Adaptation of the simpletreat chemical fate model to single-sludge biological nutrient removal wastewater treatment plants

Many recent developments in municipal waste water treatment technology are directed towards biological nutrient removal. Chemical fate models which are used to predict the behavior of individual chemicals in waste water treatment plants (WWTPs), have until now not incorporated this aspect. In this paper, two modifications to the steady-state non-equilibrium Simple Treat modeling concept are presented. These focus on an improved description of sludge recycling, and on the presence of different redox zones in the biological reactor (aerobic, anoxic, anaerobic). The updated models were applied to three different WWTP designs, and simulation results were compared to measured values for the surfactant LAS.