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. Our advanced wastewater treatment process is regulated by Alberta Environment and Parks (AEP), and involves several steps over a month-long period to settle, thicken and microbiologically digest the wastewater solids, producing biosolids.

Safely treating and returning wastewater products back to the land in a protective way is important for public and environmental health, as documented by the National Research Council and the Canadian Council of Ministers of the Environment.

Our biosolids program follows Government of Alberta guidelines.


Farming with Biosolids

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.

Calgro operations

From April to late October, Calgro works on farm lands near the Shepard Lagoons in southeast Calgary. Biosolids are moved in tanker trucks, put in field storage tanks and then into field equipment that injects the biosolids into approximately the top 8 to 15 cm of soil.

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

Benefits of biosolids

  • Biosolids provide essential nutrients for crop growth and productivity
  • Biosolids reduce the need for chemical fertilizers on farmland for as long as three years
  • Biosolids add organic matter to soil, improving nutrient and water holding capacity
  • Biosolids ensure nutrient cycles continue and that valuable, finite resources (such as phosphorus) are not wasted

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

Composting with Biosolids

In 2017, the City's composting facility opened, processing biosolids, and producing a high quality Category A compost. 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 Alberta Environment and Parks (AEP), initiated two operational-scale demonstration projects. The 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 demonstration project has been renewed in 2019 for the operational period of 2019-2023.

To learn more, visit Biosolids Demonstration Projects​.

Farming with Biosolids Picture