title: Biological removal of the xenobiotic trichloroethylene (TCE) through cometabolism in nitrifying systems.
abstract: In the present study, cometabolic TCE degradation was evaluated using NH(4)-N as the growth-substrate. At initial TCE concentrations up to 845 microg/L, TCE degradation followed first-order kinetics. The increase in ammonium utilization rate favored the degradation of TCE. This ensured that biological transformation of TCE in nitrifying systems is accomplished through a cometabolic pathway by the catalysis of non-specific ammonia oxygenase enzyme of nitrifiers. The transformation yield (T(y)) of TCE, the amount of TCE degraded per unit mass of NH(4)-N, strongly depended on the initial NH(4)-N and TCE concentrations. In order to allow a rough estimation of TCE removal and nitrification at different influent TCE and NH(4)-N concentrations, a linear relationship was developed between 1/T(y) and the initial NH(4)-N/TCE ratio. The estimated T(y) values lead to the conclusion that nitrifying systems are promising candidates for biological removal of TCE through cometabolism.
authors.affiliation: Department of Environmental Engineering, Faculty of Engineering, University of Marmara, Kuyubasi, Istanbul, Turkey. bilge.alpaslan@marmara.edu.tr
authors.forename: B Alpaslan
authors.initials: BA
authors.lastname: Kocamemi
authors.forename: F
authors.initials: F
authors.lastname: Ceçen
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D018920:Coculture Techniques / Q000379:methods; D003198:Computer Simulation; D007220:Industrial Waste / Q000517:prevention & control*; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism*; D014241:Trichloroethylene / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*; D015262:Xenobiotics / Q000378:metabolism*
chemical_list: D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D015262:Xenobiotics; D014241:Trichloroethylene; D009584:Nitrogen