Activated carbon is proving to be successful in removing this stubborn contaminant from drinking water supplies By Andy McClure and Neal Megonnell MTBE: Background and History
It is ironic: a decision to improve air pollution has ended up causing water pollution problems. In 1979, the U.S. Environmental Protection Agency (EPA) allowed the use of methyl tertiary butyl ether (MTBE) as an octane enhancer in gasoline, replacing lead as an octane booster and allowing for cleaner burning fuels and lower emissions from vehicles. In the past several years, however, an unplanned side effect of MTBE has occurred through water contamination. Due to its high solubility, low adsorption to soil and poor natural biodegradation, MTBE is a highly mobile and persistent contaminant in groundwater. As a result, over the past two decades of its use, MTBE has found its way into lakes and groundwater supplies in all 50 states.
To respond to MTBE contamination, EPA issued a drinking water advisory level of 20 to 40 parts per billion (ppb) for MTBE several years ago and placed MTBE on its Contaminant Candidate List for further evaluation. Several states, deciding not to wait for a federal regulation, have enacted their own drinking water limits for MTBE. An excellent summary of state regulations can be found on the EPA Web site at www.epa.gov/swerust1/mtbe/mtbemap.htm. . In some cases, health-based standards and taste/odor-based standards have been set.
Meanwhile, the issue of whether to ban MTBE from gasoline in the future is being hotly debated. The state of California has already banned the use of MTBE in gasoline by the end of 2003; several suppliers have announced that they will switch to ethanol as an oxygenate before that date.
While this controversy over the risks of MTBE and its future continues, existing contamination of drinking water supplies needs to be addressed.
Cleaning Up MTBE Contaminated Groundwater Used for Drinking Water: In the past several years, there have been numerous incidents of MTBE from underground storage tanks leaking into the groundwater that is often used as a source of drinking water. According to author Andy McClure of Calgoncarbon Corp., even though several other technologies can remove MTBE from groundwater, the most effective cleanup technology to remove this difficult contaminant at the residential point of entry is activated carbon.:
