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Water Res

Title:		Modelling cometabolic biotransformation of organic micropollutants in nitrifying reactors
Author(s):		Fernandez-Fontaina E; Carballa M; Omil F; Lema JM;
Address:		"Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain. Electronic address: eduardo.fernandez.fontaina@usc.es. Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain"
Journal Title:		Water Res
Year:		2014
Volume:		20140808
Issue:
Page Number:		371 - 383
DOI:		10.1016/j.watres.2014.07.048
ISSN/ISBN:		1879-2448 (Electronic) 0043-1354 (Linking)
Abstract:		"Cometabolism is the ability of microorganisms to degrade non-growth substrates in the presence of primary substrates, being the main removal mechanism behind the biotransformation of organic micropollutants in wastewater treatment plants. In this paper, a cometabolic Monod-type kinetics, linking biotransformation of micropollutants with primary substrate degradation, was applied to a highly enriched nitrifying activated sludge (NAS) reactor operated under different operational conditions (hydraulic retention time (HRT) and nitrifying activity). A dynamic model of the bioreactor was built taking into account biotransformation, sorption and volatilization. The micropollutant transformation capacity (Tc), the half-saturation constant (Ksc) and the solid-liquid partitioning coefficient (Kd) of several organic micropollutants were estimated at 25 degrees C using an optimization algorithm to fit experimental data to the proposed model with the cometabolic Monod-type biotransformation kinetics. The cometabolic Monod-type kinetic model was validated under different HRTs (1.0-3.7 d) and nitrification rates (0.12-0.45 g N/g VSS d), describing more accurately the fate of those compounds affected by the biological activity of nitrifiers (ibuprofen, naproxen, erythromycin and roxithromycin) compared to the commonly applied pseudo-first order micropollutant biotransformation kinetics, which does not link biotransformation of micropollutants to consumption of primary substrate. Furthermore, in contrast to the pseudo-first order biotransformation constant (k(biol)), the proposed cometabolic kinetic coefficients are independent of operational conditions such as the nitrogen loading rate applied. Also, the influence of the kinetic parameters on the biotransformation efficiency of NAS reactors, defined as the relative amount of the total inlet micropollutant load being biotransformed, was assessed considering different HRTs and nitrification rates"
Keywords:		"Bacteria/metabolism Benzopyrans/metabolism Bioreactors Kinetics Models, Biological Nitrification Pharmaceutical Preparations/metabolism Sewage/*microbiology Tetrahydronaphthalenes/metabolism Waste Disposal, Fluid Water Pollutants, Chemical/analysis/*metab;"
Notes:		"MedlineFernandez-Fontaina, E Carballa, M Omil, F Lema, J M eng Research Support, Non-U.S. Gov't England 2014/08/26 Water Res. 2014 Nov 15; 65:371-83. doi: 10.1016/j.watres.2014.07.048. Epub 2014 Aug 8"