March 19, 2009

Experts Meet To Discuss Water Recycling Technologies

A team of hydrologists has concluded that the only way for barren regions of the world to meet the surging demand for water is to recycle and use water that has already passed through the human body, the AFP reported.

The experts agreed that water from treating urine, feces and bathwater could be harnessed again for farm irrigation, industry and even human consumption.

Speakers at the 5th World Water Forum in Istanbul have argued that "used" water, also known as "grey" water, should comprise a percentage of what comes out of our taps.

However, they said overcoming human repugnance would likely be a bigger challenge than the engineering.

Gerard Payen, a member of the UN's consultative committee on water and sanitation, said people understandably hate the idea of drinking something that could have been sewage.

"There's a major psychological block. But it will go away bit by bit," he suggested.

So-called "toilets-to-taps" systems have been used successfully in Windhoek, the capital of the arid southern African country of Namibia, for many years.

But other nations around the world would be slow to accept such a technique.

Three years ago, inhabitants of the Queensland town of Toowoomba in Australia voted against using a similar technique for water recycling.

Antoine Frerot, managing director of Veolia Eau, a French water company that has high stakes in this sector, said modern water recycling methods already create water that is perfectly drinkable.

"Used water is a resource that is close to cities and its availability rises at the same rate of consumption," he said. "Recycling it uses less energy than desalination and avoids pollution."

Drinking water extracted from an aquifer costs around 8 cents per cubic meter and 56 cents when taken from seawater, according to Frerot's figures. Recycled used water costs around 36 cents a cubic meter.

Water companies are seeking out indirect ways of water conservation that include separation of drinking water and toilet systems, so that sea water can be used to flush toilets.

"Indirect" sewage recycling, a method that treats sewage poured out into the local river or reservoir and is then drawn up by a different intake pipe as the source for drinking water, has become another widespread practice.

On the River Thames, local utilities upstream extract and return the water several times before it reaches London.

A program in Singapore called NEWater, in which one percent of drinking water comes from recycled sewage effluent that is added to the city-state's main reservoir, has also shown promise.

Jacques Labre, a specialist with Suez Environnement, a French water services company, said passing the water through a 'natural environment' is a way of partially overcoming the psychological barrier as well as bringing in the ecosystem as an additional filter.

Louise Korsgaard, an expert with Danish consultancy DHI and a researcher at Singapore's Nanyang Technical University, said that while the psychological barrier is still quite strong, it will likely change in the future.

"It's a lot about trust in the technology," he said.


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