Removal of methyl tertiary butyl ether (mtbe) vapour from contaminated air streams using different bacterial cultures in biotrickling filters.
Methyl tertiary butyl ether (MTBE) was firstly introduced in the Islamic Republic of Iran in the end of 2001 as gasoline octane enhancer. Ordinary, reformulated gasoline contains 11-15% (v/v) of MTBE. Because of its low production cost and excellent blending characteristics, its production has been grown exponentially in the world, reaching a value of over 33 million tons per year (Fortin and Deshusses, et al., 1999). With respect to the widespread use of MTBE, (daily use of 75 thousand tons gasoline in Iran), it an extensive MTBE emission is expected as a result of the stacks and leakage from underground and aboveground fuel tanks. Relative recalcitrance of MTBE to natural attenuation combined with its physico-chemical characteristics is a threat to groundwater supplies and drinking water wells. Consequently, MTBE has been, the second most frequently detected contaminant in drinking water supplies (Fortin and Deshusses, et al ., 1999). While MTBE is thought to be less harmful than other gasoline constituents, there is still relatively incomplete knowledge on its health effects (USEPA, 1997); so in 1997, USEPA issued a drinking-water advisory for MTBE, which is in the range of 20-40 µg/L. Unfortunately, MTBE has quite different physico-chemical properties, making it more expensive to treat MTBE wastes with conventional techniques (Fortin and Deshusses, et al ., 1999). In many remediation techniques, such as air sparring, soil vapor extraction, air stripping and wastewater treatment operations, large air streams contaminated with MTBE are generated that besides, a very large emission from stacks, require treatment. Therefore, biological treatment may prove to be more feasible as a remedial technology in comparison to conventional methods (Fiorenza et al ., 2003). The most promising bioreactors for air pollution control are biofilters and biotrickling filters.