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Based in the �鶹��madou Air Quality and Odour Laboratory at the Water Research Centre (WRC), Ruth works in the area of biosolids, which are the organic materials left over from wastewater treatment. Specifically, she’s interested in why biosolids smell and what can be done to mitigate their odour.

By Ruth’s own admission, offensive smells may sound “like a first-world problem,” but odour management is actually a crucial component of managing urban water supplies.

“The main impact associated with odours is people, so typically if people are living close to a wastewater treatment plant and it really smells, there are a lot of complaints,” says Ruth, a chemical engineer by training.

“There’ll be people complaining at the plant, on the trucking routes, and at the application sites as well, particularly in somewhere like Sydney because the city is so dense.”

In the worst-case scenario, these complaints can lead to facilities being closed, which can have knock-on effects on water supply and management, as well as on the re-use of biosolids in agricultural settings.

These waste materials are vital to growing our crops because they contain a wealth of nutrients that can fertilise the land, such as nitrogen and phosphorus, as well micronutrients like copper, zinc and iron. But if they’re deemed too smelly, they’ll be relegated to landfill where the damage they can cause is nothing to … well, sniff at.

“When biosolids are applied to agricultural land, you get that cycling of nutrients and all of the benefits that come from that. If the biosolids smell really bad, that’s not going to happen,” Ruth says.

“We can’t afford to be wasting all these nutrients that are already really scarce, such as nitrogen and phosphorus. In landfill you have all these greenhouse gas emissions that are probably going to be emitted as well.”

In the �鶹��madou Air Quality and Odour Laboratory, Ruth and her peers are investigating the chemical and microbial processes that cause biosolids to smell, as well as opportunities to mitigate the resulting odours. They also want to understand how to accurately measure the emissions associated with biosolids and, in association with the WRC’s Sustainability Assessment Program (SAP) team, accurately evaluate the sustainability of biosolid systems.

It’s a far cry from the early years of Ruth’s career when she worked as a research officer at CSIRO. There, she was focused on the production of catalysts to manage vent gas emissions from industry. While that work also had an odour research component, the focus was more about developing technical control systems rather than figuring out why the odours existed in the first place.

Still, Ruth says, the role was her first introduction to research, and it also showed her that she needed better research skills if she wanted to continue down that career path. A master’s in water, wastewater and waste engineering at �鶹��madou followed, at which point Ruth was “still to-ing and fro-ing about whether to go into industry or academia,” she says. d

“Then I met my supervisor and started working on the research project that eventually became my PhD, which led me to where I am today.”

When she’s not in the lab, Ruth is a passionate educator who gains endless satisfaction from helping students figure out how to tackle pressing sustainability issues, including — but not limited to — the management and re-use of biosolids. She teaches a broad array of sustainability subjects that extend beyond her remit at the WRC. These include sustainable infrastructure and a new air quality subject due to be introduced in 2025.