The City of Wetaskiwin owns and operates a wastewater treatment system that discharges treated wastewater effluent twice annually to a tributary creek of Battle River. Effluent quality is reported provincially under the city’s ESRD Approval to Operate, and federally under Environment Canada’s Wastewater System Effluent Regulations (WSER) program.
The treated effluent quality issues arose during the Fall, 2014 discharge and again in the spring 2015. The spring effluent discharge sampling results indicated high levels of un-ionized ammonia and pH, and showed failed acute lethality testing. The city suggests, “a number of contributing factors may be influencing treatment in the wastewater lagoon system, such as: nitrification performance and nitrification inhibiting factors, organic overloading, short-hydraulic retention times, and/or potential release of ammonia from old digesting sludge”.
In response to the spring effluent quality concerns, Environment Canada requested the city submit an action plan to address quality issues and how they would improve effluent quality before discharge.
In the summer of 2014 the treated wastewater effluent sampling identified elevated levels in the test results. The city then applied for a transitional authorization from Environment Canada under the WSER program. In the fall of 2014 the transitional authorization was denied.
Correspondence with Environment Canada continued into 2015, with Environment Canada requesting the city prepare an action plan to deal with the remaining Spring, 2015 effluent. To begin the steps necessary to comply with this request the city hired M2 Engineering to develop a phased work plan to address both the immediate short-term needs and long-term needs of the lagoon system. The action plan will provide the city with a comprehensive plan to improve the quality of the remaining spring effluent, and develop an effluent discharge plan for mid-summer 2015 and Fall 2015. Discharge consideration for Spring 2016 will also be made as the 2015 action plan is implemented.
M2 Engineering estimates to add an aeration system to Cell 7 and complete necessary sampling, testing and surveys is $450,000. This will complete the short term improvements contained in the action plan.