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 degrees 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 waste-water 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 (Y-t), intrinsic maximum substrate removal (k), half-saturation constant (K-s) and endogenous decay coefficient (k(d)). K-s 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. (c) 2006 Elsevier Ltd. All rights reserved.