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

摘要

A natural fiber mat reactor was constructed and seeded with MTBE-degradingrnmicroorganism to evaluate the removal efficiency of MTBE. Different operation factorsrnwere evaluated to assess optimal removal efficiency. These factors included oxygenrnsupply flow rate, hydraulic retention time (HRT), yeast extract and initial MTBErnconcentration in the feed medium. Four models were evaluated to describe the MTBErnremoval kinetic in the reactor. Formaldehyde and tertiary butyl alcohol (the most twornreported MTBE biodegradation byproducts) were not found in the effluent, instead,rncarbon dioxide was monitored as the end product based on the results of a metabolicrnmass balance evaluation. Toxicity based on the Microtox acute toxicity test was reducedrnin the treated effluent compared to that presenting in the influent. The endocrinerndisruption potential for MTBE and MTBE bioremediation byproducts was evaluated byrnestrogen and androgen activity in vitro assays including human breast cancerrnproliferation assay; estrogen receptor regulated reporter gene and androgen receptorrnregulated reporter gene assay.