As with most filtration methods, water is carefully introduced to one side of the filter, which acts to block the passage of anything larger than the pore size. Typically bacteria, protozoa, and microbial cysts are removed but the filters are not effective against viruses since they are small enough to pass through to the other “clean” side of the filter. Ceramic water filters (CWF) may be treated with silver in a form that will not leach away. The silver helps to kill or incapacitate bacteria and prevent the growth of mold and algae in the body of the filter.
Ceramic filtration does not remove chemical contaminants per se. However, some manufacturers (especially ceramic candle filters) incorporate a high-performance activated carbon core inside the ceramic filter cartridge that reduces organic & metallic contaminants. The active carbon absorbs compounds such as chlorine. Filters with active carbon need to be replaced periodically because the carbon becomes clogged with foreign material.