Monitoring Residual Chlorine Decay and Coliform Contamination in Water Distribution Network of Kampala, Uganda

The study was undertaken to examine water quality in the distribution network of Kampala City by assessing five storage reservoirs and four consumer taps. The aim was to evaluate residual chlorine decay and relate it to the risk of recontamination. Physicochemical quality of water in the distribution network was temperature 25.6(24.23-28.66) pH 6.6 (6.5-7.1); turbidity 1.9 (0.5-4.5) NTU; colour 17.2 (2.0-54) PtCo, ammonia 0.02 (0.0-0.05) mgl^-1, and Fe2⁺ 0.005 (0-0.0.08) mgl^-1. Residual chlorine decay was significant between the Water Treatment Plant (WTP) and the storage tanks (Total Chlorine, F=35.67, P< 0.05; Free Chlorine, F=37.97, P<0.05) and consumer taps (P<0.05) and chlorine concentrations were lower that the WHO (2008) recommended levels in two reservoirs and most of the community standpipe taps. The findings in this study provide a typical scenario of water distribution network in African urban areas and the conditions that increase the risk of recontamination. The information generated is important to the scientific community for designing further research to ensure consumer safety. The Water Board can use the generated information and recommendations in this study for better planning and management of the water distribution network.