In the advanced western world, potable clean water is accessible to all citizens. But, in the developing world, it is not true for most of the poor. According to the World Health Organization (WHO) and UNICEF Joint Monitoring Program for water supply and sanitation, 11 percent of the global population, or about 783 million people, lack access to improved sources of drinking water.  Most of these people live in poorer rural areas.

While there have been many low cost solutions to address this worldwide problem, efforts are underway to produce even cheaper filters that can be mass produced at much lower cost to make it affordable for the poor.

Researchers at the Indian Institute of Technology (IIT) in Chennai, India, have developed a purification device that filters water through a specially crafted mixture of nanoparticles to remove bacteria and other harmful contaminants. The Indian IIT research indicates that nanotechnology will be able to deliver clean drinking water to rural communities for less than $3 a year per family.

According to the study co-author Thalappil Pradeep, a professor in the department of chemistry at the IIT Chennai, the filter device is currently being tested in communities in India, and could offer an affordable way to provide small families with at least 10 liters (2.6 gallons) of safe drinking water per day.

"We had to look at several problems with water: one is microbes. Another is bacteria and viruses, and then chemicals, like arsenic, lead and pesticides," Pradeep told LiveScience staff writer Denise Chow.

Per Chow’s explanation, the IIT Chennai researchers designed a water filter composed of a grainy mix of nanoparticles that release a continuous stream of silver ions to destroy microbes in the water. The report indicates that the silver ions, which flow from nanoparticles when oxidized, have been known for their ability to effectively kill bacteria.

According to the LiveScience report, other composite materials in the filter cartridge were added to remove arsenic, pesticides, lead and other heavy metals from the water. "By combining several materials together, we can have an all-inclusive purifier," Pradeep told Chow. "Everything goes through the filter, passes through these materials, and you finally get clean water," added Pradeep.

The filtration process takes approximately an hour, and the researchers' current prototype containers can hold up to 10 liters of water.

The water purifiers are currently being tested in communities in India, but it has the potential for use in other rural locations around the world, says the IIT Chennai study.