Sewage Sludge Application

In Alberta, it is common practice to apply sludge or biosolids to agricultural lands as a nutrient source; however, this must be done in accordance with standards and guidelines developed by Alberta Environment and Parks (AEP).

Challenges and benefits

The issues and benefits associated with this type of application are extensive, as are its benefits. Issues involve contamination of the receiving soils with metals, chemicals, drugs and pharmaceuticals, as well as changes to soil properties and chemistry, from repeated applications. The benefits of sewage sludge application are its nutrient value and its use as a soil amendment rather than burning or landfilling it. The Guidelines for the Application of Municipal Wastewater Sludges to Agricultural Lands are well-established, designed to maximize benefits and reduce potential hazards.

Present conditions

Many Alberta communities have approvals to apply biosolids on agricultural land. The City of Calgary's Calgro program applies some 20 million kg of biosolids to more than 2,000 hectares annually.

The City of Edmonton sends some of its biosolids to the Edmonton Compost Facility which combines them with organic residential waste. Approximately 22.5 million kg of biosolids are composted or applied to land annually.

Province-wide, most municipalities with accumulations of sewage sludge compost or apply it to agricultural land. Very little is now landfilled.

Alberta Agriculture and Forestry is looking at biosolids as a resource for improving forest productivity and growth, and assessing long-term effects of biosolids application to farmland. Alberta Health ensures that heath concerns associated with land application or other means of disposal do not negatively impact the health of Albertans.

Other jurisdictions

More than 80 per cent of Ontario municipalities have some kind of program for sludge application. The Greater Vancouver Biosolids Program generates more than 70,000 tonnes of biosolids annually, with 65 per cent recycled through reclamation projects, silviculture, ranch land fertilization and landscaping. The remainder is stockpiled until new markets are identified. Guidelines for the practice exist in British Columbia, Ontario, Manitoba, Alberta, Quebec and New Brunswick. Saskatchewan and Nova Scotia have draft guidelines.

 

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Updated: May 10, 2017