SVE/AS/GROUND-WATER EXTRACTION SYSTEM
WATERTOWN, WISCONSIN

LBG conducted a remedial investigation of this site which was impacted with significant concentrations of volatile organic compounds in the soil and ground water. Improperly disposed liquids containing TCE, PCE, xylenes, and toluene contaminated 100 feet of till and the underlying sandstone aquifer used for a public water supply.

Following the evaluation of several remedial alternatives to deal with low - permeability clay soils and bedrock, LBG designed a ground-water recovery and treatment system to achieve the goal of containing contaminants in the aquifer and eliminating the till as a secondary source.

Frequent interaction with the public was required for off-site work to assure that unnecessary interruptions in the project were avoided.

The system consists of 17 ground-water recovery wells for containment and recovery of contaminated ground water. Eight air sparge wells and 38 SVE wells were installed to remediate the contamination in the till. Recovered vapor was treated with a 1000 scfm catalytic oxidizer and 4 vapor-phase carbon units until emission rates fell below air discharge standards. Ground water is treated through a series of sedimentation basins, particulate filters, and air strippers.

LBG successfully negotiated with the Wisconsin Department of Natural Resources to discontinue use of vapor emission controls at the site. This resulted in a savings of over $900,000 over the life of the system. It also eliminated 80,000 pounds of hazardous waste and eliminated emission of 2,500 tons of greenhouse gases to the atmosphere.

As of this date, 16,000 pounds of chlorinated solvents have been recovered.