Kinetics of sugar mill wastewater treatment by down-flow anaerobic fixed bed reactors

It was found that pseudo first order kinetics described the anaerobic digestion of sugar mill wastewater using laboratory-scale fixed bed reactors. A pseudo first order equation described the relationship of COD removal rate with the effluent COD. The values of the maximum COD removal rate and saturation constant were found to be 3.02 g COD/1 day and 0.34 g COD/1 respectively. Based on the similar approach, values of the maximum specific substrate utilization rate, Um, and the coefficient of surface loading saturation, KU, were 0.44 and 0.49 Kg COD/m2 day, respectively. Similar expression was employed to evaluate the effect of the organic volumetric loading rate (Bv) and the organic volumetric loading removal rate (BvR). Variations in experimental data from the theoretical values obtained using the model were assessed with respect to the efficiency corresponding to each of the hydraulic retention times and influent concentrations. Theoretical values were calculated with a 15% error band using the kinetic parameters obtained. The experimental values were within this error band in all cases. With the pseudo first order kinetic model, values of μm and Kd were found to be 1.08 and 0.31 (1/days) respectively.