Substrate removal kinetics in an upflow anaerobic sludge blanket reactor decolorising simulated textile wastewater

A simulated wastewater containing sizing agents, azo dyes, salts and other additives was treated using a lab-scale upflow anaerobic sludge blanket (UASB) reactor at different hydraulic retention times (HRT) in order to obtain the substrate removal kinetic of the reactor through decolorization of dyes. COD removal efficiencies decreased from 80 to 29.5% when the HRT decreased from 100 to 6 h. The colour removal efficiencies were between 90 and 95% for HRTs of 100 and 6. Monod, Contois, Grau second order, modified Stover-Kincannon, and first order kinetic models were applied to determine the substrate removal kinetic of UASB reactor. The experimental data obtained from the steady-state conditions showed that Grau second order, modified Stover-Kincannon and Contois substrate removal kinetic models were suitable than the other applied models for predicting the performance of lab-scale UASB reactor treating the azo dyes.