Filtration/Adsorption Media for Bacteria and Turbidity Removal

Using Escherichia coli sorption/inactivation and sorption-desorption studies and a down-flow column test, usefulness of incorporating silver into alum-treated bituminous coal and ferric hydroxide-impregnated lignite in improving their performance as filtration/adsorption media was assessed. Silver incorporation showed enhanced E. coli reduction for alum-treated bituminous coal while E. coli reduction by ferric hydroxide-impregnated lignite with and without silver was indistinguishable. This is presumably due to high E. coli sorption by the medium without silver and inability of the sorption/inactivation test to distinguish between sorption and inactivation. Silver incorporation more markedly reduced the number of viable E. coli in the eluate of silver-incorporated alum-treated bituminous coal in a sorption-desorption study. Effluent quality (turbidity, total coliforms, and heterotrophic plate count) of a column test, employing silver-incorporated alum-treated bituminous coal and canal water suggested potential useful of the medium for a domestic water filter in rural areas of developing countries.