Biosolids have an appreciable concentration of nitrogen and phosphorus. They also contain several other nutrients that crops require including magnesium, zinc, copper, boron, sulphur, iron and calcium. Biosolids have been applied to agricultural land in Canada and internationally for more than 40 years. Yes, but in the same way that too much commercial fertilizer can be harmful, too much biosolids can also have negative impacts. In order to protect the environment, human and animal health, and to ensure a balance of nutrients, the application of biosolids on agricultural land is regulated.
Technician explains how application rates for biosolids are strictly regulated.
Ontario's guidelines do not permit the application of biosolids with metal concentrations over specific limits. These are conservatively set to prevent toxicity or health impacts in plants, animals and humans. The concentrations of regulated metals in the Ashbridges Bay Treatment Plant's biosolids are well below Ontario's guideline levels. There have been no reported illnesses caused by land application of biosolids in Canada. The Ashbridges Bay Treatment Plant's biosolids have gone through a treatment process which stabilizes them and destroys many of the disease-causing organisms.