Enhancing slow sand filter performance with an acid-soluble seston extract

An acid-soluble extract was obtained from Cayuga Lake (Ithaca, NY) seston and applied to slow sand filters at different application rates. Biological activity in the filters was inhibited with 3 mM sodium azide. The filters were challenged with a synthetic raw water containing Escherichia coli. The Cayuga Lake seston extract (CLSE) fed filters removed up to 99.9999% of the influent coliforms while the control filter (no CLSE) removed 50%. Filter performance was correlated with the amount of CLSE applied to the filters.