Location: Levelland, Texas
Client: EPA Region 6
EA was contracted to provide CERCLA RI/FS, remedial design, remedial action, and long-term response action and other support Services for the State Route 114 Groundwater Plume Superfund Site. Our scientists and engineers designed the cleanup strategy to address a groundwater plume containing benzene, 1,2-dichloroethane, LNAPL, arsenic, and manganese in a sole source high-quality drinking water aquifer at a former petroleum refinery and tank farm. Major components of the remedy include:
- Groundwater extraction and treatment system to achieve hydraulic control of the contaminant plume and restore the Ogallala aquifer to its beneficial use as a sole source drinking water supply,
- Groundwater injection system to return the treated groundwater back to the Ogallala aquifer to enhance aquifer flushing and/or assist in hydraulic control of the plume, and
- A complex SVE system as a source control measure to remove LNAPL and the organic vapor source in the vadose zone.
The SVE system can be operated both remotely and by onsite personnel and includes 21 groundwater extraction wells and 62 SVE well pairs; a thermal oxidizer for soil vapor treatment; oil and water separation; metals treatment via coagulation or filtration by chemical addition or adsorptive media filters; air stripping; vapor-phase granular activated carbon; and treated groundwater re-injection. From 2009 to 2013, off-gas from the air strippers and extracted vapors from the SVE system were treated via zeolite wheel concentrator/cryogenic-compression and condensation (C3) for removal of VOCs. During its 52 months of operation, the C3 system recovered 357,000 gallons of a commercially viable petroleum distillate, which was sold to a commercial fuel blender for re-blending. The sale of the recovered distillate resulted in over $221,000 in credits applied to the project. In 2013, EA participated in an Optimization Review, which recommended an alternative treatment system. EA designed and installed a thermal oxidation treatment system to manage the SVE system vapors, and provided construction support to EPA during decommissioning of the C3 treatment system. The thermal oxidizer was activated in November 2016, and has removed 2.3 million pounds of total volatile hydrocarbons and 12,885 pounds of benzene through December 2018. EA is currently conducting long-term response action activities, including daily monitoring, O&M, performance monitoring and operation and maintenance sampling, groundwater modeling to evaluate the effectiveness of the remedy, and preparation of annual O&M reports. EA hired local treatment plant operators for the system. The operators live in the vicinity of the site and provide daily oversight without incurring per diem costs. EA utilizes Scribe for field data management, and provides data to CLP laboratories using EPA-specified protocols.
