Leacheate and soil remediation method

A soil remediation and eluent technology, which is applied in the field of contaminated soil remediation, can solve the problems of limited treatment effect of remediation methods, limited treatment capacity, long remediation time, etc., and achieves good application prospects, easy promotion and implementation, and good removal effects.

Inactive Publication Date: 2018-12-21
BEIJING GEOENVIRON ENG & TECH
7 Cites 2 Cited by

AI-Extracted Technical Summary

Problems solved by technology

However, the single microbial degradation method has a long repair period, and the water solubility of nitrobenzene itself is poor, and there are problems such as the limited ability of a singl...
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Method used

2. in-situ leaching technology is combined with microbial stimulation technology, and in-situ leaching is carried out earlier, and pollutant concentration is greatly reduced rapidly, simultaneously, leaching agent selects alcoholic substance and nonionic surfactant mixture to increase The solubility of nitrobenzene in water improves its desorption from the soil, and alcohols can co-metabolize nitrobenzene compounds with microorganisms. The residual surfactant in the soil after leaching is conducive to the absorption and degradation of pollutants by microorganisms . Stimulation of indigenous microorganisms after leaching strengthens the degradation ability of indigenous microorganisms in the soil, solves the problem of incomplete removal of low-concentration pollutants by leaching technology, and can completely degrade the leaching agent remaining in the soil, avoiding secondary pollution. secondary pollution and reduce costs;
4. take in-situ elution technology and biostimulation technology as core, fully combine the technical principle of organic solvent/surfactant eluting, microbial stimulation to strengthen degradation, each process step design is reasonable, simple to operate, low in cost, feasible Strong, easy to popularize and implement.
Generally speaking, the present invention coordinates the remedial treatment of nitrobenzene-contaminated soil by chemical leaching process and native microbial degradation, both can quickly process high-concentration nitrobenzene pollutants, can reduce cost and reduce secondary Pollution has a very obvious advantage.
[0044] The eluent (non-ionic surfactant, alcohols such as n-butanol) of the above formula is mixed as a eluent, and the leaching effect of the nitrobenzene pollutants is good. The n-butanol in the ratio range of 3.2~6:1 can greatly reduce the adsorption of nonionic surfactant Tween 80 in soil.
[0045] In addition, n-butanol can not only increase the desorption of nitrobenzenes from the soil, reduce the adsorption of Tween 80 in the soil, but also be degraded as a microbial carbon source in subsequent processing steps. The residual surfactant Tween 80 in the soil can increase the water solubility of nitrobenzene pollutants, reduce the surface tension, and can effectively increase the contact and absorption between microbial cells and pollutants.
[0050] Preferably, in order to recycle the eluent, reduce the nitro...
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Abstract

The invention relates to a leacheate and a soil remediation method, and belongs to the field of remediation of contaminated soil. The soil remediation method is characterized by comprising the following steps of providing the leacheate, wherein the leacheate comprises mixed n-butyl alcohol and tween 80; performing home position leaching on contaminated soil to be treated which is contaminated by nitrobenzene substances with the leacheate; and promoting degrading of the nitrobenzene substances by microorganisms in the contaminated soil to be treated through exogenous stimulation. According to the soil remediation method disclosed by the invention, home position leaching is combined with microorganism stimulation degrading, and through the leaching technology, high-concentration nitrobenzenepollutants can be quickly and massively removed; a surface active agent exists, so that favorable condition is created for subsequent biological remediation; aboriginal microorganisms are subjected to bio-stimulation; and after nutrient substances are added and the water ratio is regulated, low-concentration pollutants after leaching treatment are thoroughly removed, and the leacheate remained inthe soil can be effectively removed. The soil remediation method disclosed by the invention is reasonable in technology, and low in cost; the on-the-spot home position treatment conditions are completely simulated, and the workability is high; and the soil remediation method is easy to popularize and implement, and has favorable application prospects.

Application Domain

Contaminated soil reclamationOrganic fertilisers +2

Technology Topic

NutrientHome position +11

Image

  • Leacheate and soil remediation method

Examples

  • Experimental program(3)

Example Embodiment

[0067] Example one
[0068] Soil remediation of a nitrobenzene contaminated plot.
[0069] On the site of a chemical plant in Anhui, the soil excess pollutants are 2-nitroaniline, m-nitrochlorobenzene, p-nitrochlorobenzene, and the amount of polluted earthwork is 10257m 3 The highest pollution concentration is 166.62mg/kg of 2-nitroaniline, 568.72mg/kg of m-nitrochlorobenzene, and 657.74mg/kg of p-nitrochlorobenzene. The soil remediation is carried out by this process. The specific implementation conditions are as follows:
[0070] The soil porosity of the site is 0.33, that is, the pore volume is 3384.81m 3. The eluent used is 36g/L n-butanol and 9g/L Tween 80. The composite eluent is injected into the contaminated area through the injection well, and 17000m 3 Then use extraction wells to extract groundwater and collect it on the ground, then conduct water treatment and use solvent extraction to recover the eluent, and then inject 5 times 17000m 3 Eluent, every 17000m injected 3 Then use the extraction well to extract the groundwater, and continue to extract 6768m after the injection extraction is completed 3 groundwater.
[0071] The leached soil was sampled to determine the content of 2-nitroaniline, m-nitrochlorobenzene, and p-nitrochlorobenzene. The highest pollution concentrations were 12mg/L, 41mg/L, 51mg/L, respectively.
[0072] The nutrient solution is injected through the injection well. The composition and dosage are: 59.2t of ethanol, 6.8kg of urea, 3.4kg of potassium dihydrogen phosphate, and a total volume of injected nutrients of 846.2m 3.
[0073] Sampling and monitoring soil moisture content every month are between 50% and 60%, and no water is required.
[0074] Samples were taken every month to check the concentration of pollutants. After 7 months, the concentrations of 2-nitroaniline, m-nitrochlorobenzene, and p-nitrochlorobenzene all fell below 1mg/kg, and the restoration was completed.

Example Embodiment

[0075] Example 2
[0076] Soil remediation of a nitrobenzene contaminated plot.
[0077] A petrochemical site in Tianjin, the pollutant in the soil is nitrobenzene, the average concentration is 997mg/L, and the amount of polluted earthwork is 1200m 3 , Using this technology for soil remediation, the specific implementation is as follows:
[0078] The soil porosity of the site is 0.35, that is, the pore volume is 420m 3. The eluent used is 25g/L n-butanol and 6.6g/L Tween 80. The composite eluent is injected into the contaminated area through the injection well, and injected 2100m 3 Then use an extraction well to extract the groundwater and collect it on the ground, then conduct water treatment and use solvent extraction to recover the eluent, and then inject 2100m 3 Then use extraction wells to extract groundwater, and collect it on the ground, then conduct water treatment and use solvent extraction to recover the eluent, and then inject 2100m 3 Then use extraction wells to extract the groundwater, and collect it on the ground, then conduct water treatment and use solvent extraction to recover the eluent, and continue to extract 600m after injection and extraction. 3 groundwater.
[0079] The leached soil was sampled to determine the content of nitrobenzene, and the highest pollution concentration was 81 mg/L.
[0080] The nutrient solution is injected through the injection well. The composition and dosage are: 5.5t of ethanol, 0.65kg of urea, 0.3kg of potassium dihydrogen phosphate, and a total volume of 100m of nutrients injected. 3.
[0081] Monthly sampling to monitor soil moisture content, the moisture content of the third month and the fourth month is 48%, and 47% does not need to add water 25m 3 With 30m 3.
[0082] Samples were taken every month to check the concentration of pollutants. After 4 months, the concentration of nitrobenzene dropped below 1 mg/kg, and the restoration was completed.

Example Embodiment

[0083] Example 3
[0084] Soil remediation of a nitrotoluene contaminated plot.
[0085] A contaminated site of a thermal power plant in Changsha, the pollutant in the soil is nitrotoluene, the highest concentration is 275mg/L, and the amount of contaminated earthwork is 860m 3 , Using this technology for soil remediation, the specific implementation is as follows:
[0086] The soil porosity of the site is 0.30, that is, the pore volume is 258m 3. The eluent used is 19.2g/L n-butanol and 4.8g/L Tween 80. The composite eluent is injected into the contaminated area through the injection well, and the injection is 1120m 3 Then use an extraction well to extract the groundwater and collect it on the ground, then perform water treatment and use solvent extraction to recover the eluent, and then inject 1120m 3 After that, the groundwater is extracted with an extraction well, and collected on the ground for water treatment and solvent extraction is used to recover the eluent, and then injected 1120m 3 After that, the groundwater is extracted with an extraction well, and after collecting it on the ground, the water is treated and the eluent is recovered by solvent extraction. After the extraction is completed, the extraction is continued for 258m 3 groundwater.
[0087] The leached soil was sampled to determine the content of nitrotoluene, and the highest pollution concentration was 19mg/L.
[0088] The nutrient solution is injected through the injection well. The composition and dosage are: 1.56t of ethanol, 0.20kg of urea, 0.08kg of potassium dihydrogen phosphate, and a total volume of 39m of nutrients injected. 3.
[0089] Sampling and monitoring soil moisture content every month are between 50% and 60%, and no water is required.
[0090] Samples are taken every month to check the concentration of pollutants. After 3 months, the concentration of nitrobenzene drops below 1 mg/kg, and the restoration is completed.

PUM

PropertyMeasurementUnit
Pore volume3380.0
Volume420.0
Pore volume258.0

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