AWWA ACE93180

The objective of this study was to examine the physical performance of granular media filters under conventional and biological conditions using a pilot plant filtration system. The performance parameters investigated were turbidity, PSDs (as evaluated by total particle counts (TPCs) and beta (B)), and headloss. Study One examined the performance of dual media (anthracite/sand) filters under conventional and biological conditions, specifically, pre-chlorinated (PC) backwash-chlorinated (BWC) and non-chlorinated (NC) conditions. Study Two evaluated the performance of different filter media under NC conditions. The media examined were dual media (anthracite/sand), sand, and three different types of GAC. The overall project, of which this study was a part, examined the biotreatment of organic matter, including ozone DBPs, DBP precursors, and biodegradable organic matter. These results have been reported by Miltner and Summers. In addition, the impact of backwashing on the organic removal performance of biological filters was reported by Miltner et al. In the early phases of this study, it was reported that pre-chlorination resulted in slightly lower filter effluent particle counts in comparison to backwash-chlorinated and non-chlorinated filters.