Removal of E. coli and Salmonella in pot ceramic filters operating at different filtration rates

Abstract

The use of pot ceramic filters PCF to improve the domestic water quality supply has been recognized as an alternative in regions where there is unsecure water treatment or contamination of the treated water during transport and storage and an absence of safe drinking water. The aim of this study was to evaluate a model of PCF impregnated with colloidal silver under three filtration rates (1.0, 2.0 and 3.0 L/h) and three E. coli and Salmonella spp concentrations (10⁴, 10³ and 10² CFU/mL). The evaluation was made using spiked water having a turbidity of 29.9 ± 4.4 NTU and conductivity of 176 ± 31.7 μS/cm. The results showed a turbidity removal efficiency of 97% and average effluent of 0.9 NTU. The microbiological efficiency removal was of 2 Log Reduction Value (LRV) for E. coli and 1 LRV for Salmonella spp. There were not found significant statistical differences between the filtration rates and the removal efficiencies for turbidity E. coli and Salmonella spp. It was observed that the microbiological removal efficiency was affected by biofilm formation a phenomenon that was attributed to the presence of Salmonella spp. The combination of chemical and mechanical cleaning methods contributed to the elimination of the biofilm.

Keywords: Biofilm; Drinking water; Household filters; Household treatment; Safe water; Turbidity.