Method for treatment of soil containing chromium through coupling of biogas residue microbial inoculum and ferrous sulfate

Abstract

The invention provides a method for treatment of soil containing chromium through coupling of biogas residue microbial inoculum and ferrous sulfate. Soil treated with biogas residue microbial inoculum and soil treated with ferrous sulfate are mixed, and sulfate in ferrous sulfate is reduced by means of sulfate reducing bacteria in biogas residue microbial inoculums to generate sulfide, so that hexavalent chromium can be reduced more effectively and secondary pollution of sulfate is avoided.

Description

technical field [0001] The invention provides a method for coupling treatment of chromium-containing soil with biogas residue bacterial agent and ferrous sulfate. The soil treated with biogas residue bacterial agent and ferrous sulfate treated soil is superimposed and mixed, and the sulfate in the biogas residue bacterial agent is used to reduce Bacteria reduce sulfate in ferrous sulfate to generate sulfide, while more effectively reducing hexavalent chromium, avoid secondary pollution of sulfate, and belong to the field of environmental protection. Background technique [0002] Chromium and its compounds are commonly used basic raw materials in metallurgy, metal processing, electroplating, tanning, paint, pigment and other industries. During the production process of the above industries, a large amount of chromium-containing waste gas, waste water and waste residue are produced, resulting in serious environmental pollution problems. On the other hand, how to remediate chro...

AI Technical Summary

Problems solved by technology

Although this method can restore chromium-containing soil, it consumes a lot of electricity and takes a long time to treat, so it is not suitable for large-scale disposal of chromium-containing soil.

However, the chemical reagents such as ferrous iron or sulfide used in the current in-situ repair method also have the problem of secondary pollution, and are easily oxidized by the environment to cause functional failure.

Patent No. 201310642919.6 introduces a method for in-situ restoration of Cr(VI)-containing sites using organic waste, which is a low-cost way to dispose of hexavalent chromium soils, but this method can only be used for soils with a natural anti-seepage layer at the bottom , otherwise it will accelerate the penetration of hexavalent chromium into the ground, resulting in the diffusion of hexavalent chromium

Patent 201310643015.5 introduces a method of using biogas residues to prepare Cr(VI)-contaminated site restoration flora. This method uses biogas residues and other organic wastes as raw materials, and through a special culture method, domesticates bacteria flora suitable for chromium-containing site restoration. However, the domestication period of this method is too long, which is not conducive to engineering practice

[0003] At present, the mainstream process of chromium-containing soil is still to use ferrous sulfate to reduce hexavalent chromium, but the pH of ferrous sulfate is too low, it is corrosive, and it is easy to be oxidized and deactivated in the air. , so the reduction of hexavalent chromium can only be short-term, not long-term reduction

At the same time, it is easy to cause secondary pollution of sulfate radicals

Patent No. 201410101586.0 introduces a method of using ferrous sulfate to repair Cr(VI)-containing sites in situ. Since ferrous is easy to oxidize and fail in the air, this method uses low pH citric acid to inhibit its oxidation and increase the penetration of ferrous , but correspondingly increases the cost, and makes the soil acidified, and still brings secondary pollution of sulfate