Low energy ammonia reduction from ammonia-rich sludge thickening lagoon supernatant in Canada: Pilot-scale demonstration

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Municipal wastewater generally contains excessive nutrients (nitrogen and phosphorus), which when discharged without sufficient treatment can cause eutrophication in the receiving water bodies. Digested sludge liquor, the produce water generated from the treatment of sludge (primary and secondary) that is produced from municipal wastewater treatment plant contains high concentrations of ammonia that is toxic to aquatic biota and requires further treatment. The conventional nitrification/denitrification process is energy intensive due to its significant requirement for aeration. Newer processes, such as the nitritation/denitritation and nitritation/anammox (anaerobic ammonium oxidation) processes require low oxygen demand are emerging, but information on the implementation of these processes at the full-scale is limited, especially for operations under cold Canadian conditions. In collaboration with EPCOR Water Services Inc., Liu's group has explored the strategies to adopt the nitritation/denitritation and nitritation/anammox processes using lab-scale reactors to reduce the ammonia content in the ammonia-rich sludge liquor under the cold Canadian conditions, and achieved excellent ammonia reduction efficiency. However, further study of both processes at the pilot-scale is necessary for future full-scale process selection and evaluation to meet EPCOR's needs. As such, a continuation of the previous lab-scale study is proposed here. In this study, we propose to employ the nitritation/denitritation and nitritation/anammox processes at the pilot-scale to estimate the operation and control strategies for ammonia-rich sludge liquor treatment. This objective will be achieved through multidisciplinary studies combining expertise in wastewater treatment, biofilm microbiology, and bioreactor development from the University of Alberta, and full-scale bioreactor design and operation from EPCOR. Pilot-scale nitritation/denitritation and nitritation/anammox reactors will be operated and optimized. Operational control strategies obtained from this study will be used to provide guidance for further full-scale implementation.