RCH Enterprises, Inc.


Using in-situ chemical treatments and sub-slab depressurization to address vapor intrusion


Wisconsin Rapids, Wisconsin

Project Highlights

  • In-situ chemical treatment
  • Vapor barrier installation
  • Soil vapor extraction
  • Active sub-slab depressurization
  • Indoor air exchange system
  • Monitoring

ECT continues to work closely with Wisconsin Department of Natural Resources officials to assess and eliminate exposure pathways existing beneath a repurposed 440,000-square-foot manufacturing building in Wisconsin Rapids. The client’s goal is to reduce the concentrations of trichloroethene (TCE) in the indoor air to acceptable levels on an accelerated schedule.

As part of the remedy, ECT designed and oversaw the performance of in situ chemical treatments, which ultimately demonstrated a reduction of source area contaminants to less than 99 percent of the pretreatment levels.

ECT also designed and implemented a soil vapor extraction system (SVE) for concrete slab depressurization. The system supports two extraction zones and dual carbon treatment cells, and during the first 12 months of operation extracted and treated approximately 61,812,000 ft³ of subsurface air.

An air exchange system was installed in the basement of the facility, which supports an air space of approximately 1,280,000 ft³. The system operates at approximately 300 ft³/minute (completely exchanging the air in the basement every 72 hours).

During the first year of SVE operation, more than 2,240 pounds of TCE are estimated to have been recovered, and the volume/level of TCE measured in the SVE system intake has decreased by approximately 90 percent.