Bacteriostatic filter media

A bacteriostatic water filtration media composition for use on the inlet side of precoat type water filters having a filter element on which said filtration media becomes coated in operation:

• (a) a first, adsorbent component comprising a powdered activated carbon filter material;
• (b) a second, silver-providing component, comprising an inert, water-insoluble, non-toxic, precoatable, fibrous material impregnated with 1 to 5 weight percent (on a dry basis) of elemental silver formed from reduction of an inorganic silver salt;
• (c) said second, elemental silver-providing component being intimately and uniformly dispersed within said first, adsorbent component to form said water filtration media composition;
• (d) said second, elemental silver-providing component being present in said composition in a range of from 1 to 10 percent by weight on a dry basis to provide bacteriostatic effect throughout the entire filtration media for the life of the filter;
• (e) said second component providing upon contact of water therewith slow release by dissolution of said elemental silver therefrom and dispersion of said dissolved elemental silver throughout said composition permitting said dissolved elemental silver to be effectively present in association with the carbon of said filtration media composition to provide said bacteriostatic effect during rest and during water flow throughout the entire filtration media thereby reducing the rate of plugging the filter element by bacterial growth;
• and
• (f) said media composition of said elemental silver-providing second component dispersed in said first adsorbent component having the properties of:
• (i) precoatability on the inlet side of a water filtration surface without:
• (a) inhibiting carbon adsorptive properties, or
• (b) causing densification of said carbon to promote precoat fall-off from said filtration surfaces
• (ii) inhibiting in-situ propagation of bacteria internal to the filter during stagnant periods resulting in reduction in bacterial growth through the filter element to the outlet side and elution of bacteria therefrom upon restart of water flow;
• and
• (iii) elution of less than 50 ppb of total silver during the life of the filter.