THE EFFECT OF HETEROTROPHIC YIELD ON THE ASSESSMENT OF THE CORRECTIONFACTOR FOR ANOXIC GROWTH

For single-sludge denitrification systems, modelling of anode reactors currently uses the kinetics of aerobic heterotrophic growth together with a correction factor for anoxic conditions. This coefficient is co mputed on the basis of respirometric measurements with the assumption that the heterotrophic yield remains the same under aerobic and anoxic coditions. The paper provides the conceptual proof that the yield coe fficient is significantly lower for the anoxic growth on the basis of the energetics of the related metabolic processes. This is used for th e interpretation of the Very high values for the correction factor exp erimentally determined for a number of industrial wastewaters. A defau lt Value for the anoxic heterotrophic yield coefficient is calculated for domestic sewage and compatible wastewaters and proposed for simila r evaluations. Copyright (C) 1996 IAWQ.