Assessment of Bushenyi-Ishaka water treatment and supply system using the water safety planning approach

Abstract

Access to safe drinking water is a major global health concern with microbiological risks being the most serious burden of disease associated with unsafe water, sanitation and hygiene. Annually, 2.4 million deaths due to diarrhoea are attributable to this risk factor, which is 4.1% of worldwide disease burden. The Bushenyi area in particular is currently faced with water quality challenges and a number of cases have been reported by customers relating to poor water quality, which could be attributed to improper operations during treatment and cross contamination during distribution, handling and use. The objectives of this study were to; 1) determine the hazards and risks associated with the water treatment, storage and distribution system of Bushenyi-Ishaka area through a comprehensive assessment, 2) determine the critical control points and hotspots in the water treatment and supply system, and 3) develop a decision support system for the water treatment and distribution stages towards supply of safe drinking water to customers in the Bushenyi-Ishaka area. A detailed assessment of the Bushenyi-Ishaka water supply system was conducted and relevant information was collected from the Bushenyi-Ishaka area managers and technical staff of National Water and Sewerage Corporation. Sanitary inspections were also carried out for the different water facilities (water treatment, storage and distribution) and basic physical, chemical and biological analyses were performed on water samples collected during field assessment. The results of the study showed that the water supplied by the Bushenyi-Ishaka water treatment and supply system does not meet the National Standards for portable water especially physical water quality parameters. The water was found to be acidic with over 90% of the samples having pH range of 4.5-5.8, Bushenyi market public stand post was found at a high risk with average apparent color value of 270.7 PtCo compared to the National Standard of 15 PtCo. The study revealed that the iron content of the water supplied to customers was high. Ninety percent of the water samples collected from the distribution network did not meet the standards for free residual chlorine and the most risky study site was Kashenyi public stand post with an average value of 3.43 mg/L compared to the national standard of 0.2 mg/L. The study recommends that NWSC should consider improvement of the Nyaruzinga water treatment plant to introduce sedimentation tanks to complete the coagulation, flocculation and sedimentation processes during water treatment.