A Novel Technology to Improve Drinking Water Quality Using Natural Treatment Methods in Rural Tanzania

Article excerpt

Introduction

Provision of clean and safe water in rural areas is a great challenge for the developing countries of the world since most communities rely on poor traditional sources that often provide unsafe domestic water. It is estimated that world over, about three million people die annually from water-borne diseases (World Health Organization [WHO], 1999). This situation is a source of great concern and makes water purification at the household level especially desirable and important. In Tanzania, over 80 percent of the population live in rural areas, of which only 30 percent are reported to have access to safe potable water (World Bank, 1994). The reliance of the majority of the population on polluted water supply sources poses a great risk to health. These sources are heavily polluted by animal excretions, human excreta, and sewage effluents. Fecal pollution of water supplies is attributed to poor disposal of excreta and a low standard of community hygiene.

Conventional water treatment relies on the addition of chemicals such as alum (aluminium sulfate) as coagulants and the addition of chlorine as a bactericide. The availability of these chemicals, which depends on foreign exchange, is unreliable and unpredictable. Because of economic and political constraints, the universal provision of piped water is not currently feasible. This circumstance leaves millions without access to safe drinking water (WHO, 1999). Interim solutions are clearly needed. For these reasons, the Chemistry Department of the University of Dar es Salaam is looking at alternative water purification methods (Mbogo & Malunga, 2003; Mbogo & Othman, 2000). One approach has been the on-site generation of sodium hypochlorite solution with an electrochemical hypochlorite solution generator (EHSG) as a simple method of producing a drinking-water disinfectant (Mbogo & Othman, 2000). The EHSG can be constructed and operated easily at any place and at any time in rural areas with just a chemical battery and kitchen salt. The second approach has been the use of indigenous or natural treatment methods using plant materials and solar radiation as alternatives to conventional chemical treatment methods. A majority of Tanzanians in rural areas still rely on traditional indigenous technologies for their daily needs--hence the need to study the viability of some of the indigenous technologies applied in various areas with a view to scientifically validating and promoting them.

Plant materials have for many centuries been used as coagulants in developing countries to clarify turbid water (Jahn, 1988; Schulz & Okun, 1984). In India, crushed seeds of the Nirmali tree have been used for centuries to clarify muddy water (Tripath, Chaudhuri, & Bokil 1976). Jahn and Diar (1979) have reported that in Sudan seed powder from the indigenous plant Moringa is added to drinking water to remove turbidity.

Studies have shown that synergies from the combined application of radiation and thermal treatment have a significant effect on the die-off rate of microorganisms (Wegelin, Canonicas, Michener, Pesaro, & Metzler, 1994). Although the technology of solar disinfection of water is not practiced in Tanzania, the country falls within favorable latitudes (35[degrees]N and 35[degrees]S) in terms of solar radiation intensity.

The purpose of my study was to evaluate the potential of traditional treatment methods (i.e., those based on local knowledge inherited from previous generations). The study used plant materials (seeds) from five Tanzanian plants for turbidity removal and used sterilization of water by solar energy for destruction of bacteria, and it compared the results with those of standard treatment practices.

Methods

Study Area

The study involved survey work that covered the Iramba and Bariadi districts, in the Singida and Shinyanga regions, respectively; these regions belong to the semi-arid areas of Tanzania, where scarcity and pollution of water are serious problems. …