title: Factors impacting biotransformation kinetics of trace organic compounds in lab-scale activated sludge systems performing nitrification and denitrification.
abstract: To predict TOrC fate in biological activated sludge systems, there is a need to accurately determine TOrC biodegradation kinetics in mixed microbial cultures. Short-term batch tests with salicylic acid, 17α-ethinylestradiol, nonylphenol, trimethoprim and carbamazepine were conducted with lab-scale activated sludge cultures in which the initial TOrC concentration (1mg/L and 0.0005mg/L) and readily biodegradable substrate concentrations were varied. The results indicate that pseudo-first order kinetic estimates of TOrC are not sensitive (p>0.05) to the initial TOrC concentration as long as the initial TOrC concentration (S0) to biomass (X0) ratio (on COD basis) is below 2×10(-3). The presence of readily biodegradable organic matter suppresses TOrC biotransformation rates under nitrifying and denitrifying conditions, and this impact can be adequately described using a reversible non-competitive inhibition equation. These results demonstrate the importance of closely mimicking parent reactor conditions in batch testing because biotransformation parameters are impacted by in-situ carbon loading and redox conditions.
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260, USA.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Su
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260, USA.
authors.forename: Diana
authors.initials: D
authors.lastname: Aga
authors.affiliation: Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA.
authors.forename: Kartik
authors.initials: K
authors.lastname: Chandran
authors.affiliation: Hazen and Sawyer P.C., Fairfax, VA 22030, USA. Electronic address: wkhunjar@hazenandsawyer.com.
authors.forename: Wendell O
authors.initials: WO
authors.lastname: Khunjar
mesh_terms: D019149:Bioreactors; D001711:Biotransformation; D002220:Carbamazepine / Q000032:analysis / Q000378:metabolism; D058440:Denitrification; D004997:Ethinyl Estradiol / Q000032:analysis / Q000378:metabolism; D058465:Nitrification; D010636:Phenols / Q000032:analysis / Q000378:metabolism; D020156:Salicylic Acid / Q000032:analysis / Q000378:metabolism; D012722:Sewage; D014295:Trimethoprim / Q000032:analysis / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D010636:Phenols; D012722:Sewage; D014874:Water Pollutants, Chemical; D002220:Carbamazepine; D004997:Ethinyl Estradiol; C025256:nonylphenol; D014295:Trimethoprim; D020156:Salicylic Acid
keywords: Activated sludge; Denitrification; Nitrification; Synthetic organic compounds