Determination of biokinetic parameters of wastewater biofilms from oxygen concentration profiles

Abstract

The process of scale-up and rational optimization of biofilm processes for effective wastewater treatment and reuse require better understanding of the biokinetic behavior of microorganisms in the biofilms. At present, no fast and accurate methods exist for determining kinetic parameters for biofilm systems. This study presents a modified approach to quantify biofilm kinetic parameters from oxygen concentration profiles measured in membrane-aerated biofilms (MABs) and rotating biological contactors (RBC) biofilms.

The calculated values of Monod’s half-saturation coefficient (Ks) for oxygen consumption and maximum utilization rate of oxygen (µm/Y) in MABs were estimated to be 2.01 mg O2/cm3 and 6.50×10-8 mgO2/gVS∙s, respectively. And, the values of first-order kinetic coefficient, (µm/Y)/Ks, in MABs and RBC biofilms were in the range of (0.62-1.43)×10-6 and (0.36-5.55)×10-5cm3/gVS∙s, respectively. The biofilm kinetic parameters obtained in this study were found to differ from the same parameters in activated sludge systems, which show that more experimental data for kinetic parameters in biofilms are required.