Subsurface Wetlands Treatment Facility

Artificial wetlands at Edmonton International Airport protect the environment from the runoff such as toxic ethylene and propylene glycol used in aircraft deicing procedures.

A "subsurface wetlands treatment facility," which began operating in 2001, collects and treats stormwater contaminated by airport activities. The water is piped to a holding pond, then fed into six treatment trains, each consisting of two cells measuring 43 x 43 metres. Each cell is lined with clay, contains 1,415 cubic metres of gravel, and holds up to 481 cubic metres of water. The cells are planted with native cattails, which help the wetlands filter out and break down pollutants through various biological, chemical and physical processes.

The wetlands cover 4.5 hectares and are so effective at filtering out contaminants that the cleaned runoff can flow directly into Whitemud Creek. The wetlands project was designed by the consulting firm Jacques Whitford. It cost $2 million to build; another $2.8 million was spent to rehabilitate storm sewers and construct a holding pond.