NGWA Event and Education Recordings Archive

The increased use of ethanol as an alternative to the fuel oxygenate methyl tertiary butyl ether (MTBE) to meet the Energy Policy Act (EPAct) of 2005 requirement of the renewable fuel standard (RFS) program has created new challenges in the recovery and treatment of accidental releases. The degradation of ethanol in the subsurface has the potential to produce large quantities of scent-free methane gas that could lead to explosive conditions. Additionally, the rapid degradation of the ethanol allows more toxic petroleum chemicals to impact downgradient drinking water supply wells. The need to contain and recover the groundwater is essential to protecting these water supplies. Bioremediation technology borrowed from municipal wastewater treatment plants is currently being used at a fuel station in Virginia to economically and efficiently treat the ethanol and other more toxic petroleum chemicals that are being generated from the groundwater recovery process. Bioremediation has been repeatedly used successfully as an effective technology to treat various toxic chemicals. However, the majority of bioremediation employed projects for fuel cleanups have utilized in-situ processes. Bioremediation is not typically used during high volume groundwater recovery operations due to the large footprint required for the equipment. However, the presence of ethanol at this site has created a need to alter the conventional process of this large groundwater recovery operation. This case study has also discovered that ethanol does not rapidly degrade at all sites equally and may be present for several years.