Disinfection of Intermitted Water Supply System and Its Health Impact: Um Al Nasser Village as a Case Study

Abstract

The main objective of the research is to study the effect of chlorine depletion in intermitted municipal water supply networks on the proliferation of water-borne diseases in marginalized communities. WaterCad model was built to investigate the behavior of the water systems under the action of intermittent supply and the distance from nine testing points from the chlorination source based on the flow direction. The measurements of residual chlorine in the drinking water network in the period between January 2010 until December 2013, of nine sampling points were conducted. At the same time, the prevalence of waterborne diseases amongst the local residents was registered. Results show that 68% of the sampling points in the water supply network have residual chlorine concentrations lower than the recommended values given by The World Health Organization. One variable exponential regression model is used to estimate the effect of distance on the residual chlorine decaying in intermitted water distribution system. A significant correlation between the distance and the decrease of chlorine concentration is shown, R² for 2010 is 0.75, while for 2011, 2012 and 2013 the R² is 0.81, 0.72 and 0.58, respectively. Among four water borne diseases, a significant correlation was found only for increasing the number of incidences of Diarrhea in Winter and Summer with a decrease of average residual chlorine in drinking water networks R² = 0.65 and 0.61 (ANOVA test 0.003 and 0.003), respectively. The investigation and four years monitoring are important to the water and public health relevant institutions to improve the public water supply sector.