Field Study Of Soil Vapor Extraction(SVE)

Soil vapor extraction (SVE) is a rising environmental technology for unsaturated soils contaminated with volatile organic compounds (VOCs). Its effectiveness has been demonstrated in laboratory and field tests. The study of SVE technology is still stayed at laboratory stage in domestic and the contamination survey and research of oilfield is deficient. Engineering applications of soil remediation is not taken into account.This paper is to systematically explore SVE in respects of technical methods and procedure parameter analysis mainly in field study of in-situ remediation vapor flow item, elementary mass transfer and biodegradation study involved at the same time. Soil and groundwater condition of SVE site is ascertained through soil survey and field evaluation. The main soil style is representative clay which typically distributes in Tianjin region. Shallow water table makes the field experiments feasible for in-situ SVE remediation. The main soil parameters are achieved according to regular civil engineering experimental method and laser particle size analysis at laboratory. One-dimensional column venting experiments of muddy clay simulating the SVE field is used to measure permeability properties of the representative soil of layerâ‘¡and ascertain the relationship between relative permeability and saturation of air and water.On the basis of soil survey analysis and soil column study, Soil Vapor Extraction Equipment installation and SVE extracting and monitoring system are designed and built-up. The Stepped-rate procedure is used to test performance characteristics curve of vortex pump and curve of SVE system to achieve data of extraction ability of this SVE system. Take single-well extraction system as the study object, gaseous pressure distribution and flow field in the soil are studied to ascertain some important parameters such as the radius of influence of SVE extracting pressure and air permeability of the soil.Site air respiration experiment is taken place to test the local blank value of CO2 and its changing trend SVE bio-strengthen process is thereafter considered. Monocomponent contaminant (n-hexane) removing mass transfer experiment of site SVE system is founded and the contaminant mass transfer mechanism of SVE system and water table rising influenced by venting process are studied.