Formatted Title
Remediation of a Chlorinated Solvents Contaminated Site by an Integrated System (HB+GDRS+SVE)
Background/Objectives
In an industrial unit with contamination of chlorinated solvents (mainly perchloroethylene [PCE]) in the soil and groundwater, the human health risk assessment identified concentrations above the maximum acceptable xoncentration. To mitigate the risks, a remediation system was designed to act in the saturated and non-saturated zones of the aquifer. After evaluating alternatives, an integrated remediation method was selected, consisting of a hydraulic barrier (HB): to contain dissolved phase plumes; water recirculation system (GDRS): to reduce concentrations in groundwater (saturated zone) and soil vapor extraction system (SVE): to act in the extraction of vapors retained in the soil (unsaturated zone).
Approach/Activities
The HB was installed with 11 deep pumping wells and a water treatment system using activated carbon adsorption columns to promote the removal of volatile organic compounds (VOCs). The GDRS was designed with 18 injection wells at two depths (6 shallow wells and 12 deep wells) to promote groundwater circulation and reduce concentrations in the identified centers of mass. The SVE was installed with 42 extraction wells at two depths (21 shallow wells and 21 deep wells) and the extracted vapors are also directed to an activated carbon treatment to reduce VOC concentrations.
Results/Lessons Learned
The hydrogeological characteristics of the area allowed the implementation of an integrated remediation system, which was operated for 31 months, removing 624 kg of contaminants, promoting a considerable reduction in the concentrations of organochlorine compounds in the dissolved phase (groundwater), being below the conditional MAC and values nears to reference standards for soil vapors.