posted on June 09, 2011 19:36
PM Environmental, Inc. (PM) was hired to conduct a Phase II subsurface investigation to delineate volatile organic compound (VOC) including chlorinated solvents in the soil and groundwater at the manufacturing site. Spent degreaser was reportedly discharged via piping into a storm water drainage ditch. Analytical results from this investigation indicated that the concentrations of contaminants in the soils and perched groundwater were above Part 201 Groundwater Surface/Water Interface (GSI) Criteria.
PM conducted a pilot test to determine the final design of a full-scale remediation system. Results of the pilot test indicated that Dual Phase Extraction (DPE) was a feasible remediation alternative for this facility.
PM designed and installed a full-scale remediation system which includes a 40 horse power liquid ring vacuum pump, horizontal soil vapor extraction wells and a network of groundwater recovery wells to remove the contaminated soil vapors and groundwater from the source area. Soil vapors are transferred through two (2) granular activated carbon (GAC) canisters, before discharged to the atmosphere under Rule 290 Permit to Install Exemption: Sources with Limited Emissions. Groundwater is transferred to a low profile air stripper unit, through two (2) liquid phase GAC canisters, and through a bag filter system before discharge to the storm sewer under a National Pollutant Discharge Elimination System permit. The system has operated since 2003. PM completes regular monthly operation and maintenance (O&M), quarterly groundwater sampling events, and annual system performance soil sample events which indicate that the concentrations VOCs in the soil and groundwater have been significantly reduced. PM completes monthly compliance monitoring, sampling, and reporting in accordance with the NPDES permit.