Associated Engineering worked with First Nations Engineering Services Ltd. to complete the detailed design of a comprehensive HVAC systems and odour control for the North Wall Sewage Treatment Plant and Main Lift Station Upgrade for the Mohawk Council of Kahnawake. The new plant was an integrated facility that housed sewage treatment processes (screening, grit removal, clarification, effluent filtration, UV disinfection), biosolids storage and dewatering, screening and grit storage bays, chemical rooms, blower room, control room, locker rooms, electrical room, and indoor diesel generator.
The project team completed an area classification assessment using NFPA 820 and Canadian Electrical Code. The detailed HVAC design included addressing these area classifications and resulted in a comprehensive design.
The HVAC and odour designs implemented included a ventilation strategy to properly separate classified areas from unclassified areas, provision of on-demand HVAC controls to start systems prior to operator entry with the option to start these units remotely, provision of heating to 18°C when operators are present, ventilation of air space above headworks and clarification channels to manage odours, use of high plume odour systems to manage the odours from a large airspace in the screenings and grit storage room and the biosolids room, new heating and ventilation systems to declassify the existing station's dry well and addition of an odour control unit for the exhaust from the wet well.
The team also provided process advice related to the assessment of wastewater treatment and odour control systems.