Peak Flow Management Strategies to Support Wastewater Treatment Intensification: A Science and Regulatory Based Approach

In response to increasingly stringent effluent limits, The City of Calgary initiated a study in 2019 to explore treatment intensification at its Fish Creek WWTP using a defined Peak Flow Management (PFM) approach whereby flows up to a defined Threshold Peaking Factor (TPF) are directed through the mainstream treatment processes, with excess diverted via an approved PFM strategy. Implementation of PFM reduces the peak flows through mainstream treatment, supporting process intensification by maximizing reuse of existing infrastructure, however little guidance in terms of a formal regulatory framework has been available in North America. To overcome the absence of an existing framework, the Project Team developed a regulatory framework and assessment methodology to review potential impacts of such an approach. Through the assessment of results, The City was able to demonstrate to the regulator that incorporating a PFM approach for upgrades will not have a negative impact on the receiving water.