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Soil elution technology originated from Europe and the United States and was used in the 1980s and 1990s. It has been proven through engineering applications that this technology is an effective method for treating contaminated soil. In the early technology application process, the main focus was on

Soil elution technology originated from Europe and the United States and was used in the 1980s and 1990s. It has been proven through engineering applications that this technology is an effective method for treating contaminated soil. In the early technology application process, the main focus was on the removal efficiency of pollutants. With the development of environmental protection and society, the green sustainability of technology application has received more and more attention.

Ex-situ soil elution technology uses physical separation or synergistic elution to separate heavily polluted soil fill components or transfer pollutants from the soil phase to the liquid phase by adding water or suitable synergists, and effectively reduce pollution. To reduce the amount of soil treated, wastewater from the elution system should be treated to remove pollutants before being reused or discharged to meet standards. Soil washing remediation technology can treat heavy metals and semi-volatile organic pollutants and difficult-to-volatile organic pollutants. At present, there are many application cases in the United States, Canada, Europe and Japan. There are already engineering cases in China.

The water solubility and mobility of pollutants directly affect the effect of soil washing, especially chemical washing remediation. Hydrophobic organic matter such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, etc. are generally difficult to achieve the repair goal through physical separation, and it is necessary to add eluants such as surfactants for chemical elution treatment. The mobility of heavy metals and their occurrence forms in the soil also affect the washing and repair effect. Generally, the exchangeable state and the carbonate-bound state are easier to remove. Contaminant concentration is also an important factor affecting remediation effectiveness and cost.

For example, in the application case of Desen Environmental soil elution equipment, the contaminated soil remediation volume of a contaminated land treatment project in Guangdong is about 70,000+ m3. After investigation and risk assessment of the land, it was found that heavy metals in the soil exceeded the standard combined with the future land use of the land. Planning and related restoration work need to be carried out.

After comprehensive consideration of the pollution characteristics of the plot and the geological and hydrogeological conditions, it was finally decided to use soil elution and reduction technology for remediation. The eluent was to backfill the large-grained soil that met the standard after being washed with clean water. The small-grained soil that did not meet the standard was entrusted to qualified personnel. The unit's outsourcing disposal. It achieved the established restoration goals and requirements, while also significantly reducing the project cost and achieving multiple social, economic and environmental benefits. The project was also rated as a demonstration project in Guangdong Province.

Therefore, through practical application, the water-soil ratio should be controlled as much as possible when applying soil washing remediation technology to reduce the burden of back-end water treatment. It is also important for the project's implementability, cost control, safety and environmental protection. Soil elution and reduction technology can be used as a remediation technology to permanently eliminate the risk of soil pollution. It has obvious advantages. After elution, the amount of contaminated soil is significantly reduced, and the economics of remediation and disposal are better.