Estimation of Heterotrophic Biokinetic Parameters in Wastewater Biofilms from Oxygen Concentration Profiles by Microelectrode

摘要

Knowledge of the biokinetic parameters of heterotrophic biofilm is important for reliable modeling and optimizationnof biofilm wastewater treatment systems. In this article, an approach to quantify heterotrophic biokineticnparameters, including the maximum specific oxygen uptake rate (q hnmax), the Monod half saturationncoefficient of oxygen (ko), and the maintenance decay coefficient for oxygen (Km) in wastewater biofilms, wasnpresented and evaluated. With the oxygen microprofiles measured in the biofilm by using the oxygen microelectrode,nthe heterotrophic biokinetic parameters were determined through fitting the data to the diffusionreactionnmodels. The biomass used in the model was represented in terms of the average volatile suspendednsolids (VSS) measured by weight and the spatial distribution of VSS by phospholipid analysis. Results showednthat with an addition of an external substrate at a concentration of 2000mg COD/L into biofilms, oxygennbecame the growth limiting factor. The biokinetic parameters derived from the average VSS possessed thensmallerq hnmax compared with the layered VSS. However, the heterogeneity of biomass has a slight impact on the konand Km. Sensitivity analyse showed that the proposed model was a good q hnmax estimator.