Tuesday, June 15, 2010

New desalination technique shows promise

If this works on a large scale, maybe we won't have to worry about the Yanks taking our fresh water:
The world isn’t facing a water shortage. Anyone who lives by the ocean knows that.

What we are running short of is fresh water. Only 3 per cent of the water on this planet is considered fresh water, and of that about two thirds is locked up in glaciers.

Most of the rest isn’t close to the people who need it most, with parts of Australia, India and the U.S. southwest being some of the better known water-scarce regions.

This has brought heightened attention recently to the importance of water desalination, and more specifically, lower-cost ways of removing salt from seawater that don’t require enormous amounts of heat and electricity.

On this front, a start-up from Vancouver called Saltworks Technologies has been breaking new ground with a process, explained below, called “thermo-ionic desalination.”

By way of background, most of the world’s desalination plants today separate salt by distilling seawater, but this requires an immense amount of energy to rapidly vaporize and then condense the water.

Newer desalination plants typically use a process called reverse osmosis. This is when the seawater is forced against a membrane that filters out the salt and other minerals. The approach is less energy-intensive than distillation, but the big pumps that push the water through the membrane still require lots of electricity.

How much electricity? Economist Jeff Rubin, in his book Why Your World Is About to Get a Whole Lot Smaller, cites the example of Saudi Arabia’s Shuaibah 3, the world’s largest desalination plant. It can produce 880,000 cubic metres of fresh water daily. The electricity to run this facility comes from a massive oil-burning power plant.

Shuaibah 3 is just one of several large desalination facilities in Saudi Arabia that get their power from oil-fired generation stations. “The World Bank estimates that the Middle East will need roughly another 50 to 60 billion cubic feet (1.42 to 1.7 billion cubic metres) of water annually over the next 10 to 15 years to meet the region’s burgeoning water demand,” writes Rubin. “Desalinating that immense volume of water could ultimately require the use of a million barrels of oil per day.”

This is why a company like Saltworks is so important. It has figured out a new process that can cut the energy demands of a desalination plant by more than half, and in some cases by as much as 80 per cent. Ben Sparrow, the mechanical engineer who co-founded Saltworks in 2008, says a small pilot plant is already operating in Vancouver that can process 1 cubic metre of ocean water a day.

From the Star. Interesting stuff, and a lot less troublesome than pumping water over the Rockies (or blasting out gigantic trenches with nuclear bombs, as Gary Filmon supposedly advocated in his master's thesis).