GLOBAL CHALLENGES

Nanotech Water Filter Is High-Speed, Low-Cost

Rebecca Kutzer-Rice | Date: 09-14-10 | Comments

Researchers at Stanford University are developing a cheap but highly effective water filter that could easily be implemented throughout the developing world.

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Nanotech Water Filter Is High-Speed, Low-Cost
According to the World Health Organization (WHO), nearly 4 million people die each year from water-related diseases like cholera, typhoid and hepatitis. Because one in eight people lack access to clean water supplies, the need for water sanitation has become a global crisis.

Researchers from Stanford University are working to aid communities that need access to clean water. Using a combination of nanotechnology and ancient folk remedies, the team has created a high-speed, low-cost filter that could easily be used to purify water throughout the developing world.

A Unique Design

Typical water filters trap bacteria to separate them from the water. Such filters must have pores tiny enough to catch pathogens. While these designs are effective, they lead to restricted flow rates that render filters inefficient for sanitizing large amounts of water.

Millions of people around the world lack access to clean water (source: UN).

The new filter does not catch pathogens, but lets them flow through with the water. The device, however, kills bacteria with an electrical field that runs through its highly conductive nano-coated cotton.

In lab tests, water infested with Escherichia coli (E. coli) bacteria was exposed to 20 volts of electricity in the filter for several seconds. About 98 percent of the bacteria were killed.

"This really provides a new water treatment method to kill pathogens," said Yi Cui, an associate professor of Materials Science and Engineering, according to a Stanford press release. "It can easily be used in remote areas where people don't have access to chemical treatments such as chlorine."

Because the filter does not trap the bacteria, water flows quickly through its large pores. "Our filter is about 80,000 times faster than filters that trap bacteria," Cui said in the statement.

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