Microbial complex microbial inoculant, preparation method thereof and application of microbial complex microbial inoculant in red mud treatment

Abstract

The invention discloses a microbial complex microbial inoculant, a preparation method thereof and application of the microbial complex microbial inoculant in red mud treatment, and relates to the technical field of mine ecological restoration. The invention provides a composite microbial inoculant which comprises a microbial inoculant microorganism A, a microbial inoculant microorganism B and a microbial inoculant microorganism C in a weight ratio of (1-3): (1-4): 1, the microbial inoculum microorganism A is at least one of rhizobium, azotobacter, pseudomonas, bacillus, burkholderia and glomus; the microbial inoculum microorganism A is at least one of rhizobium, azotobacter, pseudomonas, bacillus, burkholderia and glomus; the microbial agent microorganism B is at least one of desulfurization vibrio, streptococcus, acetobacter and acidophilic thiobacillus; the microbial agent microorganism C is at least one of agrobacterium, enterobacter, streptomyces and klebsiella. The microbial agent disclosed by the invention can effectively solve the problems of high salt and alkali content of the red mud and heavy metal toxicity, and also can create conditions suitable for plant growth on the red mud, so that the ecological restoration effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of mine ecological restoration, in particular to a microbial composite agent and a preparation method thereof and application thereof in red mud treatment. Background Art

[0002] Red mud is produced during the refining process of alumina. It is one of the largest solid wastes discharged by the non-ferrous metal industry. On average, 0.5-1.5 tons of red mud will be discharged for every ton of alumina produced. Red mud is gray, brown and dark red, and the color changes with the iron content. In addition to a small amount of rare earth elements, radioactive elements and fluorides, the main elements in red mud are Fe, Si, Ti, Ca, Al, Na, etc. These metal elements mainly exist in the form of oxides; a large amount of metal oxides causes the pH of red mud to remain between 10-13. The main treatment method for red mud is stockpiling. As of 2020, the cumulative stockpile of red mud in my country has exceeded 600 million tons, and it continues to increase at a rate of 70 million tons per year. The hazards of red mud are mainly manifested in the following aspects: 1. Occupying land and wasting land resources; 2. Leachate with strong alkalinity, high salinity and high heavy metal toxicity will migrate underground, causing salinization of soil and water pollution in the yard and surrounding areas; 3. Strong salinity makes it difficult for plants to survive in the red mud storage site and surrounding areas, and exposed vegetation will aggravate soil erosion; 4. Sudden environmental risks. In recent years, sudden environmental pollution incidents caused by red mud storage have occurred in Guizhou, Guangxi, Henan, Shanxi, Shandong and other places in my country. The above problems reflect the current difficulties faced by the high-quality development of the alumina industry. The continuous output of tens of millions of tons of red mud each year lacks economical and effective red mud in-situ ecological restoration and management materials. The continuous generation of pollutants during the storage of a large amount of red mud threatens the ecological safety of the surrounding environment and brings difficulties to regional ecological protection. The harm of red mud to the ecological environment is mainly caused by the leakage of pollutants such as its strong alkalinity, high salinity and high heavy metal toxicity. If the soil evolution process of red mud can be promoted, that is, the alkalinity and salinity of red mud can be controlled and the dissolution of heavy metals can be inhibited, and on this basis, basic conditions suitable for vegetation growth can be created on the surface of the red mud, effective in situ ecological restoration of the red mud can be carried out, it will be an effective strategy to solve the environmental safety problem of red mud.

[0003] Early studies generally believed that artificial improvement was a prerequisite for the soilification of red mud, but recent studies have found that without any artificial treatment, the surface of red mud that has been piled for more than 20 years has undergone natural soil formation, and further studies have found that whether it is artificially improved soil formation or natural soil formation, microorganisms are involved in or even dominate the process of red mud soilification. Soil microorganisms are the key driving force for the transformation and circulation of organic nutrients in soil ecosystems, and play an important role in soil structure formation, organic matter transformation, nutrient release, harmful substance degradation, and ecosystem stability. In recent years, research on the microbial regulation mechanism in the soil formation process of red mud has focused on the screening of tolerant microorganisms and the improvement effect of microorganisms on the physical and chemical properties of red mud. Microorganisms improve the physical and chemical properties of red mud mainly through the following aspects: 1. Reduce the alkalinity of red mud through metabolic acid production such as secretion of oxalic acid, acetic acid and citric acid; 2. Produce polysaccharides through metabolism, promote the transformation of fine particles to large particles, improve the structure of red mud aggregates, improve the compaction of red mud, and enhance its permeability. 3. Fix heavy metals in situ through physical or chemical reactions of metabolites to reduce their biological effectiveness. However, traditional microbial treatment of red mud has certain limitations. Existing studies have found that low organic matter content and extreme conditions in red mud will limit the survival and reproduction of microbial communities, affect their activity, and reduce the effectiveness of microbial treatment. In addition, the possibility of establishing vegetation on the surface of improved red mud is rarely considered, and there is a lack of attention to the restoration of damaged ecosystems on the red mud surface.

[0004] Therefore, how to combine a microbial combination that can promote the soil formation process of red mud, further reduce the alkalinity and salinity of red mud and the dissolution of heavy metals, significantly improve the nutrient deficiency of red mud, and ensure long-term, stable and effective treatment effect is a difficult problem that needs to be solved urgently. Summary of the invention

[0005] Based on this, the purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a microbial composite agent and its preparation method and application that can promote the soil formation process of red mud, further reduce the alkalinity, salinity and heavy metal dissolution of red mud, significantly improve the nutrient deficiency of red mud, and achieve long-term, stable and effective treatment effect.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a microbial composite agent, the microbial composite agent includes agent microorganism A, agent microorganism B and agent microorganism C, the weight ratio of the agent microorganism A, agent microorganism B and agent microorganism C is agent microorganism A: agent microorganism B: agent microorganism C = (1-3): (1-4): 1; the agent microorganism A is at least one of the genera Rhizobium, Azotobacter, Pseudomonas, Bacillus, Burkholderia and Glomerella; the agent microorganism B is at least one of the genera Desulfovibrio, Streptococcus, Acetobacter and Acidithiobacillus; the agent microorganism C is at least one of the genera Agrobacterium, Enterobacter, Streptomyces and Klebsiella.

[0007] The inventors found in actual research that the type of microorganisms specifically selected in the microbial agent will have a significant impact on the treatment results. The synergy of the agent microorganism A, agent microorganism B and agent microorganism C of the present invention was selected to achieve good treatment effects, further reduce the alkalinity, salinity and heavy metal dissolution of red mud, significantly improve the nutrient deficiency of red mud, and the treatment effect is long-term, stable and effective.

[0008] The present invention selects microorganism A, microorganism B and microorganism C to cooperate with each other, and on the one hand, can realize the functions of nitrogen conversion, phosphorus dissolution, potassium dissolution and organic matter degradation; specifically, organic nitrogen that is difficult for plants to directly use can be converted into absorbable nitrate nitrogen and ammonium nitrogen through mineralization and nitrification, or nitrogen gas in the environment can be converted into ammonium nitrogen through the catalytic action of nitrogenase; insoluble phosphorus can be converted into soluble phosphorus and released through the mineralization of organic acid and / or enzyme produced; insoluble potassium salt can be converted into soluble potassium that can be used by plants; organic matter can be degraded to increase the organic carbon content of red mud. On the other hand, the use of specific bacterial microorganisms can lower the pH of red mud by metabolizing to produce organic acids such as tartaric acid, citric acid, and succinic acid, thereby improving the extremely alkaline environment of red mud; by reducing sulfate to sulfide ions, they combine with free heavy metal ions in situ to form sulfide precipitates, thereby reducing the dissolution of heavy metals in red mud; by promoting the participation of free sodium ions and potassium ions in the synthesis of jarosite and Schreiberite minerals, the content of free sodium and potassium ions in red mud is reduced, thereby reducing the salinity of red mud.

[0009] Finally, the inventors found in actual research that the further synergistic use of microbial agent C and microbial agent A and microbial agent B can activate the plant's defense immune system, increase the proline content of plants under stress conditions, improve the plant's resistance to diseases and pests, and improve the plant's stress resistance.

[0010] Preferably, the microorganism A is a mixture of Rhizobium, Bacillus and Glomus, and the weight ratio of Rhizobium, Bacillus and Glomus is Rhizobium: Bacillus: Glomus=(1-4):(1-2):1;

[0011] The microorganism B of the bacterial agent is a mixture of Desulfovibrio, Streptococcus and Acidithiobacillus, and the weight ratio of Desulfovibrio, Streptococcus and Acidithiobacillus is Desulfovibrio:Streptococcus:Acidithiobacillus=(2-3):2:(1-5);

[0012] The inoculant microorganism C is a mixture of Agrobacterium, Streptomyces and Klebsiella, and the weight ratio of Agrobacterium, Streptomyces and Klebsiella is Agrobacterium:Streptomyces:Klebsiella=(3-5):(1-2):1.

[0013] The inventors found in actual research that when the above-mentioned specific species are selected for the microbial agent A, microbial agent B and microbial agent C, the alkalinity and salinity of the red mud can be further reduced, the nutrient deficiency of the red mud can be significantly improved, and a good treatment effect can be achieved. When the above-mentioned specific species are selected for the microbial agent A, microbial agent B and microbial agent C, the treated red mud has suitable conditions for plant growth, the plant survival rate is higher, the plant's defense immune system can be better activated, the plant's resistance to diseases and insect pests is better, and the plant's stress resistance is better.

[0014] Preferably, the weight percentage content of microorganism C in the microbial agent is 15-25%.

[0015] The inventors found in actual research that when the weight percentage content of microorganism C in the microbial agent is 15-25%, the synergistic effect between microorganisms can be better exerted, the alkalinity and salinity of red mud can be further reduced, the nutrient deficiency of red mud can be significantly improved, and good treatment effect can be achieved.

[0016] In addition, the present invention provides a method for preparing the microbial composite agent, comprising the following steps:

[0017] S1, inoculating the microorganism A, microorganism B and microorganism C into the culture medium for activation, respectively, to obtain activation solutions of the microorganism A, microorganism B and microorganism C, respectively;

[0018] S2. Mix the activated solutions of the microbial agent A, microbial agent B and microbial agent C and inoculate them into a culture medium to obtain a fermentation solution, and after expanded culture, obtain the microbial composite microbial agent.

[0019] Preferably, the inoculation amount in S1 is 10-28 v / v%, and the inoculation amount in S2 is 10-28 v / v%.

[0020] Preferably, the culture medium comprises 0.5-2g / L Na2SO4, 0.5-2g / L NH4Cl, 0.1-1.5g / L KH2PO4, 0.05-0.3g / L CaCl2·H2O, 0.05-0.3g / L MgSO4·7H2O, 5-20ml / L C3H5O3Na, 150-450mL / L sterilized fermentation broth, and 30-100g / L vitamin C.

[0021] Preferably, the culture medium is adjusted to a pH of 6-7 and then sterilized at 115-121° C., 0.05-0.1 MPa for 15-40 min, and cooled to room temperature before use.

[0022] Preferably, the fermentation liquid is at least one of peel fermentation liquid and biogas residue fermentation liquid, the peel used for the peel fermentation liquid is at least one of orange peel, dragon fruit peel, grapefruit peel, coconut shell, banana peel and passion fruit shell obtained by anaerobic fermentation, and the biogas residue fermentation liquid is at least one of straw, dead branches and leaves, and kitchen waste obtained by anaerobic fermentation.

[0023] Further preferably, the fermentation liquid is peel fermentation liquid. The inventors found in actual research that the use of peel fermentation liquid can provide sufficient nutrients for the growth of microorganisms and improve the activity of microorganisms in the inoculant.

[0024] Preferably, the weight percentage content of passion fruit shell in the peel fermentation liquid is 40-60%. The inventors found in actual research that under this ratio, the passion fruit shell has a better effect in promoting fermentation, and the content of substances promoting microbial fermentation such as organic acids, pectin, flavonoids and cellulose in the fermentation liquid is higher.

[0025] Preferably, in S1, the specific activation method is: avoid light, the activation temperature is 30-37°C, the activation speed is 120-180r / min, and the activation time is 24-48h; the microbial concentration in the activation solution is ≥10 8 CFU / mL.

[0026] Preferably, in the S2 fermentation yeast solution, the weight ratio of the microorganism A, microorganism B and microorganism C is microorganism A:microorganism B:microorganism C=(1-3):(1-4):1; the fermentation yeast solution is expanded and cultured, and the number of viable cells is detected to be ≥10 8 CFU / ml means the fermentation is complete.

[0027] Preferably, the specific method of the expanded culture is: the expanded culture is carried out in a fermenter, protected from light, with a pH of 5-7, a temperature of 30-37°C, a tank pressure of 0.03-0.1 MPa, and a ventilation volume of 1: 0.3-0.6 vvm; culture for 24-72 hours, and when the number of viable bacteria reaches 10 8 Fermentation is complete when the CFU / ml is above 1.

[0028] Furthermore, the present invention provides the use of the microbial composite agent in red mud treatment.

[0029] The present invention provides a red mud treatment method, which comprises the following steps:

[0030] (1) mixing the chemical conditioner, the microbial nutrient agent and the composite microbial agent with the surface red mud;

[0031] (2) Planting plants on the red mud treated in step (1) and curing them for 3-6 months.

[0032] Preferably, the chemical conditioning agent is at least one of phosphogypsum, citric acid, apatite, ammonium chloride, potassium dihydrogen phosphate, peat soil, biochar, and ferrous sulfate, and the application amount is 7-22 kg / m 2 The chemical conditioner reacts with the alkaline substances in the red mud to improve the extremely alkaline environment of the red mud; it reacts with the alkaline anions in the red mud (such as CO3 2- 、HCO3 - OH - 、AlO3 3- etc.) to produce precipitation reaction, reduce alkalinity; adsorb / chelate heavy metals to reduce their toxicity.

[0033] Preferably, the application amount of the microbial agent is 15-30 g / m 2 .

[0034] Preferably, the microbial nutrient comprises an organic nutrient and an inorganic nutrient, wherein the organic nutrient is at least one of livestock and poultry manure, fermented sludge, crop straw, humic acid, wood chaff, hay, coconut chaff, earthworm manure, mushroom compost, wine lees, and vinegar residue, and the application amount is 60-110 kg / m 2 The inorganic nutrient agent is at least one of the commercially available inorganic fertilizers such as urea, calcium phosphate, calcium magnesium phosphate, potassium nitrate, potassium chloride, etc., and the application rate is 0.7-1.8kg / m 2 .

[0035] Preferably, the added amount of the chemical conditioner, the microbial nutrient and the microbial composite agent is the mass required to be added compared to the area of ​​the red mud to be ecologically restored.

[0036] Preferably, the plant species should be determined according to the local climate, topography and surrounding landscape, and may include trees, shrubs and herbaceous plants, preferably with more than 7 species. Among them, the tree can be at least one of Leguminosae, Salicaceae, Lauraceae, Pinaceae, Phyllanthaceae, Sapindaceae or local native plants. The shrub is at least one of Moranaceae, Oleaceae, Leguminosae, Rosaceae, Ericaceae or local native plants. The herbaceous plant is at least one of Gramineae, Leguminosae, Compositae, Amaranthaceae, and local native plants.

[0037] Preferably, the amount of herbal seeds is 10-30 g / m 2 , the dosage of bag seedlings is 4-16m 2 / strain.

[0038] The maintenance is based on local climatic conditions and plant characteristics, and daily maintenance such as watering, topdressing, pest control, and replanting is carried out according to actual needs. The maintenance period is 3-6 months.

[0039] Compared with the prior art, the present invention has the following beneficial effects: (1) the microbial culture medium of the present invention uses organic waste as a carbon source, thereby realizing waste utilization and saving production costs and fermentation culture time; (2) the microbial agent of the present invention contains a variety of bacterial species and multiple functions, which can not only effectively solve the problems of high salinity and heavy metal toxicity in red mud, but also create conditions suitable for plant growth on red mud and improve plant survival rate; (3) the microbial agent of the present invention effectively improves the red mud matrix on the basis of controlling the spread of red mud pollution, creates favorable conditions for planting plants on red mud, and effectively realizes the in-situ ecological restoration of red mud; (4) the microbial agent of the present invention takes into account the problems of diseases and pests encountered by plants in the later stage of growth, and adds the agent microorganism C to improve the stress resistance, disease resistance and insect pest resistance of plants. DETAILED DESCRIPTION

[0040] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Its purpose is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise specified, the experimental reagents and instruments designed for the implementation and comparative examples of the present invention are all commonly used ordinary reagents and instruments, which can be obtained from commercial channels. In the implementation and comparative examples, the experimental methods used are conventional methods unless otherwise specified; and unless otherwise specified, the raw materials used in parallel experiments are the same batch of raw materials.

[0041] Red mud: The red mud samples for testing were collected from the 0-20cm surface layer of a red mud dump in Baise City, Guangxi. Before collection, the surface dead branches, fallen leaves, gravel and other debris were removed. The red mud samples were tested, and the pH of the sample was 10.7. The characteristic pollution factors were Cd and Pb, and the water leaching concentrations were 5.2mg / L and 8.9mg / L, respectively. A planting pot with a diameter of 16cm, a height of 16cm, and a capacity of 1.5L was selected, and 1.5kg of red mud was placed in each pot. The red mud used in the experimental process of the present invention was from the same batch.

[0042] Microbial compound agent 1-Microbial compound agent 17

[0043] Microbial compound agent 1

[0044] The invention comprises microorganism A, microorganism B and microorganism C, wherein the weight ratio of microorganism A, microorganism B and microorganism C is microorganism A:microorganism B:microorganism C=1:1:1; microorganism A comprises 1 strain of Rhizobium, 1 strain of Bacillus and 1 strain of Glomerella; microorganism B comprises 2 strains of Desulfovibrio, 2 strains of Streptococcus and 1 strain of Acidithiobacillus; microorganism C comprises 3 strains of Agrobacterium, 1 strain of Streptomyces and 1 strain of Klebsiella.

[0045] The preparation method of the above-mentioned microbial composite agent 1 comprises the following steps:

[0046] S1, inoculating the microorganism A, microorganism B and microorganism C into the culture medium for activation, respectively, to obtain activation solutions of the microorganism A, microorganism B and microorganism C, respectively;

[0047] S2. Mix the activated solutions of the microbial agent A, microbial agent B and microbial agent C and inoculate them into a culture medium to obtain a fermentation solution, and after expanded culture, obtain the microbial composite microbial agent.

[0048] The specific activation method is: avoid light, the activation temperature is 35°C, the activation speed is 160r / min, and the activation time is 48h; the microbial concentration in the activation solution is ≥10 8 CFU / mL.

[0049] The specific method of the expanded culture is: the expanded culture is carried out in a fermenter, protected from light, with a pH of 6, a temperature of 35°C, a tank pressure of 0.05MPa, and a ventilation rate of 1:0.3vvm; the culture is carried out for 72 hours, and when the number of viable bacteria reaches 10 8 Fermentation is complete when the CFU / ml is above 1.

[0050] The culture medium includes 1g / L Na2SO4, 1g / L NH4Cl, 0.6g / L KH2PO4, 0.06g / L CaCl2·H2O, 0.06g / L MgSO4·7H2O, 5ml / L C3H5O3Na, 250mL / L sterilized fermentation liquid, and 50g / L vitamin C.

[0051] The culture medium is adjusted to pH 6-7 and then sterilized at 121° C., 0.1 MPa for 20 min, and cooled to room temperature before use.

[0052] The fermentation liquid is a peel fermentation liquid, and the peels used in the peel fermentation liquid are orange peels and passion fruit shells obtained by anaerobic fermentation in a ratio of 1:1.

[0053] Microbial compound agent 2

[0054] Compared with the microbial composite agent 1, only the ratio of the agent microorganism A, the agent microorganism B and the agent microorganism C is different, specifically, the weight ratio is the agent microorganism A: the agent microorganism B: the agent microorganism C = 3:4:1; the remaining components, weight parts and preparation methods are exactly the same.

[0055] Microbial compound agent 3

[0056] Compared with the microbial composite agent 1, only the ratio of microbial agent A, microbial agent B and microbial agent C is different, specifically, the weight ratio is microbial agent A: microbial agent B: microbial agent C = 2:2:1; the remaining components, weight parts and preparation methods are exactly the same.

[0057] Microbial compound agent 4

[0058] Compared with the microbial composite agent 1, only the ratio of the agent microorganism A, the agent microorganism B and the agent microorganism C is different, specifically, the weight ratio is the agent microorganism A: the agent microorganism B: the agent microorganism C = 1:2:1; the remaining components, weight parts and preparation methods are exactly the same.

[0059] Microbial compound agent 5

[0060] Compared with the microbial composite agent 1, only the strains of the agent microorganism A, the agent microorganism B and the agent microorganism C are different. Specifically, the agent microorganism A includes 3 strains of Rhizobium, 2 strains of Bacillus and 1 strain of Glomerella; the agent microorganism B includes 3 strains of Desulfovibrio, 2 strains of Streptococcus, and 4 strains of Acidithiobacillus; the agent microorganism C includes 3 strains of Agrobacterium, 1 strain of Streptomyces and 1 strain of Klebsiella; the remaining components, weight portions and preparation methods are exactly the same.

[0061] Microbial compound agent 6

[0062] Compared with the microbial composite agent 1, only the strains of the agent microorganism A, the agent microorganism B and the agent microorganism C are different. Specifically, the agent microorganism A includes 1 Rhizobium, 1 Bacillus and 4 Glomerella; the agent microorganism B includes 1 Desulfovibrio, 1 Streptococcus, and 7 Acidithiobacillus; the agent microorganism C includes 1 Agrobacterium, 5 Streptomyces and 1 Klebsiella; the remaining components, weight portions and preparation methods are exactly the same.

[0063] Microbial compound agent 7

[0064] Compared with the microbial composite agent 1, only the strains of the agent microorganism A, the agent microorganism B and the agent microorganism C are different. Specifically, the agent microorganism A includes 1 nitrogen-fixing bacteria, 1 Pseudomonas, 1 Bacillus, and 1 Burkholderia; the agent microorganism B includes 1 Desulfovibrio, 2 Acetobacter and 1 Acidithiobacillus; the agent microorganism C includes 3 Agrobacterium and 1 Enterobacter; the remaining components, weight parts and preparation methods are exactly the same.

[0065] Microbial compound agent 8

[0066] Compared with the microbial composite agent 1, only the strains of the agent microorganism A, the agent microorganism B and the agent microorganism C are different. Specifically, the agent microorganism A includes 1 Rhizobium, 1 Azotobacter, 1 Pseudomonas, and 1 Glomerella; the agent microorganism B includes 1 Desulfovibrio, 1 Streptococcus, 1 Acetobacter, and 1 Acidithiobacillus; the agent microorganism C includes 1 Agrobacterium, 1 Enterobacter, and 1 Streptomyces; the remaining components, weight portions, and preparation methods are exactly the same.

[0067] Microbial compound agent 9

[0068] Compared with the microbial composite agent 1, only the preparation method of the microbial composite agent is different. Specifically, the culture medium in the preparation process is different, and the fermentation liquid components in the culture medium are selected differently; the remaining components, weight parts and preparation methods are exactly the same.

[0069] The culture medium includes 1g / L Na2SO4, 1g / L NH4Cl, 0.6g / L KH2PO4, 0.06g / L CaCl2·H2O, 0.06g / L MgSO4·7H2O, 5ml / L C3H5O3Na, 250mL / L sterilized fermentation liquid, and 50g / L vitamin C. After the pH of the culture medium is adjusted to 6-7, it is sterilized at 121°C and 0.1MPa for 20min and cooled to room temperature before use.

[0070] The fermentation liquid is a peel fermentation liquid, and the peels used for the peel fermentation liquid are orange peel, pitaya peel, and passion fruit shell, which are obtained through anaerobic fermentation according to the ratio of orange peel: pitaya peel: passion fruit shell=2:2:3.

[0071] Microbial compound agent 10

[0072] Compared with the microbial composite agent 1, only the preparation method of the microbial composite agent is different. Specifically, the culture medium in the preparation process is different, and the fermentation liquid components in the culture medium are selected differently; the remaining components, weight parts and preparation methods are exactly the same.

[0073] The culture medium includes 1g / L Na2SO4, 1g / L NH4Cl, 0.6g / L KH2PO4, 0.06g / L CaCl2·H2O, 0.06g / L MgSO4·7H2O, 5ml / L C3H5O3Na, 250mL / L sterilized fermentation liquid, and 50g / L vitamin C. After the pH of the culture medium is adjusted to 6-7, it is sterilized at 121°C and 0.1MPa for 20min and cooled to room temperature before use.

[0074] The fermentation liquid is a peel fermentation liquid, and the peels used for the peel fermentation liquid are orange peels, banana peels, and passion fruit shells, which are obtained through anaerobic fermentation in the ratio of orange peel: banana peel: passion fruit shell = 2:2:1.

[0075] Microbial compound agent 11

[0076] Compared with the microbial composite agent 1, only the preparation method of the microbial composite agent is different. Specifically, the culture medium in the preparation process is different, and the fermentation liquid components in the culture medium are selected differently; the remaining components, weight parts and preparation methods are exactly the same.

[0077] The culture medium includes 1g / L Na2SO4, 1g / L NH4Cl, 0.6g / L KH2PO4, 0.06g / L CaCl2·H2O, 0.06g / L MgSO4·7H2O, 5ml / L C3H5O3Na, 250mL / L sterilized fermentation liquid, and 50g / L vitamin C. After the pH of the culture medium is adjusted to 6-7, it is sterilized at 121°C and 0.1MPa for 20min and cooled to room temperature before use.

[0078] The fermentation liquid is peel fermentation liquid, and the peel fermentation liquid is obtained by anaerobic fermentation of orange peel and pitaya peel in a ratio of 2:1.

[0079] Microbial compound agent 12

[0080] Compared with the microbial composite agent 1, only the preparation method of the microbial composite agent is different. Specifically, the culture medium in the preparation process is different, and the fermentation liquid components in the culture medium are selected differently; the remaining components, weight parts and preparation methods are exactly the same.

[0081] The culture medium includes 1g / L Na2SO4, 1g / L NH4Cl, 0.6g / L KH2PO4, 0.06g / L CaCl2·H2O, 0.06g / L MgSO4·7H2O, 5ml / L C3H5O3Na, 250mL / L sterilized fermentation liquid, and 50g / L vitamin C. After the pH of the culture medium is adjusted to 6-7, it is sterilized at 121°C and 0.1MPa for 20min and cooled to room temperature before use.

[0082] The fermentation liquid is biogas residue fermentation liquid, which is obtained by anaerobic fermentation of dead branches and leaves and kitchen waste in a ratio of 2:1.

[0083] Microbial compound agent 13

[0084] Compared with the microbial composite agent 1, only the ratio of microorganism A, microorganism B and microorganism C is different, specifically, the weight ratio is microorganism A: microorganism B: microorganism C = 0.5:0.5:1; the remaining components, weight parts and preparation methods are exactly the same.

[0085] Microbial compound agent 14

[0086] Compared with the microbial composite agent 1, only the ratio of microbial agent A, microbial agent B and microbial agent C is different, specifically, the weight ratio is microbial agent A: microbial agent B: microbial agent C = 3:3:0.5; the remaining components, weight parts and preparation methods are exactly the same.

[0087] Microbial compound agent 15

[0088] Compared with the microbial composite agent 1, only the strains of the agent microorganism A, the agent microorganism B and the agent microorganism C are different. Specifically, the agent microorganism A includes 1 nitrogen-fixing bacteria, 1 Pseudomonas and 1 Geobacter; the agent microorganism B includes 1 Desulfurization Box Bacterium, 1 Symbiotic Bacteria and 1 Protocystis; the agent microorganism C includes 1 Actinomyces, 1 Clostridium and 1 Helicobacter; the remaining components, weight parts and preparation methods are exactly the same.

[0089] Microbial compound agent 16

[0090] Compared with the microbial composite agent 1, only the strains of the agent microorganism A, the agent microorganism B and the agent microorganism C are different. Specifically, the agent microorganism A includes 1 strain of Rhizobium, 1 strain of Azotobacter, and 1 strain of Syntrophobacter; the agent microorganism B includes 1 strain of Desulfovibrio and 1 strain of Acidithiobacillus; the agent microorganism C includes 1 strain of Actinomycetes, 1 strain of Clostridium, and 1 strain of Helicobacter; the remaining components, weight portions and preparation methods are exactly the same.

[0091] Microbial compound agent 17

[0092] Compared with the microbial composite agent 1, only the preparation method of the microbial composite agent is different. Specifically, the culture medium in the preparation process is different, and the culture medium does not contain fermentation liquid; the remaining components, weight parts and preparation methods are exactly the same.

[0093] The culture medium includes 1g / L Na2SO4, 1g / L NH4Cl, 0.6g / L KH2PO4, 0.06g / L CaCl2·H2O, 0.06g / L MgSO4·7H2O, 5ml / L C3H5O3Na, and 50g / L vitamin C. The culture medium is sterilized at 121°C and 0.1MPa for 20min after adjusting the pH to 6-7, and cooled to room temperature before use.

[0094] Examples 1 to 12 of the present invention and comparative examples 1 to 5 are small-scale studies, which are explored by pot experiments, and the red mud used for the test is the same batch. The pot experiment is specifically as follows: after collecting the red mud, air-drying, crushing, passing through a 30-mesh sieve, collecting the sieve underflow; taking 1.5 kg of the sieve underflow and placing it in a planting pot with a capacity of 2 L; and then conducting a treatment experiment according to the methods described in Examples 1 to 15 and comparative examples 1 to 5.

[0095] Example 1

[0096] The present invention provides a red mud treatment method, which comprises the following steps:

[0097] (1) mixing the chemical conditioner, the microbial nutrient agent and the microbial composite agent 1 with the surface red mud;

[0098] (2) sowing seeds on the red mud treated in step (1) and curing for 3 months.

[0099] In step (1), the chemical conditioning agent is a mixture of phosphogypsum and ferrous sulfate in a mass ratio of 5:2, and the application amount is 10 kg / m 2 .

[0100] The application amount of the microbial agent is 15g / m 2 .

[0101] The microbial nutrient agent includes an organic nutrient agent and an inorganic nutrient agent. The organic nutrient agent is a mixture of livestock and poultry manure and humic acid in a mass ratio of 4:1, and the application amount is 60kg / m 2 The inorganic nutrient is a mixture of calcium phosphate and potassium nitrate in a mass ratio of 1:1, and the application rate is 0.7kg / m 2 ;

[0102] In step (2), the seeds are grass (specifically bahia grass, crabgrass, ryegrass, paspalum, with a mass ratio of 1:2:2:1), Asteraceae (specifically cosmos, marigold, calendula, with a mass ratio of 3:7:2), a mixture of grass and Asteraceae in a mass ratio of 3:2, and the amount of herbal seeds used is 25g / m 2 .

[0103] Example 2

[0104] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, microbial composite agent 2 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0105] Example 3

[0106] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, microbial composite agent 3 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0107] Example 4

[0108] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, microbial composite agent 4 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0109] Example 5

[0110] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, microbial composite agent 5 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0111] Example 6

[0112] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, microbial composite agent 6 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0113] Example 7

[0114] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, microbial composite agent 7 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0115] Example 8

[0116] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, microbial composite agent 8 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0117] Example 9

[0118] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, microbial composite agent 9 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0119] Example 10

[0120] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, the microbial composite agent 10 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0121] Embodiment 11

[0122] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, the microbial composite agent 11 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0123] Example 12

[0124] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, the microbial composite agent 12 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0125] Comparative Examples 1-5

[0126] Comparative Example 1

[0127] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, the microbial composite agent 13 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0128] Comparative Example 2

[0129] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, the microbial composite agent 14 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0130] Comparative Example 3

[0131] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, the microbial composite agent 15 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0132] Comparative Example 4

[0133] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, the microbial composite agent 16 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0134] Comparative Example 5

[0135] The only difference between the red mud treatment method and Example 1 is the selection of the microbial composite agent. Specifically, the microbial composite agent 17 is selected, and the other components, weight parts and preparation methods are exactly the same.

[0136] Performance Test-1

[0137] Examples 1-12 and Comparative Examples 1-5 were used for red mud treatment, and the red mud used was exactly the same. Physical and chemical indicators were measured after harvest. Among them, the negative control group was treated the same as in Example 1 except that the added bacterial agent was sterilized at high temperature, and the blank control group was not treated. A total of 10 pots were treated in each group.

[0138] According to HJ 962-2018 - Determination of soil pH by potentiometric method, HJ 802-2016 - Determination of soil electrical conductivity by electrode method, HJ 658-2013 - Determination of soil organic carbon by combustion oxidation-titration method, HJ 832-2017 - Digestion of total metal elements in soil and sediment by microwave digestion method, and HJ 557-2010 - Leaching toxicity of solid waste by horizontal oscillation method, the pH value, EC value, total organic carbon, water-leached concentration of Cd and Pb of the samples were tested according to the described methods.

[0139] The detection method of sodium ion percentage (%) is as follows: weigh 5.0g of 60-mesh air-dried red mud into a 50mL centrifuge tube and add 25mL of ammonium acetate solution (1mol / L). The sample is shaken at 150rpm / min for 30min, centrifuged at 180rpm / min, and the supernatant is collected. The exchangeable Na, Ca, Mg, and K contents in the supernatant are determined by inductively coupled plasma atomic emission spectrometry. The calculation formula is as follows:

[0140]

[0141] Among them, C K is the potassium ion content (g / kg); C ca is the calcium ion content (g / kg); C Nais the sodium ion content (g / kg); C Mg is the magnesium ion content (g / kg);

[0142] The proline content (μg / g) was determined by taking about 0.1 g of plant sample and determining the proline content according to the ninhydrin method (Bates LS, Waldren RP, Teare ID. Rapid determination of free proline for water-stress studies [J]. Plant and Soil, 1973, 39 (1): 205-207.). The determination formula is:

[0143] Proline (μg / g·Fw) = (C×Vt) / (Fw×Vs)

[0144] Wherein, C is the proline content obtained by the standard curve (μg); Vt is the volume of the sample extract (mL); Vs is the volume of the extract used in the determination (mL); Fw is the dry weight of the sample (g).

[0145] The test results are shown in Table 1.

[0146] Table 1

[0147]

[0148]

[0149] From the comparison of the blank group, negative control group and Example 1 in Table 1, it can be seen that the inactivated microbial agent has no significant effect on the salinity and water-leached content of heavy metals such as lead and cadmium in red mud. The results show that the culture medium components in the microbial agent have little effect on the ecological restoration effect of red mud. As can be seen from Table 1, after the red mud treatment method provided by the embodiment of the present invention is treated, the physical and chemical properties of the red mud are significantly improved. After treatment, the pH of the red mud is between 6.8-7.9, the electrical conductivity EC is between 0.8-2.1ms / cm, the sodium ion percentage is between 32-45%, and the content of organic carbon in the red mud has increased significantly, at 4.5-8g / kg, and the water-leached cadmium and water-leached lead content are reduced to below 3mg / L. In addition, after the application of the microbial agent, the proline content of the plant is significantly increased, the immune system of the plant is enhanced, and the stress resistance is improved.

[0150] Performance Test-2

[0151] The present invention is applied in the field, and the implementation site is located in a red mud dump in Guangxi, with a total area of ​​about 2000m 2 The pH of red mud in this area is 10.7, and there are serious excessive heavy metals such as cadmium and lead. The microbial composite bacterial agent 4 of the present invention is used to carry out ecological restoration of the area, and the specific steps are as follows:

[0152] (1) mixing the chemical conditioner, the microbial nutrient agent and the microbial composite agent 4 with the surface red mud uniformly;

[0153] (2) Planting plants on the red mud treated in step (1) and curing them for 6 months.

[0154] In step (1), the chemical conditioning agent is a mixture of phosphogypsum and ferrous sulfate in a mass ratio of 5:2, and the application amount is 10 kg / m 2 .

[0155] The application amount of the microbial agent is 15g / m 2 .

[0156] The microbial nutrient agent includes an organic nutrient agent and an inorganic nutrient agent. The organic nutrient agent is a mixture of livestock and poultry manure and humic acid in a mass ratio of 4:1, and the application amount is 80kg / m 2 The inorganic nutrient is a mixture of calcium phosphate and potassium nitrate in a mass ratio of 1:1, and the application rate is 1.4kg / m 2 ;

[0157] In step (2), the plant bag seedlings used include Leguminosae (specifically Acacia macrophylla: Lespedeza: Amorpha fruticosa = 1:1:1), Salicaceae (specifically Salix babylonica), and Sapindaceae (specifically Sapindus mukorossi) mixed and planted in a ratio of 4:1:1, and the planting density is 16 m 2 / plant; the plant seeds used include Gramineae (specifically ryegrass: goosegrass: alkali grass = 1:1:2), Leguminosae (specifically alfalfa: Crotalaria = 3:1), Asteraceae (specifically Cosmos: Pampas grass = 2:1) in a mass ratio of 3:2:2 to form a mixture of herbal seeds in an amount of 30g / m 2 .

[0158] The detection method of performance test-2 is the same as that of performance test-1. The pH value, EC value, total organic carbon, sodium ion percentage, water-leached concentration of Cd and Pb, and proline content of the samples are tested according to the described method.

[0159] The test results are shown in Table 2;

[0160] Table 2

[0161]

[0162] As can be seen from Table 2, after the red mud dump ecological restoration was carried out using the microbial composite agent provided by the present invention, the physical and chemical properties of the red mud were significantly improved. The pH of the red mud decreased from 10.2 to 7.5 3 months after the treatment, the conductivity EC decreased from 2.7ms / cm to 2.1ms / cm, and the percentage of sodium ions decreased from 31.2% to 27.3%. After 6 months of treatment, the effect was stably maintained. The results showed that the alkalinity and salinity of the red mud after ecological restoration were greatly improved, and the red mud was basically neutral; after ecological restoration, the water-immersed cadmium content and water-immersed lead content in the red mud decreased significantly. After 3 months of treatment, the water-immersed cadmium and water-immersed lead contents decreased to 0.05mg / L and 0.3mg / L, respectively, and the cadmium and water-immersed lead contents were lower than the detection limit 6 months after treatment. 3 months after ecological restoration, the content of organic carbon in the red mud increased significantly, from 2.2g / kg to 8.6g / kg, and the nutrient concentration in the red mud remained at a high level 6 months after treatment. In addition, after applying the microbial agent, the proline content of the plant increased to 44.2μg / g-48.7μg / g. The results showed that the plant's immune system was enhanced and its stress resistance was improved.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A microbial composite agent, characterized in that: The microbial composite agent comprises an agent microorganism A, an agent microorganism B and an agent microorganism C, wherein the weight ratio of the agent microorganism A, the agent microorganism B and the agent microorganism C is: the agent microorganism A: the agent microorganism B: the agent microorganism C = (1-3): (1-4): 1; The microorganism A of the inoculant is at least one of the genera Rhizobium, Azotobacter, Pseudomonas, Bacillus, Burkholderia and Glomerella; the microorganism B of the inoculant is at least one of the genera Desulfovibrio, Streptococcus, Acetobacter and Acidithiobacillus; the microorganism C of the inoculant is at least one of the genera Agrobacterium, Enterobacter, Streptomyces and Klebsiella.

2. The microbial composite agent according to claim 1, characterized in that The microorganism A of the bacterial agent is a mixture of Rhizobium, Bacillus and Glomus, and the weight ratio of the Rhizobium, Bacillus and Glomus is Rhizobium: Bacillus: Glomus=(1-4):(1-2):1; The microorganism B of the bacterial agent is a mixture of Desulfovibrio, Streptococcus and Acidithiobacillus, and the weight ratio of Desulfovibrio, Streptococcus and Acidithiobacillus is Desulfovibrio:Streptococcus:Acidithiobacillus=(2-3):2:(1-5); The inoculant microorganism C is a mixture of Agrobacterium, Streptomyces and Klebsiella, and the weight ratio of Agrobacterium, Streptomyces and Klebsiella is Agrobacterium:Streptomyces:Klebsiella=(3-5):(1-2):

1.

3. The microbial composite agent according to claim 1, characterized in that The weight percentage content of microorganism C in the microbial agent is 15-25%.

4. A method for preparing the microbial composite agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, inoculating the microorganism A, microorganism B and microorganism C into the culture medium for activation, respectively, to obtain activation solutions of the microorganism A, microorganism B and microorganism C; S2. Mix the activated solutions of the microbial agent A, microbial agent B and microbial agent C and inoculate them into a culture medium to obtain a fermentation solution, and after expanded culture, obtain the microbial composite microbial agent.

5. The method for preparing the microbial composite agent according to claim 4, characterized in that: The culture medium includes 0.5-2g / L Na2SO4, 0.5-2g / L NH4Cl, 0.1-1.5g / L KH2PO4, 0.05-0.3g / LCaCl2·H2O, 0.05-0.3g / LMgSO4·7H2O, 5-20ml / L C3H5O3Na, 150-450mL / L sterilized fermentation liquid, and 30-100g / L vitamin C; wherein the fermentation liquid is at least one of peel fermentation liquid and biogas residue fermentation liquid.

6. The method for preparing the composite microbial agent according to claim 4, characterized in that: The fermentation liquid is peel fermentation liquid; preferably, the weight percentage content of passion fruit shell in the peel fermentation liquid is 40%-60%.

7. The method for preparing the composite microbial agent according to claim 4, characterized in that: In S1, the specific activation method is: avoid light, the activation temperature is 30-37°C, the activation speed is 120-180r / min, and the activation time is 24-48h; the microbial concentration in the activation solution is ≥10 8 CFU / mL.

8. The method for preparing the composite microbial agent according to claim 4, characterized in that: In the S2 fermented yeast solution, the weight ratio of the microorganism A, microorganism B and microorganism C is microorganism A:microorganism B:microorganism C=(1-3):(1-4):1; the fermented yeast solution is expanded and cultured to detect the number of viable bacteria ≥10 8 CFU / ml means the fermentation is complete.

9. Use of the microbial composite agent as described in any one of claims 1 to 3 in red mud treatment.

10. A red mud treatment method, characterized in that: The governance method comprises the following steps: (1) mixing the chemical conditioning agent, the microbial nutrient agent and the microbial composite agent according to any one of claims 1 to 3 with the surface red mud; (2) Planting plants on the red mud treated in step (1) and curing them for 3-6 months.

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