Testing the efficiency of sunlight for household water treatment in Ethiopia

Laboratory experiments were conducted to know the effect of sunlight on raw water treatment and reduction of indicator fecal coliform (FC) organisms from samples taken from polluted water.

After initial MPN count is done raw samples were filled in white transparent plastic bottles and exposed to sunlight for 1, 2, 3 and 4 hours.

Before the exposure of the raw water to sunlight, turbidity, FC and temperature of the raw water was 11NTU, 1100MPN/100mL and 21°C respectively. After exposure to sunlight, logarithmic reduction of FC was observed and at 4 hours exposure no FC was deteced. In the elimination of FC by sunlight, turbidity and perpendicular depth of water during sunlight exposure, has showed significant impact on the FC reduction.

When water with 7cm depth was exposed for 2 and 3 hours of sunlight exposure reduced the FC to 220 and 70 MPN/100mL and depth with 15cm were reduced to 460 and 288 MPN/100mL respectively.

The study has showed, for Ethiopian rural communities and those who are not using conventionally treated waters, how to utilize sunlight as a treatment means for potential elimination or minimization of waterborne diseases.