Wetenschap - 17 januari 2013

Pee? In the toilet please

Save water: pee in the shower. This is the advice with which Green Left councillor Bert Wassink from Aa and Hunze municipality in the Dutch province of Drenthe confidently ushered in Sustainability Year. 'The councillor has not thought it through properly,' says Grietje Zeeman, professor of New Sanitation since 13 September. 'This a nonsensical and one-dimensional plan.'

Why is regularly peeing in the shower such a bad idea?
'It only addresses one aspect of urine collection: saving water. It ignores the value of the minerals in urine, such as nitrogen and phosphate. Take phosphate. The stocks are finite and we are dependent on countries like China. The pressure is on to start extracting it. If you want to do that using minimal energy, you need concentrated urine. So it is not a good idea to pee in the shower. And not clever to broadcast the suggestion to a whole generation of children during a children's news programme.'
Are we really going to recycle our urine any time soon?
'We are now in a transitional phase and there are all sorts of pilot projects running. For example, we are researching the extraction of minerals using algae or bacteria. We are also trying to separate 'grey' water from the shower and kitchen from very dirty 'black' water from the toilet. But it could take decades before this happens on a large scale.'
What if I don't want to wait for that revolution? How can I save water now?
'You can install a new toilet system, such as a waterless urinal or a vacuum toilet. That saves a lot of water, if you consider that you now flush with six to eight litres. In the Heineken Music Hall they are extremely pleased with the waterless urinals. They are low maintenance, smell better and save a lot of water. Another option at home is only to flush every second time.' 

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