Compound microbial agent for removing nitrogen and phosphorus in eutrophicated water body as well as preparation method and application of compound microbial agent

Abstract

The invention discloses a compound microbial agent for removing nitrogen and phosphorus in eutrophic water as well as a preparation method and application of the compound microbial agent, and belongs to the technical field of environmental protection. The microbial agent is prepared by mixing main strains and auxiliary strains, the main strains comprise pseudomonas aeruginosa, bacillus licheniformis, candida rugosa, acinetobacter and rhodopseudomonas, and the auxiliary strains comprise lactobacillus plantarum, photosynthetic bacteria and aspergillus. The compound microbial agent is subjected to immobilization pretreatment by taking zeolite or activated carbon as a carrier and then is added for use, so that the stability and the use effect of the microbial agent are improved. According to the method for removing nitrogen and phosphorus in the eutrophicated water body by using the compound microbial agent and the preparation process of the compound microbial agent, pollutants such as nitrogen and phosphorus in the water body can be efficiently degraded, the eutrophication degree of the water body is remarkably reduced, chemical agents do not need to be added, secondary pollution to the environment cannot be caused, the production cost is low, and the compound microbial agent is simple and convenient to use and operate and easy to popularize.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection, and particularly to a composite microbial agent for removing nitrogen and phosphorus in eutrophic water bodies, and a preparation method and application thereof. Background Art

[0002] In recent years, water eutrophication has become a severe problem in global water environment governance. The main causes involve human activities such as excessive use of agricultural fertilizers, discharge of urban sewage and industrial wastewater, soil erosion, and waste discharge from the aquaculture industry. These activities lead to a large amount of nutrients such as nitrogen and phosphorus entering the water body, providing sufficient nutritional conditions for the growth of algae, which in turn causes rapid algae reproduction, reduces water transparency, consumes dissolved oxygen in the water, and deteriorates water quality. Water eutrophication not only disrupts the balance of the aquatic ecosystem but also seriously affects the utilization value of water resources, posing a threat to human health and social and economic development. Therefore, finding effective methods for nitrogen and phosphorus degradation has become the key to solving the problem of water eutrophication.

[0003] Currently, the methods for degrading nitrogen and phosphorus in water bodies mainly include physical and chemical methods and biological methods. Traditional physical and chemical treatment methods, including precipitation, flocculation, oxidation-reduction, etc., although can remove nitrogen and phosphorus in water bodies to a certain extent, have problems such as high production costs, low use efficiency, and easy generation of secondary pollution. In addition, the improvement effect of these methods on water quality is limited and it is difficult to meet the increasingly strict environmental protection standards and the high requirements of the public for water quality. In contrast, composite microbial agents in biological treatment technology have shown great potential in degrading nitrogen and phosphorus. A composite microbial agent is a mixture composed of multiple microorganisms with the ability to degrade nitrogen and phosphorus. These microorganisms can use nitrogen and phosphorus in the water body as nutrients for growth and reproduction, and convert nitrogen and phosphorus into harmless or low-toxic substances through metabolic actions. This method has low costs, is easy to operate, and will not cause secondary pollution to the environment, and the composite microorganisms can make full use of nutrient salts in the water to achieve efficient removal of nitrogen and phosphorus. In addition, the composite microorganisms have wide applicability to nitrogen and phosphorus pollution in various water environments, and can also promote the growth and reproduction of other beneficial microorganisms in the water body, helping to restore the balance of the aquatic ecosystem. Therefore, using composite microbial agents to degrade nitrogen and phosphorus in water bodies has become an efficient, environmentally friendly, and economical treatment method for solving the problem of water eutrophication, with broad application prospects.

[0004] For example, the patent with the publication number CN119060890A discloses a microbial agent for enhanced biological nitrogen removal, its preparation method and application. This microbial agent includes bacterial communities such as nitrifying bacteria, Bacillus, yeast, fungi, and a nutrient carrier, and is used for the efficient removal of ammonia nitrogen in sewage, which not only improves the sludge sedimentation performance but also shortens the treatment duration. The patent specification with the publication number CN118256394A discloses a nitrosifying agent for ammonia nitrogen treatment in rural black and odorous water bodies, its preparation and usage methods. This agent includes Acinetobacter bacterium solution, Thauera bacterium solution, Pseudomonas bacterium solution, and Nitrosomonas bacterium solution, and is applicable to the ammonia nitrogen degradation of different black and odorous water bodies, effectively enhancing the environmental resistance. However, the above composite microbial agents have relatively high requirements for environmental applicability, are prone to the risk of secondary pollution during long-term use, and are easily inactivated by environmental factors. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite microbial agent for removing nitrogen and phosphorus in eutrophic water bodies, its preparation method and application, which has the ability to efficiently remove nitrogen and phosphorus, high environmental adaptability and stability, low usage cost, environmental friendliness, and reduces the risk of secondary pollution, so as to solve the problems proposed in the above background technology.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A composite microbial agent for removing nitrogen and phosphorus in eutrophic water bodies is made by mixing main strains and auxiliary strains. The main strains include Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter, and Rhodopseudomonas palustris; the auxiliary strains include Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus.

[0007] Furthermore, the mixing ratio of the main strains to the auxiliary strains is (2 - 4):1.

[0008] Furthermore, the dry weight ratio of Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter, and Rhodopseudomonas palustris in the main strains is (2 - 3):(2 - 3):(1 - 1.5):(1 - 2):(0.5 - 1).

[0009] Furthermore, the dry weight ratio of Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus in the auxiliary strains is (0.5 - 1):(1 - 2):(0.5 - 1).

[0010] Furthermore, the total effective viable bacteria content in the composite microbial agent made by mixing the main strains and the auxiliary strains is ≥1.0×10 9 CFU / g.

[0011] The present invention provides another technical solution: A preparation method of a composite microbial agent for removing nitrogen and phosphorus in eutrophic water bodies includes the following steps:

[0012] S1: Activation of Bacteria Strains: Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter, Rhodopseudomonas, Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus were separately inoculated into LB medium for activation culture. They were cultured under constant temperature oscillation at 25 - 35°C and 200 - 300 rpm for 24 - 48 h to obtain the seed culture solutions of each strain.

[0013] S2: Fermentation of Bacterial Liquid: After the bacteria grew to the logarithmic phase, they were inoculated into the sterilized fermentation medium, and a carrier was added for mixed fermentation. Among them, the seed culture solution of the strain was inoculated into the fermentation medium at 5% - 10% of the volume of the fermentation broth, and the carrier was added at 0.3% - 0.5% g / mL of the volume of the fermentation broth. The fermentation temperature was controlled at 30 - 35°C, the fermentation pH was 7.0 - 7.5, the fermentation time was 24 - 36 h, and the dissolved oxygen was 0.4 - 0.6 mg / L. Fermentation was stopped when the dissolved oxygen began to rise to obtain the fermentation broth of each strain.

[0014] S3: Preparation of Bacterial Agent: The fermentation broth of each strain obtained in S2 was centrifuged and freeze-dried to obtain the high-density freeze-dried bacterial powder of each strain, and the compound microbial bacterial agent was prepared according to the corresponding ratio. Among them, the rotation speed during centrifugal concentration of the fermentation broth was 3000 - 5000 rpm, and the centrifugation time was 10 - 15 min.

[0015] Further, the components of the medium for mixed fermentation in S2 are: glucose (C6H 12 O6) 10 - 20 g / L, yeast extract 5 - 10 g / L, ammonium sulfate ((NH4)2SO4) 2 - 3 g / L, potassium dihydrogen phosphate (KH2PO4) 1 - 1.5 g / L, magnesium sulfate (MgSO4·7H2O) 0.5 - 1 g / L, ferric chloride (FeCl3·6H2O) 1.50 g / L, calcium chloride (CaCl2·2H2O) 0.1 g / L, copper sulfate (CuSO4·5H2O) 0.03 g / L. The pH was adjusted to 7.0 - 7.5 using sodium hydroxide or hydrochloric acid, and sterilization treatment was carried out.

[0016] The present invention also provides a technical solution: an application of a compound microbial bacterial agent for removing nitrogen and phosphorus in eutrophic water bodies. The compound microbial bacterial agent is adsorbed and fixed on a zeolite or activated carbon carrier with a porous structure through binding force for immobilization pretreatment, and then added to the eutrophic water body for nitrogen and phosphorus pollution degradation. Among them, the dosage of the compound microbial bacterial agent is 400 - 800 mg / l. When the water body is slightly polluted, the dosage of the compound microbial bacterial agent can be 400 - 600 mg / l. When the eutrophication degree of the water body is serious, the dosage of the compound microbial bacterial agent can be 600 - 800 mg / l or even higher, which can effectively reduce the eutrophication degree of the water body.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. A composite microbial agent for removing nitrogen and phosphorus from eutrophic water bodies, its preparation method and application provided by the present invention utilize the synergistic effect of multiple strains in eutrophic water bodies, and through mechanisms such as nitrification, denitrification, assimilation and biodegradation, effectively remove nitrogen and phosphorus pollutants in the water body, significantly reduce the degree of water body eutrophication. At the same time, through immobilization pretreatment with zeolite or activated carbon as a carrier, the stability and use effect of the microbial agent are improved, the contact area between the microorganisms and the pollutants is increased, and the nitrogen and phosphorus degradation efficiency is further improved.

[0019] 2. A composite microbial agent for removing nitrogen and phosphorus from eutrophic water bodies, its preparation method and application provided by the present invention have high environmental adaptability and stability, can flexibly adjust the dosage of the microbial agent according to the pollution degree of the water body, are applicable to various water environment conditions, have wide applicability to nitrogen and phosphorus pollution, and the microbial agent is not easily inactivated by environmental factors during use, and has broad application prospects.

[0020] 3. A composite microbial agent for removing nitrogen and phosphorus from eutrophic water bodies, its preparation method and application provided by the present invention, compared with traditional physical and chemical treatment methods, the present invention uses the composite microbial agent to degrade nitrogen and phosphorus in the water body, with lower cost, easier operation, and reduces the economic burden during the treatment process. In addition, the composite microbial agent does not produce secondary pollution during the degradation of nitrogen and phosphorus, is environmentally friendly, and meets the current environmental protection concept and sustainable development requirements. Specific Embodiments

[0021] The embodiments of the present invention will be described in detail below. However, the embodiments of the present invention are not limited thereto. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0022] An embodiment of the present invention provides a composite microbial agent for removing nitrogen and phosphorus from eutrophic water bodies, which is made by mixing main strains and auxiliary strains. The main strains include Pseudomonas aeruginosa (Pseudomonas aeruginosastrain G12), Bacillus licheniformis, Candida rugosa BL3, Acinetobacter, and Rhodopseudomonas; the auxiliary strains include Lactobacillus plantarum, Photosynthetic Bacteria, and Aspergillus. All of the above strains can be selected from any commercial purchase channel, and the total effective viable bacteria content in the composite microbial agent should be ≥1.0×10 9 CFU / g. Specifically, in the above embodiment, the mixing ratio of the main strains and the auxiliary strains is (2-4):1; the dry weight ratio of Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa BL3, Acinetobacter, and Rhodopseudomonas in the main strains is (2-3):(2-3):(1-1.5):(1-2):(0.5-1); the dry weight ratio of Lactobacillus plantarum, Photosynthetic Bacteria, and Aspergillus in the auxiliary strains is (0.5-1):(1-2):(0.5-1).

[0023] The action mechanism of the composite microbial agent of the present invention is as follows: By precisely combining and proportioning the main strains and the auxiliary strains, and utilizing the synergistic effect of these microorganisms in eutrophic water bodies, nitrogen and phosphorus pollutants in the water body are effectively removed through mechanisms such as nitrification, denitrification, assimilation, and biodegradation. For example, Pseudomonas aeruginosa can effectively convert ammonia nitrogen and nitrate through heterotrophic nitrification and aerobic denitrification; Bacillus licheniformis can assimilate nitrogen and convert nitrogen pollution into microbial protein to achieve nitrogen removal; while Rhodopseudomonas and others reduce the phosphorus content in the water body through biological absorption, transformation, or precipitation mechanisms. At the same time, the auxiliary strains not only enhance the functions of the main strains, but also promote the diversity and stability of the microbial community structure and improve the adaptability of the entire microbial agent by secreting enzymes, regulating the pH value, and promoting the circulation of nutrients. In addition, through immobilization treatment with zeolite or activated carbon, the composite microbial agent not only improves stability and prevents the loss of bacteria in the water body, but also increases the contact area through the porous structure of the carrier, strengthens the adsorption efficiency, further improves the nitrogen and phosphorus degradation efficiency, and effectively alleviates the problem of water body eutrophication.

[0024] To further better explain and illustrate the functions and effects of the composite microbial agent of the present invention, specific embodiments are also provided:

[0025] Example 1:

[0026] A composite microbial inoculant for removing nitrogen and phosphorus from eutrophic water bodies. This inoculant is prepared by mixing the main strains and auxiliary strains according to a weight ratio of 4:1. The main strains are composed of Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter sp., and Rhodopseudomonas palustris, and the dry weight ratio of each strain is 3:2:1:1:1. The auxiliary strains are composed of Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus sp., and the dry weight ratio of each strain is 0.5:1:0.5. The total effective viable bacteria content in the inoculant should be ≥1.0×10 9 CFU / g.

[0027] The composite microbial inoculant of this example is prepared according to the following method:

[0028] Step 1: Inoculate each commercially available strain into LB medium for activation, and shake-culture in a constant-temperature shaking incubator at 25°C and 250 rpm for 24 hours to ensure sufficient activation of the strains.

[0029] Step 2: Prepare the fermentation medium. The components of the fermentation medium are: C6H 12 O6 15 g / L, yeast extract 10 g / L, (NH4)2SO4 3 g / L, KH2PO4 1.5 g / L, MgSO4·7H2O 0.75 g / L, FeCl3·6H2O 1.5 g / L, CaCl2·2H2O 0.1 g / L, CuSO4·5H2O 0.03 g / L. Adjust the pH to 7 - 7.5 using HCl and NaOH, and then autoclave the fermentation medium at 121°C for 15 minutes.

[0030] Step 3: Mixed fermentation. Inoculate the activated strain seed culture solution into the sterilized fermentation medium at 6% of the fermentation broth volume, and simultaneously add zeolite as an adsorption carrier at 0.5% of the fermentation broth volume. Control the fermentation temperature at 32°C, the fermentation pH at 7.0 - 7.5, and maintain the dissolved oxygen at 0.4 mg / L, and ferment for 24 hours.

[0031] Step 4: Prepare the composite inoculant. Centrifuge the fermentation broth at 4000 rpm for 12 minutes, remove the supernatant, collect the thalli, and then perform freeze-drying to obtain high-density freeze-dried bacterial powder. The composite microbial inoculant is prepared according to the corresponding dry weight ratio of each strain in Example 1.

[0032] Example 2:

[0033] A composite microbial agent for removing nitrogen and phosphorus from eutrophic water bodies provided in this embodiment is prepared by mixing the main strains and auxiliary strains in a weight ratio of 3:1. The main strains are composed of Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter, and Rhodopseudomonas palustris, and the dry weight ratio of each strain is 2:3:1.5:1.5:1. The auxiliary strains are composed of Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus, and the dry weight ratio of each strain is 0.75:1.25:1. The total effective viable bacteria content in the agent should be ≥1.0×10 9 CFU / g.

[0034] The composite microbial agent of this embodiment is prepared according to the following method:

[0035] Step 1: Inoculate each commercially available strain into LB medium for activation, and shake-culture in a constant-temperature shaking incubator at 25°C and 250 rpm for 24 hours to ensure sufficient activation of the strains.

[0036] Step 2: Prepare the fermentation medium. The components of the fermentation medium are: C6H 12 O6 15 g / L, yeast extract 10 g / L, (NH4)2SO4 3 g / L, KH2PO4 1.5 g / L, MgSO4·7H2O 0.75 g / L, FeCl3·6H2O 1.5 g / L, CaCl2·2H2O 0.1 g / L, CuSO4·5H2O 0.03 g / L. Adjust the pH to 7 - 7.5 using HCl and NaOH, and then autoclave the fermentation medium at 121°C for 15 minutes.

[0037] Step 3: Mixed fermentation. Inoculate the activated strain seed culture solution into the sterilized fermentation medium at 8% of the fermentation broth volume, and simultaneously add activated carbon as an adsorption carrier at 0.3% of the fermentation broth volume. Control the fermentation temperature at 32°C, the fermentation pH at 7.0 - 7.5, and the dissolved oxygen maintained at 0.5 mg / L, and ferment for 30 hours.

[0038] Step 4: Prepare the composite agent. Centrifuge the fermentation broth at 4000 rpm for 12 minutes, remove the supernatant, collect the bacterial cells, and then perform freeze-drying to obtain a high-density freeze-dried bacterial powder, which is formulated according to the corresponding dry weight ratio of each strain in Example 2 to obtain the composite microbial agent.

[0039] Example 3:

[0040] A composite microbial agent for removing nitrogen and phosphorus from eutrophic water bodies provided in this embodiment is prepared by mixing the main strains and auxiliary strains according to a weight ratio of 2.5:1. The main strains are composed of Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter sp., and Rhodopseudomonas palustris, and the dry weight ratio of each strain is 2:2:1:1.5:1. The auxiliary strains are composed of Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus sp., and the dry weight ratio of each strain is 0.75:1.5:0.75. The total effective viable bacteria content in the agent should be ≥ 1.0×10 9 CFU / g.

[0041] The composite microbial agent of this embodiment is prepared according to the following method:

[0042] Step 1: Inoculate each commercially available strain into LB medium for activation, and shake-culture in a constant-temperature shaking incubator at 25°C and 250 rpm for 24 hours to ensure sufficient activation of the strains.

[0043] Step 2: Prepare the fermentation medium. The components of the fermentation medium are: C6H 12 O6 15 g / L, yeast extract 10 g / L, (NH4)2SO4 3 g / L, KH2PO4 1.5 g / L, MgSO4·7H2O 0.75 g / L, FeCl3·6H2O 1.5 g / L, CaCl2·2H2O 0.1 g / L, CuSO4·5H2O 0.03 g / L. Adjust the pH to 7 - 7.5 using HCl and NaOH, and then autoclave the fermentation medium at 121°C for 15 minutes.

[0044] Step 3: Mixed fermentation. Inoculate the activated strain seed culture solution into the sterilized fermentation medium at 10% of the fermentation broth volume, and at the same time add activated carbon as an adsorption carrier at 0.5% of the fermentation broth volume. Control the fermentation temperature at 32°C, the fermentation pH at 7.0 - 7.5, and the dissolved oxygen at 0.6 mg / L, and ferment for 36 hours.

[0045] Step 4: Prepare the composite microbial agent. Centrifuge the fermentation broth at 4000 rpm for 12 minutes, remove the supernatant, collect the cells, and then perform freeze-drying to obtain a high-density freeze-dried bacterial powder. The composite microbial agent is prepared according to the corresponding dry weight ratio of each strain in Example 3.

[0046] Comparative Example 1:

[0047] It is different from Example 1 in that the main strain ratio of the compound microbial agent is adjusted, the auxiliary strain ratio, the immobilized carrier and its addition amount remain unchanged, and the strain activation and fermentation conditions are the same. Among them, the dry weight ratios of each strain in the main strains are as follows: Pseudomonas aeruginosa: Bacillus licheniformis: Candida rugosa: Acinetobacter: Rhodopseudomonas palustris = 2:3:1.5:1:0.5.

[0048] Comparative Example 2:

[0049] It is different from Example 2 in that the auxiliary strain ratio of the compound microbial agent is adjusted, the main strain ratio, the immobilized carrier and its addition amount remain unchanged, and the strain activation and fermentation conditions are the same. Among them, the dry weight ratios of each strain in the auxiliary strains are as follows: Lactobacillus plantarum: Photosynthetic bacteria: Aspergillus composition = 0.5:2:0.5.

[0050] Comparative Example 3:

[0051] It is different from Example 3 in that no zeolite or activated carbon is added as the immobilized adsorption carrier to the compound microbial agent, the composition and ratio of the main strains and auxiliary strains remain unchanged, and the strain activation and fermentation conditions are the same.

[0052] In the examples of the present invention, an artificial freshwater lake in Chongqing was selected as the treatment object of eutrophic water body, and the compound microbial agents described in Examples 1-3 and Comparative Examples 1-3 were added thereto. This experiment focused on exploring the application effect of the compound microbial agent in real eutrophic water bodies, and verified and evaluated the actual efficacy of the compound microbial agent in removing nitrogen and phosphorus pollutants in eutrophic water bodies by analyzing various water quality indicators of the lake before and after the addition of the microbial agent.

[0053] Water quality characteristics of the eutrophic lake: The above artificial freshwater lake shows moderate eutrophication characteristics, with accumulation of organic pollutants, enrichment of nitrogen and phosphorus nutrients, significant increase in algal biomass, and water transparency reduced to less than 1.0 m. The specific water quality indicators are: CODcr (chemical oxygen demand) = 97.4 mg / l; NH3-N (ammonia nitrogen) = 15.6 mg / l; NO3-N (nitrate nitrogen) = 7.3 mg / l; TP (total phosphorus) = 1.5 mg / l;

[0054] According to the eutrophication degree of the lake, the composite microbial inoculant described in Examples 1-3 and Comparative Examples 1-3 was uniformly added thereto at a dosage of 600 mg / L. On the 1st, 3rd, 5th, and 7th days after the addition of the inoculant, the CODcr (chemical oxygen demand), NH3-N (ammonia nitrogen), NO3-N (nitrate nitrogen), and TP (total phosphorus) in the treated water body were measured and analyzed using national or industry standards. Among them, the determination of CODcr was carried out by the potassium dichromate method (GB / T 11914-1989), the determination of NH3-N was carried out by the gas-phase molecular absorption spectrometry method (HJ195-2023), the determination of NO3-N (nitrate nitrogen) was carried out by the ultraviolet spectrophotometry method, and the determination of TP (total phosphorus) was carried out by the ammonium molybdate spectrophotometry method (GB / T11893-1989).

[0055] The relevant measurement and analysis results are shown in Table 1 as follows:

[0056]

[0057]

[0058] It can be seen from the results described in Table 1 that the use of the composite microbial inoculant in Examples 1-3 has a significant degradation and removal effect on key water quality indicators such as CODcr, NH3-N, NO3-N, and TP in eutrophic water bodies. One week after the addition of the inoculant, the removal rate of CODcr reached more than 92.46%, the degradation rate of NH3-N reached more than 96.22%, up to 98.65% at most, the degradation rate of NO3-N reached more than 93.56%, up to 96.16% at most, and the degradation rate of TP reached more than 87.33%, up to 90.67% at most. In addition, by carefully comparing Example 1 with Examples 2-3, it can be found that as the weight ratio between the main strain and the auxiliary strain increases, the degradation ability of the inoculant for nitrogen and phosphorus in eutrophic water bodies shows an obvious enhancement. This finding further confirms the key role of strain ratio in the design of composite microbial inoculants, and also provides us with a new idea for improving the water purification efficiency by optimizing the strain ratio.

[0059] It can be seen from the results of Table 1 that when using the composite microbial inoculant in Comparative Examples 1-2, compared with Examples 1-2, mainly the dry weight ratio of the main strain and the auxiliary strain was adjusted, and it can be found that the degradation effect on nitrogen and phosphorus declined, which also reveals that inappropriate strain ratio may weaken the degradation ability of the inoculant. Different from Example 3, in Comparative Example 3, zeolite or activated carbon was not added as a carrier for immobilization treatment, and it can be clearly seen that the degradation effect on nitrogen and phosphorus decreased significantly, indicating that the inoculant without immobilization pretreatment may show low efficiency and stability in degrading nitrogen and phosphorus.

[0060] As described above, it is only the preferred specific implementation manner 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 within the protection scope of the present invention.

Claims

1. A composite microbial inoculant for removing nitrogen and phosphorus from eutrophic water bodies, characterized in that: It is made by mixing the main strains and auxiliary strains. The main strains include Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter sp., and Rhodopseudomonas palustris; the auxiliary strains include Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus sp.

2. The composite microbial inoculum for removing nitrogen and phosphorus in eutrophic water bodies according to claim 1, characterized in that: The mixing ratio of the main strains to the auxiliary strains is (2 - 4):

1.

3. The composite microbial inoculum for removing nitrogen and phosphorus in eutrophic water as claimed in claim 2, wherein: The dry weight ratio of Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter sp., and Rhodopseudomonas palustris in the main strains is (2 - 3):(2 - 3):(1 - 1.5):(1 - 2):(0.5 - 1).

4. The composite microbial inoculant for removing nitrogen and phosphorus in eutrophic water bodies according to claim 1, characterized in that: The dry weight ratio of Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus sp. in the auxiliary strains is (0.5 - 1):(1 - 2):(0.5 - 1).

5. The composite microbial inoculant for removing nitrogen and phosphorus in eutrophic water as described in claim 1, wherein: The total effective viable bacteria content in the compound microbial inoculant made from the main strain and the auxiliary strain is ≥ 1.0×10 9 CFU / g.

6. A preparation method of a composite microbial inoculum for removing nitrogen and phosphorus from eutrophic water bodies as described in any one of claims 1-5, characterized in that: It includes the following steps: S1: Activate the strains: Inoculate Pseudomonas aeruginosa, Bacillus licheniformis, Candida rugosa, Acinetobacter sp., Rhodopseudomonas palustris, Lactobacillus plantarum, photosynthetic bacteria, and Aspergillus sp. into LB medium for activation culture respectively, and culture them under the conditions of constant temperature oscillation at 25 - 35°C and 200 - 300 rpm for 24 - 48 h to obtain the seed culture solutions of each strain. S2: Ferment the bacterial liquid: After the bacteria grow to the logarithmic phase, inoculate them into the sterilized fermentation medium, add a carrier, and perform mixed fermentation; among them, the seed culture solution of the strain is inoculated into the fermentation medium at 5% - 10% of the volume of the fermentation liquid, the carrier is added at 0.3% - 0.5% g / mL of the volume of the fermentation liquid, control the fermentation temperature at 30 - 35°C, the fermentation pH at 7.0 - 7.5, the fermentation time at 24 - 36 h, and the dissolved oxygen at 0.4 - 0.6 mg / L. Stop fermentation when the dissolved oxygen starts to rise to obtain the fermentation liquid of each strain. S3: Prepare the microbial agent: Centrifuge and freeze-dry the fermentation liquid of each strain obtained in S2 to obtain the high-density freeze-dried bacterial powder of each strain, and prepare the compound microbial agent according to the corresponding ratio. Among them, the rotation speed during centrifugal concentration of the fermentation liquid is 3000 - 5000 rpm, and the centrifugation time is 10 - 15 min.

7. The preparation method of a composite microbial inoculum for removing nitrogen and phosphorus in eutrophic water bodies according to claim 6, characterized in that: The composition of the medium for mixed fermentation in S2 is: glucose 10 - 20 g / L, yeast extract 5 - 10 g / L, ammonium sulfate 2 - 3 g / L, potassium dihydrogen phosphate 1 - 1.5 g / L, magnesium sulfate 0.5 - 1 g / L, ferric chloride 1.50 g / L, calcium chloride 0.1 g / L, copper sulfate 0.03 g / L. Adjust the pH to 7.0 - 7.5 with sodium hydroxide or hydrochloric acid, and perform sterilization treatment.

8. Use of a composite microbial inoculant for removing nitrogen and phosphorus from eutrophic water bodies as described in any one of claims 1-5, characterized in that: Fix the compound microbial agent on a zeolite or activated carbon carrier with a porous structure through binding force for immobilization pretreatment, and then add it to the eutrophic water body for nitrogen and phosphorus pollution degradation.

9. Use of a composite microbial inoculant for removing nitrogen and phosphorus in eutrophic water bodies according to claim 8, characterized in that: The dosage of the compound microbial agent is 400 - 800 mg / l.

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