Biosolids Recycling Program - Frequently Asked Questions

What are "biosolids"?

Halton owns and operates seven wastewater treatment plants within its four local municipalities. These plants serve to treat and cleanse wastewater from the residences and businesses in Halton that would otherwise be detrimental to the environment if left untreated. Municipal “Biosolids” is a nutrient-rich, organic residual of this wastewater treatment process that in Halton is currently recycled as an agricultural fertilizer to improve and maintain soil productivity and stimulate plant growth. Halton Biosolids is applied to agricultural land only after it is fully treated and meets strict quality standards set by the Ministry of the Environment (MOE) and the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA).  

Biosolids contains nitrogen, phosphorous and organic matter as well as essential micro-nutrients such as copper, iron, molybdenum and zinc, all of which are important for plant growth and soil fertility. Beneficial use of biosolids as a fertilizer source on agricultural fields is an important means of recycling nutrients and organic matter.

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How does Halton provide biosolids to the farming community?

Halton’s Biosolids Recycling Program has been serving the Region’s agricultural community for over 30 years. The program provides biosolids to the farmers in both a liquid form and a more solid dewatered form for crop production. This is a free service to Halton farmers that results in a substantial economic benefit each year by replacing or supplementing commercial fertilizer and manure requirements.

Are biosolids good for the environment?

Recycling biosolids is good for the environment. Organic matter has been recycled for centuries to improve soil fertility and productivity. When properly applied and managed, biosolids can provide essential plant nutrients, improve soil structure and tilth, add organic matter, enhance moisture retention and reduce soil erosion.

The beneficial use of biosolids also reduces the need for commercial fertilizers which require significant natural resource consumption to manufacture and transport.

Carbon sequestration and reduction of greenhouse gases is another area where the beneficial uses for biosolids may have significant benefits for the environment.

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How is the application of biosolids regulated?

OMAFRA works closely with the MOE to administer Ontario’s successful biosolids land application program. The practice is governed by provisions and regulations set out under the Ontario Water Resources Act, the Environmental Protection Act, and the Nutrient Management Act.

The regulations under these Acts and supporting publications (e.g., guidelines, protocols, etc.) define requirements and standards to ensure that biosolids are used properly and that their use is protective of food quality, human and animal health and the environment. Ontario’s regulations for the utilization of biosolids on agricultural land are among the strictest in the world.

Halton routinely samples and monitors its biosolids through a detailed quality control program, and consistently meets all regulatory quality criteria for land application. The Region’s Sewer Use By-Law identifies discharge limits to control pollution at the source to ensure that biosolids meet and exceed all regulatory requirements.

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How often can a farmer receive biosolids on his fields?

The amount and frequency of biosolids a farmer may receive is dependant on site specific information and based on the amount of nutrients required by the crop being grown. The most recent sampling analysis and the conditions in the field at the time are used to determine the optimum application rate of the biosolids to achieve an agronomic balance and ensure the protection of the natural environment.   

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Does the application of biosolids to farmers' fields in Halton Region pose any health risks to Halton residents?

There have been no reported illnesses associated with biosolids land application operations in Halton since the program’s initiation in 1979.

Decades of scientific research form the basis of Ontario’s biosolids guidelines as determined by the Ministry of the Environment, the Ministry of Agriculture and Food, and the Ministry of Health and Long-term Care. These regulatory bodies regard the utilization of biosolids for crop production a safe, responsible practice when Ontario Regulations are followed.

Institutions such as the U.S. National Academy of Sciences, U.S. Environmental Protection Agency, Water Environment Research Foundation, European Union, Educational Institutions, and the Canadian Federal and Provincial Governments regularly conduct update studies and research on the safety of applying biosolids to agricultural lands. Results and conclusions to date are overwhelmingly supportive of this practice under the current Regulatory guidelines, as it relates to the protection of agriculture, the environment, and human and animal health.

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How is Halton's groundwater protected from biosolids use in agriculture?

Provincial guidelines and regulations specify biosolids application criteria such as separation distances from spreading boundaries to wells and watercourses, and sufficient depths to the water table and thickness of soil at the field site. These requirements are mandated to prevent any potential for groundwater contamination.

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Are there bacteria and pathogens in biosolids?

Biosolids undergo a month-long heated and biological process at Halton’s wastewater treatment plants that “stabilize” the product to the point where there is limited additional biological activity. Almost all of the pathogens in wastewater are eliminated through the treatment process. Any pathogens that are left are further reduced when exposed to the natural elements during storage and when land applied at the farmer’s field.

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Is there an odour associated with the application of biosolids to farmers' fields?

Halton biosolids are incorporated into the soil at the plant root zone and are rarely exposed on the soil surface and to the air. Halton biosolids have an earthy or musty odour and not a septic odour associated with raw sewage and some manures. Odour complaints resulting from Halton biosolids spreading operations are rare.

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Do the biosolids contain heavy metals and, if so, how are they controlled?

Metal concentrations in Halton biosolids are relatively low and consistently comply with Ontario Guidelines for biosolids land application. Biosolids metal concentrations in Halton and throughout Ontario have been significantly reduced over the past fifteen to twenty years due to concentrated efforts in monitoring and controlling industrial discharges, enforcing discharge by-laws, and improved municipal wastewater treatment. The amount of metals in Halton’s biosolids poses no risk to crops, animal or human health, and contributes insignificantly to the background metal levels that occur naturally in our soils and environment.

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Is this method of biosolids recycling cost effective? Is it sustainable?

The recycling of biosolids for agricultural production is cost effective. However, Halton’s biosolids program is challenged by a decreasing agricultural land inventory. Halton continues to investigate alternative technologies and biosolids re-use strategies to supplement its current agricultural land application program.

Halton Region has initiated a comprehensive Master Plan Study in 2009 for the management of biosolids generated by the Region’s wastewater treatment plants through to the year 2031. The primary purpose of this study is to evaluate alternative technologies and biosolids management options, and to recommend a strategy that responds to current and future challenges.

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Where can I get more information about biosolids and their uses?

To learn more about biosolids visit these websites:

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