Effectiveness of Solar Water Disinfection - "SODIS method", for the removal of total coliforms in municipal surface waters

Abstract

According to the new UNICEF/WHO report, about 2.2 billion people worldwide lack safe drinking water services, 4.2 billion people lack sanitation facilities and 3 billion lack basic hand washing facilities. The objective of this study is to evaluate the effect of the SODIS method for the removal of total coliforms in surface water. For this purpose, surface water samples were taken, avoiding exposure to sunlight during storage. Subsequently, total coliforms were isolated from the samples, which were used to make controlled contamination of the experiments, to apply the SODIS method, three ranges were established for turbidity (99, 40 and 16 NTU) and thickness (0.0140, 0.0113 and 0.0110 cm/ml) and were subjected to radiation of 1182 ± 122 W/m2 and 955.1 ± 425 w/m2. respectively. As a result, a pattern was observed in which the lower the turbidity and thickness, the higher the percentage of removal. For a low turbidity (16 NTU) a removal of 99.7 ± 0.2% was obtained and for a thickness of 0.0110 cm/ml a removal of 99.9%. Based on this, it is concluded that the SODIS method is a viable alternative for water purification and that it can be improved by reducing turbidity and increasing thermal heating and UV radiation.