Characteristics and performance of prefabricated vertical drains for soil vapor extraction remediation system.

The most common approach for remediation of unsaturated soils contaminated with volatile organic compounds (VOCs) is soil vapor extraction. Contamination in low-permeability fine-grained soils poses a significant technical challenge to in situ remediation efforts. The main objective of this paper is to evaluate prefabricated vertical drains (PVDs) as a method of increasing the effectiveness of the soil vapor extraction (SVE) process. The equivalent diameter for PVDs used for SVE applications was determined, and the radius of influence for PVDs were determined so as to measure the gas permeability for fine grained soil under differing conditions including densities, water content, and flow rates. This paper presents the discussions with regarding on the experiments using PVDs for contaminant recovery in the pilot-scale testing. The toluene tracer solution which is one of the oil contaminant BTEX (benzene, toluene, ethylbenzene, xylene) was used to evaluate contaminant remediation efficiency. The concentration of toluene from the extracted samples was measured in a sampling port with the elapsed time and flow rates after operating a PVDs system. [ABSTRACT FROM AUTHOR]