The present invention is directed to a microporous filter medium treated
with a microbiological interception enhancing agent comprising a cationic
chemical having a medium to high charge density and a molecular weight
greater than about 5000 Daltons, adsorbed on at least a portion of the
microporous structure, and a biologically active metal in direct proximity
to the cationic chemical and also on at least a portion of the microporous
structure, wherein the flow of fluid through the filter medium decreases
in response to an amount of polyanionic acids present in an influent.
Robust microbiological interception is still maintained due to the
extended empty bed contact time as a result of the diminished flow rate.
