Chemical analysis and filtration efficiency of ceramic point-of-use water filters

Abstract

Ceramic water filters (CWFs) are globally employed as a point-of-use water treatment technology. Although, there are no standards to regulate the use of these CWFs in developing countries, they are gaining acceptability for domestic water treatment. This study sought to assess and compare the efficiency of commercially available types of CWFs and to propose a consumer selection guide for the purchase and use of CWFs. The CWFs selected for the study were, Ball filter with activated carbon (BF + AC), Candle filter (CF), and Pot filter (PFcs) coated with colloidal silver. The elemental and mineral oxide composition of the selected CWFs were analysed with x-ray fluorescence method. Furthermore, the raw unfiltered water (from three different common sources), and the filtrates obtained with the CWFs were analysed for their physicochemical, metal ion removability, and microbial correction. The x-ray fluorescence analysis indicated that Al2O3 and SiO2 were the major mineral oxide compositions of the selected CWFs. These metal oxides were present in varying concentrations. The CWFs showed turbidity reduction of 74.28–99.40%, Mn and Fe reduction of 54.04–98.48% and 48.82–97.50% respectively. In addition, the total coliform reduction by the selected CWFs ranged from 2.31 to 76.97%. It was therefore observed from the results that, the efficiency of commercially available CWFs varied in the order BF + AC > CF > PFcs. BF + AC was the most efficient in both physicochemical and microbial correction of all water sources. CWF selection guide for consumers based on different sources of water which considered the physicochemical parameters, biological parameters and Water Quality Index was discussed. This has an implication for regulation and standardization of CWFs.

Keywords

• Trace metal
• Physicochemical
• Water quality index
• Environment
• Adsorption
• Geology