Engineering Capacity for Generations to Come
Growing communities place significant pressure on water and wastewater systems requiring municipal and regional governments to monitor and increase capacity. Port Darlington WPCP was constructed in 1982 with a rated capacity of 4.5 M litres per day (MLD), which included only two treatment trains. An addition of two treatment trains in 1992 increased the plant capacity to 13.6 MLD. In 2007, an assessment conducted by WSP determined that an additional expansion to 27.3 MLD was necessary to meet expected population growth in the community of Bowmanville. Subsequently, WSP was retained by the Region of Durham to provide project management and engineering services for the preliminary and detailed design, tender, contract administration and construction services for the Port Darlington WPCP Phase II Expansion project.
Innovative Solutions to Address Critical Issues
The existing wastewater plant outfall placed a critical limitation to the capacity of the plant. To estimate the lake impacts based on effluent criteria for the ultimate plant capacity, WSP conducted an extensive investigation and computer modeling of the existing outfall. Based on this model, all required outfall modification work was carefully scheduled within the construction stages. The construction staging was also a critical factor in the design of Port Darlington expansion. Thus, the design team maintained extensive communication with the plant’s operations staff to minimize impacts on operations during construction.
Comprehensive Services to a Critical Upgrade
Key components of the work include upgrades to the existing raw sewage pumping station, liquid treatment trains, digester facility and the SCADA system. A new headworks facility consisting of two new bar screens and vortex grit removal systems was constructed along with a septage receiving facility. The project scope also included the addition of new primary clarifiers; air and energy building housing three new boilers fueled by either natural or digester gas, hot water pumping system, and high speed air blowers supplying air to the new aeration system; new aeration tanks with a fine bubble aeration system, secondary clarifiers with improved scum collection system, return and waste activated sludge pumping systems, disinfection system utilizing sodium hypochlorite and dechlorination, metal salt feed system for the entire facility, substation, standby diesel generator system and HVAC system.