For most people in the United States, water filters simply make the stuff taste better. But for many people in developing countries, a low-cost filter can mean the difference between life and death. Worldwide, almost two and a half million people each year die from diarrheal illnesses, many of which are caused by unsafe water.
Doctoral students from the Department of Environmental Sciences and Engineering in the School of Public Health will do extensive tests of three types of low-cost filters, using a seventy-five thousand dollar research grant from the U.S. Environmental Protection Agency (EPA). In a competition with sixty-four other teams, the Carolina group was one of only seven teams to win one of the EPA’s first-ever People, Prosperity and the Planet Awards, based on results of pilot tests they had conducted. The students will use the grant to continue their work, testing the effectiveness of biosand filters, ceramic filters, and Proctor and Gamble’s PUR water disinfection system.
In the doctoral students’ pilot study, lab tests showed that all three treatment technologies removed viruses and bacteria from the water, but to differing degrees. The biosand filter was the least effective, but also the least expensive: it contains no consumable parts and is made of concrete. It can probably be used for decades, says Mark Elliott, one of the doctoral students on the research team. The ceramic filter can also be effective for years. The PUR system involves a continuous cost of about one cent per liter of water treated because the system uses a sachet of chemicals that must be replaced.
The pilot study also tested a modification of the porous ceramic filter that team member Joe Brown developed. The filter uses an iron coating to create a positively charged surface designed to adsorb viruses, which are negatively charged. In a pilot study, the enhanced filter removed a greater number of viruses than did traditional ceramic filters.
Scientists have extensively studied the effectiveness of the PUR system at preventing illness. But they haven’t conducted extensive tests on the other two types of filters. So the team will carry out field tests of the biosand filter in the Dominican Republic and of the ceramic filters in Cambodia. Team members Christine Stauber and Joe Brown will lead the studies.
“We are trying to determine how much each of the filters reduces waterborne disease,” Elliott says.
Doctoral student and team member Lisa Casanova will study the ability of the PUR system to reduce waterborne pathogens such as hepatitis A virus.
Mark Sobsey, professor of environmental sciences and engineering, leads the team, which also includes Dale Whittington and Francis DiGiano, professors of environmental sciences and engineering. The team’s goal is to develop a program in global water sanitation and health that will provide research and training opportunities for future graduate and undergraduate students at Carolina.
