In Situ Chemical Oxidation (ISCO) using OxyZone® has been used to bring sites with persistent and recalcitrant contaminants to closure when other technologies and methods have failed to meet project goals. In this case study, both ISCO using Fenton’s Reagent and pump and treat using granulated activated carbon failed to meet drinking water standards at the Site.

A release of approximately 200 gallons of No. 2 Fuel Oil from a 275 gallon above ground storage tank (AST) located in a garage was reported by the homeowner. The release occurred approximately 75 feet down gradient and 200 feet up gradient of private drinking water wells on the property and adjacent property, respectively. Following closure of the tank, petroleum impacted soil was excavated to the extent feasible and transported off-site for disposal.

To maintain stability of the residential structure, excavation was limited and soil remained beneath the garage containing Volatile and Extractable Petroleum Hydrocarbon (VPH/EPH) fractions at concentrations exceeding the applicable Massachusetts Contingency Plan Soil Standard (S-1/GW-1). Groundwater in overburden and shallow fractured bedrock was impacted by VPH/EPH above the GW-1 groundwater standard for drinking water.

EnChem Engineering, Inc. then installed five injectors down to bedrock with screens placed just above the bedrock surface. An additional extraction well was also installed downgradient of the treatment area to provide better coverage for the pump and treat system.

Post OxyZone® process results for VPH and EPH fractions and target analytes were reported at a concentration below the GW-1 groundwater standards for 2 years indicating successful destruction of the persistent residual petroleum hydrocarbons.