Filterra^® Bioretention System

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ABOUT

The Filterra® stormwater bioretention system consists of a prefabricated concrete structure with mulch, soil media, plants and drainage infrastructure found in conventional bioretention. The media is specially formulated to remove suspended solids, nutrients, heavy metals and oil and grease from stormwater runoff while retaining a high flow through capacity that minimizes the surface footprint area required for installation. The system is typically applied for the treatment of runoff from small catchments such as roads and parking lots.

The concrete container comes in various sizes ranging from 1.2 by 1.2 meters (4 x 4 feet) to 1.8 by 3.6 meters (6 by 12 feet). The top slab is fitted with a decorative tree gate. The schematic of the system in Figure 1 shows the function of the system. Runoff enters the unit along the curb through a 10 to 15 cm (4 to 6 inch) high curb inlet throat. Runoff bypassing the inlet during high flows is directed to a catchbasin inlet or other form of drainage infrastructure downstream of the unit. Devices with internal bypasses are also available.

Flows entering the inlet are dispersed across the top surface mulch layer. Freeboard depth of approximately 23 cm (9 inches) between the media layer and the system bypass is typically provided for temporary storage to promote settling. The 8 cm (3 inch) mulch layer is underlain by approximately 56 cm (22 inches) of engineered filter media with a specified gradation and organic matter content to ensure consistent and dependable hydraulic functionality and fertility. A perforated 10 to 15 cm (4 to 6 inch) underdrain wrapped in a fiberglass mesh and surrounded by 15 cm of gravel is placed along the concrete floor for rapid drainage of filtered runoff. Planting material may include flowers, grasses, shrubs or small trees, varying based on site-specific climate and aesthetic considerations. Various configurations of the device are available including those that infiltrate directly through the bottom of the unit and/or drain treated water to a neighbouring trench or chamber system that reduces runoff volumes through infiltration into the surrounding soils.

CONTACT

Imbrium Systems, Inc.
407 Fairview Drive
Whitby, Ontario
L1N 3A9, Canada
Tel: +1 503-310-8903
jgarbon@imbriumsystems.com

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