Ex-Situ Treatment of MTBE in Groundwater using a Trickling Filter Bioreactor

The trickling filter is a conventional wastewater treatment technology that has been used for decades for municipal and high BOD wastewaters. However, this technology has seen limite application in the United States for gasoline-impacted groundwater. Further, the initially widespread skepticism in the United States regarding biodegradability of methyl tert-butyl alcohol (MTBE) caused bioremediation technologies to be discounted as feasible remediation solutions. However, a number of applications of trickling filter bioreactor (TFB) systems in Europe have shown that TFB technology is a technologically sound and cost-effective method for remediating MTBE in groundwater. TFB technology was recently applied at a gasolinecontaminated site where MTBE concentrations in groundwater reached 980 mg/L at the source. Due to the site's proximity to a stream designated as high quality by the Pennsylvania Department of Environmental Protection (DEP), active remediation of the contaminant plume was necessary to avoid stream degradation and the consequential penalties for natural resource damages. A groundwater remediation system was designed and constructed, which included a trickling filter bioreactor as an innovative approach to groundwater remediation. Plume capture and control was achieved through the installation of two interceptor trenches for groundwater recovery. To date, MTBE removal efficiency has reached 85%, and is anticipated to reach 95% after additional system modifications. MTBE concentrations in groundwater at the site have also shown a significant decrease.This project was recently granted an Environmental Action Award by the Bucks County Chapter of the National Audubon Society.