A scheme to manage human waste in a way more beneficial to the environment is to be launched in Beijing in time for the Olympic games.
Sewage disposal is a major headache
So far, trials of ecological sanitation - Ecosan - have not received high
prominence, although a three-year project has seen some aspects installed in 19 different urban areas in Mali.
But by 2006, the entire suburb of Yangsong, a newly built area of the
Chinese capital, will use Ecosan as its waste treatment system.
Ecosan techniques include the separation of urine from faeces, the use of "biogas" as fuel, and the re-use of "greywater", the waste water from
showers, baths and clothes washing.
Ecosan promoters at the Third World Water Forum in Kyoto, Japan, are hopeful that the media attention that will focus on Beijing for the Olympics will enable the idea of Ecosan to become part of mainstream thinking on sewage treatment.
And there are economic benefits to a more effective use of human waste too, the forum heard.
"There are 12 billion kidneys working 24 hours a day," Arno Rosemarin, of the Ecosan programme in Sweden, said.
"We have not tapped this resource."
In particular, urine is rich is the element phosphorous, an essential component of fertiliser.
The bulk of current phosphorous reserves are located in one place - the border between Morocco and Western Sahara - and aggressive mining of the element is rapidly reducing the stocks. They are expected to run out by 2100.
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But a study at Kyoto University has found that a simple application of magnesium to urine extracts 97% of the phosphorous present in it.
Small amounts of the dye indigo are also present, which likewise can be extracted and used.
Furthermore, urine does not even have to be treated to provide great
Experiments in the US have found that corn grown using substantial quantities of urine grew 50% bigger than corn grown using none at all.
But these benefits can only be realised if urine is separated from other waste material at source.
The pioneering of Ecosan in Beijing - following successful trials in 50
villages in China's Yongning County - is no coincidence.
China's problems in human waste disposal are massive, and the country is seen by the UN as crucial to helping it meet the Millennium Development Goal of halving the proportion of the world's population without access to basic sanitation.
In addition, many of the country's rivers are badly polluted as raw sewage often gets only basic treatment at best.
The problems of sewage in rivers are well documented, ranging from the spread of disease to the testes of male trout having been found to contain female eggs.
This, believes Professor Saburo Matsui of Kyoto University, is due to the amount of the female hormone oestrogen that leaks into the water from human urine.
But even Ecosan's promoters expect that it will take a long time for Ecosan to become accepted as an alternative to conventional thinking.
"The problem in industrial countries is that we have spent so much on sewers that it is difficult to change," Christine Werner, head of Ecosan in
Germany, told the forum.
Meanwhile, Walter Stottmann, of the World Bank, said that Ecosan had to be considered as only one of a number of different approaches to sewage treatment.
He warned that it was important to "Avoid the 'Ecosan club' being a biased promoter of a single technical solution as a cure for all."