Biochemical remediation method for polluted farmland soil in power transmission line construction

Abstract

The invention discloses a biochemical remediation method for polluted farmland soil in power transmission line construction, which comprises the following steps of: 1, investigating the soil pollution condition on site, and inserting a plastic isolation plate into the soil to isolate the polluted soil range, the method comprises the following steps of 1, collecting and culturing dominant microbial florae from unpolluted soil around a construction area, 2, collecting and carrying out enlarged culture on the dominant microbial florae from the unpolluted soil around the construction area, 3, spraying and fixing microorganisms on a carrier, 4, carrying out biochar adsorption, and 5, adding a magnetic material into farmland soil to reduce the influence of electromagnetic radiation on the soil and crops.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and in particular to a biochemical remediation method for farmland soil contaminated by transmission line construction. Background Art

[0002] Power transmission and transformation projects include the construction of transmission lines and transformer installation. For safety reasons, many transmission line construction projects occupy farmland, inevitably damaging farmland soil, especially during the laying of underground cables. Transmission line construction can contaminate farmland soil in several key ways: 1. The soil structure and surface topography are subject to significant vibration during transmission line installation, which can easily lead to soil erosion and loosen the surface soil. For example, excavation of tower bases exposes the ground surface, harming the growth of existing vegetation. Furthermore, prolonged soil trampling and mechanical compaction during construction can alter soil compaction. 2. Soil organisms and microorganisms can change. For example, earthworms and beneficial microorganisms can disappear over the long construction period. Even artificial restoration of the soil after construction is complete cannot correct the deterioration of the topsoil's physical and chemical structure, resulting in insufficient fertility and a loss of biological and microbial populations. This can make the soil in the restoration area unfavorable for crop growth, and even electromagnetic fields generated during transmission line operation. Although there is no consensus on whether electromagnetic radiation from power lines directly causes changes in soil chemical properties, some studies have shown that long-term electromagnetic environment may affect the activity of certain metal ions in the soil.

[0003] The invention patent with publication number CN114147062A discloses a soil bioremediation method. By introducing biofertilizer and a mixture into the soil, the biofertilizer provides nutrients for microbial growth, thereby promoting the reproduction of microorganisms in the soil and degrading pollutants in the soil, thereby achieving better soil remediation effects. At the same time, the rice bran, sawdust, etc. contained in the biofertilizer are conducive to keeping the soil loose. By introducing earthworms into the soil, earthworms are used to improve the thoroughness and efficiency of soil remediation, which is in line with the concept of green ecological restoration.

[0004] However, in the above-mentioned soil bioremediation method, direct spreading of biofertilizer and plowing causes the contaminated soil area to be mixed with different soils again, which can easily cause the pollution range to expand and cause secondary pollution, increase the difficulty of remediation, and fail to effectively limit the scope of soil contamination. Therefore, the present invention proposes a biochemical remediation method for farmland soil contaminated by transmission line construction to solve the problems existing in the prior art. Summary of the Invention

[0005] In response to the above problems, the purpose of the present invention is to propose a biochemical remediation method for farmland soil contaminated by transmission line construction. The biochemical remediation method for farmland soil contaminated by transmission line construction extracts and expands the culture of dominant microbial flora from uncontaminated soil samples around the construction area for soil remediation, so that the soil in the contaminated area can be restored to the same physical and chemical structure as the soil in the uncontaminated area as soon as possible, thereby achieving targeted remediation of farmland soil contaminated by transmission line construction and improving soil remediation efficiency. By spraying the microorganisms on a carrier fixed on the carrier during application and then mixing the carrier with the contaminated soil, the stability of the microorganisms is improved to ensure the remediation effect.

[0006] To achieve the purpose of the present invention, the present invention is implemented through the following technical solution: a biochemical remediation method for farmland soil contaminated by transmission line construction, comprising the following steps:

[0007] Step 1: Investigation and Isolation: Conduct an on-site investigation of soil contamination and isolate the contaminated soil area by inserting plastic isolation panels into the soil;

[0008] Step 2: Microbial screening: Collect and expand the culture of dominant microbial flora from uncontaminated soil around the construction area;

[0009] Step 3: Microbial remediation: Spray the microorganisms onto a carrier, then mix the carrier with the contaminated soil to improve the stability and survival rate of the microorganisms and prolong their action time in the soil;

[0010] Step 4: Biochar adsorption: Spread the biochar evenly in the farmland soil within the contaminated area. Mix the biochar into the soil through tillage to adsorb organic pollutants. At the same time, the biochar's large specific surface area and pore structure can absorb part of the electromagnetic radiation energy.

[0011] Step 5: Magnetic material improvement: Add magnetic materials to farmland soil to allow the magnetic materials to interact with the electromagnetic field, changing the distribution and intensity of the electromagnetic field, thereby reducing the impact of electromagnetic radiation on soil and crops.

[0012] A further improvement is that in step 1, the depth of the plastic isolation board inserted into the soil is 1 meter.

[0013] A further improvement is that the collection of dominant microbial populations in step 2 includes the following steps: soil sampling, selective culture, gradient dilution, spreading culture and strain screening.

[0014] The specific steps are:

[0015] (1) Use a sampling shovel or other tools to remove the surface soil about 5 cm thick to avoid contamination by airborne microorganisms; collect soil from a depth of 5 to 25 cm, as this layer contains a larger number of microorganisms and a richer variety; place the collected soil samples in clean polyethylene bags, kraft bags, or glass bottles, and mark the sampling location, time, soil type, and other information.

[0016] (2) Prepare a suspension of soil sample, dilute the suspension in a gradient manner, and then take an appropriate amount of the suspension and inoculate it onto a solid culture medium.

[0017] (3) Cultivate under appropriate culture conditions so that individual microorganisms form colonies on the culture medium.

[0018] (4) Continue to expand the colony until the viable count exceeds 100 million / mL.

[0019] Further improvement is that: the carrier in step 3 is activated carbon, the number of microorganisms inoculated in the soil is 10 5 ~10 7 cfu / kg.

[0020] A further improvement is that the tillage depth in step 4 is 15 to 30 centimeters and the amount of biochar used is 10 to 20 tons per hectare.

[0021] A further improvement is that the biochar in step 4 is carboxyl- and amino-modified biochar.

[0022] Furthermore, the method for preparing the carboxyl- and amino-modified biochar comprises the following steps: (1) pre-treating the biomass raw material and then pyrolyzing it to obtain biochar;

[0023] (2) mixing biochar and hydrogen peroxide solution at a solid-liquid ratio of 1:10; stirring and reacting, filtering and collecting the residue; drying the residue to obtain carboxyl-modified biochar;

[0024] (3) The carboxyl-modified biochar was mixed with deionized water, and after thorough stirring, triethylenediamine amination reagent (the amount added was 5 wt% of the carboxyl-modified biochar) was added; the mixture was heated to 60°C and maintained for 40 min, and then cooled to generate an amino-modified biochar aqueous solution; the amino-modified biochar aqueous solution was filtered, washed, dried, and cooled in sequence to prepare carboxylamino-modified biochar.

[0025] Furthermore, the biochar raw material is selected from at least one of corn straw, rice bran, sorghum straw, and wheat straw.

[0026] A further improvement is that the magnetic material in step five is magnetite powder, and the proportion of the magnetite powder is 0.1 to 0.3 tons per hectare.

[0027] The beneficial effects of the present invention are as follows: by extracting and expanding the culture of dominant microbial flora from uncontaminated soil samples around the construction area for soil remediation, the present invention can restore the soil in the contaminated area to the same physical and chemical structure as that of the soil in the uncontaminated area as soon as possible, thereby achieving targeted remediation of farmland soil contaminated by transmission line construction and improving soil remediation efficiency. By spraying the microorganisms onto a carrier fixed thereon during application and then mixing the carrier with the contaminated soil, the stability of the microorganisms is improved to ensure the remediation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0029] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the examples. The examples are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0030] In the following examples, the specific steps of the method for collecting and expanding the culture of dominant microbial populations from soil are as follows:

[0031] (1) Use a sampling shovel or other tools to remove the surface soil about 5 cm thick to avoid contamination by airborne microorganisms; collect soil from a depth of 5 to 25 cm, as this layer contains a larger number of microorganisms and a richer variety; place the collected soil samples in clean polyethylene bags, kraft bags, or glass bottles, and mark the sampling location, time, soil type, and other information.

[0032] (2) Prepare a suspension of soil sample, dilute the suspension in a gradient manner, and then take an appropriate amount of the suspension and inoculate it onto a solid culture medium.

[0033] (3) Cultivate under appropriate culture conditions so that individual microorganisms form colonies on the culture medium.

[0034] (4) Continue to expand the colony until the viable count exceeds 100 million / mL.

[0035] In the following examples, the preparation method of carboxyl- and amino-modified biochar includes the following steps: (1) pre-treating the biomass raw material and then pyrolyzing it to obtain biochar;

[0036] (2) Mix corn straw biochar and hydrogen peroxide solution at a solid-liquid ratio of 1:10; after stirring and reacting, filter and collect the residue; and dry the residue to obtain carboxyl-modified biochar;

[0037] (3) The carboxyl-modified biochar was mixed with deionized water, and after thorough stirring, triethylenediamine amination reagent (the amount added was 5 wt% of the carboxyl-modified biochar) was added; the mixture was heated to 60°C and maintained for 40 min, and then cooled to generate an amino-modified biochar aqueous solution; the amino-modified biochar aqueous solution was filtered, washed, dried, and cooled in sequence to prepare carboxylamino-modified biochar.

[0038] It should be noted that the technical means not described in the embodiments of the present invention are all conventional technical means and are not limited by the embodiments of the present invention.

[0039] Example 1

[0040] according to Figure 1 As shown, this embodiment provides a biochemical remediation method for farmland soil contaminated by transmission line construction, comprising the following steps:

[0041] Step 1: Investigation and Isolation: Conduct an on-site investigation of soil contamination and use plastic isolation boards inserted into the soil to isolate the contaminated soil area. The plastic isolation boards are inserted into the soil to a depth of 1 meter. The plastic isolation boards are used to separate the contaminated soil from the uncontaminated soil, effectively preventing pollutants in the soil from diffusing with water infiltration. Compared with the excavation and stacking method, there is no need to dig up the contaminated soil from the contaminated area, which effectively improves the remediation efficiency of contaminated farmland soil.

[0042] Step 2: Microbial screening: Collect and expand the culture of dominant microbial flora from uncontaminated soil around the construction area;

[0043] Step 3: Microbial remediation: Spray the microorganisms onto a carrier and mix the carrier with the contaminated soil to improve the stability and survival rate of the microorganisms and prolong the action time of the microorganisms in the soil; the carrier is activated carbon and the number of microorganisms inoculated in the soil is 10 5 cfu / kg, decompose pollutants in the soil through the metabolic activities of microorganisms. Pseudomonas can use petroleum hydrocarbons for growth and reproduction, and decompose them into carbon dioxide and water. Without causing too much disturbance to the soil, it takes advantage of the fast reproduction speed and strong metabolic capacity of microorganisms to repair non-polluted soil.

[0044] Step 4: Biochar adsorption: Spread the biochar evenly and directly on the farmland soil within the pollution range, mix the biochar into the soil through plowing to achieve the adsorption of organic pollutants, and use the thermal conductivity of biochar with a large specific surface area and pore structure to adsorb part of the electromagnetic radiation energy; the plowing depth is 15 cm, and the biochar dosage is 10 tons per hectare; the main polar functional groups on the surface of biochar include carboxyl, phenolic hydroxyl, carbonyl, lactone, pyrone, anhydride, etc., which constitute the good adsorption characteristics of biochar. Biochar provides a good habitat for the soil, and its porous interface can provide a shelter for microorganisms. The organic carbon in biochar can be used as a carbon source for microorganisms. In the soil where biochar is applied, the number and types of bacteria and microorganisms will increase, allowing them to participate in the nutrient cycle and the decomposition process of organic matter in the soil, which is beneficial to improving soil fertility.

[0045] Step 5: Magnetic material improvement: Add magnetic material to farmland soil to make the magnetic material interact with the electromagnetic field, change the distribution and intensity of the electromagnetic field, and thus reduce the impact of electromagnetic radiation on soil and crops; the magnetic material is magnetite powder, and the proportion of magnetite powder is 0.1 tons per hectare.

[0046] Example 2

[0047] according to Figure 1 As shown, this embodiment provides a biochemical remediation method for farmland soil contaminated by transmission line construction, comprising the following steps:

[0048] Step 1: Investigation and Isolation: Conduct an on-site investigation of soil contamination and use plastic isolation boards inserted into the soil to isolate the contaminated soil area. The plastic isolation boards are inserted into the soil to a depth of 1 meter. The plastic isolation boards are used to separate the contaminated soil from the uncontaminated soil, effectively preventing pollutants in the soil from diffusing with water infiltration. Compared with the excavation and stacking method, there is no need to dig up the contaminated soil from the contaminated area, which effectively improves the remediation efficiency of contaminated farmland soil.

[0049] Step 2: Microbial screening: Collect and expand the culture of dominant microbial flora from the uncontaminated soil around the construction area.

[0050] Step 3: Microbial remediation: spray the microorganisms onto a carrier and mix the carrier with the contaminated soil to improve the stability and survival rate of the microorganisms and prolong the action time of the microorganisms in the soil; the carrier is activated carbon and the number of microorganisms inoculated in the soil is 10 6 cfu / kg, decompose pollutants in the soil through the metabolic activities of microorganisms. Pseudomonas can use petroleum hydrocarbons for growth and reproduction, and decompose them into carbon dioxide and water. Without causing too much disturbance to the soil, it takes advantage of the fast reproduction speed and strong metabolic capacity of microorganisms to repair non-polluted soil.

[0051] Step 4: Biochar adsorption. Spread the biochar evenly and directly in the farmland soil within the pollution range. Mix the biochar into the soil through plowing to achieve the adsorption of organic pollutants. At the same time, use the thermal conductivity of biochar with a large specific surface area and pore structure to adsorb part of the electromagnetic radiation energy. The plowing depth is 25 cm, and the biochar dosage is 15 tons per hectare. The main polar functional groups on the surface of biochar include carboxyl, phenolic hydroxyl, carbonyl, lactone, pyrone, anhydride, etc., which constitute the good adsorption characteristics of biochar. Biochar provides a good habitat for the soil, and its porous interface can provide a shelter for microorganisms. The organic carbon in biochar can be used as a carbon source for microorganisms. In the soil where biochar is applied, the number and types of bacteria and microorganisms will increase, allowing them to participate in the nutrient cycle and the decomposition process of organic matter in the soil, which is beneficial to improving soil fertility.

[0052] Step 5: Improve the magnetic material and add magnetic material to the farmland soil to make the magnetic material interact with the electromagnetic field, change the distribution and intensity of the electromagnetic field, and thus reduce the impact of electromagnetic radiation on the soil and crops; the magnetic material is magnetite powder, and the proportion of magnetite powder is 0.2 tons per hectare.

[0053] Example 3

[0054] The following steps are involved:

[0055] Step 1: Investigation and Isolation: Conduct an on-site investigation of soil contamination and use plastic isolation boards inserted into the soil to isolate the contaminated soil area. The plastic isolation boards are inserted into the soil to a depth of 1 meter. The plastic isolation boards are used to separate the contaminated soil from the uncontaminated soil, effectively preventing pollutants in the soil from diffusing with water infiltration. Compared with the excavation and stacking method, there is no need to dig up the contaminated soil from the contaminated area, which effectively improves the remediation efficiency of contaminated farmland soil.

[0056] Step 2: Microbial screening: Collect and expand the culture of dominant microbial flora from the uncontaminated soil around the construction area.

[0057] Step 3: Microbial remediation: spray the microorganisms onto a carrier and mix the carrier with the contaminated soil to improve the stability and survival rate of the microorganisms and prolong the action time of the microorganisms in the soil; the carrier is activated carbon and the number of microorganisms inoculated in the soil is 10 7 cfu / kg, decompose pollutants in the soil through the metabolic activities of microorganisms. Pseudomonas can use petroleum hydrocarbons for growth and reproduction, and decompose them into carbon dioxide and water. Without causing too much disturbance to the soil, it takes advantage of the fast reproduction speed and strong metabolic capacity of microorganisms to repair non-polluted soil.

[0058] Step 4: Biochar adsorption. Spread the biochar evenly and directly in the farmland soil within the pollution range. Mix the biochar into the soil through plowing to achieve the adsorption of organic pollutants. At the same time, use the thermal conductivity of biochar with a large specific surface area and pore structure to adsorb part of the electromagnetic radiation energy. The plowing depth is 30 cm, and the biochar dosage is 20 tons per hectare. The main polar functional groups on the surface of biochar include carboxyl, phenolic hydroxyl, carbonyl, lactone, pyrone, anhydride, etc., which constitute the good adsorption characteristics of biochar. Biochar provides a good habitat for the soil, and its porous interface can provide a shelter for microorganisms. The organic carbon in biochar can be used as a carbon source for microorganisms. In the soil where biochar is applied, the number and types of bacteria and microorganisms will increase, allowing them to participate in the nutrient cycle and the decomposition process of organic matter in the soil, which is beneficial to improving soil fertility.

[0059] Step 5: Improve the magnetic material and add magnetic material to the farmland soil to make the magnetic material interact with the electromagnetic field, change the distribution and intensity of the electromagnetic field, and thus reduce the impact of electromagnetic radiation on the soil and crops; the magnetic material is magnetite powder, and the proportion of magnetite powder is 0.3 tons per hectare.

[0060] The physical and chemical properties of the soil after repair in Examples 1-3 were monitored in real time. The time required for Example 1 to recover to the same physical and chemical properties as the surrounding soil was 45 days, Example 2 was 51 days, and Example 3 was 49 days.

[0061] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A biochemical remediation method for farmland soil contaminated by transmission line construction, comprising the following steps: Step 1: Conduct an on-site investigation of soil contamination and isolate the contaminated soil area by inserting plastic isolation panels into the soil; Step 2: Collect and expand the culture of dominant microbial flora from uncontaminated soil around the construction area; Step 3: Spray the microorganisms onto a carrier, then mix the carrier with the contaminated soil to improve the stability and survival rate of the microorganisms and prolong their action time in the soil; Step 4: Spread the biochar evenly in the farmland soil within the contaminated area. Mix the biochar into the soil through tillage to adsorb organic pollutants. At the same time, the biochar's large specific surface area and pore structure will absorb part of the electromagnetic radiation energy. Step 5: Add magnetic materials to the farmland soil so that the magnetic materials interact with the electromagnetic field, changing the distribution and intensity of the electromagnetic field, thereby reducing the impact of electromagnetic radiation on the soil and crops.

2. The biochemical remediation method for farmland soil contaminated by power line construction according to claim 1, characterized in that: In the step 1, the depth of the plastic isolation board inserted into the soil is 1 meter.

3. The biochemical remediation method for farmland soil contaminated by power line construction according to claim 1, characterized in that: The collection of dominant microbial populations in step 2 includes the following steps: soil sampling, selective culture, gradient dilution, spreading culture and strain screening.

4. The biochemical remediation method for farmland soil contaminated by power line construction according to claim 1, characterized in that: The carrier in step 3 is activated carbon, and the number of microorganisms inoculated in the soil is 10 5 ~10 7 cfu / kg.

5. The biochemical remediation method for farmland soil contaminated by power line construction according to claim 1, characterized in that: The tillage depth in step 4 is 15 to 30 centimeters, and the amount of biochar used is 10 to 20 tons per hectare.

6. The biochemical remediation method for farmland soil contaminated by power line construction according to claim 1, characterized in that: The biochar in step 4 is carboxyl- and amino-modified biochar.

7. The biochemical remediation method for farmland soil contaminated by power transmission construction according to claim 1, characterized in that: The magnetic material in step five is magnetite powder, and the ratio of the magnetite powder is 0.1 to 0.3 tons per hectare.

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