Enhanced Soil Vapor Extraction

Conventional volatile organic compound (VOC) recovery membranes (silicone rubber) preferentially transport organics over air. Although this silicone rubber has shown some success, it is not appropriate upstream of catalytic oxidation. Catalytic oxidation requires modest increases in VOC concentration at pressure to maintain performance. This is best achieved by using a reverse separation membrane that simply permeates the air and keeps the VOC at concentration while maintaining pressure. VOC separations from air is a major environmental issue. Numerous sources of VOC emissions exist, including gasoline underground storage tanks, soil contamination, and tank farms. This research project will focus on demonstrating the utility of a new class of Compact Membrane Systems, Inc. (CMS) membranes for reducing the cost of soil vapor extraction (SVE). Even though the project focuses on SVE applications, it is believed that the CMS membrane technology has broad value in many air-VOC separations. The goal is to demonstrate a 20 percent cost reduction in SVE processing. CMS has developed a system that uses a specially coated membrane and pressure differential that separates clean air from VOCs and allows the fresh air to be exhausted into the atmosphere. This system will be built and evaluated first in CMS¿ laboratory and then at an actual soil vapor extraction site. Specifically, in collaboration with industrial partners, CMS will demonstrate performance at an actual diesel fuel SVE site during Phase I. Results will be compared to alternative technologies, such as carbon absorption and catalytic oxidation. Also, in the economical evaluation, CMS will consider specific hybrid systems if necessary to meet goal targets. The market opportunity is large. In SVE application, more than 200,000 sites require remediation. In a parallel opportunity for venting of gasoline storage tanks, there is an opportunity to reduce annual gasoline emissions to the atmosphere by 0.15 percent, which is 180 million gallons per year. At $1.50/gallon, this is an annual fuel savings of $270 million.