The client’s plant began operation in 1937 and produced machined aircraft and automotive parts. The parts were degreased using trichloroethene (TCE) starting at an unknown date until the early 1990s. During the cleanup of a petroleum hydrocarbon spill, the client detected chlorinated compounds and petroleum hydrocarbons in soil near a ditch area. The client entered the site into the Indiana Voluntary Remediation Program. Estimates concluded that remediation would approach $1,000,000.
Owing to the fine-grained soil conditions, traditional methods of remediation were unlikely to achieve the applicable cleanup goals. TRC evaluated the data and concluded that the remedial technology chosen by the previous consultant would likely not achieve the cleanup objectives. TRC proposed the construction of a phytoremediation system using an EBuffer® system, limited groundwater pump and treat utilizing an existing groundwater treatment system, and natural attenuation to address exposure risks. This remedial strategy limited potential VOC migration while providing long-term VOC mass reduction in soil and groundwater at a reasonable cost. A total of 780 poplar and willow trees were planted. Modeling predicts that the EBuffer® system will uptake over 100,000 gallons of groundwater in an average climatic year, primarily during the summer months (June and September), and will provide a hydraulic residence time of 7.5 years within the root zone.
This remedial alternative reduced the potential VOC migration while providing long-term VOC mass reduction in soil and groundwater at a lower cost. The capital cost was $500,000 less than the previous consultant’s proposed remediation, which was projected to approach $1,000,000. Because the system is passive, no energy (electrical requirements) costs are incurred. The trees provide an attractive buffer to the neighboring subdivision. Routine system operations and maintenance (O&M) costs were reduced significantly. Trees installed as part of the phytoremediation system sequestered a significant amount of CO2 annually.
Contact TRC today for more information about our services or this project.