While there are other options for treating waste water, the system applied at the University of Ghent uses a special membrane, is said to be energy-efficient and to be applicable in areas off the electricity grid.

"We're able to recover fertilizer and drinking water from urine using just a simple process and solar energy," said University of Ghent researcher Sebastiaan Derese.

The urine is collected in a big tank, heated in a solar-powered boiler before passing through the membrane where the water is recovered and nutrients such as potassium, nitrogen and phosphorus are separated.

Under the slogan #peeforscience, the team recently deployed the machine at a 10-day music and theatre festival in central Ghent, recovering 1,000 litres of water from the urine of revellers.

The aim is to install larger versions of the machine in sports venues or airports but also to take it to a rural community in the developing world where fertilisers and reliable drinking water are short in supply, Derese said.