Are desalination plants worth it?

In many jurisdictions, the answer is no. But if you're in Australia's Victoria state where the agricultural industry is withering away from drought and cities have to impose water rationing, it's a bargain.

Even if you're not in some of the hardest hit areas of the globe, the economic argument for desalination will likely improve over the next few years. Right now, desalinated water from state-of-the-art facilities in Israel or Singapore costs about 56 cents a cubic meter, said Mark Shannon, Director of the NSF STC WaterCAMPWS at the University of Illinois. (Shannon will speak at the Water Innovations Alliance in Chicago next week.) Meanwhile, new technologies – such as forward osmosis, gravity, capacitors or carbon nanotube membranes – will likely bring the price down.

"I am confident that we will hit 25 cents a cubic meter," he said.

Currently, delivering water to U.S. consumers costs about 50 cents a cubic meter, he said. In cities like New York and Chicago, it can run $1.45 a cubic meter.

"London is the highest in the world," he said.

At the conference, Shannon will discuss his plans for an anaerobic digester (the same sort of bacteria-filled box some are using to convert manure into methane) to convert sewage into recycled water, methane and saleable minerals. Read more here.