WCW24

More stringent effluent requirements for BOD, TSS, ammonia and phosphorus are being mandated at lagoon facilities across Canada. Add in a cold climate that adversely affects winter treatment performance, and many lagoons struggle to stay in compliance with their current permit or meet the challenges of new regulations. Lemna Environmental Technologies (LET) will present an updated approach for lagoon based wastewater treatment including a brief comparison of past design standards with current methods, an overview of lagoon technologies used for advanced treatment including nutrient removal, and in-depth review of several cold weather case studies demonstrating how lagoons are being successfully updated in order to meet the challenges of present and future effluent requirements. Using wastewater treatment process design modeling software, which models biological, chemical, and physical treatment processes, LET has optimized the design, performance and reliability of lagoon based treatment systems. Using historical DMR data from an installation base of over 500 facilities, LET created a unique software model of its LemTec Biological Treatment Process, which utilizes a combination of aerated and settling lagoon cells for biochemical oxygen demand (BOD) and total suspended solids (TSS) removal, and the Lemna Polishing Reactor (LPR) for nitrification. The model enables LET to consider the effects of non-steady state factors such as peak flows, constituent loading, and ambient air and water temperatures on treatment performance, improving upon traditional steady state wastewater treatment process design methodology. The discussion will provide data and specific case studies demonstrating the predicted performance vs. actual data, using the calibrated model. Regional case studies will be used to demonstrate the benefits of modeling practices for lagoon design.