Why the technology was selected:
In 2002, no other technology seemed possible to meet the remediation objective based on soil type (i.e. tight clay) and degree of contamination (i.e. more than 4,000 down to 20 ft (?)since the maximum remedial benefit from the Illinois Fund to the drycleaning facility was $140,000 in total. Also, the technology vendor was confident that the remediation objectives can be reached within 120 days of implementation of the HSVE system. (This was a pilot project for the Fund)

Date implemented:
8/26/2002

Final remediation design:
The treatment system uses a series of in-ground coils to transfer heat, increase the volatility of the organic contaminants, and facilitate removal of the volatile solvents from the soil using a vapor extraction system. After operation for 120 days, the system was modified slightly. Although the system was working, it was felt some system modifications should be made to ensure that the remediation of the remaining chlorinated solvents would be completed in a timely fashion. Modifications included an additional heat point and an additional extraction well in the remaining hot spot.

Other technologies used:
Heat Soil Vapor Extraction (HSVE) -- in situ

Results to date:
It was originally thought that 120 days would be adequate to clean up the site. Initially, after 90 days of operation, the HSVE system has resulted in lower PCE concentrations, with reductions from soil concentrations of 4,300 mg/kg to 2,400 mg/kg and also, one of the two areas where the remediation system was installed seemed to be cleaned up. Even so, operation of all the heating coils continued at the entire site to provide further remediation only at the at those areas where the objectives have not yet been met. The treatment at the site had been extended until June 30, 2003. In July 2003, the confirmatory site investigation showed that the HSVE system failed to meet the remediation objectives after 330 days of operation although it was originally thought that the objectives could be met within 120 days.

Next Steps:
Additional Site Investigation is being conducted to further identify the source of contamination near the hot spot area especially for potential groundwater contamination. (No contamination was discovered down to 48 ft during the initial site investigation back in 2001.) Another remedial technology is being reviewed.

Cost to Design and Implement:
$65,482.15 (w/ O&M costs)