A novel technology to improve drinking water quality using natural treatment methods in rural Tanzania.

It is estimated that one billion people worldwide do not have access to treated drinking water. This paper reports on an investigation into the potential of indigenous or natural water treatment methods as alternatives to conventional chemical water treatment methods. The seeds of five natural plant species--Vigna unguiculata, Phaseolus mungo, Glycine max, Pisum sativam, and Arachis hypogea--were evaluated for the removal of turbidity, and their efficiency was compared with that of alum. The use of a solar energy-saving method to disinfect drinking water--leaving it to heat under the sun to reduce bacteria colonies--also was evaluated, The study revealed that for raw water with turbidity of 482 nephelometric turbidity units, coagulation with seed extracts from natural plant species reduced natural turbidity by 96.7 to 100 percent when the seed extract was used as the primary coagulant and by 100 percent when it was used as a coagulant aid. The study showed further that natural coagulants were as effective as commercial alum [Al2(SO4)3] and even superior for clarification because the optimum dosage was low compared with that of alum. Leaving samples of water clarified by natural coagulants on a black-painted roof for 8 hours achieved up to 100 percent bacteria kill.