Treatment method of heavy metal contaminated soil

A treatment method and technology for contaminated soil, applied in the field of treatment of heavy metal contaminated soil, can solve problems such as difficult acceptance by owners, reduced treatment efficiency, increased risk of secondary pollution, etc. Enhanced effect of washing treatment

Active Publication Date: 2020-11-17
FUJIAN LONGKING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Therefore, although the existing soil leaching technology can achieve the reduction of heavy metal-contaminated soil to a certain extent, there are still some problems: (1) The fine soil particles separated by the existing leaching technology are difficult to directly remove due to the high content of pollutants. On-site backfilling requires solidification / stabilization treatment, which not only increases the treatment cost, but also increases the risk of secondary pollution, so it is difficult to be accepted by the owner; (2) Due to human activities and weathering, the fine particle content of the soil When the content of fine particles increases, the permeability becomes poor, and when the content of fine particles exceeds 30wt%, the content of fine particles is too high, and the treatment efficiency is greatly reduced, so the existing leaching technology is difficult to apply to the treatment of soil with high fine particle content

Method used

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Examples

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Effect test

preparation example Construction

[0033] In the preparation step of the above-mentioned plant extract provided by the present invention, the plant parts to be extracted are first soaked in water. Wherein, the plant parts to be extracted include but not limited to one or more of pericarp, stem and leaf, preferably one or more of Sapinberry pericarp, Daqing leaf and water hyacinth leaf; The plant parts to be extracted are preferably pulverized before soaking, and the particle size after pulverization is preferably ≤2 mm; the water consumption for soaking is preferably 2 to 50 times the plant mass, specifically 2 times or 2.5 times , 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, 8.5 times, 9 times, 9.5 times, 10 times, 15 times, 20 times times, 25 times, 30 times, 40 times or 50 times; the soaking temperature is preferably 5 to 35°C, specifically 5°C, 10°C, 15°C, 20°C, 25°C (room temperature), 30°C or 35°C; the soaking time is preferably 30-120 min, ...

Embodiment 1

[0044] The soil for testing comes from an industrial site in Zhangzhou. The soil classification belongs to yellow-brown soil. The soil is heavily polluted by heavy metals. The sampling layer is 0-20cm from the surface, the soil pH=5.33±0.25, and the CEC is 17.7cmol / kg; >0.074mm accounts for 40.01wt% , 0.074~0.002mm accounts for 48.40wt%; <0.002mm accounts for 11.59wt%, the total Cd content is 23.6±4.5mg / kg, and the water content is 20%, which belongs to silty clay.

[0045] 1) Prepare plant extract:

[0046] Add Sapindus fruit peel into a pulverizer for crushing to obtain crushed material with a particle size of <2 mm; put the crushed crushed material into a leaching device, add water 10 times the weight of the plant, and soak for 60 minutes at room temperature; after soaking, decoct Boil for 30 minutes, then let stand for 2 hours; finally carry out solid-liquid separation in a centrifuge, the speed of the centrifuge is set to 4000r / min, and the centrifugation time is 5 minute...

Embodiment 2

[0054] The soil for testing comes from an industrial site in Longyan. The soil classification belongs to red loam soil. The soil is seriously polluted by heavy metals. The sampling layer is 0-5m, the soil pH=6.35±0.25, and the CEC is 8.48cmol / kg; >0.074mm accounts for 57.0wt%, 0.074 ~0.002mm accounts for 30.5wt%; <0.002mm accounts for 12.5wt%, the total Pb content is 600±14.5mg / kg, and the water content is 25%, which belongs to silty clay.

[0055] 1) Prepare plant extract:

[0056] Add Sapindus fruit peel into a pulverizer for crushing to obtain fragments with a particle size of <2 mm; put the crushed fragments into an extraction device, add water 50 times the weight of the plant, and soak for 30 minutes at room temperature; after soaking, decoct Boil for 40 minutes, then let stand for 2 hours; finally, carry out solid-liquid separation in a centrifuge, the centrifuge speed is set to 3500r / min, and the centrifugation time is 5min. After the centrifugation, the sapinberry peel...

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PUM

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Abstract

The invention belongs to the field of environmental protection, and particularly relates to a treatment method for heavy metal contaminated soil. The treatment method provided by the invention comprises the following steps: a) mixing heavy metal contaminated soil with a plant leaching solution, and granulating to obtain microspheres, wherein the plant leaching solution contains carboxyl, hydroxyland polycyclic hydrocarbon; b) stacking the microspheres to obtain a microsphere stack; and c) leaching the microsphere stack to obtain the treated soil. The treatment method provided by the inventionfills the technical blank that the current high-fine-grain-content soil is difficult to leach and treat, and the treatment of the heavy metal contaminated soil can be realized only by simple granulation, heaping and spraying. According to the method, high-end crushing, screening and solid-liquid separation equipment does not need to be used, solidification / stabilization treatment and backfillingof soil fine particles do not need to be considered, investment and operation cost are greatly reduced, and the method has wide market popularization prospects and good environmental benefits and economic benefits.

Description

technical field [0001] The invention belongs to the field of environmental protection, and in particular relates to a treatment method for heavy metal polluted soil. Background technique [0002] Soil leaching refers to the process of injecting or infiltrating eluent into the soil, making it flow through the soil layer to be treated, analyzing the pollutants in the soil, and then treating and reusing the eluent containing pollutants. This technology can be used for the treatment or pretreatment of radioactive substances, organic substances, heavy metals or other inorganic substances polluted soil. [0003] The existing leaching technology has two main mechanisms of action: (1) Separation of coarse particles (particle size > 0.074mm) and fine particles (particle size ≤ 0.074mm) soil. Since pollutants tend to be distributed in fine-grained soils, coarse-grained soils with pollutant concentrations below the remediation target value after leaching are screened out for direct...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08B09C1/02
CPCB09C1/08B09C1/02
Inventor 胡杰华肖尧钟安良何苏祺吴丹霞陈俊华郭丹花
Owner FUJIAN LONGKING
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