The incorporation of enhanced biological phosphorus elimination in the single sludge process is a contemporary challenge in the design of biological wastewater treatment plants. The simultaneous biological removal of nitrogen and phosphorus is a process of considerable technical and biological complexity owing to the mixed substrates and the diversity of microorganism populations. In addition, an interaction takes place between the phosphorus-accumulating organisms and the nitrogen-eliminating organisms owing to the physiological demands. When designing wastewater treatment plant, it is necessary to establish anaerobic zones for producing the short fatty acids necessary for phosphorus removal, an xic zones for denitrification, and aerated zones for nitrification and phosphorus removal.
We have developed a mathematical model based on IA WPRC-model No I for this process scenario. In addition to the degradation kinetics of carbonaceous components and nitrogen, the model describes the microkinetics of enhanced biological phosphorus elimination. The assumptions of the model are discussed in relation to the recent literature. The range of values found in the literature and the used default values of the model parameters are listed. The simulation program is presented, and first results of simulation are shown.