Process for Inhibiting Biological Growth On a Gravity Fed Disc Filter

A rotary disc filter is provided with a system for inhibiting biological fouling from biological growth on filters that form a part of the rotary disc filter. A biocide is pumped from a biocide supply tank to a manifold and mixed with a backwash to form a backwash-biocide solution. The backwash-biocide solution is sprayed onto filter media during a backwashing operation and the presence of the biocide inhibits and eliminates biological growth on the filter media.