Sand County Environmental designed and installed a soil vapor remediation system at a former dry-cleaning facility. Small concentrations of a cleaning solvent were present in the exhaust, representing an inefficiency of the dry-cleaning technology of the time. Over years of operation, solvent at the exhaust pipe dissolved in rainwater and made its way into the soil. The chemical is a volatile organic compound (VOC), a type of chemical that turns quickly from liquid to vapor at room temperature. As the chemical percolated down through the soil (dissolved in rainwater), it gradually turned to a gas and travelled through interconnected air-spaces, weaving through the soil and eventually up cracks in the building’s foundation.

If these vapors enter residences and workplaces, it can represent a health risk to the people inside. Sand County Environmental designed a system to remove potentially harmful vapors by drawing air up from impacted soil and through two reactive-carbon canisters. After the air runs through the filtration system, it is released into the atmosphere as clean air. With this system, the threat to indoor air quality is mitigated and the cleaning solvent in the soil is removed. This option is less expensive and energy-intensive than traditional soil remediation by excavation. The extraction system has now been running at the former dry cleaners for about 8 months; ongoing sampling shows that VOC levels are dropping.