Abstract
Background: Anthracite is capable of adsorption and removal of contaminants especially heavy metals from potable water. This study was carried out to assess the efficiency of single (sand) and dual media (sand+ anthracite) filters for the removal of Fe, Zn and Mn from potable water in Shahid Beheshti and Ekbatan water treatment plants in City of Hamedan in 2016.
Methods: In this cross-sectional descriptive study, due to the fact that the water supply in both water treatment plant is similar, totally 24 water samples were collected from both water treatment plants output. After preparation and processing of the samples in the laboratory, element (Fe, Zn and Mn) contents in samples were determined using inductively coupled plasma-optical emission spectrometer with three replications. All statistical analyses were performed using SPSS based on the Shapiro-Wilk test, Independent T-Test, Pearson Correlation Coefficient and One Sample T-Test.
Results: The maximum average concentrations of elements (µg/l) were 1200±1070 for Fe, 110±50 for Zn and 170±140 for Mn respectively and for all metals related to Ekbatan water treatment plant. Also, comparing the mean concentrations of the evaluated metals with maximum permissible limits established by WHO showed a significant difference. Thus, the mean concentrations of Zn and Mn were significantly lower than the MPL in both water treatment plants. It was also noted that there were no statistically significant differences found in the mean content of analyzed elements between the water samples collected from the Shahid Beheshti and Ekbatan water treatment plants.
Conclusion: Considering that the filters with anthracite layer in Ekbatan water treatment plant have lost the capability for removal of heavy metals ions due to their long-term function and possibly poor quality properties, restoration or replace the anthracite layer of filter media of this water treatment plant is recommended.