Biodegradation kinetics of high strength oily pet food wastewater in a membrane-coupled bioreactor (MBR)

Aerobic respirometric experiments were conducted at a temperature of 40 °C to determine biokinetic parameters describing growth and decay of aerobic biomass acclimatized in a membrane-coupled bioreactor (MBR). The kinetic parameters were determined with the volatile fatty acids (VFA) acetic acid and propionic acid as substrates as well as the soluble fraction of a high strength rendering wastewater as substrate. The oxygen uptake rate (OUR) and cumulative oxygen uptake (OU) recorded during the experiments were fitted to Monod kinetic model to obtain true yield (Yt), intrinsic maximum substrate removal (k), half-saturation constant (Ks) and endogenous decay coefficient (kd). Ks were determined to be 181, 271 and 806 mg COD l−1 and k as 1.89, 1.08 and 0.85 mg COD mg VSS−1 h−1 for acetate, propionate and rendering wastewater, respectively. The continuous-flow MBR was operated under two HRT conditions, 10 and 5 d, attaining high BOD removal efficiencies of 99% and 87%, respectively. The observed yield in the MBR was 0.03 g VSS g−1 COD.