FAQ

Biosolids are a nutrient-rich, solid by-product of wastewater treatment. At Winnipeg’s sewage treatment plants, the solids are separated from the liquid wastewater. These solids, also known as sludge, consist mainly of organic matter, and are further treated and dewatered. After treatment, the solids are called biosolids.

Prior to January 1, 2011, the City applied a portion of the biosolids on farmland. Biosolids were delivered, spread and incorporated on farmland at no cost to landowners. In 2010, approximately 48% of Winnipeg’s biosolids were applied on the land, and the rest was sent to landfill at Brady Road Resource Management Facility.

In January 2011, the land application program ended due to changes in the Water Protection Act (Manitoba). The updated regulation prohibits land application in winter and decreases the allowable application rate of biosolids to farmland.

In 2014, the City completed the Biosolids Master Plan, which recommends multiple strategies to beneficially reuse biosolids. The City is currently pursuing three beneficial reuse strategies for biosolids:

• In May 2015, the City began a pilot project to compost a portion of the biosolids. Composting biosolids produces a stable end product, which is high in organic matter and can be used as a soil amendment.
• In 2019, the City began a biosolids land application program, which sees 20,000 wet tonnes biosolids applied to farmland annually from May to October.
• In 2021, the City plans to operate a soil fabrication program from November to April, which uses soil derived from biosolids, wood chips, and street sweepings as a top cover at the Summit Road Landfill.

Composting is a biological process that requires a carbon source (like woodchips) and a nitrogen source (like biosolids) but does not require a mineral source (street sweepings). Soil fabrication requires a mineral source and is a physical mixing process. Compost is something that is added to soil and does not support sustained vegetation on its own, whereas fabricated soil can support vegetation.

The City monitored for odours during the three-year pilot program. Odours were observed to be reduced after mixing biosolids with woodchips and street sweepings. No odours were detected offsite during the biosolids receiving operations.

The soil fabrication program is located within the boundaries of the Summit Landfill leachate and surface water collection and containment system. Ongoing water quality monitoring will occur to ensure impacts to the environment are minimized.

The Summit Landfill cover is expected to take eight to ten years to complete.

Some of the criteria that the City is monitoring to help determine if the pilot program is successful include: 

• Soil quality
• Vegetation growth
• Surface water, ground water, and odour impacts
• Winter viability
• Operational viability
• Costs

The Environment Act Licence will only permit the soil to be used on-site at the Summit Landfill and is needed to complete the landfill cap system. The soil is not approved for use off-site, including for yards and gardens.