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Recycling urine may be the answer to a looming global shortage of phosphorus, according to an Australian researcher.

Associate Professor Cynthia Mitchell, of the Institute for Sustainable Futures at the University of Technology, Sydney (UTS), said the world's deposits of phosphorus are due to run out in about 50 years.

She believes recycling the 132 gallons (500 liters) of urine each person produces a year is the solution.

"Urine is the most concentrated source of phosphorus," she said. "At the moment we dilute that through our sewage system and send it out to the ocean.

"In the industrialized world we must start moving to a resource-recovery approach rather than the current waste-treatment approach."

Phosphorus is a key component in agricultural fertilizers and a lack of phosphorus would affect future soil quality and production.

But Mitchell blames a 'poo taboo' for the failure of governments to move on the issue of recycling urine.

In a public lecture at UTS later this week, Mitchell will call for a "revolution in sanitation" across Australia.

She said technology that allows urine to be separated in the home is already being used in Sweden.

All new homes in the local council of Tanum are required to have urine-separation toilets.

These look similar to flushing toilets but the urine is directed down a second set of pipes to a holding tank, which farmers empty at regular periods, using the urine as fertilizer.

Mitchell said the recycling systems have side benefits for the environment because the toilets use less water and less energy is needed at the treatment stage.

But uptake of the technology has been limited.

A Queensland trial, run by Department of Natural Resources and Waterresearcher Cara Beal, is now under way with 10 toilets being installed in the Currumbin Valley, near the Gold Coast of Australia.

Mitchell said the impending phosphorus supply crisis should be the catalyst for rethinking attitudes toward the use of fecal matter.

But urine-separating toilet systems have to overcome the same public inhibitions that make recycling sewage for drinking water unpalatable to some.

"There is a poo taboo that happens and happens differently in different cultures," she said.

In Sweden where the urine-separating toilet technology is being embraced, there is a history of residents collecting urine and transporting it to nearby farming areas to use as fertilizer.

But Mitchell is in no doubt the "revolution" will happen

"It has to for the simple reason that we are going to run out of other concentrated forms of phosphorus in about 50 years," she said.

"We are going to need sources of fertilizer ... and the most concentrated, readily accessible source of phosphorus is us."

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