Engineered remediation equipment and remediation method for heavy metal arsenic and lead contaminated soil

Abstract

The invention discloses engineered remediation equipment and remediation method for heavy metal arsenic and lead contaminated soil. The remediation equipment comprises a slurry making system, a screening and washing system, a leaching and leaching system and a dehydration system which are connected in sequence. The remediation method comprises the steps: (1) preparing slurry; (2) screening and washing; (3) leaching and extracting; and (4) dehydrating. Key parameters such as a slurry-making water-soil ratio, a screening and washing water-soil ratio and an agent leaching liquid-solid ratio are improved, meanwhile, according to the nature of south and north soil, south clay soil is more beneficial to attachment of arsenic, lead and other heavy metals, and the particle size grading limit of screening and washing and agent leaching in the remediation process is defined; economic cost accounting is carried out on the process, the engineered remediation equipment and remediation method for the heavy metal arsenic and lead contaminated soil are provided, and the remediation efficiency of the soil can be economically and effectively improved.

Description

technical field [0001] The invention relates to an engineered repair equipment and method for soil contaminated by heavy metal arsenic and lead, belonging to the field of heavy metal soil repair. Background technique [0002] In recent years, with the rapid development of social economy and high-intensity human activities, the overall soil environment in my country is not optimistic. Some areas have serious soil pollution, and the soil environment problems of industrial and mining wasteland are prominent. The total number of points exceeding the standard in the country's soil is 16.1%, and the number of points exceeding the standard for inorganic pollutants accounts for 82.8% of the total number of points exceeding the standard. , a wide range, especially in the smelter and its surrounding soil, the detection rate of arsenic and lead is high. [0003] At present, the commonly used remediation technologies for heavy metal-contaminated soil are solidification stabilization an...

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Problems solved by technology

[0003] At present, the commonly used remediation technologies for heavy metal-contaminated soil are solidification stabilization and leaching techniques, but the "Contaminated Land Restoration Technical Guidelines for Contaminated Land Remediation Technical Guidelines for Solidification and Stabilization Technology (Trial) 2017" stipulates that long-term monitoring and maintenance of the site is required after solidification and stabilization. , the long-term monitoring time is in principle not less than 5 years, so the requirements for restoration technology, site and personnel management are high, which increases the circulation and utilization time of the site, so the characteristics of high efficiency of the rinsing process and short repair cycle make it It has become a common remediation method for heavy metal contaminated soil

[0004] The existing heavy metal arsenic and lead leaching equipment still has deficiencies. In the existing patent, CN111438178A discloses a soil leaching treatment method, introduces the leaching process, and determines the type, concentration, and liquid-solid ratio of the leaching agent. and other leaching parameters, but did not specify the key parameters such as particle size and water-soil ratio entering the equipment during the operation of the leaching equipment, and did not consider the economy of leaching costs; CN105750316A discloses a multi-stage screening type ectopic soil leaching The restoration method uses 10mm, 2mm, and 1mm as the coarse sieve particle size, and 10mm as the washing particle size. After the soil is classified by particle size, it is treated with solidification and stabilization technology. In the example, the leaching effect of the northern soil is considered, but not The difference of soil properties between north and south and the applicability of solidification and stabilization technology to land use

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