In recent years, in response to the actual needs of soil environmental protection and the development needs of soil environmental science and technology, the Ministry of Science and Technology, the National Natural Science Foundation of China, the Chinese Academy of Sciences, the Ministry of Environmental Protection and other departments have planned to deploy some soil remediation research projects and special topics. It has effectively promoted and promoted the research and development of soil pollution control and remediation science and technology across the country.
The "Twelfth Five-Year Plan for the Comprehensive Prevention and Control of Heavy Metal Pollution" pointed out that the key to the current soil remediation work in my country lies in understanding the situation, piloting and demonstrating advanced and applicable technologies to provide a basis for large-scale remediation work. At present, a large number of soil remediation technology research results in my country are still in the transition stage from laboratory development to large-scale practical use. Most of the remediation work faces problems such as imperfect systems, low technical standards, unsatisfactory treatment effects, and lack of applicable standards. At the inaugural meeting of the Association's Heavy Metal Pollution Prevention and Soil Remediation Professional Committee, Professor Liu Yangsheng from the School of Environmental Science and Engineering of Peking University conducted an inventory of soil pollution remediation technologies in my country.
Liu Yangsheng said, “Applicable soil remediation technology generally involves concept design of the laboratory, problem identification, simulation control experiment, small-scale field experiment, technology demonstration, accumulation of engineering experience, and finally the management of practical technology. Several stages". At present, my country's heavy metal contaminated soil treatment technologies mainly include:
The guest soil replacement method is to dig out the contaminated soil, solidify and stabilize it, and thermally gasify volatile heavy metals. The cleaned soil can be used for backfilling. Liu Yangsheng pointed out that on the one hand, the amount of clean soil used for replacement is limited, and on the other hand, the removal of contaminated soil needs to be landfilled in the restoration method of completely using guest soil replacement. Therefore, this method is generally applicable to heavily polluted small-scale sites. repair. For sites where the method of diluting the guest soil is used for restoration, it is necessary to control the infiltration of heavy metals to prevent and control the pollution of groundwater.
Electrokinetic remediation is to concentrate pollutants near the cathode or anode, pump out the polluted water body through a pump, and replenish groundwater after treatment. The pollutants in the soil are washed out in this way. This technology can only treat heavy metal ions dissolved in water; for many insoluble heavy metals in the soil, it is necessary to adjust the pH of the soil to be acidic or add a large amount of organic chelating agent to dissolve the heavy metal ions into the aqueous solution. Liu Yangsheng introduced that the remediation method is still in the laboratory research stage due to its complex technology, greater impact on the soil environment, and relatively high cost.
Heavy metal pyrolysis. This technology is suitable for the remediation of soil contaminated by heavy metals such as mercury and arsenic in industrial sites, but attention should be paid to the recovery of heavy metals and the treatment of waste water. After heat treatment, the microorganisms and organic matter contained in the soil are decomposed, resulting in the loss of basic functions of the soil and desertification, so it is not suitable for the restoration of farmland soil.
The soil leaching method is to excavate the contaminated soil, sieving and washing, clean the soil and then backfill. The waste water and sludge produced in this process must be treated. This technology has a high removal efficiency of water-soluble heavy metals and can quickly repair contaminated soil; it is suitable for low-polluted soils, and chemical leaching can make the concentration of heavy metals in the soil close to or meet the requirements of soil use standards; especially suitable for small-area contaminated sites ( Light soil or sandy soil). However, this method has higher requirements on the rinse agent, and environmentally friendly detergents should be selected; in addition, in addition to water-soluble heavy metals, the removal efficiency of other forms of heavy metals is low. Therefore, it cannot be applied to the remediation of heavy metal contaminated soil on a large scale.
The cylindrical scrubber is supported by four tugs, and the barrel rotates at low speed along with the motor and reducer to drive large and small gears. The material containing mud and stone powder is fed through the feeding device from the feeding port, and the material entering the rotating drum is continuously carried, tossed, stirred, and scrubbed by a stirring device with a specific angle and a rod installed in the drum. , In the process of moving from the feeding end to the discharging end, it is continuously washed by the high-pressure water jet in the forward or reverse direction during multiple cycles. The cleaned material is dehydrated by the dewatering device at the discharge end and then discharged to the finished product pile. Sewage and fine sand containing sludge flow out through the discharge end and enter the next step to finely screen out fine sand, and pure mud enters the sewage treatment process. Compared with other washing equipment, the cylindrical scrubbing machine has the following advantages: 1. Large processing capacity and strong cleaning ability. 2. The long cylindrical cylinder allows the material to stay in the equipment for a long time, and there is sufficient friction between the material and the material, thereby decomposing the impurities and soil on the surface of the material and classifying them by size. 3. The cylinder body is made of special high wear-resistant materials, which is strong and durable. 4. Use heavy-duty bearings, gears and tugs. 5. The motor and gear system with large output power produces high-efficiency torque. Desen Environment is a high-tech environmental protection enterprise with environmental engineering application technology research and development as the core and equipment processing and manufacturing as the auxiliary. Equipment quality is guaranteed. Interested users can call us for details.
The "Twelfth Five-Year Plan for the Comprehensive Prevention and Control of Heavy Metal Pollution" pointed out that the key to the current soil remediation work in my country lies in understanding the situation, piloting and demonstrating advanced and applicable technologies to provide a basis for large-scale remediation work. At present, a large number of soil remediation technology research results in my country are still in the transition stage from laboratory development to large-scale practical use. Most of the remediation work faces problems such as imperfect systems, low technical standards, unsatisfactory treatment effects, and lack of applicable standards. At the inaugural meeting of the Association's Heavy Metal Pollution Prevention and Soil Remediation Professional Committee, Professor Liu Yangsheng from the School of Environmental Science and Engineering of Peking University conducted an inventory of soil pollution remediation technologies in my country.
Liu Yangsheng said, “Applicable soil remediation technology generally involves concept design of the laboratory, problem identification, simulation control experiment, small-scale field experiment, technology demonstration, accumulation of engineering experience, and finally the management of practical technology. Several stages". At present, my country's heavy metal contaminated soil treatment technologies mainly include:
The guest soil replacement method is to dig out the contaminated soil, solidify and stabilize it, and thermally gasify volatile heavy metals. The cleaned soil can be used for backfilling. Liu Yangsheng pointed out that on the one hand, the amount of clean soil used for replacement is limited, and on the other hand, the removal of contaminated soil needs to be landfilled in the restoration method of completely using guest soil replacement. Therefore, this method is generally applicable to heavily polluted small-scale sites. repair. For sites where the method of diluting the guest soil is used for restoration, it is necessary to control the infiltration of heavy metals to prevent and control the pollution of groundwater.
Electrokinetic remediation is to concentrate pollutants near the cathode or anode, pump out the polluted water body through a pump, and replenish groundwater after treatment. The pollutants in the soil are washed out in this way. This technology can only treat heavy metal ions dissolved in water; for many insoluble heavy metals in the soil, it is necessary to adjust the pH of the soil to be acidic or add a large amount of organic chelating agent to dissolve the heavy metal ions into the aqueous solution. Liu Yangsheng introduced that the remediation method is still in the laboratory research stage due to its complex technology, greater impact on the soil environment, and relatively high cost.
Heavy metal pyrolysis. This technology is suitable for the remediation of soil contaminated by heavy metals such as mercury and arsenic in industrial sites, but attention should be paid to the recovery of heavy metals and the treatment of waste water. After heat treatment, the microorganisms and organic matter contained in the soil are decomposed, resulting in the loss of basic functions of the soil and desertification, so it is not suitable for the restoration of farmland soil.
The soil leaching method is to excavate the contaminated soil, sieving and washing, clean the soil and then backfill. The waste water and sludge produced in this process must be treated. This technology has a high removal efficiency of water-soluble heavy metals and can quickly repair contaminated soil; it is suitable for low-polluted soils, and chemical leaching can make the concentration of heavy metals in the soil close to or meet the requirements of soil use standards; especially suitable for small-area contaminated sites ( Light soil or sandy soil). However, this method has higher requirements on the rinse agent, and environmentally friendly detergents should be selected; in addition, in addition to water-soluble heavy metals, the removal efficiency of other forms of heavy metals is low. Therefore, it cannot be applied to the remediation of heavy metal contaminated soil on a large scale.
The cylindrical scrubber is supported by four tugs, and the barrel rotates at low speed along with the motor and reducer to drive large and small gears. The material containing mud and stone powder is fed through the feeding device from the feeding port, and the material entering the rotating drum is continuously carried, tossed, stirred, and scrubbed by a stirring device with a specific angle and a rod installed in the drum. , In the process of moving from the feeding end to the discharging end, it is continuously washed by the high-pressure water jet in the forward or reverse direction during multiple cycles. The cleaned material is dehydrated by the dewatering device at the discharge end and then discharged to the finished product pile. Sewage and fine sand containing sludge flow out through the discharge end and enter the next step to finely screen out fine sand, and pure mud enters the sewage treatment process. Compared with other washing equipment, the cylindrical scrubbing machine has the following advantages: 1. Large processing capacity and strong cleaning ability. 2. The long cylindrical cylinder allows the material to stay in the equipment for a long time, and there is sufficient friction between the material and the material, thereby decomposing the impurities and soil on the surface of the material and classifying them by size. 3. The cylinder body is made of special high wear-resistant materials, which is strong and durable. 4. Use heavy-duty bearings, gears and tugs. 5. The motor and gear system with large output power produces high-efficiency torque. Desen Environment is a high-tech environmental protection enterprise with environmental engineering application technology research and development as the core and equipment processing and manufacturing as the auxiliary. Equipment quality is guaranteed. Interested users can call us for details.
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