Former Dry Cleaner

A pilot scale remedial event was conducted in Durham, NC at a former dry cleaner site to exhibit the efficacy of a proposed remedial design. The site was identified as having impacted soils and groundwater due to the historical use of tetrachloroethylene (PCE).

In April 2011, an 18' self-contained mobile injection trailer was used to deliver the remedial materials via permanent injection wells. Open rock wells were utilized to deliver materials from 30' to 40' and create a pilot scale permeable reactive barrier.

The injection program consisted of three injection wells utilized to inject a mixture of remedial materials containing blue green algae, sodium sulfite, calcium propionate, zero valent iron, and soluble kelp.

A single inflatable TMA 350 packer system was used to inject the materials below 25' bgs. The remedial mixture was designed to be a pilot scale remedial action at the site to restrict plume migration while also reducing CVOC concentrations locally via enhanced reductive dechlorination.

The pilot scale program was designed to act as a proof of concept and promote anaerobic conditions in the groundwater, thereby enhancing bacterial populations within the anoxic groundwater.

Monitoring well MW-26 is located within the pilot scale remedial treatment area, immediately downgradient of the three injection points and screened between 27-37.5 feet bgs.

Vinyl chloride increased from below detection to 20 µg/L, which is normal as it is a byproduct of cis-1,2-DCE. Continued reductive dechlorination is expected in the pilot area.