Project Information

Rocky Mountain House, Alberta

Project Type:
Municipal Wastewater Treatment

Completion Date: January 2014

Treatment Objectives

Design Flow:
3,333 m3/day (0.88 MGD)

Effluent Quality Requirements:
25 mg/L cBOD5

Project Background & Challenges

Nearly one kilometer above sea level, and one hour's drive West of the midpoint between Edmonton and Calgary, sits Rocky Mountain House. As its name suggests, the picturesque town sits in the foothills of Alberta's Rockies, on the shores of the North Saskatchewan River.

With its lagoons located in town, the town had explored the option of moving its wastewater treatment further away; however, when that became a longer-term consideration, Rocky Mountain House found itself in need of more capacity without running afoul of its limits, all while staying within its existing footprint using the infrastructure already in place.

The Nexom Answer

Rocky Mountain House decided on an optAER Aerated Lagoon System to an upgrade their existing 3-cell lagoon system. The optAER system was designed to meet 10-year hydraulic and loading requirements (combined flows at 3333 m3/day) and consisted of the following upgrades, technologies, and processes:

  • Retained existing lagoon system.
  • optAER fine-bubble partial mix aeration in existing cells 1, 2, and 3.

Site Construction

Upgraded System Performance

Since the lagoons have been upgraded, average monthly effluent cBOD5 and TSS numbers received from Rocky Mountain House over the course of a full year have been consistently below the targeted level.


With an upgraded lagoon system that will be able to handle the town's wastewater for the foreseeable future, both from the perspective of capacity and the ability to meet the necessary limits, the pressure to move the wastewater treatment facility out of town is reduced significantly. Rocky Mountain House is free to make long-term plans for 2023 and beyond with the comfort a smoothly-running, low-O&M optAER system provides.