Investigation on the Effect of Household Water Treatment Plants on the Drinking Water Quality of Ilam City

The presence of various impurities including suspended solids, chemical compounds, bacteria, viruses and other pathogens can reduce the water quality and it has been increased the use of household water treatment plants. Therefore, this study aimed to investigate the effect of household water treatment plants on the microbial and chemical characteristics of drinking water in Ilam city.
In this cross - sectional study, 50 household water treatment plants were randomly selected in all the regions of the Ilam city. The parameters of turbidity, pH, free residual chlorine, total dissolved solids (TDS), electrical conductivity (EC), heterotrophic bacteria count (HPC) and fecal and total coliforms were measured in the inlet and outlet water samples of the household water treatment plants.
Findings: The results showed that the removal efficiencies of free residual chlorine, total dissolved solids, electrical conductivity, and turbidity by the household water treatment plants were 100, 70.44, 70.31 and 61.05%, respectively. The removal efficiency for total coliform was 21.61%. The finding also showed that the household water treatment plants had negative effects on the removal of heterotrophic bacteria and fecal coliforms, so that the number of these organisms in the outlet water samples was higher than of inlet.
The results indicated that the household water treatment plants had not acceptable efficiency on the removal of microbial contamination and in many cases even increased the microbial contamination. The water treatment plants also eliminate all the free residual chlorine contents in the water that can be result in the secondary microbial contamination of the treated water.