Combined remediation method for heavy metal contaminated soil

Abstract

The invention discloses a combined remediation method for heavy metal contaminated soil. The combined remediation method for the heavy metal contaminated soil comprises the steps that a soil remediation agent is prepared after oyster shell powder, coal ash, cow dung, calcium molybdate, calcium aluminate, calcium superphosphate, calcium oxalate, (trimethylsilyl) phosphate, palygorskite, sodium silicoaluminate, poly dimethyl diallyl ammonium chloride, alkali aluminum sodium carbonate, barium metaborate, sodium selenite, poly(3,4-ethylenedioxythiophene), potassium ferrite and aluminate, and bergapten are weighed and mixed by weight; the heavy metal contaminated soil is crushed and mixed with water and the soil remediation agent, and pre-remediated soil is obtained 1-4 months later; and the pre-remediated soil is loosened and remediated through enrichment of earthworms. According to the combined remediation method for the heavy metal contaminated soil, through the combined remediation of the soil remediation agent and the earthworms, the heavy metal concentration in the soil is promoted to be decreased greatly, and the soil can be used for safety production as soon as possible; and the remediation effect is stable, the remediation time is short, and fertilize required for growth of plants can be provided. The remediation efficiency for the heavy metal contaminated soil is improved on the whole.

Description

technical field [0001] The invention relates to the technical field of soil remediation, in particular to a method for joint remediation of heavy metal polluted soil. Background technique [0002] Soil heavy metal pollution refers to the phenomenon that due to the addition of metals to the soil due to human activities, the heavy metals in the soil are significantly higher than the original content, and the quality of the ecological environment is deteriorated. The heavy metals that pollute the soil mainly include mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr) and metalloid arsenic (As) and other elements with significant biological toxicity, as well as zinc (Zn) and copper with certain toxicity. (Cu), nickel (Ni) and other elements. Mainly come from pesticides, wastewater, sludge and atmospheric deposition, etc. For example, mercury mainly comes from mercury-containing wastewater, cadmium and lead pollution mainly comes from smelting emissions and vehicle exhaust depo...

AI Technical Summary

Problems solved by technology

[0004] (1) Excavated soil method and soil replacement method have a large amount of engineering, high investment costs, and damage to the soil structure, and the replaced soil must be properly treated to prevent secondary pollution

Therefore, it is not suitable for the treatment of large-scale contaminated soil

[0005] (2) The disadvantage of the electrodynamic restoration method is that it is difficult to implement in actual China due to the small distance of the current action and the actual contaminated soil area, and its high operating cost is unbearable

[0006] (3) The cost of chemical leaching is high, and the reagents used for rinsing the soil will cause secondary pollution if they enter the soil

[0007] (4) The disadvantage of the thermal desorption method is: it can only be used to process heavy metals (such as Hg, Se, etc.) that are volatile; Secondary pollution