Submerged attached growth reactor (SAGR) will allow future development in the Town of Oxbow

With a population of 1,328, the Town of Oxbow has an undersized wastewater treatment system that is prone to short-circuiting. As such, the system does not meet any legislated discharge criteria. This prevents any new development in the area, as the province’s Water Security Agency cannot allow any new hook-ups to the system. To solve this problem, the municipality wishes to install a submerged attached growth reactor (SAGR) consisting of a fully aerated clean stone bed. The existing primary cell will not go offline, which will allow wastewater treatment to continue throughout the construction phase. The resulting operation would meet projected 2035 wastewater demand while using environmentally responsible and sustainable technology.

Innovative aspects:

• The installation will be the only single cell, shallow facultative lagoon in Western Canada converted to an aerated cell upstream of a SAGR system while maintaining the geometry of the existing cell
• The project will use a unique approach to convert the existing storage lagoon cells into natural grassland habitat due to their location in a floodplain

Environmental benefits:

• Anticipated reduction in carbonaceous oxygen demand (COBD5) levels by 76%, total suspended solids (TSS) by 26% and total residual chlorine (TRC) by 99%
• Reduction in both total coliform and fecal coliform levels by more than 99%

Economic benefits:

• The net projected profit of the lagoon in 2039 calculated to be $994,000
• Sewer charges, lagoon disposal fees and taxation rates expected to be kept at 2018 rates throughout the project’s life, while an increase in rates over time will reduce the payback period and increase the projected net profit

Social benefits:

• Treating an additional 158,775 m3/year of wastewater will provide the municipality with potential business and job growth linked to new development
• The proposed lagoon system’s conversion to an aerated cell will produce limited odour, which will benefit the industrial and residential properties in the area