Heavy-metal-polluted site soil leaching remediation method and device

Abstract

The invention relates to a heavy-metal-polluted site soil leaching remediation method and a heavy-metal-polluted site soil leaching remediation device. The method comprises the steps that: (1) soil pollutant types, densities, particle composition, pH value and organic matter content are detected; (2) the polluted soil is flushed by using water; a leaching agent is added, and the soil is leached; (3) separation is carried out by using a roller screen; on-screen substances are backfilled, and under-screen substances are subjected to fine separation; (4) under-screen substances are processed by using a hydrocyclone separation device; when obtained sand reaches a test standard, the sand can be backfilled; (5) alkali is added for regulating the pH value, and a heavy metal precipitating agent Na2S is added, such that heavy metal is converted into metal sulfide precipitate; (6) after the heavy metal precipitation reaction, a flocculant is added, such that coagulating sedimentation is carried out; after coagulating sedimentation, solid-liquid separation is carried out by using a plate-and-frame filter press; and (7) pH value of wastewater produced by solid-liquid separation is regulated by adding sulfuric acid, and is recycled in the leaching step. The method provided by the invention has the technical effects that: after heavy-metal-polluted soil is processed, heavy metal pollutants can be separated with physical separation (particle separation) and chemical extraction methods; and the leaching liquid (water) can be repeatedly utilized.

Description

technical field [0001] The invention relates to the technical field of contaminated soil remediation, in particular to a method and equipment for heavy metal contaminated soil. Background technique [0002] In recent years, during the adjustment of industrial structure and urban land use structure in our country, some industrial enterprises occupying superior positions in urban areas have withdrawn from prosperous areas through relocation, relocation and reconstruction. After the relocation of these enterprises, pollutants such as heavy metals, pesticides, volatile and persistent organic toxic substances left behind have become environmental hazards in urban land development and utilization. The safety of urban living environment is worrying, and risk assessment and restoration are urgently needed. In the "12th Five-Year Plan" of the national environmental protection, the strengthening of soil environmental protection, as a prominent environmental problem that needs to be ef...

AI Technical Summary

Problems solved by technology

[0010] The existing technologies basically focus on the development and application of leaching agents and the development of a small amount of experimental equipment, but there is little research on the combination optimization and digestion and absorption of the equipment for the site soil heterotopic remediation project, which greatly limits the development of this technology. Application of this technology in soil remediation engineering

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