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2001 Wastewater — Co-winner 1

City of Toronto, Ontario

Creating a new sewer-use bylaw to cut toxic waste

Population: 2.4 Million

The City of Toronto's new sewer-use bylaw aims to prevent industries from discharging toxic materials by reducing or eliminating their generation from the source. Adopted July 6, 2000, the bylaw places strict limits on 38 otherwise unrestricted chemicals. The city estimates that this approach will reduce the amount of toxic waste in Toronto's sewer system by 25 to 50 per cent within six years. It will also reduce the amount of toxic fumes emitted into the air once industries start using less toxic compounds and reduce hazardous liquid and solid waste disposal.


Throughout the 1990s, the community around Toronto's Ashbridges Bay Sewage Treatment Plant became increasingly concerned about the city's practice of incinerating biosolids (sewage sludge). Residents living near the plant reported that fumes from incineration had caused respiratory problems in some of their children. Although this connection was never proved, residents successfully lobbied city councillors to take action. Eventually, council issued a directive that by December 2000, incineration would stop.

Prior to that decision, Toronto works and emergency services staff had already responded to the concerns of residents with a plan to turn a liability into an asset. Instead of incinerating contaminated biosolids, workers planned to turn them into two valuable products: one would be a nutrient source for agricultural land and the other an alkaline biosolids substance to rehabilitate mine tailings. In 1996, the city initiated two separate pilot projects to test the products for what would become known as the Biosolids Beneficial Use Program.

One of the pilot projects was derailed before the biosolids could be used. In the mine tailings rehabilitation program the city's contractor treated the biosolids with lime and high temperature. The process was designed to create a very alkaline product that the city could then use to neutralize highly acidic mine tailings in northern Ontario. However, the city abandoned the treatment process after receiving complaints from residents about the odour.

The other pilot project — to use biosolids as a nutrient source on agricultural land-has so far been successful. The project ended in August 2001. Over a five-year period, the city's contractor has applied 10,000 tonnes of dry biosolids to farms in the southern Ontario. Although farmers, eager to make use of this free-of-charge soil enhancer, have embraced the project, the use of biosolids on agricultural land is very controversial. Environmental groups have expressed concern to the city about the presence of toxic waste in the biosolids.

Ontario has strict limits on 11 heavy metals in biosolids. Under those guidelines, however, biosolids can still contain toxic organic compounds, many of which were not in use when the province drafted its restrictions decades ago. City staff recognized from the outset that to address the concerns of environmentalists, it should adopt a program to improve the quality of agricultural biosolids beyond the provincial requirements.

"Just meeting the [Ontario] sludge guidelines isn't good enough," said Industrial Waste and Stormwater Quality Manager Vic Lim. "That's partly because of [negative] public perception and also because the current guidelines have been on the books for more than 25 years. We have taken the initiative to improve the quality of biosolids so that the public will have more confidence. So they will not be so afraid."


The new sewer-use bylaw, passed in July 2000, has met all of its objectives to date. By 2007, staff expects industry pollution prevention plans to result in:

  • a 25 to 50 per cent reduction of toxic discharges to Lake Ontario, with industries systematically identifying wasteful practices;
  • a significant reduction in the amount of wastes that are either emitted into the air or collected for hazardous-liquid and solid-waste disposal;
  • more efficient industrial operations (staff expects that this program will help industries use less energy, water and raw materials per unit of production);
  • increased productivity and profit for industry with fewer emissions of greenhouse gases; and
  • industrial managers and workers who are more knowledgeable about environmental concerns.
As these results become apparent, Toronto expects other municipal governments to adopt parts of the city's sewer-use bylaw. Kingston has already implemented all of the bylaw provisions that prohibit organic chemicals and heavy metals. The regions of Peel, York and Durham are now re-examining their own bylaws, using Toronto's new sewer-use bylaw as a template.

Reducing the discharge of toxic wastes into Toronto's sewers will inevitably lead to fewer toxic substances at the city's treatment plants and result in higher quality biosolids and improved final effluents. As the quality of the product improves, Toronto expects demand for biosolids to increase.

The new sewer-use bylaw also lays an important foundation for the protection of human health.
"For the first time in Canada, a bylaw includes a long list of prohibited, highly toxic organic compounds in addition to the 11 heavy metals that were already prohibited," said Lim. "By drastically reducing those chemicals we're improving health and safety for workers and the public in general."

Lessons Learned

  • Major changes need to be made over time. It took four years to develop the new sewer-use bylaw, which allowed the city time to develop, consult and refine each draft. The bylaw is well understood and has broad support.
  • It is vital to solicit input from the community and to address its specific needs and goals.
  • Other communities considering a similar initiative should get political support from city council for the development stage of the process. "Eventually, councils are the ones that are going to decide whether to adopt the bylaw," said Lim. "They have to be informed. If not, they are more subject to lobbying by industry."
Page Updated: 21/12/2015