Microbiological Performance of Ceramic Water Filters as Household Water Treatment Technology in Bangladesh

Abstract

Ceramic Water Filter (CWF) or Mineral pot filter (MPF) as household water treatment (HWT) option is becoming a widespread technology in urban and rural areas in developing countries. But the microbiological performance of CWF wasn’t being investigated. A study was undertaken to evaluate the performance of CWF under realistic household usage conditions and laboratory controlled environment. A total of 75 CWFs were purchased and distributed among the preselected people of coastal area and the performance was studied microbiologically and physico-chemically as field evaluation. From baseline results, it is reported that, all the source water were contaminated by the disease causing organisms specially rain feed ponds among the sources. Field evaluation showed, CWF can remove E. coli in median log10 reduction ranged from 1.8 -2.8 in four monitoring cycles. For pond water, E. coli > 2 log10 reduction was observed inconsistently. The filters also removed Vibrio cholerae non- O1/non-O139 .The number of water samples satisfying the WHO no risk level increased significantly because of filtration. CWF significantly reduced health risk upto 98% in compared to source water condition. Turbidity of the water was found less than 1 NTU after filtration. In laboratory controlled experiment, 24 filters from three different CWF brands were purchased to evaluate the laboratory performance of CWF against E. coli bacteria, MS-2 bacteriophage virus and Clostridium perfringens spores according to the WHO protocol. Results showed, filter performance declined with the increasing filtration period, signified the overestimated lifespans claimed by manufacturers. Also the filters were moderately effective but inconsistent in reducing E. coli (1.03–2.15 log10 reduction), MS2 (0.52–1.52 log10 reduction) and less effective against C. perfringens spores (0.50–1.06 log10 reduction). These filters can effectively reduce turbidity (> 98% removal) and color (> 90% removal). In complying WHO guideline, only one brand achieved protective target in some occasions than other brands. This laboratory outcome showed close to similar results with field data and study in Cambodia in relation to the removal of bacteria, turbidity and color and WHO compliance of protective target by CWF. Laboratory results inferred that these commercially available filters, if properly maintained, can be effective and reliable in household level but more research is needed to confirm its effectiveness in reducing microbial indicators and other potential pathogens in both field and laboratory controlled environment.