Saturday, July 14, 2007

drinkable sea water

BROWNSVILLE, Texas — On a one-acre site alongside a string of docked shrimp boats and fronting the turquoise waters of the Brownsville ship channel is a $2.2 million assembly of pipes, sheds and whirring machinery — Texas' entree into making Gulf of Mexico sea water suitable to drink.
Plant operator Joel del Rio is its guardian, constantly checking the intake pumps, the pretreatment filters, the discharge pond and the long pipes of the desalination unit. In an occasional moment of truth, he opens a small spigot at the end of a fat pipe and fills a plastic glass in hopes the finished product will taste "like regular bottled water."
"Sea water," he said. "It's never going to run out."
The plant is a pilot project for the state's first, $150 million full-scale sea water desalination plant slated for 2010.
Desalting the sea water is expensive, mostly because of the energy involved in pushing water through layers and layers of filters to strain it. Current cost estimates run at about $650 per acre foot (326,000 gallons), as opposed to $200 for purifying fresh water. But a glimpse around the world shows that when water needs are crucial, governments and private investors ante up.
About two-thirds of the world's desalinated water is produced in Saudi Arabia, Kuwait and North Africa, with the Persian Gulf getting some 60 percent of its drinking water through desalination. Perth, Australia, is looking to meet a third of its fresh water demand through desalination.
Israel in March showed off its plant at the Mediterranean port of Ashkelon that's able to process 87 million gallons of water a day. Singapore in 2005 opened a sea water desalination plant designed to meet at least 10 percent of the nation's water needs. General Electric Co. in May announced a $220 million contract to build a plant in South Africa.
Global output is less than 0.1 percent of all drinking water. But according to a a recent report by Global Water Intelligence, the worldwide desalination industry is expected to grow 140 percent over the next decade, entailing $25 billion in capital investment by 2010, or $56 billion by 2015.
While the United States has hundreds of plants to purify brackish ground water, sea water desalination is just getting started. Tampa Bay's $158 million sea water desalination plant opened in March after years of problems with design and a lawsuit with a contractor.

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