Type of Site:
Free Phase NAPL
The post treatment reductions of toluene concentrations in groundwater were significant. An overall 90% reduction in contaminant mass was achieved. It is concluded these reductions were aided by the increased mixing from agitation caused by the aggressive spray activity and backfilling.
Post treatment sampling data revealed that the nutrients inherent in buffering the Cool-Ox® formulation, combined with excess oxygen produce, and the carbon source available from partially oxidized (now biodegradable) contaminants; combined to stimulate the activity and proliferation of natural intrinsic microbes. Thus, biodegradation became a major component of the remedy. This continuing long-term phenomenon created a decreasing trend in groundwater contaminant concentrations that has been observed at other sites as well. No laboratory produced bacteria were applied
Subsequent to application, contaminant concentrations reached closure levels in approximately twenty-four (24) months. The site was then placed in the Monitored Natural Attenuation Program as a candidate for No Further Action. It has since closed.