ent 377 (2007) 255–272
www.elsevier.com/locate/scitotenv
Science of the Total Environm
Efficiency of conventional drinking-water-treatment processes in
removal of pharmaceuticals and other organic compounds
Paul E. Stackelberg a,⁎, Jacob Gibs b, Edward T. Furlong c, Michael T. Meyer d,
Steven D. Zaugg c, R. Lee Lippincott e
a U.S. Geological Survey, 425 Jordan Road, Troy, NY 12180, USA
b U.S. Geological Survey, 810 Bear Tavern Road, West Trenton, NJ 08628, USA
c U.S. Geological Survey, Denver Federal Center, Building 95, MS 407, Lakewood, CO 80225, USA
d U.S. Geological Survey, 4821 Quail Crest Place, Lawrence, KS 66049, USA
e New Jersey Department of Environmental Protection, P.O. Box 409, Trenton, NJ 08628, USA
Received 11 July 2006; received in revised form 23 January 2007; accepted 28 January 2007
Available online 23 March 2007
Abstract
Samples of water and sediment from a conventional drinking-water-treatment (DWT) plant were analyzed for 113 organic
compounds (OCs) that included pharmaceuticals, detergent degradates, flame retardants and plasticizers, polycyclic aromatic
hydrocarbons (PAHs), fragrances and flavorants, pesticides and an insect repellent, and plant and animal steroids. 45 of these
compounds were detected in samples of source water and 34 were detected in samples of settled sludge and (or) filter-backwash
sediments. The average percent removal of these compounds was calculated from their average concentration in time-composited
water samples collected after clarification, disinfection (chlorination), and granular-activated-carbon (GAC) filtration. In general,
GAC filtration accounted for 53% of the removal of these compounds from the aqueous phase; disinfection accounted for 32%, and
clarification accounted for 15%. The effectiveness of these treatments varied widely within and among classes of compounds; some
hydrophobic compounds were strongly oxidized by free chlorine, and some hydrophilic compounds were partly removed through
adsorption processes. The detection of 21 of the compounds in