WCW24

Situated in Northern Manitoba, Barren Lands First Nation (BLFN) is home to approximately 520 people. The First Nation initially operated a two-cell facultative lagoon to treat wastewater from both Barren Lands First Nation and the neighbouring community of Brochet. The lagoon was initially constructed in 2006 and although plenty of capacity remained, the lagoon was in need of several major repairs. The liner had floated in multiple locations forming pockets of gas which breached the surface of the lagoon. Adding to that, the berm had also collapsed in several locations and previous attempts to repair only achieved moderate levels of improvement. The First Nation's confidence in the lagoon had waned and a new aerated lagoon was selected as a replacement. Stantec Consulting Ltd. was retained to provide design and engineering services for a new sewage lagoon, lift station upgrades, along with repairs and upgrades to the existing sewage collection system. Several of the lift stations were experiencing operational issues which causes upstream manholes to overflow at times. All 5 of the existing lift stations received new pumps while three lift stations needed control system upgrades. A forcemain flushing and CCTV camera program was included to clean the forcemain and locate areas in need of repair. With a goal of simplicity and ease of operation, a new HDPE lined two-cell aerated lagoon using high efficiency fine bubble diffusers was selected for its smaller footprint versus a facultative lagoon. Following the lagoon and two cell Submerged Attached Growth Reactor was designed to provide nitrification for removal of ammonia. The new lagoon cells were constructed with self-draining under drains and vent pipes, which combined with a layer of sand covering the HDPE liner will prevent the liner from floating. The second lagoon cell was designed to be 1.4m lower than the first cell following the profile of bedrock encountered onsite and allowing the entire system to be designed to flow by gravity through all stages before discharge into the nearby lake.