Treatment Performance of Wastewater Stabilization Ponds in Canada's Far North

In Canada, a new harmonized national framework has been proposed for the level of treatment achieved by municipal wastewater management systems. Due to its extreme climatic conditions and remoteness, the Canadian Far North is identified as requiring careful consideration to produce a viable means to improve human and environmental health protection. As the new wastewater standards are implemented, many arctic wastewater systems will likely need to be upgraded. The objectives of this paper were to (i) provide an overview of the main wastewater treatment challenges, and types of treatment systems used in the North, (ii) review performance models used to size wastewater stabilization ponds (WSPs), and the applicability of these models to the Canadian Arctic, and (iii) provide an overview of the treatment performance and design of wastewater stabilization ponds used in three communities in Nunavut. Single cell WSPs, sized to retain wastewater for up to 365 days, are the most common engineered municipal wastewater treatment in use in the Canadian Far North. However, very little information exists with respect to the their treatment performance, and whether performance models developed in Southern regions would be applicable to these systems. Initial monitoring and assessment of three WSPs in the Territory of Nunavut has shown that these systems are very dynamic, possessing large spatial and temporal variations in temperature, dissolved oxygen and pH. The key to predicting WSP performance is to develop a comprehensive understanding of how the extreme arctic climate, in particular photoperiod and temperature, influence the biogeochemistry of WSPs.