Good works filter down

Low-tech solution has high rate of success in fighting water diseases

Jan 12, 2008
By Prashant Nair
Special to The Chapel Hill News (North Carolina, USA)

CHAPEL HILL -- If the Carolina Global Water Partnership succeeds in bringing safe water to rural Cambodia, it will likely be due to household water filters that cost just a few dollars each.

Mark Sobsey, the environmental scientist at UNC's School of Public Health who heads the project, successfully tested two kinds of water purification systems: ceramic filters and biosand filters.

Ceramic water purifiers look like flower pots and contain clay and a combustible organic material like sawdust. When fired in the kiln, the sawdust disappears, leaving behind tiny holes that trap bacteria and parasites. The filter can be attached to a faucet and has a plastic receptacle to hold water.

"You fill it at night and safe drinking water is available in the morning," Sobsey said.

Non-governmental organizations Research Development International, International Development Enterprises and the Cambodian Red Cross have joined hands to manufacture and sell the filters at $8 a piece. They sell about 500 filters a week in three factories.

Sobsey has evidence the filters work. "We saw a 45 percent reduction in diarrheal disease in families that used the filters versus those that did not," he said. Diarrhea causes more than 80 percent of deaths among Cambodian children under 5 years old.

Biosand filters consist of a bed of sand particles atop a layer of gravel that prevents the sand from washing away. An outlet at the bottom cycles water through the sand layer before it is discharged. Covered with water at all times, the sand contains harmless microbes that kill pathogens in the water by competing for nutrients with the pathogens or directly ingesting the pathogens.

"These are not high-tech treatment technologies," said Peggy Bentley, a public health expert at the UNC School of Public Health. "We know that they work, but we just don't have the business models to sell them in the countries where they're needed."

Most of the filters now are subsidized, marketed and sold by the non-governmental organizations. The UNC group is collaborating with the Kenan Flagler Business School to create business models to make the filters commercially viable.

Lisa Jones Christensen, a business professor, will use her expertise on microfinancing to promote the filters. Microfinancing involves giving small loans to local women to help them buy filters in bulk and sell them to households.

"It works on a social model where women get together with creditors and agree to pay back loans at a stipulated time. Some women may cover for others who are unable to repay loans on time," Christensen said. "There's a social cushion that the standard bank does not provide. That's the secret to the success of microfinance."

Water-use habits and economic conditions vary widely across Cambodia, which may make finding a one sales strategy fits all solution unlikely.

"We're entering the markets of developing countries all the way from the homes of the poor to indigenous corporations, and that has its own challenges," Christensen said. "The poor will be suspicious that we have corporate interests, and the corporations will wonder when the philanthropy will end and the money-making begin."

Prashant Nair is a graduate student in medical journalism at UNC and writes about medicine, health and environmental issues. He can be reached at nair@email.unc.edu

Chapel Hill (USA) water filters save Cambodians

A Chapel Hill project is helping supply safe drinking water to Cambodian homes by selling affordable water filters. (Photo: Joe Brown)

Jan 3, 2008
By Prashant Nair
chh@heraldsun.com
The Herald-Sun (Durham, North Carolina, USA)

CHAPEL HILL -- Ka Har, 55, a mushroom grower from the Angkor Ban village in Cambodia, lives on the banks of one of the world's longest rivers -- the Mekong of Southeast Asia. One of Har's biggest concerns was getting safe drinking water for his family. Harvested rain water and boiled water from the river kept Har and his family disease-free.

That was until June 2006 when Har heard a radio advertisement for a newly-developed water filter and saw a market demonstration in his native village. Ever since Har bought a filter for his home, he has stopped worrying about how to get safe drinking water.

Har is only one example of the 11 million rural Cambodians whose lives may be changed for the better by an initiative conceived several thousand miles away in Chapel Hill.

The Carolina Global Water Partnership is a collaborative project to prevent children in Southeast Asia from dying of water-borne diseases by bringing safe water to their homes.

Diarrhea accounts for more than 80 percent of the deaths among Cambodian children below 5 years of age. Mark Sobsey, an environmental scientist at the School of Public Health at UNC, wants to prevent Cambodian children from dying of diarrhea. Sobsey heads the project aimed at promoting inexpensive, household water purifiers in rural Cambodia.

Cambodian governmental records are imperfect and downplay the magnitude of the water problem, Sobsey said. About 35 percent of rural Cambodians have access to improved water -- microbiologically unsafe water that has been partially treated to remove particulates -- for their basic needs, he added. "The rest do not even have access to that."

The situation in urban Cambodia is slightly better, but a lot of the pipe water is contaminated, Sobsey said. "It's a national problem in Cambodia. Thailand and Vietnam are a little better."

Sobsey successfully tested two kinds of water purification systems -- ceramic filters and biosand filters -- to decontaminate water at a low cost in Cambodia.

Ceramic water purifiers are clay pot filters which resemble flower pots and contain a mixture of clay and a combustible organic material like sawdust. When these clay pots are fired in the kiln during manufacture, the sawdust disappears, leaving behind tiny holes smaller than the size of a typical bacterium. Bacteria and parasites are trapped in the holes when contaminated water is filtered.

Three Cambodian nongovernmental organizations called Research Development International, International Development Enterprises and the Cambodian Red Cross have joined hands to manufacture and sell the filters at $8 a piece. The filter has an average life of three years and filters about half a gallon of water an hour.

Sobsey has scientific evidence that the filters work. He conducted randomized clinical trials to validate the efficiency of the filters by comparing the incidence of diarrhea in 70 households in Cambodia for six months in homes that used the standard version of the filter, the improved one or no filter at all.

"We saw a 45 percent reduction in diarrheal disease in families that used the filters versus those that did not," Sobsey said.

The downside of using the filter is that the pot may break, or the faucet to which it is attached may have to be replaced. "This happens roughly about every two years, and each replacement part costs about three to four dollars," Sobsey said.

Biosand filters are the other innovation that Sobsey successfully promoted in Cambodia. In a biosand filter, a cylindrical or rectangular bed of sand particles lies atop a layer of gravel that prevents the sand from washing away. An outlet at the bottom of the filter cycles water through the sand layer before it is discharged.

Covered with water at all times, the sand contains harmless microbes that kill pathogens in the water by competing for nutrients with the pathogens or directly ingesting them.

In a study published in the March 2006 issue of the journal Water Science and Technology, Sobsey's team showed that biosand filters removed 93 percent of the harmful bacteria from water in a field analysis of 55 household filters in Bonao, a village in the Dominican Republic.

"The standard version of a biosand filter has a concrete housing and is cumbersome to transport. We're promoting a plastic housing for the filters," Sobsey said.

"It's the marketing models which are crucial to the success of this project," Sobsey said, explaining his collaboration with the UNC Kenan-Flagler Business School.

The Carolina Global Water Partnership aims to combine the assets of the UNC School of Public Health and Kenan-Flagler to create business models and commercialization strategies for the filters.

"UNC has several years of pre-existing relationships with research institutions and NGOs [nongovermental organizations] in Cambodia," said Tom Outlaw, a graduate student at Kenan-Flagler and project director of the Carolina Global Water Partnership.

Outlaw worked on regulatory issues surrounding the federal Safe Drinking Water Act for the water sanitation department of the EPA. He hopes to bring his expertise in water safety and business administration to the drawing board for outlining business models to sell the filters.

Outlaw plans to involve local entrepreneurs, convene local business partners and get commercial and nonprofit organizations to work together toward the sustainable sale of the filters.

The project will receive support from P&G and Dow Chemicals for funding, sponsoring trials and surveys and providing raw materials for the filters, said Lisa Jones Christensen, a professor of business administration at Kenan-Flagler. "It would be a folly not to think that an idea of this scale would involve many corporate partners," she added.

Jan Rosenboom, the team leader for the water sanitation program of the World Bank, works with the Cambodian Ministry of Rural Development to assess the performance and usability of Sobsey's filters in Cambodian villages.

The Water Sanitation Program and UNICEF called for proposals from academic groups to test the filters and market them in Cambodia. Sobsey and Outlaw seized this opportunity to combine forces. This spurred the UNC collaborative project.

"We evaluate the filters because consumers cannot check if the claims made by the proponents of these filters are true," Rosenboom said.

The trouble with NGOs is that they give rise to undesirable secondary trade, Rosenboom said. Although the filters are distributed free or sold at nominal rates, the sale is unregulated. Certain households buy filters in bulk and sell them to others for a margin, increasing the cost of the filters and their effective distribution. Middlemen mark up the filter prices to make small but significant profits. Such price hikes deter people from buying the filters and lead to unsafe water habits, Rosenboom added.

"Our goal is to move away from the social marketing model and to develop a commercial market for the filters where they may be sold at a fixed price and be bought at any time," Rosenboom said. The biggest challenge is to set a price at which these filters may be sold without manufacturers incurring a loss, he added. At $8 each, the filters may not be affordable to many families, Rosenboom said.

"These people don't even have money to meet their caloric needs. How will they find the means to buy water filters?" Rosenboom wondered. "We're hoping that the market and business models will take care of the financing," he added.

Research Development International, a U.S. nonprofit organization in Cambodia, has made inroads in that area. Mickey Sampson, the country director of Research Development International, is involved in marketing the filters to Cambodians.

"We do surveys from time to time and have found that people like to use the filters because they're so easy to use," Sampson said. The organization sold 26,000 filters to Cambodian families in 2006.

"We're primarily targeting schools to market the filters," Sampson said. Sampson distributes the filters to school teachers in Cambodian villages. Sampson's team visited schools, gave the filters to teachers and monitored their use in the teachers' homes. His team also conducted public information campaigns using music, puppets and drama to teach children the importance of filtering water.

Arsenic and fluoride contamination in surface water is another problem in Cambodia. Sampson's team dug shallow community wells from which chemically safe water could be taken without using buckets. Although the wells were widely used, people did not feel responsible for them, Sampson said. That experience taught Sampson's team not to give away the filters.

"When you give something away, it has no value, and the people don't have a true sense of ownership," Sampson said. So they sell the filters at $8 a piece. Since many Cambodian teachers need a second job to eke out a living, they willingly agree to work as marketers for a small fee. Using schools as portals to distribute the filters increased use, Sampson said.

If the pilot study by the Sobsey-Outlaw colloboration yields promising results, the team hopes to involve local business partners toward developing a self-sustaining filter industry in Cambodia and other Southeast Asian countries.