Performance evaluation of Malathion biodegradation in batch and continuous packed bed bioreactor (PBBR)

The aim of this work was to study the biodegradation of Malathion in batch and continuous packed bed (Polyurethane foam; PUF) bioreactor (PBBR). After 10 days, 89% Malathion removal was observed in batch PBBR. Continuous PBBR was operated at various flow rates (5-30 mL/h) under optimum condition over a period of 75 days. Inlet loading rates and elimination capacities were observed in the range of 36-216 and 7.20-145.4 mg/L/day with an average removal efficiency of more than 90% under steady state conditions. GC/MS analysis confirms phosphorodithionicacid, O, O, S-trimethylester and diethylmercaptosuccinate as metabolites. Biodegradation of Malathion under inhibitory and non-inhibitory conditions was studied using Monod and Andrew-Haldane models and the kinetic constants were calculated and found to be mu(max): 0.271 per day; K-s: 126.3 mg/L using Monod and mu(max): 0.315 per day; K-s: 151.32 mg/L; K-i: 594.75 mg/L using Andrew-Haldane models. (C) 2016 Elsevier Ltd. All rights reserved.