1. Bioremediation methods for soil pollution. Soil contaminants can be purified through biodegradation or plant absorption. Earthworms are animals that improve soil self-purification and can also be used to treat municipal and industrial waste, as well as harmful substances such as pesticides and heavy metals. Therefore, earthworms are known as "the strong men of ecology" and "purifiers". Actively promote the use of microbial degrading agents contaminated with pesticides to reduce pesticide residues. Use plant absorption to remove pollution: seriously polluted soil can be changed to some non-edible plants, such as flowers, trees, fiber crops, etc., can also be planted some non-edible plants with strong ability to absorb heavy metals, such as sheep's tooth fern plants have a strong ability to absorb and aggregate heavy metals in the soil, the absorption rate of cadmium can reach 10%, and continuous planting for many years can effectively reduce the soil cadmium content.
2. Chemical methods for soil pollution control. For soil with mild contamination of heavy metals, the use of chemical amendments can convert heavy metals into insoluble substances, reducing their uptake by plants. The application of lime in acidic soil can increase the soil pH value, so that cadmium, zinc, copper, mercury, etc. form hydroxide precipitation, thereby reducing their concentration in the soil and reducing the harm to plants. For soils with excessive nitrate nitrogen accumulation and has flowed into the groundwater body, one is to greatly reduce the amount of nitrogen fertilizer, and the other is to apply urease inhibitors, nitrification inhibitors and other chemical inhibitors to control the large accumulation of nitrate and nitrite.
3. Increase the application of organic fertilizer. The application of organic fertilizer can increase soil organic matter and nutrient content, which can not only improve soil physical and chemical properties, especially soil colloidal properties, but also increase soil capacity and improve soil purification capacity. For soil contaminated by heavy metals and pesticides, the application of organic fertilizers can increase the adsorption capacity of soil colloids, while soil humus can complexate pollutants, significantly improve the ability of soil passivation of pollutants, thereby weakening its toxicity to plants.
4. Control soil redox conditions. Adjusting the redox status of soil greatly affects the behavior of heavy metal valence elements in soil, which can convert some heavy metal pollutants into poorly soluble precipitates, control their migration and transformation, and reduce the degree of pollutant harm. Adjusting the soil redox potential, that is, the Eh value, is mainly achieved by adjusting the ratio of soil water and gas. In production practice, it is often implemented through soil moisture management and tillage measures, such as flooded paddy irrigation, when the Eh value can be reduced to 160mv, many heavy metals can form poorly soluble sulfides and reduce their toxicity.
5. Change and turn the soil. For lightly polluted soil, the method of turning the soil deep or changing to non-polluted guest soil is adopted. For heavily polluted soil, topsoil removal or replacement can be adopted. The advantage of these methods is that the improvement is more thorough and suitable for small area improvement. However, for the improvement of large-scale contaminated soil, it is very laborious and difficult to implement.
6. Implement targeted measures. For the treatment of heavy metal contaminated soil, the pollution is mainly reduced or eliminated through bioremediation, the use of lime, the application of organic fertilizer, irrigation to adjust soil Eh, and the exchange of guest soil. For the prevention and control of organic pollutants, the degradation of pollutants is accelerated by increasing the application of organic fertilizers, using microbial degrading agents, and regulating soil pH and Eh, thereby eliminating pollution.
Soil pollution control process
● On-site investigation of pollution sources
● Overall planning to achieve goals efficiently with effective resources
● Formulate one enterprise, one strategy, one plan
Equipment installation ● Equipment installation and commissioning according to national standards
● Test and accept the quality emission of the project
● Maintenance and operation after project acceptance