that the viscous material can be efficiently decomposed in a low energy and mild state, and the access to the microorganism of the catalyst becomes easy. .

  Viscous substances are mainly composed of polysaccharides, proteins, and nucleic acids. Since it is as above-mentioned, as a catalyst which can decompose | disassemble a viscous substance, an enzyme is mentioned and it will not specifically limit if a viscous substance can be decomposed | disassembled. Examples of enzymes capable of decomposing viscous substances include the following. Examples of polysaccharides include polysaccharide-degrading enzymes, and enzymes that hydrolyze β-1,4-glucan bonds. Examples of polysaccharide-degrading enzymes include cellulase group, hemicellulase group, xylase group, mannositase and the like. As for proteins, proteases can be mentioned, and a group of proteases that hydrolyze peptide bonds can be mentioned. Examples of nucleic acids include nucleolytic enzymes and nuclease groups that hydrolyze phosphodiester bonds between ribonucleic acid sugars and phosphates.

For example, by mixing the first biocatalyst containing the host organism on which the protease and cellulase are presented on the cell surface with the excess sludge F, the viscous material contained in the excess sludge F is decomposed by these biocatalysts. Is done.
The first biocatalyst may include only one type of catalyst or may include a plurality of types of catalysts. When the first biocatalyst includes a plurality of types of catalysts, a plurality of types of host organisms that express one type of catalyst may be included, or one type or a plurality of types of host organisms that express a plurality of types of catalysts may be included. You may go out.

The operating temperature of the viscous substance decomposition tank 10b can be appropriately set according to the host organism and the type of biocatalyst presented on the surface thereof, and is about 20 ° C to 55 ° C as an example. Considering the temperature, 37 ° C. is more preferable. Moreover, it is preferable from the viewpoint of uniform temperature distribution of the organic sludge that stirring is appropriately performed by a provided stirring device.
The pH of the treatment liquid in the viscous substance decomposition tank 10b can be appropriately set according to the host organism and the type of biocatalyst presented on the cell surface.

  The second biocatalyst culture tank 20a is a tank that performs culture production of the second biocatalyst. The 2nd biocatalyst presents the catalyst which decomposes | disassembles the structural component of the cell wall of the microorganisms contained in biological sludge on the cell surface of a host organism, and the organism itself which produces this catalyst is mentioned. Examples of the catalyst produced by a living body include proteins such as enzymes, and hydrolase, oxidoreductase, transferase, eliminase, isomerase, and synthase are preferable, and hydrolase is more preferable.

The second biocatalyst culture tank 20a includes means for suitably growing host cells. Examples of such means include temperature control means, pH control means, substrate concentration control means such as a turbidimeter, pressure control means, stirring means and the like.
As an example, when using yeast as a host cell, the 2nd biocatalyst culture tank 20a is controlled so that the environment in a tank will be 20-30 degreeC and pH 4-7.

  The biological sludge treated in the viscous material decomposition tank 10b is introduced into the cell wall decomposition tank 20b. The biological sludge treated in the viscous substance decomposition tank 10b is referred to as biological sludge in the sense that it is derived from surplus sludge F that is biological sludge.

The cell wall decomposition tank 20b is a tank that decomposes the constituent components of the cell walls of microorganisms contained in the biological sludge treated in the viscous substance decomposition tank 10b with the second biocatalyst. A second biocatalyst is introduced into the cell wall decomposition tank 20b by the adjusting unit 20c and merges with the biological sludge treated in the viscous substance decomposition tank 10b. The adjustment unit 20c is, for example, a pump or a valve.
By using the second biocatalyst to lower the molecular components of the cell walls of microorganisms contained in the biological sludge treated in the viscous substance decomposition tank 10b, the treatment in each subsequent decomposition tank and the biological sludge in the digestion tank 50 are performed. It becomes possible to perform the anaerobic digestion process of this with high efficiency.

  The degrading enzyme capable of degrading the component of the cell wall of the microorganism is not particularly limited as long as it can decompose the component of the cell wall. Examples of the degrading enzyme capable of degrading the components of the cell wall of microorganisms include enzymes capable of hydrolyzing peptidoglycan, which is a substance constituting the cell wall. An example is a group of lysozyme enzymes that specifically hydrolyze peptidoglycan bonds that make up the strong structure of the cell wall. The second biocatalyst preferably does not contain a host organism in which a protease is presented on the cell surface.

For example, by mixing the second biocatalyst containing the host organism on which the lysozyme is presented on the cell surface with the biological sludge treated in the viscous material decomposition tank 10b, the microorganisms in the biological sludge can be converted to these biocatalysts. Is decomposed by.
The second biocatalyst may include only one type of catalyst or may include a plurality of types of catalysts. When the second biocatalyst includes a plurality of types of catalysts, a plurality of types of host organisms that express one type of catalyst may be included, or one type or a plurality of types of host organisms that express a plurality of types of catalysts may be included. You may go out.

The operating temperature of the cell wall decomposing tank 20b can be appropriately set according to the host organism and the type of biocatalyst presented on the surface thereof, and is about 20 ° C. to 55 ° C. as an example. In view of the above, 37 ° C. is more preferable. Moreover, it is preferable from the viewpoint of uniform temperature distribution of the organic sludge that stirring is appropriately performed by a provided stirring device.
The pH of the treatment liquid in the cell wall decomposition tank 20b can be appropriately set according to the host organism and the type of biocatalyst presented on the surface thereof.

  The third biocatalyst culture tank 30a is a tank that performs culture production of the third biocatalyst. The third biocatalyst presents a catalyst for decomposing microbial cell membranes and / or cytoplasmic components contained in the biological sludge on the cell surface of the host organism, and examples include the organism itself that produces the catalyst. Examples of the catalyst produced by a living body include proteins such as enzymes, and hydrolase, oxidoreductase, transferase, eliminase, isomerase, and synthase are preferable, and hydrolase is more preferable.

The third biocatalyst culture tank 30a includes means for suitably growing host cells. Examples of such means include temperature control means, pH control means, substrate concentration control means such as a turbidimeter, pressure control means, stirring means and the like.
As an example, when using yeast as a host cell, the 3rd biocatalyst culture tank 30a is controlled so that the environment in a tank will be 20-30 degreeC and pH 4-7.

  The biological sludge treated in the cell wall decomposition tank 20b is introduced into the cell membrane / cytoplasmic decomposition tank 30b. The biological sludge treated in the cell wall decomposition tank 20b is referred to as biological sludge in the sense that it is derived from surplus sludge F that is biological sludge.

The cell membrane / cytoplasm decomposition tank 30b is a tank for decomposing the cell membrane and / or cytoplasmic components of microorganisms contained in the biological sludge treated in the cell wall decomposition tank 20b with the third biocatalyst. A third biocatalyst is introduced into the cell membrane / cytoplasmic decomposition tank 30b by the adjusting unit 30c and merges with the biological sludge treated in the cell wall decomposition tank 20b. The adjustment unit 30c is, for example, a pump or a valve.
Anaerobic digestion of biological sludge in the subsequent digestion tank 50 by reducing the molecular components of the microbial cell membrane and / or cytoplasm contained in the biological sludge treated in the cell wall decomposition tank 20b by the third biocatalyst. The processing can be performed with high efficiency.

  Note that the cell membrane is not as strong as a viscous substance or cell wall, and can be reduced in molecular weight by a biocatalyst relatively easily. Therefore, it is possible to advance the molecular weight reduction of the cytoplasm while efficiently destroying the cell membrane of the microorganism.

The degrading enzyme capable of degrading the components of the microbial cell membrane is not particularly limited as long as it can decompose the components of the microbial cell membrane. Examples of the degrading enzyme capable of degrading the constituents of the microbial cell membrane include enzymes capable of hydrolyzing lipids, which are substances constituting the microbial cell membrane, and enzymes capable of degrading cell membrane membrane proteins. Regarding lipids, lipolytic enzymes can be mentioned. Examples of lipolytic enzymes include lipase enzymes that can hydrolyze lipids. Examples of cell membrane proteins include proteases, and examples of proteases that hydrolyze peptide bonds.
The degrading enzyme capable of degrading the microbial cytoplasmic component is not particularly limited as long as it can decompose the microbial cytoplasmic component. Examples of a degrading enzyme capable of degrading a cytoplasmic component of a microorganism include enzymes capable of hydrolyzing starch, proteins, lipids and the like, which are substances contained in the cytoplasm. As for starch, a group of amylase enzymes capable of hydrolyzing starch can be mentioned. As for proteins, proteases can be mentioned, and a group of proteases that hydrolyze peptide bonds can be mentioned. Regarding lipids, lipolytic enzymes can be mentioned. Examples of lipolytic enzymes include lipase enzymes that can hydrolyze lipids.

For example, by mixing a third biocatalyst containing a host organism in which amylase, protease, and lipase are presented on the cell surface and biological sludge treated in the cell wall decomposition tank 20b, the cell membrane of microorganisms in the biological sludge and The cytoplasm is degraded by these biocatalysts.
The third biocatalyst may include only one type of catalyst or may include a plurality of types of catalysts. When the third biocatalyst includes a plurality of types of catalysts, a plurality of types of host organisms that express one type of catalyst may be included, or one type or a plurality of types of host organisms that express a plurality of types of catalysts may be included. You may go out.

The operating temperature of the cell membrane / cytoplasmic decomposition tank 30b can be appropriately set according to the host organism and the type of biocatalyst presented on the surface thereof, and is about 20 ° C. to 55 ° C. as an example. In consideration of an appropriate temperature, 37 ° C. is more preferable. Moreover, it is preferable from the viewpoint of uniform temperature distribution of the organic sludge that stirring is appropriately performed by a provided stirring device.
The pH of the treatment liquid in the cell membrane / cytoplasmic decomposition tank 30b can be appropriately set according to the host organism and the type of biocatalyst presented on the surface thereof.

Hereinafter, the biocatalyst will be described.
Living organisms synthesize enzymes based on their own genetic information (DNA). Therefore, by artificially introducing a gene encoding information on sludge degrading enzyme into a specific organism (genetical recombination), it is possible to cause the microorganism to produce the target enzyme.

The organism itself that produces the biocatalyst includes a microorganism, and the host organism according to the embodiment is preferably a microorganism. As microorganisms, gram-negative bacteria of the genus Pseudomonas such as Pseudomonas alcaligenes, P. putida, and P. dacunhae; Gram-negative bacteria of the genus Gluconobacter such as Gluconobacter melanogenes; and gram-negative bacteria of the genus Alcaligenes A such as Alcaligenes eutrophus Examples include acetic acid bacteria such as suboxydans; coliform bacteria such as Escherichia coli, E. freundii, and Enterobacter aerogenes; and other gram-negative bacteria such as Erwinia carotovora, Serratia marcescens, Protaminobacter rubrum, and Proteus mirabilis.
Also, lactic acid bacteria such as Streptococcus faecalis, Leuconostoc mensenteroides, and Lactobacillus delbruckii; Gram-positive bacteria of the genus Bacillus such as Bacillus subtilis and B. megaterium; Other Gram-positive bacteria such as Corynebacterium glutamicum, Brevibacterium ammoniagenes, B. flavum, Propionibacterium sp.
Furthermore, Nocardia rhodocrous, Streptomyces phaeochromogenes, S. rimosus, S. roseochromogenes, S. tendae, S. rimosus and other actinomycetes, Saccharomyces sp., Hansenula jadinii, Candida tropicalis, Rhodotorula minuta, etc. And filamentous fungi such as Curvularia lunata, Aspergillusochraceus, A. niger, and Penicillium chrysogenum.
Of the microorganisms described above, two or more different microorganisms may be used as a host as a biocatalyst. Typical host microorganisms include yeast, E. coli and the like.

  Biocatalysts include aminoacylase, α-amylase, glucoamylase, cellulase, invertase, carboxypeptidase, leucine aminopeptidase, penicillin amidase, AMP deaminase, protease, lysozyme, papain, chitinase, cholesterol ester hydrolase, alkaline phosphatase, β-glucosidase , Β-D-galactosidase, asparaginase, glutaminase, urease, penicillinase, creatininase, creatinase, creatine deiminase, pectinase, catalase, lipase, hemicellulase, xylase, mannosease, aminopeptidase, chymotrypsin, urokinase, urease, aurease Glucose phosphatase, ribonuclease, Seed restriction enzyme (endodeoxyribonuclease), phospholipase, saccharase and the like, amylase, cellulase, protease, lysozyme are preferred.

FIG. 6 is an explanatory diagram of a biocatalyst suitably used in the embodiment. As shown in FIG. 6, by adding a command sequence to be displayed on the cell surface of the host organism to the enzyme gene, the synthesized enzyme can be presented (armed) on the cell surface.
As an example of a method for presenting the enzyme to the host cell, a method of introducing a gene encoding the enzyme and a cell surface display protein into a specific microorganism by genetic manipulation can be mentioned. Enzymes are synthesized from the cells of microorganisms by gene expression and then presented on the cell surface. More specifically, the following sequence, secretion signal, target enzyme, agglutinin protein, and a sequence containing a gene encoding the anchor attachment signal may be introduced into a host microorganism (yeast). Agglutinin protein serves as an anchor for fixing the enzyme. An anchor attachment signal includes glycosyl phosphatidylinositol (GPI). By introducing a sequence having the above characteristics into yeast, the target enzyme can be armed into the host microorganism. Microorganisms on which enzymes are presented serve as biocatalysts and act to lower the molecular weight of substances contained in biological sludge.

Using the above technique, a specific microorganism, such as commonly used yeast, Escherichia coli, etc. is used to produce a biocatalyst having the ability to lower the molecular weight by the above method and used for sludge lowering treatment. It is possible.
In addition, when microorganisms that produce valuable materials such as yeast are used as biocatalysts, these microorganisms themselves can also use low molecular weight sludge as feed, for example, in the sludge by the action of cellulase presented on the surface of the yeast. The cellulose is decomposed into low molecular sugars, and it is possible to produce valuable materials such as yeast using this low molecular sugar, performing alcoholic fermentation, and producing bioethanol. One or more enzymes may be expressed in the host cell. From the viewpoint of expression efficiency, it is preferable to express one type of protein, and it is more preferable to express one type of different protein in each of a plurality of host cells.
By presenting an enzyme suitable for the degradation of a hardly degradable target on the surface layer of the biocatalyst, the sludge depolymerization efficiency of the biocatalyst can be improved.

  The biological sludge treated in the cell membrane / cytoplasm decomposition tank 30b is introduced into the digestion tank 50. The biological sludge treated in the cell membrane / cytoplasm decomposition tank 30b is referred to as biological sludge in the sense that it is derived from surplus sludge F that is biological sludge.

The digestion tank 50 is a tank that is disposed at the subsequent stage of the cell membrane / cytoplasmic decomposition tank 30b, and anaerobically digests the biological sludge treated in the cell membrane / cytoplasmic decomposition tank 30b to convert it into biogas.
Various anaerobic microorganisms (hydrolyzing bacteria, acid-producing bacteria, methane-producing bacteria, etc.) mainly composed of methanogens are fixed in the digestion tank 50. The digester 50 preferably includes a stirring device such as one provided with a rotary stirring blade. The digested sludge digested in the digestion tank 50 is sent to the dehydrator 90 by the adjusting unit 60. The adjustment unit 60 is, for example, a pump or a valve.

  In the digestion tank 50, high-molecular organic substances such as carbohydrates, proteins, and lipids in the organic sludge may be decomposed into low-molecular organic substances by the hydrolyzing bacteria that have been established. Next, the low-molecular-weight organic substance may be decomposed into lower fatty acids such as acetic acid and propionic acid by the acid-producing bacteria fixed in the digestion tank 50. Eventually, it is decomposed from lower fatty acids such as acetic acid into methane and carbon dioxide by the methanogenic bacteria that have settled in the digestion tank 50.

The operating temperature of the digester 50 is preferably set depending on the activation temperature of the methanogen, preferably 37 ° C. to 55 ° C. which is the activation temperature of mesophilic and high temperature bacteria, and the optimum temperature of the biocatalyst In view of the above, 37 ° C. is more preferable. Moreover, it is preferable from the viewpoint of uniform temperature distribution of the organic sludge that stirring is appropriately performed by a provided stirring device.
The pH of the treatment liquid in the digestion tank 50 is preferably in the range of 8.5 to 9.5 which is the optimum pH for anaerobic digestion, and adjusted to 8.5 to 9.0 using slaked lime at the start of anaerobic digestion. It is more preferable.

  The dehydrator 90 is not particularly limited as long as it includes means for dehydrating the digested sludge introduced from the digester 50, and examples thereof include a centrifugal dehydrator and a compression dehydrator.

The dewatered sludge is discarded after incineration or drying, or the dehydrated sludge is reused as fertilizer.
The sludge liquid obtained by the dehydration process is returned to the sewage treatment facility as return water.

Before the sludge is released to the environment as fertilizer and before the liquid is returned to the sewage treatment facility, the sludge and sludge are passed through a sterilizer to kill microorganisms in the sludge. It is preferable to make it. About dehydrated digested sludge, it is possible to kill microorganisms by incineration or drying at 120 ° C. or higher.
Examples of the killing method include disinfection with chlorine, ozone, ultraviolet rays, sterilization by heating, sterilization by pH adjustment, and sterilization by pressure control. With such a configuration, the biocatalyst cultured in each biocatalyst culture tank can be prevented from leaking into the environment.
The sterilizer is not particularly limited as long as it has means for killing microorganisms in organic sludge, and examples thereof include those equipped with heating means, pH adjusting means, pressure control means and the like. It may be provided with a sterilization means using saturated steam at high temperature and high pressure like an autoclave.

Among the sterilizers, those equipped with heating means are preferable. In the high-temperature sterilization method using a heating means, microorganisms can be easily killed. For example, commonly used high temperature sterilization conditions are 120 ° C. and 15 minutes.
In order to heat by the high temperature sterilization method, combustion waste heat generated at the time of biogas power generation may be recovered and used for heating.

  According to the sludge treatment system 1a of the first embodiment, the structure of the microorganism aggregate (floc) contained in the excess sludge F is treated in the order of the viscous substance and the cell wall of the microorganism using the biocatalyst, and the floc structure is obtained. It is possible to break down sequentially from the outside to the inside. Thereby, the low molecularization of the excess sludge F is made efficient, the digestion efficiency and digestion speed in the digestion tank 50 are improved, and the gas conversion efficiency of organic matter in the sludge can be improved.

  According to the sludge treatment system 1a of the first embodiment, considering the floc structure, having a plurality of decomposition tanks and a plurality of biocatalyst culture tanks, the viscous substances contained in the excess sludge F, and the excess sludge F Can be treated in different decomposition tanks. With such a configuration, when the viscous substance is decomposed, the possibility that the catalyst suitable for the decomposition of microorganisms is decomposed or deteriorated is reduced, and the sludge treatment efficiency can be improved. In addition, with such a configuration, it is possible to set optimum treatment conditions for each decomposition tank, and it is possible to improve sludge treatment efficiency.

  According to the sludge treatment system 1a of the first embodiment, as described above, it is possible to reduce the amount of digested sludge discharged from the digestion tank 50 and dewatering due to the efficiency of reducing the molecular weight of the excess sludge F. The improvement of the property is achieved, and the treatment cost of digested sludge can be reduced.

  According to the sludge treatment system 1a of the first embodiment, as described above, the digestion rate in the digestion tank 50 is improved, so that the digestion tank 50 can be made compact.

  According to the sludge treatment system 1a of the first embodiment, as described above, the digestion speed in the digestion tank 50 is improved, so that the digestion time in the digestion tank 50 can be shortened.

  According to the sludge treatment system 1a of the first embodiment, the digestion tank 50 can be made compact as described above, so that the heating cost and the stirring cost of the digestion tank 50 can be reduced.

  According to the sludge treatment system 1a of the first embodiment, since the biocatalyst is used for lowering the surplus sludge F, once the biocatalyst can be designed, the biocatalyst can be logarithmized only by giving organic matter as bait. The cost of using the catalyst can be reduced.

  According to the sludge treatment system 1a of the first embodiment, the biocatalyst that presents the catalyst on the cell surface of the host organism is used, and the enzyme remains in the tank even if the host organism that is the biocatalyst dies. Since it remains, it can be used continuously as a sludge treatment agent.

  According to the sludge treatment system 1a of the first embodiment, since large-scale machines and devices used in physical and chemical treatments (ultrasonic treatment, ozone treatment, heat treatment, etc.) are unnecessary, the initial cost and running cost can be reduced. Can be reduced.

(Second Embodiment)
In the second embodiment, the sludge treatment system 1 includes a cell membrane decomposition tank 31b (third decomposition tank) and a cytoplasmic decomposition tank 40b (fourth decomposition tank) in the subsequent stage of the cell wall decomposition tank 20b. And the point provided with the 4th biocatalyst culture tank 40a (4th biocatalyst culture tank) differs from 1st Embodiment. In the second embodiment, only differences from the first embodiment will be described.

  FIG. 2 is a diagram illustrating a configuration example of the sludge treatment system 1 in the second embodiment. In the second embodiment, the sludge treatment system is referred to as “sludge treatment system 1b”. The sludge treatment system 1b is not limited to a specific facility as long as it is a facility that decomposes biological sludge containing microorganisms. The sludge treatment system 1b is, for example, a sewage treatment plant or a food factory. In the first embodiment, the sludge treatment system 1b is a sewage treatment plant as an example.

  The third biocatalyst culture tank 31a is a tank that performs culture production of the third biocatalyst. The 3rd biocatalyst presents the catalyst which decomposes | disassembles the component of the cell membrane of the microorganisms contained in biological sludge on the cell surface of a host organism, and the organism itself which produces this catalyst is mentioned. Examples of the catalyst produced by a living body include proteins such as enzymes, and hydrolase, oxidoreductase, transferase, eliminase, isomerase, and synthase are preferable, and hydrolase is more preferable.

  The biological sludge treated in the cell wall decomposition tank 20b is introduced into the cell membrane decomposition tank 31b.

The cell membrane decomposition tank 31b is a tank for decomposing components of the cell membrane of microorganisms contained in the biological sludge treated in the cell wall decomposition tank 20b with the third biocatalyst. A third biocatalyst is introduced into the cell membrane decomposition tank 31b by the adjusting unit 31c, and merges with the biological sludge treated in the cell wall decomposition tank 20b. The adjustment part 31c is a pump or a valve as an example.
By using the third biocatalyst to lower the molecular components of the cell membrane of microorganisms, the treatment in the subsequent cytosolic decomposition tank 40b and the anaerobic digestion treatment of biological sludge in the digestion tank 50 can be performed with high efficiency. It becomes possible.
By destroying the cell membrane of the microorganism and eluting the cytoplasm in the cell, cytoplasmic components that are easily used as a substrate for methane fermentation are eluted, and the efficiency of decomposition of the cytoplasmic components can be improved.

  Examples of the degrading enzyme capable of degrading the constituent components of the cell membrane of the microorganism include the same as those described in the first embodiment.

  The fourth biocatalyst culture tank 40a is a tank that performs culture production of the fourth biocatalyst. The 4th biocatalyst presents the catalyst which decomposes | disassembles the cytoplasmic component of the microorganisms contained in biological sludge on the cell surface of a host organism, and the organism itself which produces this catalyst is mentioned. Examples of the catalyst produced by a living body include proteins such as enzymes, and hydrolase, oxidoreductase, transferase, eliminase, isomerase, and synthase are preferable, and hydrolase is more preferable.

  The biological sludge treated in the cell membrane decomposition tank 31b is introduced into the cytoplasmic decomposition tank 40b.

The cytoplasmic decomposition tank 40b is a tank that decomposes the cytoplasmic components of the microorganisms contained in the biological sludge treated in the cell membrane decomposition tank 31b with the fourth biocatalyst. The fourth biocatalyst is introduced into the cytosolic decomposition tank 40b by the adjusting unit 40c, and merges with the biological sludge treated in the cell membrane decomposition tank 31b. The adjustment part 31c is a pump or a valve as an example.
By using a fourth biocatalyst to lower the molecular components of the cytoplasm of the microorganism, anaerobic digestion treatment of biological sludge in the subsequent digestion tank 50 can be performed with high efficiency.
The cytoplasm contains substance granules stored as an energy source of microorganisms, for example, polysaccharides such as starch, and lipids. Since these substances also serve as substrates for methane fermentation, they greatly contribute to the amount of methane gas generated. By using a biocatalyst to reduce the molecular weight in advance at a high reaction rate, the digestion reaction in the subsequent digestion tank 50 can proceed more smoothly.

  Examples of the degrading enzyme capable of degrading the components of the cytoplasm of the microorganism include those described in the first embodiment.

  As described above, in the sludge treatment system 1b of the second embodiment, the structure of the microbial aggregate (floc) contained in the excess sludge F is obtained by using a biocatalyst, a viscous substance, a microbial cell wall, a microbial cell membrane, and a microbial It is possible to break down the floc structure in order from the outside to the inside by processing in the order of the cytoplasm. Thereby, the molecular reduction of the excess sludge F is further improved, the digestion efficiency and digestion speed in the digestion tank 50 are improved, and the gas conversion efficiency of organic matter in the sludge can be improved. Moreover, the digestion time in the digestion tank 50 can also be shortened.

(Third embodiment)
In 3rd Embodiment, the sludge processing system 1 is further provided with the enzyme deactivation apparatus 100 which deactivates the enzyme contained in a biocatalyst between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b. This is different from the first embodiment. In the third embodiment, the biocatalyst is a first biocatalyst. In the third embodiment, only differences from the first embodiment will be described.

  FIG. 3 is a diagram illustrating a configuration example of the sludge treatment system 1 in the third embodiment. In the third embodiment, the sludge treatment system is referred to as “sludge treatment system 1c”. The sludge treatment system 1c is not limited to a specific facility as long as it is a facility for decomposing biological sludge containing microorganisms. The sludge treatment system 1c is, for example, a sewage treatment plant or a food factory. In the third embodiment, the sludge treatment system 1c is a sewage treatment plant as an example.

  The sludge treatment system 1c further includes an enzyme deactivation device 100 that deactivates enzymes contained in the biocatalyst between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b, as compared with the sludge treatment system 1a. In 3rd Embodiment, the enzyme deactivation apparatus 100 deactivates the enzyme contained in a 1st biocatalyst.

The viscous material contained in the excess sludge F usually contains protein. For this reason, from the viewpoint of efficiently reducing the molecular weight of the excess sludge F viscous material, the first biocatalyst preferably contains a host organism in which a protease is presented on the cell surface. In this case, the sludge containing the first biocatalyst treated in the viscous substance decomposition tank 10b is introduced into the cell wall decomposition tank 20b, whereby the protease of the first biocatalyst is introduced into the cell wall decomposition tank 20b. Will be. However, the protease may also digest the second biocatalyst introduced into the cell wall decomposition tank 20b. In order to prevent this, it is effective to arrange the enzyme deactivation device 100 in the subsequent stage of the decomposition tank in which the biocatalyst containing the host organism in which the protease is presented on the cell surface is stored. More specifically, the enzyme contained in the first biocatalyst is disposed by disposing the enzyme deactivation device 100 that deactivates the enzyme contained in the biocatalyst between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b. It is effective to deactivate. With such a configuration, it is possible to prevent a decrease in the activity of the second biocatalyst in the cell wall decomposition tank 20b.
Enzyme deactivation methods in the enzyme deactivation apparatus 100 include enzyme denaturation by heating, enzyme denaturation by pH adjustment, injection of antibodies, deactivation of enzyme activity centers by introduction of chelating agents, and the like. It is not limited to.

  The enzyme deactivation device 100 is not particularly limited as long as it has a means for deactivating the sludge degrading enzyme, and has a heating means, a pH adjusting means, a neutralizing antibody charging means, and a chelating agent charging means. Can be mentioned.

In the third embodiment, the enzyme deactivation apparatus 100 is provided between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b. However, the enzyme deactivation apparatus 100 is digested with the cell wall decomposition tank 20b. Between the tank 50, you may be provided. Examples of the space between the cell wall decomposing tank 20b and the digestion tank 50 include between the cell wall decomposing tank 20b and the cell membrane / cytoplasmic decomposing tank 30b, and between the cell membrane / cytoplasmic decomposing tank 30b and the digesting tank 50.
Since sludge treated in each digestion tank contains a large amount of sludge decomposing enzyme, if organic sludge is put into the digestion tank 50 as it is, the activity of anaerobic microorganisms in the digestion tank 50 may be reduced. is there. For this purpose, before the sludge is introduced into the digestion tank 50, it passes through an enzyme deactivation device and deactivates sludge degrading enzymes, particularly enzymes that degrade the cell walls and cell membranes of microorganisms. It is possible to prevent a decrease in the activity of sex microorganisms.
According to said viewpoint, it is preferable that the enzyme deactivation apparatus 100 is arrange | positioned between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b, or between the cell membrane / cytoplasmic decomposition tank 30b and the digestion tank 50. More preferably, the enzyme deactivation apparatus 100 is disposed between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b, and between the cell membrane / cytoplasmic decomposition tank 30b and the digestion tank 50.

Further, the arrangement of the enzyme deactivation device 100 described in the third embodiment can be similarly applied to the second embodiment. For example, in the second embodiment, the enzyme deactivation apparatus 100 may be provided between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b, and between the cell wall decomposition tank 20b and the digestion tank 50, It may be provided. Examples of the space between the cell wall decomposition tank 20b and the digestion tank 50 include, for example, between the cell wall decomposition tank 20b and the cell membrane decomposition tank 31b, between the cell membrane decomposition tank 31b and the cytosolic decomposition tank 40b, and between the cytoplasmic decomposition tank 40b and the digestion tank 50. Between.
The enzyme deactivation device 100 is preferably disposed between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b, or between the cytoplasmic decomposition tank 40b and the digestion tank 50. More preferably, the enzyme deactivation apparatus 100 is disposed between the viscous substance decomposition tank 10b and the cell wall decomposition tank 20b and between the cytoplasmic decomposition tank 40b and the digestion tank 50.

  In the third embodiment, the enzyme deactivation apparatus 100 is provided. However, since the sterilization apparatus can usually achieve enzyme deactivation, the sterilization apparatus can be used instead of the enzyme deactivation apparatus. May be provided. Examples of the sterilization apparatus include apparatuses similar to those described in the first embodiment.

  As described above, in the sludge treatment system 1c of the third embodiment, the activity of the biocatalyst in the subsequent decomposition tank can be prevented by deactivating the enzyme contained in the biocatalyst.

(Fourth embodiment)
In the fourth embodiment, the sludge treatment system 1 is further provided with a sterilizer 110 that kills microorganisms in biological sludge between the cell membrane / cytoplasm decomposition tank 30b and the digestion tank 50. It is different from the embodiment. In the fourth embodiment, the microorganisms in the biological sludge are microorganisms in the first biocatalyst, the second biocatalyst, the third biocatalyst, and the excess sludge F. In the fourth embodiment, only differences from the first embodiment will be described.

  FIG. 4 is a diagram illustrating a configuration example of the sludge treatment system 1 in the fourth embodiment. In the third embodiment, the sludge treatment system is referred to as “sludge treatment system 1d”. The sludge treatment system 1d is not limited to a specific facility as long as it is a facility that decomposes biological sludge containing microorganisms. The sludge treatment system 1d is, for example, a sewage treatment plant or a food factory. In the fourth embodiment, the sludge treatment system 1d is a sewage treatment plant as an example.

  When microorganisms are used as biocatalysts, if organic sludge mixed with biocatalysts is introduced into the digestion tank 50, there is a possibility of consuming methane bacteria that mainly perform methane fermentation, such as organic acids, and generation of biogas. The amount may be reduced.

  In the sludge treatment system 1d of the fourth embodiment, before the sludge treated in each decomposition tank is put into the digestion tank 50, the microorganisms are killed by the sterilizer 110 and converted to useful microorganisms such as methane bacteria in the digestion tank 50. The methane fermentation reaction can be promoted.

  In the conventional sludge treatment system, sludge is solubilized by performing pretreatment by adding ozone, an alkaline agent, and ultrasonic crushing. All of these are physical chemical methods, and a large amount of energy and chemicals may be required. Conventional sludge treatment systems require increased running costs and the introduction of many incidental facilities, and it has been difficult to spread these technologies.

  In each of the above embodiments, the sludge treatment system 1 includes the third biocatalyst culture in addition to the first biocatalyst culture tank, the first decomposition tank, the second biocatalyst culture tank, and the second decomposition tank. Although the tank and the third decomposition tank are provided, the biocatalyst culture tank and the decomposition tank are the first biocatalyst culture tank, the first decomposition tank, the second biocatalyst culture tank, and the second Only the decomposition tank may be used. Here, a 1st decomposition tank is a tank which decomposes | disassembles the structural component of the viscous substance contained in biological sludge with the said 1st biocatalyst. A 2nd decomposition tank is a tank which decomposes | disassembles the component of the microorganisms in the biological sludge processed in the said 1st decomposition tank with a said 2nd biocatalyst.

  According to at least one embodiment described above, the structure of the microbial aggregate (floc) contained in the excess sludge F is processed in the order of viscous substances and microorganisms using a biocatalyst, and the structure of the floc is externally internal. It is possible to break down in order. Thereby, the low molecularization of the excess sludge F is made efficient, the digestion efficiency and digestion speed in the digestion tank 50 are improved, and the gas conversion efficiency of organic matter in the sludge can be improved.

  According to at least one embodiment described above, the viscous substance contained in the excess sludge F and the excess sludge F can be obtained by considering the floc structure and having a plurality of decomposition tanks and a plurality of biocatalyst culture tanks. The contained microorganisms can be treated in different decomposition tanks. With such a configuration, when the viscous substance is decomposed, the possibility that the catalyst suitable for the decomposition of microorganisms is decomposed or deteriorated is reduced, and the sludge treatment efficiency can be improved. In addition, with such a configuration, it is possible to set optimum treatment conditions for each decomposition tank, and it is possible to improve sludge treatment efficiency.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1a ... Sludge treatment system, 1b ... Sludge treatment system, 1c ... Sludge treatment system, 1d ... Sludge treatment system, 10a ... 1st biocatalyst culture tank, 10b ... Viscous substance decomposition tank, 10c ... Adjustment part, 10d ... Adjustment part , 20a ... second biocatalyst culture tank, 20b ... cell wall decomposition tank, 20c ... adjustment section, 30a ... third biocatalyst culture tank, 30b ... cell membrane / cytoplasmic decomposition tank, 30c ... adjustment section, 31a ... third Biocatalyst culture tank, 31b ... cell membrane decomposition tank, 31c ... adjustment part, 40a ... fourth biocatalyst culture tank, 40b ... cytoplasmic decomposition tank, 40c ... adjustment part, 50 ... digestion tank, 60 ... adjustment part, 70 ... substrate Tank, 80 ... adjuster, 90 ... dehydrator, 100 ... enzyme deactivation device, 110 ... sterilizer

Claims (6)

A first biocatalyst culture tank for culturing the first biocatalyst;
A first decomposition tank for decomposing a constituent component of a viscous substance contained in biological sludge with the first biocatalyst;
A second biocatalyst culture tank for culturing the second biocatalyst;
A second decomposition tank that is disposed downstream of the first decomposition tank and decomposes the constituent components of microorganisms in the biological sludge treated in the first decomposition tank by the second biocatalyst;
A digestion tank that is disposed downstream of the second decomposition tank, anaerobically digests the biological sludge treated in the second decomposition tank, and converts it into biogas;
With
The first biocatalyst presents a catalyst for decomposing a constituent of a viscous substance contained in biological sludge on the cell surface of a host organism,
The sludge treatment system, wherein the second biocatalyst presents a catalyst for decomposing constituent components of microorganisms in the biological sludge on the cell surface of the host organism.   The sludge treatment system according to claim 1, wherein the second biocatalyst presents a catalyst for decomposing components of cell walls of microorganisms in the biological sludge on the cell surface of the host organism. A third biocatalyst culture tank for culturing the third biocatalyst;
A third decomposition tank that is disposed downstream of the second decomposition tank and decomposes the constituent components of microorganisms in the biological sludge treated in the second decomposition tank by the third biocatalyst;
With
The sludge treatment system according to claim 1 or 2, wherein the third biocatalyst presents a catalyst for decomposing microbial cell membranes and / or cytoplasmic components in the biological sludge on the cell surface of the host organism. . A fourth biocatalyst culture tank for culturing the fourth biocatalyst;
A fourth decomposition tank that is disposed downstream of the third decomposition tank and decomposes the constituent components of microorganisms in the biological sludge treated in the third decomposition tank by the fourth biocatalyst;
With
The third biocatalyst presents a catalyst for decomposing components of cell membranes of microorganisms in biological sludge on the cell surface of the host organism,
The sludge treatment system according to claim 3, wherein the fourth biocatalyst presents a catalyst for decomposing cytoplasmic components of microorganisms in the biological sludge on the cell surface of the host organism.   Furthermore, the enzyme deactivation apparatus was provided between the said 1st decomposition tank and the said 2nd decomposition tank, and / or between the said 2nd decomposition tank and the said digestion tank. The sludge treatment system according to one item.   Furthermore, a sterilizer for killing microorganisms in biological sludge is provided between the first decomposition tank and the second decomposition tank and / or between the second decomposition tank and the digestion tank. The sludge treatment system as described in any one of 1-4.

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