Kinetics Of Para-nitrophenol And Chemical Oxygen Demand Removal From Synthetic Wastewater In An Anaerobic Migrating Blanket Reactor

摘要

A laboratory scale anaerobic migrating blanket reactor (AMBR) was operated at different HRTs (1-10.38 days) in order to determine the para-nitrophenol (p-NP) and COD removal kinetic constants. The reactor was fed with 40 mg L~(-1) p-NP and 3000 mg L~(-1) glucose-COD. Modified Stover-Kincannon and Grau second-order kinetic models were applied to the experimental data. The predicted p-NP and COD concentrations were calculated using the kinetic constants. It was found that these data were in better agreement with the observed ones in the modified Stover-Kincannon compared to Grau second-order model. The kinetic constants calculated according to Stover-Kincannon model are as follows: the saturation value constant (K_B) and maximum utilization rate constants (R_(max)) were found as 31.55 g COD L~(-1) day~(-1),29.49 g COD L~(-1) day~(-1) for COD removal and 0.428 gp-NPL~(-1) day~(-1),0.407 gp-NPL~(-1) day~(-1) for p-NP removal, respectively (R~2 = 1). The values of (a) and (fa) were found to be 0.096 day and 1.071 (dimensionless) with high correlation coefficients of R~2=0.85 for COD removal. Kinetic constants for specific gas production rate were evaluated using modified Stover-Kincannon, Van der Meer and Heerrtjes and Chen and Hasminoto models. It was shown that Stover-Kincannon model is more appropriate for calculating the effluent COD, p-NP concentrations in AMBR compared to the other models. The maximum specific biogas production rate, G_(max), and proportionality constant, G_B, were found to be 1666.7 mL L~(-1) day~(-1) and 2.83 (dimensionless), respectively in modified Stover-Kincannon gas model. The bacteria had low Haldane inhibition constants (K_(ID) = 14 and 23mg L~(-1)) for p-NP concentrations higher than 40 mg L~(-1) while the half velocity constant (K_s) increased from 10 to 60 and 118 mg L~(-1) with increasing p-NP concentrations from 40 to 85 and 125 mg L~(-1).