Polymer Addition to Increase Trunk Sewer Flow Capacity at Resort Municipality of Whistler during 2010 Olympics

ABSTRACT

The 2010 Winter Olympic and Para-Olympic Games were expected to draw a record number of visitors to Whistler. They were also expected to generate significant sanitary sewer flows, which if coinciding with elevated wet weather inflow and infiltration (I&I), could overload the conveyance capacity of the existing trunk sewer system. Kerr Wood Leidal Associates Ltd.’s (KWL’s) hydraulic modelling of the trunk sewer system in 2008 confirmed the potential for the sewer to overflow under such extreme hydraulic conditions. To develop a solution, KWL evaluated several trunk sewer capacity upgrading options, and polymer addition was identified as being both technically feasible and cost-effective. Polymer addition was particularly appealing because it solves a short-term problem for a small capital and operating cost relative to the projected capital costs of other identified mitigation measures.

This presentation will describe the results of the winter 2009/10 trials prior to the Olympics, as well as the sewer flows seen during the 2010 Olympics, and final polymer addition results. The results quantify the benefit of polymer addition to the Whistler trunk sewer system and identify issues that arose during operation of the system. Lessons learnt, such as the optimum polymer addition strategy (i.e., preferred polymer, dosed concentration, injection location, and configuration), will also be discussed.

Key learning points are:

• Development of modelling and design parameters for a once-in-a-lifetime sewer flow event
• Innovative technology application of polymer for conveyance system capacity increase
• Deployment of a temporary, real time sewer level monitoring system

BIOGRAPHY

John Hart is a senior wastewater treatment engineer with 17 years of experience in wastewater treatment, hazardous waste management, air pollution, and environmental auditing. John’s first degree is in Chemical Engineering and was followed by a Masters degree in Civil/Environmental Engineering. His experience includes work for a wide variety of municipal and industrial clients in British Columbia, across Canada and China.

Lucy Cotter is an intermediate wastewater treatment engineer, and a chemical engineer, with 6 years of experience in industrial and municipal wastewater treatment, and industrial process engineering consulting in Australia, Canada, France and the Pacific.