Partial Denitrification Model Development in the Context of Shortcut Nitrogen Removal Processes

As part of the industry’s direction towards nitrogen removal intensification in wastewater treatment, partial denitrification (PdN) is a promising and a more reliable alternative to partial nitrification (or nitritation) in mainstream deammonification processes, where heterotrophs (OHO) produce nitrite required for anaerobic ammonia oxidizers (AnAOB) for efficient nitrogen removal [4]. The process is called PdNA (i.e. PdN+AnAOB). It is estimated that 50% reduction in air requirement and 80% reduction in carbon addition can be achieved compared to conventional nitrification/denitrification. In this study, the biological denitrification reactions in Sumo 2 were modified to allow for partial denitrification (or denitratation) when volatile fatty acids are used as a carbon source. The model was calibrated using batch anoxic bioassays spiked with acetate and data from PdNA suspended growth pilot data. The validation runs had fairly constant nitrate uptake rates. Hence, the future work for developing and validating the model will entail calibrating the model using various carbon sources and at various nitrate specific uptake rates.