ABSTRACT
The study was undertaken to measure the variational change in residual chlorine decay in water distribution network. A total of 330 water sample were collected at different periods of the day for ten days. Ten water sample locations at water stand taps, were taken for the study area in Calabar South Local Government Area of Cross River State, Nigeria. The effect of various Pipe diameter, water sample point distance, change in chlorine concentration with time on residual chlorine and regression model of residual chlorine as a function of dosage, pipe diameter and temperature were investigated. First order decay equation was used to model and analyse the variational change in residual chlorine concentration. It was observed that, the residual chlorine concentration decreased as pipe diameter increased. The loss of chlorine in water was found to be smaller in larger pipe diameters. The residual chlorine concentration decreases as distance increased. A linear relationship was observed to exist between residual chlorine concentration and change in chlorine concentration with time. Furthermore, from the regression model, the R square value range from 0.73-0.93 being the coefficient of correlation of the regression, showed a good correlation for morning ,afternoon and night period for the total variation of the chlorine concentration at the water stand taps which accounted for by dosage, temperature and pipe diameter. The dosage, temperature and pipe diameter were the independable variables indicated as X1, X2, X3 and Y as the dependable variable been the residual chlorine at the stand taps. Conclusively, since the R square values of the regression model was considered high, this indicate the goodness of fit of the analysis.
