Biosolids Safety: A Dalhousie Professor Gets Down and Dirty

Dr. Gordon Price

Dr. Gordon Price- Courtesy Dalhousie University

Municipalities struggling to find the best ways to manage the biological muck removed from wastewater may soon be getting some help from a Dalhousie University professor.

Dr. Gordon Price is leading a national research effort looking into a process called alkaline stabilization, a popular process used by many municipalities, including Halifax. In the process, municipalities mix quicklime with their biosolid waste, making the material less acidic. They then sell it to farmers for use as an agricultural liming additive.

But the option is not without its critics.

“There are a lot of unanswered questions about the safety and effectiveness of using biosolids from the municipal wastewater treatment system in agriculture, like how do organic chemicals break down and change as they move through the system?” says Dr. Price. “My project is trying to get some answers for regulators and for end users.”

Supporters of the process argue alkaline stabilization not only sterilizes the biosolids, but also helps improve the pH of the soil where the mixture is used. This change is particularly helpful in Nova Scotia, which has predominantly acidic soil that needs intervention in order to be agriculturally productive.

Critics suggest the risks of using biosolids as a soil amendment are less clear and broader system-based studies are needed to help further our understanding. They suggest there may be a significant amount of research into the effects of heavy metals in soil on human health, but the possible ecological and health impacts of organic chemicals associated with biosolids has not been studied to the same degree.

Organic chemicals can include ingredients from prescription drugs to personal care products, such as soaps and shampoos.

Dr. Price’s long-term research project will study how the organic chemicals in biosolids move through an ecosystem, going from the soil to water, to plants and how they affect the organisms, like earthworms, that live in the soil.

The tools to identify chemicals and their concentrations were purchased using funding from the Nova Scotia Research and Innovation Trust (NSRIT) and the Canada Foundation for Innovation. Researchers at four other universities, as well as government and private partners, are also collaborating on this project

“The instrumentation that we purchased with the NSRIT grant has really made this work possible and has facilitated Dalhousie leading this national project,” says Dr. Price.

Learn more about Dr. Price’s project.


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