‘Liquid gold’: Australian scientists look to recycle human urine to fertilise city parks

Could human urine be liquid gold for horticulturists?

A new trial is examining if "number one" could be a cheap and sustainable source of fertiliser for plants and lawns in Australia's city parks.

The study, by Griffith University, aims to find out if "urine diversion toilets" being trialled in Brisbane and Sydney, might stop valuable excretions of potassium, phosphorus and nitrogen from disappearing down the S-bend.

"It's the perfect liquid gold and currently we just flush it down the toilet," associate professor Cara Beal, of Griffith University's Cities Research Institute, said.

Beal said the four-year project would investigate different toilet designs and incorporate new technology developed by a University of Melbourne chemical engineer.

Human urine is sterile, but can also contain undesirables such as pathogens, hormones and antibiotics that need to be processed.

"But the good stuff is the nitrogen, phosphorus and potassium that plants love. The technology is important, but that's not the barrier to closing that nutrient loop and reusing our most precious resource we generate," Beal said.