When he ordered his colleagues at the Water and Sanitation Association of Zambia (WASAZA) to save all their urine in a plastic bottle in the office toilet, they thought he was mad. But German sanitation specialist Christopher Kellner wanted to demonstrate why he calls urine “liquid gold”.
“(Urine) contains the three most important plant nutrients which farmers buy as artificial fertiliser. These are nitrogen, phosphorus) and potassium – but it also contains all eight micronutrients plants need for growth,” Kellner explains.
Seconded to the Water and Sanitation Association of Zambia (WASAZA) by the Bremen Overseas Research and Development Association (BORDA) and the Centre for International Migration and Development of Germany, Kellner wasted no time setting up a urine-fertilised vegetable garden on the grounds of the WASAZA offices in Luskaka.
Workers’ pee is collected and used in the garden on Great East Road, across the road from the University of Zambia campus, and vegetables given to the urine donors to illustrate the valuable commodity that’s usually pissed away.
Kellner and his team at WASAZA are busy pushing on with developing and popularising a latrine that will separate human waste into two components – urine and solid matter, so they can be processed into two different forms of manure.
Kellner is piloting a system called a “fertiliser-producing toilet” which focuses on re-use of solid waste. Such a toilet, once integrated into gardening, will never fill up.
When a user sits on one of the new toilets, the urine will go one way to a storage tank fitted with a compressor and a valve, from where it can be collected for direct use as liquid fertiliser after dilution.
The solid waste will fall into a shallow pit where it will be covered with soil and compacted; it will dry it out and neutralise it before it is ready for use as fertiliser. Any smell is vented out through a pipe.
“The original idea is to enrich the vegetative growth in our immediate vicinity. But it can be sold at prevailing prices. These days dried sludge from sewerage works has a price of ZMK7,500 (around $1.60) per ton,” notes Kellner.
According to the Zambian government’s 2000 census, just under 15 percent of Zambia’s 1.8 million households had access to flush toilets or ventilated improved pit latrines. Even simple pit latrines are considered a luxury in rural communities and in the high-density urban settlements aruof Lusaka and the Copper Belt, where poverty is endemic.
Kellner says the toilet they are building now costs $1,800. “But the challenge is to get the same basic idea realised for a quarter of this or even less.”
Kellner reckons that on average, a person will produce 500 litres of urine and around 50 kg of faeces a year; so a a family of six can easily turn their waste into fertiliser for 1,000 square metres of garden.
“If we can popularise this type of pit latrine, then we can drastically cut the fertiliser costs of small farmers. We can encourage people to have fun and success from their gardens.”
Read more about urine diverting toilets on Akvopedia’s sanitation portal.
Source: Lewis Mwanangombe, IPS, 26 Dec 2009