Biosolids & land application

Biosolids are the leftover material from wastewater treatment. It is full of valuable nutrients and organic matter that can:

• Improve soil quality and crop yields
• Reduce soil erosion
• Increase moisture absorption and retention in soil
• Reduce the need for chemical fertilizers

How we make biosolids

Wastewater goes through a series of treatment processes. These processes remove pollutants and solid material. The solid material is a product called sludge.

All our treatment plants produce sludge. Only the North End Wastewater Treatment Plant (NEWPCC) can process sludge into biosolids. This means that we have to haul the sludge produced at our other treatment plants to NEWPCC.

At NEWPCC, the sludge goes through a digestion process. This process breaks down the sludge, reduces its volume, and produces biogas. We collect the biogas and use it as a fuel for process heating and space heating at NEWPCC.

The final step to turning sludge into biosolids is the thickening process. After the digestion process, the treated, leftover sludge is thickened using centrifuges. Centrifuges are equipment that separate liquids from solids.

Beneficial reuse of biosolids

Municipalities around the world use biosolids as a type of fertilizer. Manitoba's Water Protection Act directs us to recover and recycle as many nutrients as possible by making and using biosolids. Using biosolids keeps them out of the landfill and reduces greenhouse gas emissions.

In 2014, we completed the Biosolids Master Plan. The Biosolids Master Plan recommended several ways to use biosolids. To test out these strategies, we began the following projects:

• Biosolids Composting Pilot Project
• Biosolids Land Application Pilot Project
• Soil Fabrication Demonstration Project

Biosolids Composting Pilot Project

We ran a Biosolids Composting Pilot Project from 2015 to 2018. The pilot produced a low pathogen, nutrient rich compost. Biosolids composting occurs on an as-needed basis to meet the needs of our landfill.

Biosolids Land Application Pilot Project

In 2017, we began the Biosolids Land Application Pilot Project. The pilot included public engagement with stakeholders. The pilot project resulted in 2,621 wet tonnes of biosolids being applied to agricultural land in the RM of Macdonald. Since 2018, we have applied around 20,000 wet tonnes of biosolids a year to local agricultural lands.

Soil Fabrication Demonstration Project

In 2017, we began our Soil Fabrication Demonstration Project. Soil was fabricated by combining biosolids, wood chips, and either street sweepings or clay. We use the fabricated soil as the regulatory required cover in the Summit Landfill. The vegetation that grows in the fabricated soil then uses the biosolids nutrients. Since the project began, we have used about 35,000 wet tonnes of biosolids a year.

These projects all followed regulatory requirements for biosolids use.

Biosolids safety

Land application is a sustainable way to manage biosolids. The provincial regulations that control our Biosolids Land Application Program include:

• The Water Protection Act (Manitoba)
  • This Act directs us to reuse biosolids and recover and recycle as many nutrients as possible. It also includes rules for biosolids land application:
    • You can only apply biosolids for a certain type of crop (not for strawberries, carrots, etc.)
    • You must test the biosolids before using them
    • You can only apply a certain amount of biosolids based on site specific conditions
    • You need to keep a minimum distance away from homes, wells, water bodies, etc.
    • You have to wait a set period of time before livestock can graze fields where biosolids have been applied
    • You need to test the soil for three years after applying biosolids
• The Nutrient Management Regulation (Manitoba)
  • This regulation protects water quality by encouraging responsible nutrient application. The Regulation defines zones that limit biosolids application. Biosolids application is not permitted in the nutrient buffer zones. Buffer zones include land near water bodies, wetlands, groundwater features, or flood zones.
• Our Environment Act Licence
  • This Licence regulates the level of metals that can be present in the soil
  • Lots of these metals occur naturally in soil. Many of these metals (e.g. magnesium, copper and zinc) are useful for crops

Scientists and health experts routinely review biosolids land application regulations.

Per- and polyfluoroalkyl substances (PFAS)

PFAS substances are human-made chemicals that are not easily broken down. Products that have PFAS substances include fire-fighting foam, non-stick cookware, and certain fabrics. PFAS can exist in the environment for long periods of time. These chemicals can sometimes be found in biosolids.

Our biosolids have been tested for PFAS and we are below the limits set by the Government of Canada. We are following the research and regulations on PFAS as it relates to biosolids. We will continue to follow Provincial regulations as they develop.

The Government of Canada is also researching the effects of PFAS.