Active Dry Cleaner

Project Summary

An active dry cleaner, located in Green Brook, NJ, was contaminated with chlorinated solvents (primarily PCE) due to operations by previous owners. Soil consists of clayey sands to 5 feet below ground surface (ft bgs) underlain by weathered shale and bedrock at approximately 10 ft bgs. Depth to water ranged from 9 to 11 ft bgs.

The vadose zone impacts were addressed by excavation. Remedial solutions were evaluated to address the remaining groundwater impacts. Prior to remediation, the site conditions were strongly aerobic, indicated by elevated ORPs and dissolved oxygen levels. The remediation was to be conducted in an active commercial strip mall parking lot.

Remedial Plan

The in-situ remediation plan included the application of emulsified zero valent iron and antimethanogenic reagents (EZVI-CH4™) via permanent injection wells. Based on the site-specific conditions, a total of 750 gallons of EZVI-CH4™ were applied via the injection wells to remediate the area of concern.

Each well was installed with stainless steel casings through the overburden and weathered rock with open holes from 15 to 25 ft bgs. Single packers were used to isolate the desired injection depths in the bedrock. The site remained active with businesses open during the injection program.

Results

• 6 months post-injection, ORP levels in target monitoring wells averaged -135 mV, showing strong EZVI-CH4™ influence.
• 9 months post injection, PCE concentrations reported from the targeted monitoring wells were reduced below the NJDEP Groundwater Quality Standards of 1 µg/L.
• All post treatment monitoring events reported PCE concentrations remained below the NJDEP standards.
• No daughter products (dichloroethene or vinyl chloride) were detected following the EZVI application.
• Site reached regulatory closure within the desired time frame.