Former Manufactured Gas Plant (MGP) production from circa 1860s through the 1950s at a site in Norwich, New York, resulted in impacts to both on-site and off-site soils and groundwater. Site remediation includes four phases of treatment: in situ solidification (ISS) of on-site source materials; recovery of NAPL from off-site; in-situ chemical oxidation (ISCO) of off-site areas; and enhanced bioremediation of off-site groundwater.

Approximately 52,103 cubic yards (39,835 cubic meters) of impacted sand and gravel were solidified in-situ using auger mixing technology, and over 54,000 gallons (210,000 liters) of NAPL have been recovered to date. An ISCO bench-scale study revealed that four applications of hydrogen peroxide will reduce BTEX and naphthalene by 99% and TPH by 50%. Full-scale ISCO application will occur upon completion of NAPL recovery, followed by enhanced bioremediation of dissolved phase contamination (benzene and naphthalene).