Perth's Submerged Activated Growth Reactor SAGR Field Test

The Town of Perth will conduct a field test to determine the capability of a Submerged Activated Growth Reactor (SAGR) to optimize and upgrade Perth’s existing 4-cell lagoon, which is approaching its maximum hydraulic capacity. The SAGR is a post-treatment tertiary biological filtration facility that uses submerged activated growth medium to polish effluent and reduce the required residence time in the lagoon. The field test aligns with the key strategic initiatives identified in Perth’s Strategic Plan 2022, including reducing the town’s impact on the Tay River. The field test will involve the construction of a small-scale version of the SAGR, in the form of an aerated cell filled with crushed stone or other media, and activated treatment bacteria. At this stage the installation will operate in a closed loop system by returning effluent into one of the existing lagoon cells, with no discharge into the Tay River. The field test will verify the extent to which the SAGR technology can increase the lagoon’s capacity to meet Perth’s future needs with the addition of a tertiary biological filtration enhancement, and determine the size requirements and the best location for a new facility. The field test will also provide an assessment of the effluent quality standards that can be met and determine the technical and economic elements necessary for a permanent installation, including environmental monitoring and sampling protocols, regular operational inspection and maintenance needs, and regulatory approval requirements. A Final Report will summarize the findings and provide recommendations for next steps. If the field test is successful, Perth will move toward full-scale implementation of the SAGR solution, which is expected to improve performance, increase the system’s treatment capacity, and extend the life-span of the existing lagoon. Given that most small towns in Canada are on a lagoon system, this initiative will provide a model for widespread and cost-effective replicability, particularly given that the SAGR can be implemented at a fraction of the cost of comparable treatment through a biomechanical plant solution. The full-scale project would represent an innovative and sustainable approach to optimizing and extending the life of lagoons. (Project description from original funding application)