Oil spills and hydrocarbon contamination of source waters poses a significant risk to downstream water treatment plants (WTP) ability to treat and supply safe drinking water. This study was undertaken to assess the City of Saskatoon's WTP risk of a spill event upstream and its current ability to treat hydrocarbon contaminated source water. The first phase of the study assessed the risks of a spill event upstream of the WTP. Three high risk release scenarios were identified and further investigated: pipeline crossing, transport truck, and rail car. Each scenario was modeled to estimate the travel time and concentration of the plume at the intake at different river conditions. The next phase studied the current WTP's ability to treat contaminated water. Petroleum products consist of many compounds in different physical phases, and each treatment process may only remove a portion of the contamination. With its current technology, the WTP could achieve high removals of free and emulsified oil, but the removal of dissolved contaminants could be improved. The final stage explored alternate technologies that fill the treatment deficiencies and investigate the feasibility of potential alternate water sources to provide emergency raw water. Dosing powdered activated carbon at the intake was recommended for treating dissolved contaminants. Groundwater and alternative surface water sources were found to be not cost-effective or easily implementable. Additional recommendations of the study include implementing a river water quality monitoring and testing program and preparing a response and communication plan the City can execute in case of an emergency.
