Using IFAS to Meet the Challenges of Significant Wet Weather Flows, Low Nitrifier Growth Rate and High rDON to Achieve Biological Nutrient Removal

The poster presents the challenges experienced and solutions provided in upgrading an existing high purity oxygen wastewater treatment plant for Biological Nutrient Removal (BNR) at the City of Winnipeg's South End Water Pollution Control Centre (SEWPCC). The plant operations is significantly challenging due to the high flows associated with spring thaw and summer rainfall events. Also low temperature (during spring thaw), low volatile fatty acids accompanied by low nitrifier maximum specific growth rate and the presence of a high fraction of soluble unbiodegradable influent TKN (rDON) adds process complexity. To meet these challenges, an Integrated Fixed Film Activated Sludge (IFAS) BNR process utilizing floating media in conjunction with a novel approach for wet weather flow treatment was determined to be the most cost effective approach to achieve effluent nitrogen and phosphorus limits.