Method for treating heavy metal pollution in soil by using a low-position leaching high-position extraction technology

Abstract

The invention discloses a method for treating heavy metal pollution in soil by using a low-position leaching high-position extraction technology. The method comprises: constructing a packed drain well, laying a clay working bed course on the earth surface, arranging a leaching agent pipe in the packed drain well, arranging a vacuum filtering pipe in the vertical direction of the working bed course, digging a ditch groove, laying a plastic film on the upper portion of the working bed course, drilling at the positions, corresponding to the leaching agent pipe and the vacuum filtering pipe, on the plastic film, preparing a carbon dioxide leaching agent, introducing the carbon dioxide leaching agent into the leaching agent pipe, controlling the flow rate of carbon dioxide while opening a vacuum system, controlling the vacuum degree and the leaching agent introducing time, and controlling the vacuum extraction time. According to the present invention, the leaching process and the extractionprocess are performed simultaneously, wherein carbon dioxide diffuses upward to accelerate and expand the range of the bicarbonate forming soil so as to achieve the complete leaching treatment, and the heavy metal salt in the mellow soil layer cannot migrate downward due to the migration effect of the vacuum pressure so as to effectively prevent groundwater and soil from being polluted by the heavy metal salts.

Description

technical field [0001] The invention belongs to the technical field of soil treatment, and in particular relates to a method for treating heavy metal pollution in soil by low-level leaching and high-level extraction technology. Background technique [0002] With the massive development and utilization of mineral resources, the rapid development of industrial production and the widespread use of various chemical products, pesticides and fertilizers, pollutants containing heavy metals enter the environment through various channels, causing soil, especially farmland soil, to become increasingly polluted by heavy metals . At present, there are different degrees of pollution in the soil of various countries in the world. The global average annual emission of Hg is about 1.5×104t, Cu is about 3.4 million tons, Pb is about 5 million tons, Mn is about 15 million tons, and Ni is about 100 tons. In Europe, there are millions of hectares of farmland polluted by heavy metals; in Japan,...

AI Technical Summary

Problems solved by technology

[0017] 1. High energy consumption and high operating costs

[0018] 2. The development of soil leaching technology and complete sets of equipment that can be applied on a large scale is relatively lagging behind

[0019] 3. It is easy to reactivate and produce secondary pollution

[0020] 4. The repair cycle is long and the effect is not significant

[0021] 5. The eluent cannot be controlled by organized flow, and it is easy to flow into the groundwater environment and pollute the groundwater

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