Evaluation of point-of-use drinking water treatment systems' performance and problems

Applications of Point-of-Use Drinking Water Treatment Units (POU-DWTUs) are common in many parts of the world. This paper presents the operational conditions of POU-DWTUs in Iran (Qom province) as a case and discuses the problems and the possible health-related aspects. The devices which were studied consisted of primary filter, carbon filter, Reverse Osmosis membrane, and storage tank. During a cross sectional study, 240 water samples from the input and output of different POU-DWTUs were collected and analyzed. Half of POU-DWTUs users did not have correct information about the operational principles and 35% of them were not satisfied about taste and odor of the treated water. Analysis showed that POU-DWTUs were able to reduce the dissolved solids content more than 90% and produced soft water. However the amount of heavy metals removed by POU-DWTUs varied from 5% for Al to 86% for Cd and their removal average was 43%. 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. Moreover, considering possible long-term health effects of soft water consumption and some microbial contamination of treated water, it is imperative to take proper actions for effective provisions on quality of water produced by POU-DWTUs.