Kinetic and Physiological Evaluation of Ammonium and Nitrite Oxidation Processes in Presence of 2-Chlorophenol
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Kinetic and Physiological Evaluation of Ammonium and Nitrite Oxidation Processes in Presence of 2-Chlorophenol J. E. Pérez-Alfaro & G. Buitrón & J. Gomez & A.-C. Texier & F. M. Cuervo-López
Received: 29 October 2012 / Accepted: 26 December 2012 / Published online: 8 January 2013 # Springer Science+Business Media New York 2013
Abstract The effect of 2-chlorophenol (2-CP) on ammonium and nitrite-oxidizing processes was kinetically evaluated in batch cultures with nitrifying sludge at steady state. Assays with ammonium or nitrite as energy source and 2.5, 5.0, or 10.0 mg 2-CP-C/l were conducted. Control assays without 2-CP were also performed. Ammonium-oxidizing activity was completely inhibited at the different 2-CP concentrations, whereas nitrite-oxidizing activity was present as nitrite was completely consumed and converted to nitrate irrespectively of 2-CP concentration. In the presence of 2.5 and 5.0 mg 2-CP-C/l, no significant effect on specific rates of nitrite consumption and nitrate production was observed, but a significant decrease on these parameters was observed at 10.0 mg 2-CP-C/l. The nitrifying sludge previously exposed to 2-CP was unable to completely recover its ammonium and nitrite oxidation capacity. Nevertheless, complete 2-CP consumption was achieved in all assays. The effect of 2-CP on ammonium oxidation was observed at kinetic and metabolic pathway level, whereas the effect on nitrite oxidation was observed only at kinetic level. The results obtained in this work evidenced that in order to achieve a successful nitrification process the presence in wastewater of even 2.5 mg 2-CP-C/l should be avoided. Keywords Ammonium oxidation . 2-Chlorophenol . Inhibition . Nitrite oxidation . Membrane . Nitrification
Introduction Chlorophenols are included in the rank of organic pollutants with a high priority for elimination [1]. These compounds are widely distributed in air, soil, water, and in many J. E. Pérez-Alfaro : J. Gomez : A.-C. Texier : F. M. Cuervo-López (*) Department of Biotechnology, Universidad Autónoma Metropolitana-Iztapalapa, Iztapalapa, Mexico City CP 09340, Mexico e-mail: [email protected] G. Buitrón Department of Environmental Bioprocess of Engineering Institute, Universidad Nacional Autónoma de México, Mexico City, Mexico
Appl Biochem Biotechnol (2013) 169:990–1000
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industrial wastewaters [2]. 2-Chlorophenol (2-CP) is widely used for wood preservation, manufacturing herbicides, insecticides, fungicides, and flame retardants, resulting in its accumulation in superficial and underground water [3]. Several biological processes at different conditions have been used to remove chlorophenols from wastewaters, such as aerobic [4, 5], anaerobic [6], or combination of them [3, 7]. It has been reported that aerobic 2-CP elimination results in intermediaries accumulation which led inactivation of catechol 2,3-dioxygenase enzyme [8], whereas at anaerobic conditions, Beristain-Montiel et al. [9] observed mineralization and methanization of 2-chlorophenol but a previous sludge acclimation to
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