IMPLEMENTATION OF TOXIC INHIBITION IN WASTEWATER TREATMENT PLANT BENCHMARK SIMULATION MODELS

The activated sludge process of wastewater treatment plant benchmark simulation models has been modified to include the effect of soluble, biodegradable or non biodegradable toxic substances. The response of the activated sludge process to acute and chronic toxicity is monitored by means of a batch short-term respirometer. Generic inhibition functions have been introduced to model the effect of a toxicant on heterotrophs and nitrifiers growth and death. Constant inhibition kinetic parameters are used for acute toxicity modelling. For chronic toxicity modelling the variability of toxicant concentration and characteristics is taken into account by a transformation of these kinetic parameters into state variables.