Degradation of Mtbe Using Fenton Reagent

195 INTRODUCTION In an attempt to reduce the environmental consequences associated with incomplete fuel combustion, the US Clean Air Act Amendments of 1990, required that oxygenates are added to reformulated gasoline. Since 1979, methyl tert butyl ether (MTBE) has been used in the USA as an octane enhancing replacement for lead, primarily in mid and high grade gasoline. It is the most commonly used (85%) fuels oxygenate (Johnson et al., 2000). The reformulated gasoline contains 2.7% oxygen (by weight), which is approximately 11-15% of MTBE by volume (Johnson et al., 2000). The widespread use of MTBE for gasoline oxygenation has led to its introduction into groundwater from spills and leaky underground storage tanks. The wide application of MTBE is problematic (Franklin et al., 2000). The bad taste and odour of MTBE can be detected down to 0.02 mg/L and inhalation of MTBE vapors may cause headaches and nausea at higher concentration (ppm) (Burgess et al., 1998). In the USA, MTBE has been classified as a possible human carcinogen and a draft lifetime health advisory limit of 20-35 μg/L issued (Squillace et al., 1996). In addition, MTBE has the undesirable characteristic of being highly mobile in the environment as it is transported in the same velocity as groundwater in the aquifer. MTBE is poorly adsorbed, chemically and biologically stable, and very soluble in water, so making it very persistent in the environment. Conventional treatment of MTBE contaminated groundwater is inefficient and unsatisfactory. Air stripping is difficult and requires a high air-towater ratio (>200/l for 95% removal) because of its very low Henry’s low constant. The low affinity of MTBE towards granular activated carbon makes this process undesirable and expensive (Anderson, 2000). It can be treated biologically (Bradley et al., 1999) with special bacterial strains or natural isolated under aerobic conditions. However, the bacteria grow slowly with low yields of biomass and sometimes unstable. As a result, a viable bioremediation process for MTBE has not been fully developed. DEGRADATION OF MTBE USING FENTON REAGENT