Laboratory efficacy of locally manufactured ceramic water filters in removing

• Published in: Environmental science water research & technology 2022-03, Vol.8 (3), p.619-629
• Main Authors: Heylen, Camille, String, Gabrielle, Lantagne, Daniele
• Format: Article
• ISSN: 2053-1400; 2053-1419
• DOI: 10.1039/d1ew00821h

Locally-manufactured ceramic water filters (CWFs) remove Escherichia coli via physical screening, physicochemical mechanisms, and disinfection; performance varies across local production. It was unknown whether CWFs remove Vibrio cholerae , the (smaller and metabolically different than E. coli ) bacteria causing cholera. To fill this gap, we tested hydraulic and microbiological ( V. cholerae and E. coli ) performance of eight different CWFs (in duplicate) produced by established factories in the laboratory for three consecutive days. Four CWFs were silver-impregnated. Across all filters, average Log Reduction Values (LRV) were 1.9-5.7 for V. cholerae and 2.9-7.0 for E. coli on day 1. V. cholerae LRVs were 5.3-5.6 for silver-impregnated filters, and 1.9-4.3 for non-impregnated filters; E. coli LRVs were 5.1-7.0 for silver-impregnated and 2.9-4.0 for non-impregnated filters. The correlation between E. coli and V. cholerae LRVs was non-linear ( R 2 = 0.003-0.24) for silver-impregnated filters, and linear ( R 2 = 0.23-0.81) for non-impregnated filters. Our results highlight: 1) high variability in CWF performance; 2) silver disinfection as the most critical mechanism to remove V. cholerae ; 3) CWFs can be used in cholera outbreak settings to remove V. cholerae , if silver remains on the filter; and, 4) assessing filter microbiological performance with specific organisms of interest, not only reference organisms, may be necessary. Results highlight that locally-manufactured ceramic water filters from different factories have high variability in V. cholerae removal efficacy, and silver disinfection is the most critical mechanism to remove V. cholerae from drinking water.