Bacteria and virus removal effectiveness of ceramic pot filters with different silver applications in a long term experiment

“In 2012 more than 4 million people used a ceramic pot filter (CPF) as household water
treatment system for their daily drinking water needs. In the normal production protocol
most low cost filters are impregnated with a silver solution to enhance the microbial
removal efficiency. The aim of this study was to determine the role of silver during the
filtration and subsequent storage. Twenty-two CPFs with three different silver applications
(non, only outside and both sides) were compared in a long-term loading experiment with
Escherichia coli (K12 and WR1) and MS2 bacteriophages in natural challenge water under
highly controlled laboratory circumstances. No significant difference in Log Removal
Values were found between the filters with different silver applications. The results show
that the storage time in the receptacle is the dominant parameter to reach E. coli inactivation
by silver, and not the contact time during the filtration phase. The hypothesis that
the absence of silver would enhance the virus removal, due to biofilm formation on the
ceramic filter element, could not be confirmed. The removal effectiveness for viruses is still
of major concern for the CPF. This study suggests that the ceramic pot filter characteristics,
such as burnt material content, do not determine E. coli removal efficacies, but rather the
contact time with silver during storage is the dominant parameter to reach E. coli
inactivation.” ©2013 Elsevier Ltd. All rights reserved.
(Citaat: van der Laan, H., van Halem, D., et al. Bacteria and virus removal effectiveness of ceramic pot filters with different silver applications in a long term experiment – Water Research 51(2014), p.47-54)