Studies of Modifications in Water Filtration

Abstract

This article discusses treatment modifications including high‐rate filtration with coarse, lightweight media on top of sand; control of floc strength and its passage with polyelectrolytes in the filter influent; the use of filters for flocculation of low alum doses as well as for removal of turbidity; and, the use of granular activated carbon in filter beds. The effect of these innovations was studied in pilot plants of various sizes to determine the passage of coliform bacteria, powdered activated carbon, virus, and gross turbidity through the filters.