Compiled audio recordings (13’27”)
Greenway was a project carried out in March, 2013. I visited the Greenway Pollution Control Centre in London, Ontario, and made a series of audio recordings using standard stereo and binaural microphones.
Greenway Pollution Control Centre (sewage treatment plant) is the oldest and largest of London’s treatment plants and processes 1.5 million litres of sewage every day. The first step of the process involves filtering to remove grit and other inorganic materials. Sludge is then treated with bacteria in clarification ponds to consume organic material and convert ammonia to nitrates, and then with chemicals to remove phosphorus. Organic materials separated in the clarification ponds are pressed to remove water and the solids are disposed of by incineration or landfill. The final disinfection step uses ultraviolet light, and the cleaned effluent is then discharged into the Thames River.
Sewage treatment on this site began in 1901 with the establishment of a “sewage farm” – a system where sewage is pumped into open fields where it is filtered and cleaned by natural processes. The plant has been upgraded many times as environmental science has improved, to try to minimize the impact of the treated effluent on river organisms. Phosphorus removal started in the early 1970s and ammonia conversion started in the late 1970s. Ultraviolet light disinfection was introduced in 1988, replacing the use of chlorine, which produced compounds toxic to fish.