How effective are wastewater treatment plants in eliminating water pollution?
Conventional wastewater treatment plants remove suspended solids and some of the organic matter. More advanced plants also remove phosphorus and nitrogen, which are nutrients for aquatic plants. Both of these nutrients are present in human sewage as well as in runoff from agricultural areas. Laundry detergents were once a major source of phosphorus, but regulations controlling its use in detergent manufacturing have minimized its impact on receiving waters in Canada.
