During a site investigation, Benzene was detected in several groundwater samples collected at an underground injection well site. Light phase non-aqueous liquids (LNAPL) was also observed in several monitoring wells. To prevent the Benzene and LNAPL from entering a nearby creek, an interceptor trench was installed downgradient of the site. A sump was installed in the trench and the recovered groundwater was pumped into an onsite treatment system designed by AGES. The system consisted of an oil/water separator to remove LNAPL and carbon treatment to remove the Benzene. The creek bank was also stabilized with a grout Fabriform cover. To allow for the discharge of treated groundwater to the creek, a NPDES permit was required.
NPDES Permitting and Sampling
AGES worked with the State of West Virginia to obtain a NPDES permit to allow for discharge of treated groundwater to the creek. AGES completed the permit application, obtained all approval signatures and submitted all required results and data to the state. The permit was approved without comment, and discharge to the creek began after the system went operational. AGES staff conducted the monthly outfall sampling for the parameters required by the permit. Results and monitoring reports (DMRs) were then completed and submitted to the state in a timely manner. Following the reduction of Benzene concentration to below the applicable action level, the permit was terminated and the components of the groundwater treatment system were removed.
Special Project Features
Demonstrated ability to characterize a site, obtained permits necessary to comply with state discharge requirements and designed groundwater treatment system.