METHYL TERTIARY-BUTYL ETHER (MTBE) BIODEGRADATION IN A CONTINUOUS UPFLOW FIXEDBIOFILM REACTOR

A natural fiber mat reactor was constructed and seeded with MTBE-degrading microorganism to evaluate the removal efficiency of MTBE. Different operation factors were evaluated to assess optimal removal efficiency. These factors included oxygen supply flow rate, hydraulic retention time (HRT), yeast extract and initial MTBE concentration in the feed medium. Four models were evaluated to describe the MTBE removal kinetic in the reactor. Formaldehyde and tertiary butyl alcohol (the most two reported MTBE biodegradation byproducts) were not found in the effluent, instead, carbon dioxide was monitored as the end product based on the results of a metabolic mass balance evaluation. Toxicity based on the Microtox acute toxicity test was reduced in the treated effluent compared to that presenting in the influent. The endocrine disruption potential for MTBE and MTBE bioremediation byproducts was evaluated by estrogen and androgen activity in vitro assays including human breast cancer proliferation assay; estrogen receptor regulated reporter gene and androgen receptor regulated reporter gene assay.