CEPA Part III: nutrients

Part III of the Canadian Environmental Protection Act (CEPA) regulates the nutrient content of cleaning agents and water conditioners. When the act was created, the Phosphorus Concentration Regulations, previously under the Canada Water Act, were incorporated under Part III. During the 1960s, one of the major concerns regarding the degradation of the Great Lakes focused on nutrient enrichment or excessive growth of vegetation preventing use of waters by humans, plants and animals. Phosphorus was identified as the controlling element and, in 1972, controls were placed on the phosphorus content of household detergents. During the same period, programs were implemented at major municipal treatment plants in the Great Lakes Basin to control effluent phosphorus levels.

The National Water Research Institute continued its assessment of changing nutrient discharges from sewage treatment plants in basins such as Hamilton Harbour and Severn Sound. The Institute also examined the confounding effects of exotic species, like zebra mussels, as well as metals in Lake Erie and the Bay of Quinte in Ontario.

The Wastewater Technology Centre is currently evaluating low-cost alternatives for enhancing nutrient removal from biological sewage treatment plants. The technologies currently being demonstrated include:

• The installation of biomass support media as a low cost alternative to upgrade for ammonia removal;
• A modification from continuous to intermittent aeration that will result in complete nitrogen removal as well as energy savings;
• The installation of simple secondary clarifiers to enhance plant capacity for nutrient removal; and
• The retrofit of a sewage treatment plant for complete biological nitrogen and phosphorous removal.

National Hydrology Research Institute has completed a three-year project to assess the effects of stressors on the Fraser River in British Columbia. A particularly successful aspect of this research initiative has been the development of a citizens’ program for monitoring water quality. Using simple sampling techniques, local residents are able to use bottom-dwelling invertebrates as indicators of the health of the aquatic ecosystem. The Institute also began a new research program to determine the relationships between the quantity of added nutrients and the response of bottom-dwelling organisms. The cumulative effects of long-term nutrient loading and the consequences of interactions between nutrients and toxic substances will be determined.