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1725943 
Journal Article 
Characterization of NOM removal by biological activated carbon 
Klevens, CM; Collins, MR; Negm, R; Farrar, MF 
1996 
79-88 
WOS:A1996BG76D00009 
Treatment to reduce biodegradable organic substrate following ozonation was a primary concern in a 38 Lpm pilot study for Croton Reservoir (New York City) water. Raw water filtration by GAC was compared to treatment by ozone/biological activated carbon (BAC) filtration processes which may precede the diatomaceous earth filters proposed for this source. Results from the one year characterization program showed 44-57% reduction in formation of trihalomethanes and haloacetic acids after BAC compared to 14+/-% removals accomplished by GAC alone. Biodegradable organic substrate doubled from ozonation (0.5 mg0(3)/mgC) but was degraded to close to the raw water levels through the biofilters. Substrate in BAC treated effluents was comprised of more slowly biodegradable compounds than were present in the raw water. The changes in dissolved organic carbon characteristics from ozonation (i.e., to more hydrophilic, smaller, less reactive compounds) were confirmed using standard NOM fractionation techniques, and were predicted from the change in specific UV-absorbance, from 2.7-3 L/mg-m in the raw to 1.5 +/- 0.3 L/mg-m in ozonated and BAC effluents. Viable bacteria colonization reached similar levels within BAC and GAC filters but distributions with depth were different depending on source of substrate (ozonated or raw water) and hydraulic loading rate. 
granular activated carbon; biological activated carbon, ozone; natural organic matter; biomass; biodegradable organic carbon