A risk management strategy was required for an industrial manufacturing facility, as a result of chlorinated solvents having been found in the soil and shallow groundwater underneath a former degreaser and Above Ground Storage Tanks (ASTs). TCE and cis-1,2-DCE accounted for ~90% of the total Chlorinated Hydrocarbons (CHCs). The remedial objective was to mitigate risk to ground- water in the shallow drift and the underlying Sandstone Principal Aquifer.

AECOM provided a phased treatment train solution including a dual phase ex- traction system (DPE) to effect mass removal of TCE and breakdown products, resulting in recovery of 1250kg over three to four years. 97% of this mass came from soil vapour and 3% from shallow groundwater. The DPE system reduced contaminant levels in unsaturated soils and substantially decreased the lateral extent of contamination in the saturated zone. Due to the diminishing returns of contaminant recovery the scheme was decommissioned and AECOM subsequently worked with REGENESIS to provide a follow-on in situ treatment of the residual contamination in groundwater.