Composite immobilized microbial preparation for purifying water body and preparation method of composite immobilized microbial preparation

Abstract

The invention relates to the technical field of sewage treatment, in particular to a composite immobilized microbial preparation for purifying water and a preparation method thereof, and the composite immobilized microbial preparation is prepared from the following raw materials in parts by weight: 20-25 parts of a composite treatment agent, 60-80 parts of a microbial agent, 7-8 parts of activated carbon, 2-4 parts of sodium bicarbonate, 1-3 parts of silicon dioxide and 20-30 parts of water. The composite treating agent disclosed by the invention is formed by loading silicate particles on a copolymer formed by a specific condensation polymerization reaction, has good water solubility and reaction activity, can effectively adsorb and chelate harmful substances in a water body, and meanwhile, promotes microbial colonization and degrades organic matters. The clarity and the adsorption capacity of the water body are improved by adding the silicate particles and the activated carbon, the pH value is adjusted by sodium bicarbonate, the stability is enhanced by silicon dioxide, and the whole treating agent is durable.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and particularly to a composite solidified microbial agent for purifying water bodies and a preparation method thereof. Background Art

[0002] Composite solidified microbial agents combine multiple microbial strains with different metabolic functions through biotechnology, and compound and solidify specific functional microorganisms with carriers to form a new type of water treatment material. Traditional water treatment methods, such as physical precipitation, chemical oxidation, and membrane filtration, although they can remove pollutants in water bodies to a certain extent, are often accompanied by problems such as high treatment costs, easy generation of secondary pollution, and limited treatment effects. The composite solidified microbial agent combines various microbial strains such as aerobic bacteria, anaerobic bacteria, and facultative anaerobic bacteria, and makes full use of the different metabolic characteristics of these microorganisms. Under suitable conditions, the microorganisms can act synergistically to efficiently degrade complex pollutants such as organic matter, ammonia nitrogen, and phosphorus in water bodies and convert them into harmless substances, thereby significantly improving water quality. In practical applications, composite solidified microbial agents have shown remarkable results in the water body restoration of various water areas such as wastewater treatment plants, lakes, and rivers. They can not only effectively remove pollutants such as organic matter, nitrogen, and phosphorus, but also reduce the usage amount of chemical agents, thereby reducing secondary pollution to the environment.

[0003] In the prior art, the invention patent with the patent publication number CN103667144A discloses a domestic sewage treatment bactericide, which includes polyacrylamide, polyethyleneimine, silicon dioxide, and composite microorganisms, and can achieve a sewage suspended solid removal rate of 99.8%, a BOD removal rate of 98%, and a COD removal rate of 98.6%. However, in practical applications of the sewage treatment bactericide, when 10g - 100g of polyacrylamide is added per ton of sewage, the phenomenon of increased water viscosity will occur, increasing the flow resistance and possibly blocking the dosing pipeline, affecting the purification of water bodies. In addition, the microbial agent contains multiple microorganisms, and the adaptability of these microorganisms may vary due to changes in environmental conditions. In high-concentration wastewater, some microorganisms may not be able to grow and reproduce effectively, resulting in a decrease in the efficacy of the agent, thereby affecting the overall treatment effect. Although composite solidified microbial agents can degrade pollutants such as organic matter, ammonia nitrogen, and phosphorus in water bodies, their removal effects on certain specific pollutants, such as heavy metals and refractory organic matter, are limited. Summary of the Invention

[0004] In order to solve the problems mentioned in the above background art, the present invention provides a composite solidified microbial agent for purifying water bodies and a preparation method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A composite solidified microbial agent for purifying water body, comprising the following raw materials by weight: 20-25 parts of a composite treatment agent, 60-80 parts of a microbial agent, 7-8 parts of activated carbon, 2-4 parts of sodium bicarbonate, 1-3 parts of silicon dioxide, and 20-30 parts of water.

[0007] Further, the composite treatment agent is prepared through the following steps:

[0008] S1. Under the protection of nitrogen or argon, polyglutamic acid and polyvinyl alcohol-vinylamine are added to deionized water, heated to 50-60 °C, stirred to obtain a transparent solution, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and p-toluenesulfonic acid are added, the temperature is raised to 70-80 °C, and the mixture is kept warm and stirred for reaction for 3-4 h, the stirring speed is 50-100 rpm. After the reaction ends, it is cooled to room temperature and filtered to obtain a copolymer;

[0009] S2. The silicate powder is dispersed in deionized water, ultrasonically treated for 10-20 min, the ultrasonic treatment frequency is 100-200 W, the power is 40-50 kHz, the copolymer and polyethylene glycol are slowly added, stirred at room temperature for 1-2 h, the stirring speed is 50-100 rpm, filtered, washed three times with deionized water, and dried to constant weight to obtain the composite treatment agent.

[0010] Further, the microbial agent includes one or more of Bacillus subtilis, Bacillus licheniformis, Nitrobacter, Lactobacillus, Pseudomonas aeruginosa, and Bacillus pumilus.

[0011] Further, the polyvinyl alcohol-vinylamine in step S1 is prepared through the following steps:

[0012] Under the protection of nitrogen or argon, polyvinyl alcohol and vinylamine are added to methanol, heated in an oil bath to 40-50 °C, benzoyl peroxide is added, kept warm and stirred for reaction for 1-2 h, the stirring speed is 50-100 rpm. After the reaction ends, it is left to stand for precipitation, filtered, washed three times with deionized water, and dried to constant weight to obtain polyvinyl alcohol-vinylamine.

[0013] Further, the mass ratio of polyglutamic acid, polyvinyl alcohol-vinylamine, deionized water, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and p-toluenesulfonic acid in step S1 is (50-55):50:200:(3-5):(0.8-1.5).

[0014] Further, the mass ratio of the silicate powder, deionized water, copolymer, and polyethylene glycol in step S2 is (10-12):50:(3-5):(0.1-0.3).

[0015] Further, in step S2, the silicate includes one or more of magnesium silicate, sodium silicate, sepiolite, montmorillonite, and kaolin.

[0016] Further, the mass ratio of polyvinyl alcohol, vinylamine, methanol, and benzoyl peroxide is (10 - 11):(5 - 5.5):100:(0.1 - 0.2).

[0017] According to another aspect of the present invention, a method for preparing the above-mentioned composite solidified microbial agent is provided, including the following steps:

[0018] Add 1.5 g of glucose, 0.5 g of yeast extract, 7 g of peptone, 1 g of sodium chloride, and 0.45 g of disodium hydrogen phosphate to 100 mL of distilled water to prepare a broth medium. Inoculate the mixed strains into the broth medium, with the inoculation amount of bacteria being 9.0%. Carry out activation culture at 28.5 °C and pH value = 6.5 until colonies are formed or the bacterial liquid becomes turbid to obtain a microbial agent;

[0019] Mix the microbial agent and the composite treatment agent evenly by weight, control the temperature at 30 - 35 °C, add activated carbon, sodium bicarbonate, and silicon dioxide, put them into a mixer, add water, and mix to obtain a composite solidified microbial agent after mixing evenly.

[0020] Advantages of the present invention:

[0021] 1. In the technical solution of the present invention, the composite treatment agent is composed of a copolymer formed by the polycondensation reaction of polyglutamic acid (PGA) and polyvinyl alcohol - vinylamine (PVA - VAm), and silicate particles loaded thereon. During the polycondensation process, 1-(3 - dimethylaminopropyl)-3 - ethylcarbodiimide hydrochloride serves as a condensing agent to promote the reaction between the carboxyl group in PGA and the amino group in PVA - VAm, forming a molecular chain with a complex network structure. Polar groups such as amide bonds and hydroxyl groups are distributed on the copolymer molecular chain, endowing the copolymer with good water solubility and reaction activity, and also providing a basis for its interaction with silicate particles. Through ultrasonic treatment, the silicate powder is uniformly dispersed in water to form a stable suspension, and the copolymer molecular chain is adsorbed on the surface of silicate particles through hydrogen bond action or electrostatic attraction to form a preliminary loading structure. Subsequently, polyethylene glycol (PEG) serves as a surfactant or stabilizer to form a stable coating layer, further enhancing the loading effect of the copolymer on the surface of silicate particles. During the stirring process, physical entanglement also occurs between the copolymer molecular chain and silicate particles, forming a firm loading structure, increasing the specific surface area of the composite treatment agent, and making it present a fluffy aggregate structure, which is conducive to full contact with harmful substances in the water body.

[0022] 2. In the technical solution of the present invention, polar groups such as amide bonds and hydroxyl groups on the copolymer molecular chain can have strong interactions with harmful substances such as heavy metal ions and organic pollutants in water. Through adsorption and chelation, the harmful substances are fixed on the molecular chain, effectively preventing their diffusion in the water body. The fluffy structure and enlarged pores of the silicate particles further increase the specific surface area of the composite treatment agent and improve its adsorption and chelation ability.

[0023] 3. In the technical solution of the present invention, the active groups on the copolymer molecular chain provide good attachment sites for microorganisms, promoting the colonization and growth of microbial agents in the water body. The good biocompatibility of PGA ensures the normal growth and metabolic activities of microorganisms and will not have a toxic effect on them. The metabolic action of microorganisms further degrades organic matter, nitrogen, phosphorus and other nutrients in the water, improving the self-purification ability of the water body.

[0024] 4. In the technical solution of the present invention, the silicate particles have a certain filtering effect, which can intercept suspended solids and macromolecular organic matter in the water, improving the clarity of the water body. As a part of the composite treatment agent, activated carbon has a large specific surface area and a rich pore structure, and can adsorb trace organic matter and odor substances in the water. Under appropriate conditions, activated carbon can release the adsorbed substances through desorption, realizing the regeneration and utilization of the adsorbent and reducing the treatment cost. Sodium bicarbonate can adjust the pH value of the water body, maintain the suitable environment required for the growth of microorganisms, and ensure the normal metabolic activities of microorganisms. As a stabilizer, silicon dioxide enhances the physical and chemical stability of the composite treatment agent, preventing it from agglomerating or decomposing during use and improving the persistence of the treatment agent. Specific embodiments

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work fall within the scope of protection of the present invention.

[0026] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0027] Preparation Example 1

[0028] Polyvinyl alcohol-vinylamine is prepared by the following steps:

[0029] Under the protection of nitrogen or argon, 100 g of polyvinyl alcohol and 50 g of vinylamine were added to 1000 g of methanol, heated to 40 °C in an oil bath, 1 g of benzoyl peroxide was added, and the mixture was stirred at a constant temperature for 1 h with a stirring speed of 50 rpm. After the reaction, it was allowed to stand for precipitation, filtered, washed three times with deionized water, and dried to a constant weight at 60 °C to obtain polyvinyl alcohol-vinylamine.

[0030] The composite treatment agent was prepared through the following steps:

[0031] S1. Under the protection of nitrogen or argon, 50 g of polyglutamic acid and 50 g of the above-prepared polyvinyl alcohol-vinylamine were added to 200 g of deionized water, heated to 50 °C, stirred to obtain a transparent solution, 3 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.8 g of p-toluenesulfonic acid were added, the temperature was raised to 70 °C, and the mixture was stirred at a constant temperature for 3 h with a stirring speed of 50 rpm. After the reaction, it was cooled to room temperature and filtered to obtain a copolymer.

[0032] S2. 100 g of magnesium silicate powder was dispersed in 500 g of deionized water, ultrasonicated for 10 min at a frequency of 100 W and a power of 40 kHz. 30 g of the copolymer and 1 g of polyethylene glycol 200 were slowly added, and the mixture was stirred at room temperature for 1 h with a stirring speed of 50 rpm, filtered, washed three times with deionized water, and dried to a constant weight to obtain the composite treatment agent.

[0033] Preparation Example 2

[0034] The polyvinyl alcohol-vinylamine was prepared through the following steps:

[0035] Under the protection of nitrogen or argon, 105 g of polyvinyl alcohol and 52.5 g of vinylamine were added to 1000 g of methanol, heated to 45 °C in an oil bath, 1.5 g of benzoyl peroxide was added, and the mixture was stirred at a constant temperature for 1.5 h with a stirring speed of 60 rpm. After the reaction, it was allowed to stand for precipitation, filtered, washed three times with deionized water, and dried to a constant weight at 60 °C to obtain polyvinyl alcohol-vinylamine.

[0036] The composite treatment agent was prepared through the following steps:

[0037] S1. Under the protection of nitrogen or argon, 52.5 g of polyglutamic acid and 50 g of the above-prepared polyvinyl alcohol-vinylamine were added to 200 g of deionized water, heated to 55 °C, stirred to obtain a transparent solution, 4 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1 g of p-toluenesulfonic acid were added, the temperature was raised to 75 °C, and the mixture was stirred at a constant temperature for 3.5 h with a stirring speed of 60 rpm. After the reaction, it was cooled to room temperature and filtered to obtain a copolymer.

[0038] S2. Disperse 110 g of montmorillonite powder in 500 g of deionized water, perform ultrasonic treatment for 15 min at an ultrasonic frequency of 150 W and a power of 45 kHz. Slowly add 40 g of copolymer and 2 g of polyethylene glycol 200, stir at room temperature for 1.5 h at a stirring speed of 600 rpm, filter, wash three times with deionized water, and dry to constant weight to obtain a composite treatment agent.

[0039] Preparation Example 3

[0040] Polyvinyl alcohol-vinylamine is prepared through the following steps:

[0041] Under the protection of nitrogen or argon, add 110 g of polyvinyl alcohol and 55 g of vinylamine to 1000 g of methanol, heat in an oil bath to 50 °C, add 2 g of benzoyl peroxide, keep warm and stir for reaction for 2 h at a stirring speed of 100 rpm. After the reaction ends, let it stand for precipitation, filter, wash three times with deionized water, and dry to constant weight at 60 °C to obtain polyvinyl alcohol-vinylamine.

[0042] The composite treatment agent is prepared through the following steps:

[0043] S1. Under the protection of nitrogen or argon, add 55 g of polyglutamic acid and 50 g of the above-prepared polyvinyl alcohol-vinylamine to 200 g of deionized water, heat to 60 °C, stir to obtain a transparent solution, add 5 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1.5 g of p-toluenesulfonic acid, raise the temperature to 80 °C, keep warm and stir for reaction for 4 h at a stirring speed of 100 rpm. After the reaction ends, cool to room temperature, filter to obtain a copolymer;

[0044] S2. Disperse 120 g of sepiolite powder in 500 g of deionized water, perform ultrasonic treatment for 20 min at an ultrasonic frequency of 200 W and a power of 50 kHz. Slowly add 50 g of copolymer and 3 g of polyethylene glycol 200, stir at room temperature for 2 h at a stirring speed of 100 rpm, filter, wash three times with deionized water, and dry to constant weight to obtain a composite treatment agent.

[0045] Example 1

[0046] A preparation method of a composite solidified microbial agent includes the following steps:

[0047] Add 1.5 g of glucose, 0.5 g of yeast extract, 7 g of peptone, 1 g of sodium chloride, and 0.45 g of disodium hydrogen phosphate to 1000 mL of distilled water to prepare a broth medium. Inoculate the mixed bacteria (Bacillus subtilis 40%, Bacillus licheniformis 30%, Nitrobacter 20%, and Lactobacillus 10%) into the broth medium with a bacterial inoculation amount of 9.0%, and perform activation culture at 28.5 °C and pH value = 6.5 until colony formation or the bacterial liquid becomes turbid to obtain a microbial agent;

[0048] Mix 60 parts of microbial inoculant and 20 parts of the composite treatment agent prepared in Preparation Example 1 evenly by weight, control the temperature at 30°C, add 7 parts of activated carbon, 2 parts of sodium bicarbonate and 1 part of silicon dioxide, put them into a mixer, add 20 parts of water, and mix. After mixing evenly, a composite solidified microbial preparation is obtained.

[0049] Example 2

[0050] A preparation method of a composite solidified microbial preparation, comprising the following steps:

[0051] Add 1.5 g of glucose, 0.5 g of yeast extract, 7 g of peptone, 1 g of sodium chloride, and 0.45 g of disodium hydrogen phosphate to 1000 mL of distilled water to prepare a broth medium. Inoculate the mixed strains (50% Bacillus subtilis, 40% Bacillus pumilus, and 10% Lactobacillus) into the broth medium, and the inoculation amount of the bacteria is 9.0%. Activate and culture at 28.5°C and pH = 6.5 until colonies form or the bacterial liquid becomes turbid to obtain a microbial inoculant.

[0052] Mix 70 parts of microbial inoculant and 22.5 parts of the composite treatment agent prepared in Preparation Example 2 evenly by weight, control the temperature at 32°C, add 7.5 parts of activated carbon, 3 parts of sodium bicarbonate and 2 parts of silicon dioxide, put them into a mixer, add 25 parts of water, and mix. After mixing evenly, a composite solidified microbial preparation is obtained.

[0053] Example 3

[0054] A preparation method of a composite solidified microbial preparation, comprising the following steps:

[0055] Add 1.5 g of glucose, 0.5 g of yeast extract, 7 g of peptone, 1 g of sodium chloride, and 0.45 g of disodium hydrogen phosphate to 1000 mL of distilled water to prepare a broth medium. Inoculate the mixed strains (40% Bacillus licheniformis, 30% Bacillus subtilis, 20% Nitrobacter, and 10% Pseudomonas aeruginosa) into the broth medium, and the inoculation amount of the bacteria is 9.0%. Activate and culture at 28.5°C and pH = 6.5 until colonies form or the bacterial liquid becomes turbid to obtain a microbial inoculant.

[0056] Mix 80 parts of microbial inoculant and 25 parts of the composite treatment agent prepared in Preparation Example 3 evenly by weight, control the temperature at 35°C, add 8 parts of activated carbon, 4 parts of sodium bicarbonate and 3 parts of silicon dioxide, put them into a mixer, add 30 parts of water, and mix. After mixing evenly, a composite solidified microbial preparation is obtained.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 1 is that polyglutamic acid is used to replace the composite treatment agent prepared in Preparation Example 1, and the remaining steps are the same as those in Example 1.

[0059] Comparative Example 2

[0060] The difference between this comparative example and Example 2 is that polyvinyl alcohol-vinylamine is used to replace the composite treatment agent prepared in Preparation Example 2, and the remaining steps are the same as those in Example 2.

[0061] Comparative Example 3

[0062] The difference between this comparative example and Example 3 is that sepiolite powder is used to replace the composite treatment agent prepared in Preparation Example 3, and the remaining steps are the same as those in Example 3.

[0063] Comparative Example 4

[0064] The difference between this comparative example and Example 1 is that the composite treatment agent prepared in Preparation Example 1 is not added, and the remaining steps are the same as those in Example 1.

[0065] 80 kg of a certain fishery aquaculture wastewater was collected and evenly divided into 8 groups. 6 g of the composite solidified microbial agents prepared in Examples 1-3 and Comparative Examples 1-4 were respectively added. Another control group was set up and an equal amount of distilled water was added. After 7 days, the water quality of each group was detected. Referring to GB 3838-2002 "Surface Water Environment Quality Standard" to test some key indicators, the results of some key indicators are shown in Table 1:

[0066] Table 1. Water quality detection results of Examples 1-3 and Comparative Examples 1-4 (mg / L)

[0067]

[0068] 80 kg of a certain coking wastewater was collected and evenly divided into 8 groups. 6 g of the composite solidified microbial agents prepared in Examples 1-3 and Comparative Examples 1-4 were respectively added. Another control group was set up and an equal amount of distilled water was added. After 7 days, the water quality of each group was detected. Referring to GB16171-2012 "Pollutant Discharge Standard for Coking Chemical Industry" to test some key indicators, the results of some key indicators are shown in Table 2:

[0069] Table 2. Water quality detection results of Examples 1-3 and Comparative Examples 1-4 (mg / L)

[0070]

[0071] As can be seen from Table 1, the values of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) in Examples 1 - 3 are both low, indicating that the microorganisms in the composite solidified microbial preparation can effectively decompose organic matter and reduce the pollution load of water bodies. In contrast, the BOD and COD values of Comparative Examples 1 - 4 are relatively high. The ammonia nitrogen and total phosphorus contents in Examples 1 - 3 are both low, indicating that the microbial preparation can effectively remove nitrogen and phosphorus elements in water bodies and reduce the risk of eutrophication. The ammonia nitrogen and total phosphorus contents in Comparative Examples 1 - 4 are relatively high, indicating that after replacing the composite treatment agent, the nitrification and denitrification effects of microorganisms may be inhibited, resulting in a decrease in the nitrogen and phosphorus removal efficiency. The sulfide content in Examples 1 - 3 is very low, indicating that the microbial preparation can effectively oxidize sulfide and reduce its toxicity. The sulfide content in Comparative Example 3 is abnormally high, which may be due to the accumulation of sulfide caused by sepiolite powder itself or its interaction with microorganisms.

[0072] As can be seen from Table 2, the values of suspended solids, BOD, and COD in Examples 1 - 3 are all low, indicating that the composite solidified microbial preparation can effectively remove suspended solids and organic matter in coking wastewater. In contrast, the values of these indicators in Comparative Examples 1 - 4 are relatively high, proving the promoting effect of the composite treatment agent on microbial activity. The ammonia nitrogen, total phosphorus, and total nitrogen contents in Examples 1 - 3 are all low, indicating that the microbial preparation can effectively remove nitrogen and phosphorus elements in water bodies. In contrast, those in Comparative Examples 1 - 4 are relatively high, indicating a decrease in the nitrogen and phosphorus removal efficiency of microorganisms. The sulfide, petroleum, and volatile phenol contents in Examples 1 - 3 are all low, indicating that the microbial preparation can effectively decompose these toxic and harmful substances. In contrast, those in Comparative Examples 1 - 4 are relatively high, especially sulfide and volatile phenol, indicating a weakened decomposition ability of microorganisms for these substances. The benzene content in Examples 1 - 3 is very low, indicating that the microbial preparation can effectively remove or degrade benzene. In contrast, the benzene content in Comparative Examples 1 - 4 is relatively high, indicating a low benzene removal ability of microorganisms.

[0073] Components such as polyglutamic acid and polyvinyl alcohol - vinylamine copolymer in the composite treatment agent may provide the nutrients or carriers required for microbial growth and enhance the activity of microorganisms. At the same time, components such as magnesium silicate may act as adsorbents to remove some pollutants and provide a better growth environment for microorganisms. Different microorganisms in the mixed strains may work synergistically to decompose organic matter, remove nitrogen and phosphorus elements, oxidize sulfide, etc., thereby improving the water quality improvement effect.

[0074] In summary, the composite solidified microbial preparation prepared in Examples 1 - 3 showed significant water quality improvement effects when treating fishery aquaculture wastewater and coking wastewater.

[0075] In the description of the specification, the descriptions referring to terms such as "preparation example", "embodiment", "each embodiment", etc. mean that the specific features, structures, materials or characteristics described in connection with that embodiment or preparation example are included in at least one embodiment or preparation example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or preparation example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or preparation examples in a suitable manner.

[0076] As mentioned above, the above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A composite solidified microbial preparation for purifying water, characterized in that: The raw materials include the following by weight: 20-25 parts of composite treatment agent, 60-80 parts of microbial agent, 7-8 parts of activated carbon, 2-4 parts of sodium bicarbonate, 1-3 parts of silicon dioxide and 20-30 parts of water.

2. The composite solidification microbial preparation for purifying water according to claim 1, characterized in that: The composite treatment agent is prepared by the following steps: S1. Under nitrogen or argon protection, add polyglutamic acid and polyvinyl alcohol-vinylamine into deionized water, heat to 50-60°C, stir to obtain a transparent solution, add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and p-toluenesulfonic acid, heat to 70-80°C, stir to react for 3-4h, cool to room temperature after the reaction, filter to obtain a copolymer; S2. Disperse silicate powder in deionized water, perform ultrasonic treatment for 10-20 min, slowly add copolymer and polyethylene glycol, stir at room temperature for 1-2 h, filter, wash and dry to obtain a composite treatment agent.

3. The composite solidification microbial preparation for purifying water according to claim 1, characterized in that: The microbial agent includes one or more of Bacillus subtilis, Bacillus licheniformis, nitrifying bacteria, lactobacillus, Pseudomonas aeruginosa and Bacillus pumilus.

4. The composite solidified microbial preparation for purifying water according to claim 2, characterized in that: In step S1, polyvinyl alcohol-vinylamine comprises the following steps to prepare: Under the protection of nitrogen or argon, polyvinyl alcohol and ethyleneamine are added to methanol, heated to 40-50°C in an oil bath, benzoyl peroxide is added, and the mixture is stirred and reacted for 1-2 hours. After the reaction is completed, the mixture is allowed to stand for precipitation, filtered, washed, and dried to obtain polyvinyl alcohol-ethyleneamine.

5. The composite solidification microbial preparation for purifying water according to claim 2, characterized in that: In step S1, the mass ratio of polyglutamic acid, polyvinyl alcohol-vinylamine, deionized water, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and p-toluenesulfonic acid is (50-55):50:200:(3-5):(0.8-1.5).

6. The composite solidified microbial preparation for purifying water according to claim 2, characterized in that: The mass ratio of silicate powder, deionized water, copolymer and polyethylene glycol in step S2 is (10-12):50:(3-5):(0.1-0.3).

7. The composite solidification microbial preparation for purifying water according to claim 2, characterized in that: The silicate in step S2 includes one or more of magnesium silicate, sodium silicate, sepiolite, montmorillonite and kaolin.

8. The composite solidified microbial preparation for purifying water according to claim 4, characterized in that: The mass ratio of polyvinyl alcohol, ethyleneamine, methanol and benzoyl peroxide is (10-11):(5-5.5):100:(0.1-0.2).

9. A method for preparing a composite solidified microbial preparation for purifying water as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: The microbial agent and the composite treatment agent are mixed uniformly according to weight, the temperature is controlled at 30-35° C., activated carbon, sodium bicarbonate and silicon dioxide are added, and the mixture is put into a mixer, water is added, and mixed. After mixing, a composite solidified microbial agent is obtained.

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