Performance Evaluation of a High-Rate Treatment Bioretention Filter

As adoption of the Low Impact Development (LID) approach to water management continues to expand, one challenge practitioners face is the application of LID practices in existing built up urban areas where space is limited.  In retrofit scenarios, practices that are underground and those capable of high rate treatment with a small surface footprint make the most sense.

This study evaluates the performance of the Filterra® bioretention filter for reduction of stormwater runoff volumes and pollutant loads.  Filterra® is an engineered biofiltration device that allows for high rate treatment of stormwater runoff in a compact system.  Installed at the Living City Campus in January 2017, the unit is designed to capture stormwater runoff and filter the water through a specially designed reactive filter media. The filtration process captures and immobilizes pollutants and promotes their decomposition and incorporation into the biomass of the local ecosystem. Stormwater that passes through the system is captured and discharged via an underdrain a the bottom of the unit.

Monitoring initiated in 2017 was focused on measuring the quality and quantity of stormwater runoff before and after it passed through the Filterra® unit.  Based on data collected, the device’s performance, maintenance requirements and costs are considered relative to those of other LID measures suitable for space constrained sites.  A technical brief detailing findings of this study is now available under ‘downloads’.