The world's biggest problem? Dirty water, say some

What's the biggest hazard for the future? Global warming? Oil shortages?

A small, but growing number of people think that a looming shortage of drinking water constitutes a much larger crisis. Water consumption is doubling every twenty years, but the supply isn't growing at the same rate, according to Kevin McGovern, chairman of venture firm McGovern Capital, quoting U.N. statistics.

"We have a crisis," he said at the Foresight Nanotechnology Conference taking place in Burlingame, Calif. this week.

Many of the world's health problems are already apparent. "About half of the world's hospital beds in the world are occupied by people with water borne diseases," he said. Three billion people in the world don't have easy access to a toilet and thousands of kids die a day from water-related complications.

McGovern, of course, is not just a disinterested observer. As a nanotech investor, he is putting money into water purification ideas. One company, KX Industries, will soon show off a filtration system that can eliminate both dangerous chemicals and viruses. Better yet, the replaceable filter element will only cost a dollar or so, so people in India will be able to buy it.

Another company, Argonide, meanwhile, has come out with water filters made with electropositive alumina fibers. "The nano alumina particles act like a dirt magnet," said president Fred Tepper. The filters also get rid of viruses.

A filter that can suck out arsenic, a big problem in Bangladesh, will arrive from Argonide in 2007.