A low-cost solution to rural water disinfection

To address the problem of water-borne diseases and the poor success rates of chlorination in the developing world, Compatible Technology International (CTI) began the design of a chlorinator more appropriate for the target populations. An initial assessment demonstrated that none of the disinfection systems commercially available at that time were economically or technically suited to the task. Hence, the design criteria were as follows: (1) The unit should be simple, nonelectrical, field-constructible, and suitable for village-level operation and maintenance. (2) It should handle water flow rates between 2-10 gallons per minute (gal/min) and should deliver a consistent dose of chlorine regardless of water flow rate. CTI selected solid tablets of calcium hypochlorite as the source of the oxidizing agent. CTI has been very sensitive to community acceptance of their new device. Community acceptance is absolutely essential to the ultimate success of this project. The community measures the success of the devices by the palatability of the water they drink and through observations that their children have fewer incidents of diarrhea. While obtaining high-quality chlorine tablets has been a problem, the program has been very well received by the communities, as evidenced by the fact that UNOM (Operation and Maintenance Division of the Nicaraguan Health Ministry) cannot keep up with the requests for the units. Laboratory results show that the village water systems with the chlorinators are free of coliform bacteria. Record keeping in these villages is almost nonexistent. However, anecdotal information indicates that infantile diarrhea is reduced when the chlorinator is installed.