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Ex-situ decontamination method for low-permeability contaminated soil

A low-permeability, polluted soil technology, applied in the restoration of polluted soil, etc., can solve the problems of ineffective, low-permeability fine particle polluted soil with poor treatment effect and inapplicability

Inactive Publication Date: 2018-12-07
BEIJING ZHONGYAN DADI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are at least two defects in the existing ex-situ treatment technologies for polluted soil: first, for the permeability coefficient below 10 -4 The treatment effect of the low permeability fine particle contaminated soil of cm / s is very poor
Second, it is only effective for a specific pollutant. For example, technologies suitable for the treatment of organic-contaminated soil are generally not suitable for the treatment of inorganic-contaminated soil; may not work

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] Contaminated soil is mainly kaolin clay with a density of 1.27g / cm 3 , the permeability coefficient is 7.1×10 -8 cm / s; Pb 2+ Content 2000mg / kg, Zn 2+ Content 1100mg / kg. It was originally intended to be transported to the landfill for permanent landfill, but now it is used as a landscape mountain green space after decontamination by the present invention.

[0063] The construction can be stacked with an area of ​​200m×150m. Each layer of polluted soil is 1m thick, totaling 40 layers.

[0064] The cathode uses a stainless steel tube as the electrode, and the anode is a titanium alloy tube with a ruthenium oxide coating; the diameter is 1.6 cm, and the tube wall is distributed along the cross section at 30° and every 2 cm along the long direction ϕ 2mm hole; the length of the electrode is 50m, and a wire is drawn out at an interval of 25m on the electrode. The voltage gradient between the positive and negative electrodes was 2.5 V / cm.

[0065] Removal rate: Zn 2+ =...

Embodiment 2

[0076] Contaminated soil is mainly kaolin, pH 6.3, density 1.27g / cm 3 , cation exchange capacity 5.22 cmol / kg, permeability coefficient 1.05 10 -7 cm / s; moisture content 66.4%. Cd 441.23mg / kg (effective state 243.66 mg / kg).

[0077]The construction can be stacked with an area of ​​120m×300m. Each layer of polluted soil is 1.5m thick, totaling 30 layers. The anode is: a PVC water pipe with a diameter of 1cm carbon fiber cable and a diameter of 2cm. ϕ 4 holes, the outermost layer is covered with a layer of non-woven fabric. The cathode is a 1.0cm×0.5cm stainless steel strip jacketed with a PVC water pipe with a diameter of 2cm, and the pipe wall is distributed along the cross-section at 60° and along the long direction of 3cm ϕ 4mm hole, the outermost layer is covered with a layer of non-woven fabric. Each section of electrode is 60m long, and a wire is drawn out at an interval of 30m on the electrode. The electrode interval of each layer of electrodes is 1.2m. The pow...

Embodiment 3

[0092] The original site of an electroplating factory, polluted soil, pH=5.0, particle size 20μm 14.04%; permeability coefficient 1.15 10 -6 cm / s. Pollutant content: Cd 4.65mg / kg (effective state 0.86 mg / kg), Pb 384.15 mg / kg (effective state 64.17 mg / kg), Cu 66.24 mg / kg (effective state 6.73 mg / kg), Zn 245.28 mg / kg kg (effective state 98.24 mg / kg).

[0093] This technology is used to backfill the polluted soil in a valley after treatment. Each layer of contaminated soil is 1.0m thick, and there are 25 layers in total. A commercially available conductive polymer drainage board was used as an electrode, and a wire was drawn out on the electrode at an interval of 15m. The electrode interval of each layer of electrodes is 1.0m. The voltage gradient between positive and negative electrodes is 1.5V / cm, and the power supply mode is intermittent power supply, 15 minutes of power supply, 15 minutes of rest. Inject tap water into the anode and inject 0.3M citric acid into the cat...

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Abstract

The invention discloses an ex-situ decontamination method for low-permeability contaminated soil, and belongs to the field of contaminated soil treatment. The ex-situ decontamination method is characterized in that a plurality of electrodes which can conduct electricity and water are horizontally arranged at certain intervals and in parallel to form an electrode group, the electrode group and contaminated soil layers are stacked alternately, and the polarity of the direct current power supply to which any electrode is connected is opposite to the polarity of the direct current power supply towhich at least one of the electrodes surrounding the contaminated soil layers is connected; direct currents applied by the electrodes generates an electric field in the contaminated soil, meanwhile appropriate liquid is injected through the electrodes to regulate and control the chemical reaction environment in the contaminated soil, the pollutants in the contaminated soil migrate to the electrodes under the action of the electric field and are carried out by water via a water-filled pipeline of the electrodes, and the pollutants are removed from the contaminated soil. The ex-situ decontamination method can carry out the treatment of large-volume contaminated soil and can remove a variety of pollutants in the contaminated soil at the same time, the treatment time is short, and land occupation for construction is less.

Description

technical field [0001] The invention relates to an off-site decontamination method for low-permeability polluted soil, and belongs to the technical field of solid waste treatment. Background technique [0002] Polluted soil with low permeability means that the permeability coefficient is lower than 10 -4 cm / s fine-grained polluted soil, including: polluted low-permeability natural soil and fine-grained waste slag containing pollutants discharged by some industries in the production process. According to different pollution sources, polluted soil can be divided into two categories: organic polluted soil and inorganic polluted soil; all kinds of polluted soil can be divided into many different types, for example: heavy metal polluted soil in inorganic polluted soil, heavy metal polluted soil There are different according to the heavy metals contained. According to different treatment methods, pollutant treatment technologies can be divided into in-situ treatment technology (...

Claims

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Application Information

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IPC IPC(8): B09C1/08
CPCB09C1/085
Inventor 刘兴华刘金龙王京
Owner BEIJING ZHONGYAN DADI TECH CO LTD
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