In-situ remediation method for heavy metal cadmium moderate pollution of farmland

Abstract

The invention relates to the technical field of environmental engineering, in particular to an in-situ remediation method for heavy metal cadmium moderate pollution of a farmland, the in-situ remediation method comprises the following steps: 1) a soil remediation agent and an organic fertilizer a are added into a 0-20 cm soil layer of cadmium polluted paddy land tillage planting soil; 2) an organic fertilizer b and calcium oxide are added into 20-40 cm soil layer soil which is not polluted, and the pH value is adjusted to be 6.5-7.5; 3) the 20-40 cm soil layer soil with the organic fertilizeradded is overturned to the 0-20 cm surface layer soil; 4) and the purpose of remediation of the cadmium-polluted soil is achieved by remediation for 90-150 days. The soil remediation method is wide inapplication range and short in repair period, the risk of residual heavy metals on the environment can be blocked, and the remediation agent is complexed and chelated with pollutants, and in particular, powdered rock phosphate in the remediation agent can enable the cadmium in the polluted soil to be converted from a high activity exchange state to a low activity acid solution state and residue state, so that the biological effectiveness and the migration capacity of the cadmium can be effectively reduced.

Description

technical field [0001] The invention relates to the technical field of environmental engineering, in particular to an in-situ repair method for moderately polluted farmland heavy metal cadmium. Background technique [0002] With the development of science and technology and the acceleration of industrialization, heavy metal pollution has now become the focus of people's attention on environmental pollution. According to the "National Soil Pollution Survey Bulletin" published by the Ministry of Environmental Protection and the Ministry of Land and Resources in 2017, the overall situation of the national soil environment is not optimistic. The soil pollution in the area is serious, the soil environment quality of cultivated land is worrying, and the soil environment problems of industrial and mining wasteland are prominent. Among them, cadmium in various media such as soil, sludge, irrigation sewage, and atmospheric deposition particles has formed a threat to food "from the soi...

AI Technical Summary

Problems solved by technology

Physical and chemical restoration mainly include electrochemical soil restoration method, leaching technology, electrokinetic restoration, chemical modifier method, surface active cleaning agent restoration method, oxidation or reduction technology and photocatalytic degradation technology, although the advantages of physical and chemical treatment are the treatment effect Both the cost and the cost are relatively moderate, but the physical and chemical methods have certain limitations and will cause secondary pollution; bioremediation mainly includes microbial remediation technology, phytoremediation technology, and microbial remediation technology using some characteristics of microorganisms themselves. Adsorption capacity, reduce the toxicity or bioavailability of heavy metals in the soil, change the living environment of microorganisms in the rhizosphere of crops, absorb, fix or volatilize heavy metals through plants, and passivate the heavy metals in the soil by microorganisms, thereby changing the bioavailability of heavy metals , reduce the toxic effect on other crops, phytoremediation technology has the advantages of permanent treatment effect, in-situ treatment process, low treatment cost, and environmental aesthetic compatibility, but its long construction period and high cost; polluted soil Joint remediation technology is divided into "physical-chemical" joint remediation technology and plant-microbial joint remediation, in which physical and chemical remediation is to use the physical and chemical properties of pollutants to remove pollutants from Removal in soil, plants act on pollutants mainly through absorption, transformation, degradation, and volatilization. Soil microorganisms are active colloids in soil, which have the characteristics of large specific surface, charged, and vigorous metabolic activities. They are generally found in polluted soils. In the soil, a variety of highly tolerant fungi and bacteria are enriched, and these microorganisms affect the toxicity of pollutants in the soil through multiple modes of action

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