The City of Calgary's biosolids management program recovers and recycles nutrient-rich organic matter from our advanced wastewater treatment process.

If you have questions about our biosolids management program or would like to participate in our Calgro Program, please call 311.

About Biosolids

Biosolids are a nutrient-rich organic material produced by advanced wastewater treatment. Biosolids contain nitrogen, phosphorus, potassium and organic materials in addition to essential micro-nutrients.

The nutrient-rich properties of biosolids make it valuable as a natural nutrient source and soil conditioner for agricultural lands, as well as a high-quality component of compost.

A regulated, safe product

Biosolids have been used in Canada and around the world for decades. Biosolids are regulated by the province. In Alberta, our advanced wastewater treatment process and the land application of biosolids  are regulated by Alberta Environment and Protected Areas (AEPA).  The federal government (Canadian Council of Ministers of the Environment (CCME)) has a Canada-wide approach that also supports the beneficial use of biosolids within Canada. The CCME has documented biosolids land application as a means to safely treating and returning beneficial products back to the land in a protective way which is important for public and environmental health.

Biosolids are produced through an approximately month-long, multi-step advanced wastewater treatment process. During this time, wastewater solids are microbially digested, settled and thickened to ensure the product is safe and beneficial for the land.

Our biosolids land application programs follow Government of Alberta guidelines.


Farming with Biosolids

The City of Calgary beneficially uses biosolids in three main ways:

CalgroTM operations

Since 1983, local farmers have been fertilizing their fields with biosolids by participating in our Calgro™ program. This innovative program is the result of a joint initiative between the Government of Alberta and The City to establish best management practices for land application.

From April to late October, Calgro works on farm lands near the Shepard Lagoons in southeast Calgary. Biosolids are transported from the Shepard Lagoons to approved agricultural land, where specialized equipment is used to subsurface inject biosolids 5 - 10 cm below the ground surface into the soil.

Following provincial guides, soils that receive biosolids can be used to grow cereal grains, small oilseeds, dried legumes, forage crops, trees and sod.

If you are interested in participating in our Calgro program, call 311.

Composting with Biosolids

Since 2017, the Calgary Composting Facility has been composting dewatered biosolids produced at the Bonnybrook Wastewater Treatment Plant into Category A compost that is sold commercially. Learn more about the Composting Facility.

Biosolids demonstration projects

As part of the City's biosolids management program, we are committed to pursuing research into the best ways to manage biosolids and increase program resiliency.

In 2013, the City of Calgary, in consultation with AEPA, initiated two operational-scale demonstration projects. The multi-awarded projects are based upon using dewatered biosolids to improve the quality of soils considered "marginal" for agriculture and to provide a nutrient source for a willow tree farm. The City’s willow farm is the largest willow plantation in North America. Harvested willow whips and woody biomass has many uses but is primarily used as feedstock material for composting.

To learn more, visit Biosolids Demonstration Projects​.

Benefits of biosolids

Biosolids are used to improve the quality of soil for farming, reduce the need for chemical fertilizers and are a high-quality component of compost.

Biosolids ensure nutrient cycles continue and that valuable, finite resources (such as phosphorus) are not wasted.

Land application of biosolids enhances soil health by improving physical, chemical, and biological properties of the soil, ensuring nutrient cycles continue and increasing crop productivity by the addition of moisture and organic matter to soil.

Biosolids also help sequester carbon, reducing the release of carbon dioxide (a greenhouse gas) to the atmosphere.

Farming with Biosolids Picture