Method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi

Abstract

The present invention discloses a method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi, comprising the following steps: mixing biomass and soil contaminated by electrolytic manganese slag to obtain compost raw materials; inoculating white rot fungi in the compost raw materials to obtain a pile; composting and fermenting the pile to obtain compost mature material, thereby completing the repair of soil contaminated by electrolytic manganese slag. The present invention effectively reduces the leaching amount of heavy metal manganese by inoculating white rot fungi, effectively reduces the mobility and bioavailability of heavy metal manganese, effectively changes the structure of microbial communities, increases the number and diversity of microorganisms, improves the seed germination index, and realizes the repair of soil in contaminated sites. It has the advantages of quickly starting composting repair, effectively reducing the leaching amount of heavy metal manganese, reducing the mobility and bioavailability of heavy metal manganese, increasing microbial diversity and community abundance, and improving the seed germination index.

Description

Technical Field

[0001] The invention relates to the technical field of heavy metal soil remediation, and in particular to a method for remediating soil contaminated by electrolytic manganese slag by inoculating white rot fungi. Background Art

[0002] Electrolytic manganese slag is the acid leaching slag produced in the process of producing metallic manganese (Mn). According to statistics, every ton of electrolytic manganese metal produced will produce 7t to 9t of waste slag, and the leaching slag produced belongs to Class II industrial solid waste. China's electrolytic manganese smelters discharge nearly 10 million tons of electrolytic manganese slag each year, and China has always been the world's largest contributor of electrolytic manganese slag. It is well known that electrolytic manganese slag contains NH4 + -N and Mn and other pollutants, open-air storage, not only occupies land, but also heavy metal ions will enter the surrounding water and soil with rainwater erosion and weathering, thus causing soil and water pollution and endangering the environment. Traditional soil heavy metal remediation technologies such as heat treatment and soil leaching methods are prone to environmental damage and narrow scope of use due to large economic investment, high energy consumption, low treatment efficiency and other problems, and do not conform to the concept of green and sustainable development. The current research technologies include: establishing a landfill anti-seepage system and direct landfill; using quicklime to stabilize and solidify manganese and ammonia nitrogen; recovering valuable substances in electrolytic manganese slag to prepare fertilizers and produce building materials products. From the perspective of economy, energy or environmental protection, the above methods do not involve in-situ remediation of electrolytic manganese slag, which is not conducive to the production of resource utilization of electrolytic manganese slag. However, manganese is a trace element necessary for plant growth and development, and it is urgent to find a method to achieve harmlessness and resource utilization of electrolytic manganese slag.

[0003] my country is a large agricultural country. With the increase in population, the production of agricultural waste has gradually increased. According to statistics, my country's annual output of crop straw residues exceeds 600 million tons, ranking first in the world, of which rice straw accounts for the largest proportion, reaching 32.3%. Crop straw is huge in quantity, complex in composition and diverse in variety. If it is not handled properly, it will cause harm to the agricultural ecosystem and even involve pollution of the atmospheric environment, water environment and soil. Therefore, effective means need to be taken to treat it reasonably. At present, the main methods of treating agricultural waste are incineration and composting. Incineration will undoubtedly bring secondary pollution and energy consumption and loss. In contrast, composting has the advantages of low energy consumption and low risk of secondary pollution. Rice straw is a carrier of matter and energy, containing nutrients such as nitrogen, phosphorus, potassium, a large amount of cellulose and lignocellulose.

[0004] Composting is a process that uses microorganisms to achieve the biochemical transformation of biodegradable organic matter in waste into stable humus-like substances, which can be used to realize the resource utilization of agricultural waste. In addition, the composting process can not only promote the transformation of unstable complex organic matter into harmless and stable humus, but also passivate the heavy metals in the compost raw materials, reduce the mobility and bioavailability of heavy metals, reduce the ecological risks caused by heavy metals, and improve the quality of contaminated soil. Electrolytic manganese slag contaminated soil has problems such as high total concentration of heavy metal manganese leaching, low soil organic matter content, small number of microbial species, low abundance, and difficulty in achieving ecological restoration. As a result, the traditional composting method is not effective in repairing electrolytic manganese slag contaminated soil, and there are problems such as low heavy metal passivation efficiency, secondary pollution risk, and inability to effectively improve the microecological environment of manganese slag contaminated soil.

[0005] Therefore, how to comprehensively solve the above-mentioned problems existing in the prior art and explore a new method that can effectively repair soil contaminated by electrolytic manganese slag, which can be used to passivate heavy metal manganese, reduce the mobility and bioavailability of heavy metal manganese, increase soil organic matter, increase the abundance of soil microbial communities, and improve the soil seed germination index, etc., is of great significance for achieving the treatment and ecological restoration of soil contaminated by electrolytic manganese slag. Summary of the invention

[0006] In view of the above-mentioned technical problems that need to be solved, the present invention provides a method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi. The present invention establishes a composting method for inoculating white rot fungi to repair soil contaminated by electrolytic manganese slag, thereby effectively reducing the leaching amount of heavy metal manganese, changing the soil microbial community structure, increasing the number and diversity of microorganisms, and improving the seed germination index.

[0007] In order to achieve the above object, the present invention provides a method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi, comprising the following steps:

[0008] S1, mixing biomass and electrolytic manganese slag contaminated soil to obtain compost raw materials;

[0009] S2, inoculating white rot fungi into the compost raw material to obtain a compost body;

[0010] S3, composting, fermenting and decomposing the pile to complete the restoration of the soil contaminated by the electrolytic manganese slag.

[0011] The above method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi is further characterized in that the biomass in S1 is vegetable leaves, rice straw and bran.

[0012] The above-mentioned method for inoculating white rot fungi to repair electrolytic manganese slag contaminated soil, further, the dry weight mass ratio of the vegetable leaves, rice straw, bran and electrolytic manganese slag contaminated soil is 2.5-5.5:4-6:6.5-8.5:2.5-5.5. Further, the dry weight mass ratio of the vegetable leaves, rice straw, bran and electrolytic manganese slag contaminated soil is 4:5:7:4.

[0013] The above method for repairing electrolytic manganese slag contaminated soil by inoculating white rot fungi, further, the total leaching concentration of heavy metal manganese in the electrolytic manganese slag contaminated soil in S1 is 1000mg / L~1400mg / L, and the organic matter content is 10.00%~14.04%.

[0014] The above-mentioned method of inoculating white rot fungi to repair soil contaminated by electrolytic manganese slag further has the number of soil microbial species of 346 to 371, and the bacterial community structure is mainly composed of Actinobacteria, Proteobacteria and Cyanobacteria.

[0015] In the above method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi, further, the inoculation amount of the white rot fungi in S2 is 0.5% to 1%.

[0016] The above-mentioned method of inoculating white rot fungi to repair soil contaminated by electrolytic manganese slag, further, the composting fermentation in S3 is specifically: covering the surface of the repair pile with insulation material, turning the pile every 1 to 2 days in the first week; thereafter, turning the pile every 3 to 5 days, for a total duration of 30 days; during the composting fermentation process, the moisture content of the pile is maintained at 55% to 65%, and the pH value of the pile is maintained at 6.0 to 7.5.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] 1. The present invention provides a method for repairing electrolytic manganese slag contaminated soil by inoculating white rot fungi. The present invention creatively inoculates white rot fungi before starting composting, aiming at the problems that the content of metal manganese in electrolytic manganese slag contaminated soil is very high, with a total amount of 1000mg / L to 1400mg / L, the content of organic matter is low, only 10.00% to 14.04%, the pH value is between 6.1 and 6.5, and there are few indigenous microorganisms or low activity, which makes it difficult to achieve harmlessness and resource utilization. The present invention creatively inoculates white rot fungi before starting composting. By inoculating white rot fungi, the bacterial community structure and dominant strains of the pile are affected, the physical and chemical parameters of the pile are optimized, the leaching amount of heavy metal manganese is reduced, and the mobility and bioavailability of heavy metal manganese are reduced.

[0019] First, inoculating white rot fungi into the compost raw materials obtained by mixing biomass and electrolytic manganese slag contaminated soil accelerated the increase in compost temperature. The temperature of the compost was maintained between 50℃ and 65℃, which was conducive to the activity and metabolism of microorganisms and effectively eliminated pathogenic microorganisms. The temperature of the compost inoculated with white rot fungi increased faster than that of the uninoculated reference group, and NH4 + Accumulation occurs, the pH value slightly increases, and microbial activity becomes more active, which promotes the passivation of heavy metal manganese and reduces the leaching amount, mobility and bioavailability of heavy metal manganese. The total leaching concentration of heavy metal manganese in the soil repaired by this method is only 0.5mg / L~2.5mg / L.

[0020] Secondly, the inoculation of white rot fungi also accelerates the reduction of organic matter in the soil of contaminated sites during composting. Microorganisms release heat in the process of degrading organic matter, which accelerates the increase of the temperature of the pile, maintains the temperature of the pile at a high temperature level, and shortens the restoration cycle.

[0021] Finally, the composting process of inoculating white rot fungi changed the existing form of heavy metal manganese in the soil, converting heavy metal manganese from a weak acid extractable state to an oxidizable state and a residual state. Inoculating white rot fungi can increase the number of composting microbial species, so that the number of microbial species in the electrolytic manganese slag contaminated soil after restoration reached 460-487, while it was only 346-371 before restoration. Inoculating white rot fungi to remediate electrolytic manganese slag contaminated soil also changed the microbial community structure and dominant bacterial composition in the soil. Before inoculating white rot fungi, the dominant bacterial community in the soil was mainly actinomycetes. After inoculating white rot fungi to remediate electrolytic manganese slag contaminated soil, the dominant bacterial community turned to Firmicutes, Proteobacteria and Bacteroidetes. Among them, Actinomycetes play an important role in the decomposition of organic matter and are important organic matter decomposers in the composting process. They can effectively degrade complex organic matter in compost raw materials, such as cellulose, lignin and protein, and accelerate the maturity of the pile; Proteobacteria, including many nitrogen-fixing bacteria, can effectively improve the nitrogen fixation capacity of the remediated soil; Firmicutes also play a role in nitrogen fixation and cellulose degradation. In addition, Firmicutes and Bacteroidetes bacteria can effectively degrade plant cellulose, xylan, plant starch (such as amylose and amylopectin), etc., providing the carbon source required by other microorganisms for soil remediation.

[0022] In summary, the method of inoculating white rot fungi provided by the present invention to repair soil contaminated by electrolytic manganese slag changes the existence form of heavy metal manganese, greatly reduces the leaching of heavy metal manganese in the soil of electrolytic manganese slag contaminated sites, optimizes the microbial community structure and dominant bacterial community in the repaired soil, and can achieve deep repair of soil contaminated by electrolytic manganese slag.

[0023] 2. The present invention provides a method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi, and limits the inoculation amount of white rot fungi to 0.5% and 1% of the dry weight of the compost (and sets a blank control, in which the inoculation amount of white rot fungi is 0%). It is found that by controlling the inoculation amount of white rot fungi, the changes in the physical and chemical parameters of the compost compost during the composting process can be affected, the leaching concentration of heavy metal manganese can be reduced, the toxicity and bioavailability of heavy metal manganese can be reduced, the biological community structure and dominant bacterial community of the soil contaminated by electrolytic manganese slag can be optimized, the seed germination index can be improved, the repair of soil contaminated by electrolytic manganese slag can be achieved, and the optimal inoculation amount of white rot fungi is found to be 0.5% (v / w).

[0024] 3. The present invention provides a method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi, using soil contaminated by electrolytic manganese slag and agricultural waste such as vegetable leaves, rice straw, and bran as raw materials to achieve "waste treatment with waste". Among them, rice straw is used as a supporting material to adjust the porosity of the compost, which is beneficial to the dispersion of oxygen inside the pile and reduces the generation of anaerobic zones. Waste vegetable leaves and bran adjust the organic matter content and C / N ratio of the pile, so that the organic matter content of the pile is maintained at about 80% and the C / N ratio is maintained at about 25%, providing sufficient nutrient matrix for microorganisms, and realizing the orderly composting repair of soil contaminated by electrolytic manganese slag.

[0025] Furthermore, the present invention specifically defines the dry weight ratio of vegetable leaves, rice straw, bran and electrolytic manganese slag contaminated soil as 4:5:7:4. Composting to repair electrolytic manganese slag contaminated soil is a process in which microorganisms continuously mineralize organic matter and passivate heavy metal manganese. Organic matter is the basis for the survival and reproduction of microorganisms in this process. During the composting process of the present invention, the organic matter content of the pile body is reduced from 65% to 70% to 40% to 50%. The initial organic matter content of the pile body is 65% to 70%, which provides a basis for microorganisms to stably degrade organic matter, release heat, and maintain at a high temperature stage, meeting the conditions required for the growth and reproduction of microorganisms.

[0026] 4. The present invention provides a method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi, and the total leaching amount of heavy metal manganese in the contaminated soil is reduced by about 99.8%. After composting the soil contaminated by electrolytic manganese slag, the total leaching concentration of heavy metal manganese is lower than 2.5 mg / L, reaching the concentration limit of manganese ions lower than 5.0 mg / L specified in the national "Comprehensive Sewage Discharge Standard" (GB8978-1996). After composting the soil contaminated by electrolytic manganese slag, the germination index of ryegrass seeds reaches 30-70%. Therefore, the present invention provides a method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi with compost, which has the advantages of quickly starting composting repair, reducing the leaching amount of heavy metal manganese, reducing the mobility and bioavailability of heavy metal manganese, increasing microbial diversity and community abundance, optimizing the dominant microbial flora, and increasing the seed germination index. It can be used to repair soil contaminated by heavy metal manganese, and is an economical and effective repair method with good use value and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0028] Figure 1 This is a surface morphology picture of the pile on the 7th day in Example 1 of the present invention (white rot fungus hyphae).

[0029] Figure 2 This is a graph showing the change in total concentration of metallic manganese leaching during the pile restoration process in Example 1 of the present invention.

[0030] Figure 3 The figure shows the changes in bacterial community composition during the restoration process in Example 1.

[0031] Figure 4 The temperature variation curves of the repaired pile in Example 1 of the present invention and Comparative Example 1 are shown.

[0032] Figure 5 This is a diagram of seed germination after the pile has been used to repair contaminated soil in Example 1 of the present invention.

[0033] Figure 6 This is a diagram of seed germination after the pile was used to repair contaminated soil in Comparative Example 1 of the present invention.

[0034] Figure 7 This is a seed germination diagram of the original soil of the electrolytic manganese slag contaminated site of the present invention. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0036] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods. The methods in the following embodiments are conventional methods in the art unless otherwise specified.

[0038] Example

[0039] The materials and instruments used in the following examples are all commercially available.

[0040] Embodiment 1:

[0041] A method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi of the present invention comprises the following steps:

[0042] (1) Pretreatment: The vegetable leaves, rice straw, bran, and electrolytic manganese slag-contaminated soil are naturally air-dried, the vegetable leaves and rice straw are crushed, and the electrolytic manganese slag-contaminated soil is crushed and ground.

[0043] (2) The pretreated vegetable leaves, rice straw, bran, and electrolytic manganese slag contaminated soil are mixed in a dry weight ratio of 4:5:7:4 to obtain a compost raw material.

[0044] (3) Spray a spore suspension of white rot fungi (strain BKM-F-1767, purchased from China Center for Type Culture Collection (Wuhan, China)) with a dry weight of 0.5 wt% of the raw materials of the compost body into the compost raw materials, stir and mix, and obtain a compost body 1.

[0045] (4) After the surface of the pile 1 is covered with insulation material, composting and fermentation are carried out. In the first week of the start-up of the composting, the pile is turned over once every 1-2 days, and then once every 3-5 days, for a total of 30 days; after the 15th to 20th day of the start-up of the composting, the pile is naturally decomposed on site for 5-10 days to obtain the mature compost. The moisture content in the pile is maintained at 55-65% during the whole composting process.

[0046] After testing, the total concentration of heavy metal manganese leached in the electrolytic manganese slag contaminated soil is 1000mg / L-1400mg / L (the total concentration of heavy metal manganese leached in the present invention is determined according to the first step of the BCR extraction method), and the organic matter content is 10.00%-14.04%. After the compost raw materials are mixed, a pile 1 is obtained, and the total concentration of heavy metal manganese leached in the pile 1 is 280mg / L. Before inoculating white rot fungi, the number of microbial species in the electrolytic manganese slag contaminated soil is only 371, and the dominant bacterial flora of the soil is mainly composed of actinomycetes, proteobacteria and cyanobacteria. After inoculating white rot fungi compost to repair the electrolytic manganese slag contaminated soil, the total concentration of heavy metal manganese leached in the soil is only 0.5mg / L, and the reduction amount reaches 99.8%, reaching the concentration limit of manganese ions below 5.0mg / L specified in the national "Comprehensive Sewage Discharge Standard" (GB8978-1996). After inoculation of white rot fungi to repair the electrolytic manganese slag contaminated soil, the number of microbial species increased to 487, and the dominant bacterial flora of the soil turned to Firmicutes, Proteobacteria and Bacteroidetes. The germination index of ryegrass seeds was 70% (the calculation method in the present invention: seed germination index = number of seeds germinated during the germination peak / number of test seeds × 100%). After inoculation of white rot fungi to repair the electrolytic manganese slag contaminated soil, the pH of the soil was 7.13, showing neutrality, the organic matter content was 39.73%, the water content was 61.42%, and the physical and chemical parameters were suitable for plant growth.

[0047] From the above data, it can be seen that the process of inoculating 0.5% white rot fungus compost to repair electrolytic manganese slag contaminated soil can effectively realize the passivation of metallic manganese, greatly reducing the leaching concentration of heavy metal manganese in electrolytic manganese slag contaminated soil from 280 mg / L to 0.5 mg / L, changing the existence form of heavy metal manganese, reducing the mobility and bioavailability of heavy metal manganese, increasing microbial diversity and community abundance, optimizing the heavy microbial community structure and dominant bacterial community in the repaired soil, and realizing the ecological restoration of electrolytic manganese slag contaminated soil.

[0048] Figure 1 This is the morphology of the pile surface during the pile restoration process in Example 1, which is covered with hyphae of white rot fungi.

[0049] Figure 2 The total concentration of heavy metal manganese leached during the pile restoration process in Example 1 was reduced from 280 mg / L to 0.5 mg / L, and the metal passivation rate reached 99.98%. The toxicity, bioavailability and mobility of metal manganese were reduced accordingly, forming a relatively stable oxidizable state and a residual state with low mobility and low toxicity.

[0050] Figure 3The changes in bacterial community composition during the heap repair process in Example 1. In the figure, A shows the species level composition of the bacterial community structure of the heap when the heap is not inoculated with white rot fungi: 48.73% of Actinobacteria, 22.74% of Proteobacteria, 20.58% of Cyanobacteria, 3.27% of Firmicutes, and 2.67% of Bacteroidetes; in the figure, B shows the species level composition of the bacterial community structure after inoculating white rot fungi compost to repair the electrolytic manganese slag contaminated soil: 11.82% of Actinobacteria, 42.62% of Proteobacteria, 0.02% of Cyanobacteria, 15.78% of Firmicutes, and 28.99% of Bacteroidetes. The process of inoculating white rot fungi compost to repair heavy metal manganese contaminated soil optimizes the structure of the soil bacterial community. The change in the bacterial community structure can effectively improve the nitrogen fixation capacity and cellulose degradation of the repaired soil, and improve the fertility of the repaired soil.

[0051] Comparative Example 1:

[0052] The method is basically the same as Example 1, except that no white rot fungi are inoculated in Comparative Example 1. The specific process includes the following steps:

[0053] The following steps are involved:

[0054] (1) Pretreatment: The vegetable leaves, rice straw, bran, and electrolytic manganese slag-contaminated soil are naturally air-dried, the vegetable leaves and rice straw are crushed, and the electrolytic manganese slag-contaminated soil is crushed and ground.

[0055] (2) The pretreated vegetable leaves, rice straw, bran, and electrolytic manganese slag contaminated soil are mixed in a dry weight ratio of 4:5:7:4 to obtain a pile 2.

[0056] (3) After the surface of the pile 2 is covered with insulation material, composting and fermentation are carried out. In the first week of the start-up of the pile, the pile is turned over once every 1-2 days, and then once every 3-5 days, for a total of 30 days; after the 15th to 20th day of the start-up of the composting, the pile is naturally decomposed on site for 5-10 days to obtain the mature compost. The moisture content in the pile is maintained at 55-65% during the whole composting process.

[0057] After testing, it can be seen from the comparison between Comparative Example 1 and Example 1 that the total concentration of heavy metal manganese leaching is less reduced without inoculating white rot fungi. At the same time, the total concentration of heavy metal manganese leaching is 10.0 mg / L, which is reduced to 96.4%, but it does not reach the concentration limit of manganese ions below 5.0 mg / L specified in the National Sewage Comprehensive Discharge Standard (GB8978-1996), and the purpose of harmlessness is not achieved. After the white rot fungi were not inoculated to repair the electrolytic manganese slag contaminated soil, the number of microbial species increased to 460, and the dominant bacterial flora of the soil was mainly actinomycetes, proteobacteria and cyanobacteria.

[0058] Experiment 1: Investigate the temperature changes in the stacks of Example 1 and Comparative Example 1.

[0059] Temperature is the main parameter of the reaction microbial activity in the composting process and an important parameter for evaluating the decomposition performance of organic matter in the composting process. The complete composting process includes the heating stage, high temperature stage, cooling stage and maturity stage. In different stages of composting, bacteria, fungi, actinomycetes and prokaryotes show different metabolic intensities according to the change of temperature. During the composting process, the temperature of the pile should be controlled between 50℃ and 65℃.

[0060] Figure 4 The temperature change of pile 1 in Example 1 and the temperature change of pile 2 in Comparative Example 1. It can be seen from the figure that the inoculation of white rot fungi in the pile in Example 1 not only accelerates the increase of the temperature of the pile, but also prolongs the high temperature stage of composting to repair the electrolytic manganese slag contaminated soil. On the 3rd day, the temperature of the pile in Example 1 had risen to 51°C and remained above 50°C for 8 days, while the pile in Comparative Example 1 was only maintained above 50°C for 3 days. The change in the temperature of the pile in Comparative Example 1 and Example 1 shows that the inoculation of 0.5% white rot fungi accelerated the temperature rise of the pile and prolonged the high temperature stage of the pile, effectively promoting the start and orderly progress of composting.

[0061] Experiment 2: The germination rate of ryegrass seeds in the piles of Example 1 and Comparative Example 1 was investigated.

[0062] Figure 5 This is a diagram of germination of ryegrass seeds after the pile 1 in Example 1 repaired the soil contaminated by electrolytic manganese slag. The number of germinated seeds reached 42, and the seed germination index was 70%, indicating that after the repair, the mobility, toxicity and bioavailability of heavy metal manganese were reduced, and the repair of the soil contaminated by electrolytic manganese slag was effectively achieved.

[0063] Figure 6 This is a diagram of germination of ryegrass seeds after the restoration of pile 2 in Comparative Example 1. The number of germinated seeds reached 21, and the seed germination index was 35%, indicating that after composting restoration, the mobility and toxicity of heavy metal manganese were partially reduced, but compared with the process of inoculating white rot fungi to restore the electrolytic manganese slag contaminated soil in Example 1, the reduction in the leaching state of heavy metal manganese was less, and it still had high toxicity, and failed to achieve the restoration of electrolytic manganese slag contaminated soil.

[0064] Figure 7 This is a seed germination diagram of the original soil of the electrolytic manganese slag contaminated site in the present invention, and no seeds have germinated.

[0065] From the above results, it can be seen that the present invention uses inoculation of white rot fungi to repair the soil contaminated by electrolytic manganese slag, changes the existence form of heavy metal manganese, greatly reduces the leaching of heavy metal manganese in the soil contaminated by electrolytic manganese slag, optimizes the microbial community structure and dominant bacteria in the repaired soil, improves the seed germination index, and effectively realizes the repair of the soil contaminated by electrolytic manganese slag.

[0066] Summarize:

[0067] Inoculation of white rot fungi compost can effectively reduce the leaching of metallic manganese in electrolytic manganese slag contaminated soil, reduce its mobility and biological toxicity, and achieve the restoration of electrolytic manganese slag contaminated soil. After inoculation of white rot fungi compost to repair electrolytic manganese slag contaminated soil, the seed germination index is between 30% and 70%, the number of microbial species increases, the bacterial community is optimized, the ecological function of the soil is restored, the ecological restoration of electrolytic manganese slag contaminated soil is achieved, and the harmlessness and resource utilization of electrolytic manganese slag are achieved.

[0068] Embodiment 2:

[0069] A method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi of the present invention comprises the following steps:

[0070] (1) Pretreatment: The vegetable leaves, rice straw, bran, and electrolytic manganese slag-contaminated soil are naturally air-dried, the vegetable leaves and rice straw are crushed, and the electrolytic manganese slag-contaminated soil is crushed and ground.

[0071] (2) The pretreated vegetable leaves, rice straw, bran, and electrolytic manganese slag contaminated soil are mixed in a dry weight ratio of 4:5:7:4 to obtain a compost raw material.

[0072] (3) Spray a suspension of white rot fungi spores at 1 wt% of the dry weight of the raw materials of the compost body into the compost raw materials, stir and mix, and obtain a compost body 3.

[0073] (4) After covering the surface of the pile 3 with insulation material, composting and fermentation are carried out. In the first week of the repair pile, the pile is turned over every 1-2 days, and then every 3-5 days, for a total of 30 days; after the 15th to 20th day of composting, the pile is naturally decomposed on site for 5-10 days to obtain mature compost. The moisture content in the pile is maintained at 55-65% during the whole composting process.

[0074] After testing, the total leaching concentration of heavy metal manganese after inoculation of white rot fungi to repair electrolytic manganese slag contaminated soil was only 2.5 mg / L, and the reduction reached 99.1%, reaching the concentration limit of manganese ions below 5.0 mg / L stipulated in the National "Comprehensive Sewage Discharge Standard" (GB8978-1996). After inoculation of 1wt% white rot fungi to repair electrolytic manganese slag contaminated soil, the number of microbial species increased to 475, and the dominant bacterial flora in the soil turned to Firmicutes, Proteobacteria and Bacteroidetes. The seed germination index was 35%. After inoculation of white rot fungi to repair electrolytic manganese slag contaminated soil, the pH of the soil was 7.15 and neutral, the organic matter content was 36.01%, the water content was 60.35%, and the physical and chemical parameters were suitable for plant growth.

[0075] Summary: By controlling the inoculation amount of white rot fungi in the process of composting and repairing electrolytic manganese slag contaminated soil, it was observed that the appropriate inoculation amount is conducive to the increase of the temperature of the pile, prolonging the high temperature stage of the pile, and effectively eliminating pathogens; improving the physical and chemical parameters of the soil for pile repair, reducing the leaching of metal manganese, and reducing the toxicity and bioavailability of heavy metal manganese. It was also found that the inoculation amount of white rot fungi with the best passivation effect of heavy metal manganese is conducive to effectively controlling the inoculation amount of white rot fungi in practical applications, making full use of resources while achieving efficient passivation of heavy metal manganese, adjusting the structure of microbial communities, and increasing the number of microbial communities and species abundance.

[0076] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi, characterized in that: The following steps are involved: S1, mixing biomass and electrolytic manganese slag contaminated soil to obtain compost raw materials; S2, inoculating white rot fungi into the compost raw material to obtain a compost body; S3, composting, fermenting and decomposing the pile to complete the restoration of the soil contaminated by electrolytic manganese slag, and the white rot fungus is BKM-F-1767.

2. The method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi according to claim 1, characterized in that: The biomass described in S1 is vegetable leaves, rice straw and bran.

3. The method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi according to claim 2, characterized in that: The dry weight mass ratio of the vegetable leaves, rice straws, bran and electrolytic manganese slag contaminated soil is 2.5~5.5﹕4~6﹕6.5~8.5﹕2.5~5.

5.

4. The method for remediating soil contaminated by electrolytic manganese slag by inoculating white rot fungi according to claim 1, characterized in that: The total leaching concentration of heavy metal manganese in the electrolytic manganese slag contaminated soil in S1 is 1000 mg / L~1400 mg / L, and the organic matter content is 10.00%~14.04%.

5. The method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi according to claim 1, characterized in that: The inoculation amount of the white rot fungi in the S2 is 0.5% to 1%.

6. The method for repairing soil contaminated by electrolytic manganese slag by inoculating white rot fungi according to claim 1, characterized in that: The composting fermentation in S3 is specifically as follows: covering the surface of the pile with insulation material, turning the pile every 1-2 days in the first week; thereafter, turning the pile every 3-5 days, with a total duration of 30 days; and during the composting fermentation process, the moisture content of the pile is maintained at 55%-65%, and the pH value of the pile is maintained at 6.0-7.5.

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