A Chemical Risk Assessment And Remediation Of Contaminated Sites

With urbanization, industrial restructuring deepen, many cities began to migrate the main city of the industrial enterprises, producing a large presence of environmental risks venue. A chemical plant built in 1987, 2009 cut-off relocation during the main products in the production of pesticides, the legacy of soil contamination sites may exist. In the chemical field left field for the study of the relocation site after the implementation of soil contamination risk assessment, repair technology research in laboratory tests contaminated soil, experimental research and restoration in the risk assessment process and on the basis of indoor pollution venues repair work design in order to achieve the remediation of polluted sites, as well as similar risk assessment of contaminated sites and site remediation reference, formed the following main conclusions or design results:(1). The space environment, the original contamination site hazard identification, identified the main contaminant of concern.(2). Health risk assessment of the site to determine the pollutant effects on human health risks are: benzene, ethylbenzene, chlorobenzene, xylene(total), 1,2-dichloroethane, dieldrin, α- BHC BHC β-, γ- BHC, mercury, nickel, cadmium, arsenic, zinc, copper. Pollutants above the human exposure assessment, toxicity assessment, risk characterization the conclusion that the risk control value.(3). Determination of organic contaminated soil leaching process using ethanol, heavy metal contaminated soil stabilization using the curing process. By fixing technology test results: Soil and ethanol benzene equilibrium constants Kp = 6.56; technology test conditions: 100% ethanol concentration, leaching times to four times, ultrasonic time 20 min, the quality of soil and ethanol volume ratio of 1 : 10, the final soil concentration of 2.16 mg / kg, the highest removal rate reached 97.54 percent, the results showed that ethanol leaching method can effectively remove the organic matter in the soil. Heavy metal contaminated soil stabilization method using solidification repair process conditions: cement content in 300%, 30% fly ash addition, the amount of lime added to the stabilizing effect of the curing 10%, preferably, the leachate concentration of Cd 11.4 mg / L, the removal rate reached 98.86 percent.(4). In the field of organic pollution of soil after repair design, calculated according to the actual situation, benzene contaminated soil washed three times to repair the target. Determine repair earthwork excavation 1224.78m3, wet weight 2118.87 t, require the loss of ethanol 42.38m3. The heavy metal contaminated soil site design requires remediation of contaminated soil 1177.76 m3, wet weight 2037.5t, after digging the soil capacity increase, the volume required for curing heavy metal contaminated soils have 2882 m3, requires loss cement 12469 t, ash 416 t, lime 208 t. The cured body disposal site volume 6342.6m3, disposal site width 20 m, the length of 158.6m, the total depth of 5.5m.