Ceramic water filters as point-of-use water purifiers
Diarrheal disease kills an estimated 1.8 million people each year, the majority of whom are under five years of age. At one time it was though that bringing water into villages through wells and pipes would reduce the incidence of diarrhea. But even protected-spring, piped in water systems can deliver highly contaminated water to household taps due to improper design, maintenance or operation. Further, clean water from a tap or well is easily contaminated en route to consumption by dirty hands or unsafe water storage.
Treating water at the household level has been shown to be more effective in preventing diarrhea than improving water quality at the source (at the spring or at the well-head). A growing number of studies suggest that point-of-use water purification translates into reductions in diarrheal disease at a level that is comparable to other water, sanitation, health and hygiene interventions.
Because of this, ceramic water filters have become a popular intervention for NGOs. They are simple to use, inexpensive ($25 - $40), and can be manufactured/assembled locally thereby presenting an enterprise opportunity. The filters come in a range of sizes and configurations, but have several similar components: a container for untreated water, a porous ceramic filter that is treated with a colloidal silver solution to prevent microbial growth within the filter, a container for the clean, filtered water, and a spout. The filters need to be cleaned periodically, but will last for 2 to 3 years before clogging up.
A range of randomized studies indicate that ceramic filters reduce diarrhea in treatment groups by 40% to 50% over control groups that aren’t using the filters. This is competitive with other interventions such as sanitation programs and hand washing. Since the clean water is used right out of the tap for drinking or cooking, there is less of a chance of re-contamination than water brought from a well in a dirty container, or contaminated by dirty hands retrieving water from a bucket.
Each filter manufacturer/distributor will have program guidelines that your NGO can follow. There will likely be 5 or 6 competing products in your region, so take your time visiting the different companies. Ask them if their products have been tested. Ask if you can visit a community that is using their filters. The community members will be able to tell you whether they are happy with the filters, whether they are using them consistently, and if they have had any problems.
This is a Tier 2 Water and Sanitation intervention and should be considered only after Tier 1 Water and Sanitation and Health and Hygiene activities are in place. The learning process of the Tier 1 activities will prepare beneficiaries for better understanding the reasons for using the ceramic water filters.
References:
Clasen T, Brown J, Collin M, Preventing diarrhea with household ceramic water filters: Assessment of a pilot project in Bolivia, 2006, International Journal of environmental Health Research, 16(3): 231-239
Improving Household Drinking Water Quality: Use of Ceramic Water Filters in Cambodia, 2007, Water and Sanitation Program. http://www.wsp.org/UserFiles/file/926200724252_eap_cambodia_filter.pdf
Fewtrell L, Kaufmann RB, Enanoria W, Haller L, Colford Jr. JM, 2005, Water, sanitation, and hygiene interventions to reduce diarrhea in less developed countries: a systematic review and meta-analysis, Lancet Infect Dis 2005; 5: 42-52
Diarrheal Disease: Solutions to Defeat a Global Killer, 2009, PATH. http://www.eddcontrol.org/files/Solutions_to_Defeat_a_Global_Killer.pdf