You are here:
Anaerobic Biodegradation of Biofuels (Ethanol, Biodiesel, n-Propanol, n-Butanol, and iso-Butanol) in Aquifer Sediment (PP)
Citation:
ADAIR, C. J. AND J. T. WILSON. Anaerobic Biodegradation of Biofuels (Ethanol, Biodiesel, n-Propanol, n-Butanol, and iso-Butanol) in Aquifer Sediment (PP). Presented at The 22nd National Tanks Conference , Boston, MA, September 20, 2010.
Impact/Purpose:
To understand the fate of biofuels, ethanol in particular if these materials are released from underground storage tank systems.
Description:
In the late 1990s, there was a perception that “green” fuels such as ethanol posed less of a threat to ground water because they were readily degraded. This lead to a conclusion that the transition to “green” fuels would require less vigilance and that the existing level of effort from the state agencies for monitoring and inspection of UST sites might not be necessary. The recently published field demonstrations of the negative interaction between ethanol in ground water and the biodegradation of the petroleum components of biofuels, as well as the concomitant methane production has provided convincing evidence that biofuels required the same level of vigilance as petroleum gasoline. With increasing use of biofuels, ethanol in particular, in the fuel supply nationwide, and increases in the number of stations that sell gasoline that contains more than 10% ethanol, U.S. EPA needs to understand the fate of these materials if they are released from underground storage tank systems. ORD is currently concluding a two year laboratory microcosm study comparing the rate of anaerobic biodegradation of ethanol, n-butanol, iso-butanol, n-propanol, and B-100 biodiesel in aquifer sediment from fuel spill sites. In the microcosm studies there was anaerobic biodegradation of the biofuels, concurrent consumption of sulfate, and the production of methane and volatile fatty acids. At low initial concentrations (60 to 120 mg/L) concentrations of all the biofuels were below the detection limit (approximately 1 mg/L) in two months. There was near stoichiometric production of methane. At higher initial concentrations (340 to 630 mg/L) ethanol was degraded to the detection limit in three month. However, approximately half of the initial concentrations of n-Propanol, iso-Propanol, and n-Butanol were removed in three months, then degradation slowed or stopped, concomitant with the accumulation of the corresponding fatty acid.