Researchers estimate waste from absorbent products used by adults is already two to three times what infants produce.

And it could be four to 10 times as much by the end of this decade,

Lead author environmental engineer Dr Emma Thompson Brewster, from Southern Cross University, says there’s currently no large-scale solution for used incontinence products or disposable nappies.

Almost all of them wind up in landfill where the plastics, glues and synthetic absorbent materials they contain add to the country’s contamination burden.

Thompson Brewster says understanding the complex waste stream is crucial if solutions to extract value and minimise environmental harms are to be found.

“What drove me to look at absorbent hygiene products is that it’s such a difficult stream of waste.

“Urine and faeces makes up about 60 per cent of the product mass. It’s got biodegradable materials, maybe some cellulose fibres, or super absorbent polymer. It also might have plastic material as well, liners and waterproof layers. It’s a very complicated product.”

Even so, overseas efforts are starting to show these items can be part of the circular economy.

“There are trials going on, and research being done, into how we can recover some of the fibres, some of the nutrients – if we’ve got a fully biodegradable product, converting it into compost using industrial composting technologies.

“I hope we can work towards that in the future. This paper answers what’s happening now. The next question is what are our options moving forward.”

Thompson Brewster says incontinence products are essential health care products that contribute to people’s quality of life and users must not feel any guilt about the waste.

“This work highlights where a shift in policy and waste management processes should focus, to create effective change.”

The study, jointly conducted with the University of Queensland, says regulatory incentives will be needed to prompt change.