Evaluation of physical and chemical characteristics of water treated by household water treatment systems

Abstract

Introduction: Raise of people awareness about drinking water contaminants impurities and the demand for better water quality have led to widespread application of point-of-use (POU) water treatment devices. The aim of this study was to investigate the effects of POU-DWTUs in reduction of Heavy metls and DBPs from Tabriz drinking water supply network. Materials and Methods: In This cross-sectional descriptive study, a total number of 60 samples taken from the inlet and outlet water of 30 household water treatment devices. Samples were analyzed for water chemical and physical quality. The results were analyzed by using descriptive and analytical statistics. Result: The average concentration of chemical paramers were: Alkalinity, TH, Ca, Mg, K, Na, Cl, SO4, HCO3 and NO3 126, 186, 48, 18, 3.3, 32.4, 44,58, 153 and 12.4 mg/l and 24, 23, 3, 5, 0.6, 10, 8, 4.04, 30 and 4 mg/l input and output respectively. The removal efficiency for Alkalinity, TH, Ca, Mg, K, Na, Cl, SO4, HCO3 and NO3 were 87, 90, 79, 83, 71, 72, 79, 92, 80 and 80% respectively.The average concentration of Fe, Mn, Zn, Cu and Pb were 130, <200, 480, 30 and 12.4 μg/l and 50, 0, 40, 7.3 and 6.5 μg/l input and output respectively. The amount of heavy metals removed by POU-DWTUs varied from 79% for Zn to 49% for Cu 47% for Fe and 47% for Pb. The average concentration of THM and HAAs inlet were 89.8 and 79 μg/l and 31 and 24.5 μg/l outlet respectively. According to the results of this study, removal performance of THM and HAA were 62% and 70% respectively Conclusion: Analysis showed that the average concentration of TDS was in acceptable level and POU-DWTUs reduce the solids content more than 70%. The average concentration of Heavy metals were in acceptable level But high concentration of Pb in both raw and treated water was remarkable. It was found that POU-DWTUs are not successful and reliable in the complete removal of heavy metals. Whereas drinking water has irrelevant role in providing the bodyII mineral requirements, but, users of these devices should be made aware of the reduced intake of minerals by drinking water. Considering the efficiency of household POU drinking water treatment systems in reducing heavy metals and disinfection by products that have health effects on humans, it is recommended that adequate supervision be provided on the supply of standard and suitable products in the market