ABSTRACT
Public water supply is distributed through water pipe network, which affects the quality of water that gets to the consumers when the integrity of the pipe distribution network is compromised. Hence, this study aimed at investigating and modelling water quality deterioration in the distribution network of Kaduna Metropolis. In order to achieve this water samples were obtained from selected points along the distribution network of Kaduna metropolis for water quality analysis. The parameters analyzed were residual chlorine concentration, pH, turbidity and dissolved oxygen. Linear regression equations obtained from the relationship between pairs of parameters were used in a MATLAB/SIMULINK environment to model the change in the various water quality parameters along the network. The results clearly showed that the quality of water produced at the treatment plant is below standard water specifications (Nigerian Standard for Drinking Water Quality, 2007) with turbidity and pH having average values of 9.5 NTU and 5.7 respectively; this quality deteriorates significantly along the network. Residual chlorine concentration was below 0.35mg/l at all points in the network and ranged from 0 to 0.3 mg/l; turbidity levels varied between 2.6 to 10.6 NTU were observed at the treatment plant and reservoirs/booster stations; pH and dissolved oxygen levels varied slightly between 5.4 to 7.4 and 0.4 to 0.7 mg/l along the network. Leakages were also observed along the network. On an average, the model was 77% accurate in predicting values of water quality parameters along the network. Also significant differences observed between the water quality values at Kaduna North Water Works and the selected sampling points. This indicates that the quality of water deteriorates along the network and is not safe for human consumption. Improvement of treatment processes and rehabilitation of the water distribution network were suggested to improve quality of water produced and distributed to the consumers in Kaduna metropolis.