PW08 Ecotoxicity and Environmental Chemistry of Antibiotics
Exhibit Hall
8:00 AM - Wednesday, 12 November 2003
(PW127) Fate of Pharmaceuticals in a Bench-Scale Water Treatment Plant.
Bundy, Mike1, Doucette, William1, Ericson, Jon2, Sims, Ronald1, 1 Utah State University, Logan, Utah, USA2 Pfizer Global Research and Development, Groton, CT, USA
ABSTRACT- A modular bench-scale drinking water treatment plant (DWTP) was constructed and used to examine the potential removal of four radiolabeled organic chemicals (caffeine, salicylic acid, trovafloxacin mesylate, and estradiol) relative to a conservative bromide (Br-) tracer during the treatment process. The compounds were selected to be representative of a variety of pharmaceuticals in terms of their physical/chemical properties (i.e. charge and hydrophobicity) and potential removal processes (i.e. sorption, chlorination, biodegradation, photolysis) within DWTPs. Radiolabeled compounds were used to facilitate detection at environmentally relevant levels and to enable a more rigorous mass balance analysis. The bench-scale system was comprised of several unit operations representative of those used in municipal facilities throughout North America including: coagulation, flocculation, sedimentation, dual-media gravity filtration, granular activated carbon treatment (GAC), and chlorination. The modular design of the system enabled unit operations to be easily added, removed or modified. Without GAC treatment, results indicate removals of 5, 25, 35 and 5% relative to a conservative tracer (Br-) for caffeine, trovaloxacin mesylate, salicylic acid, and estradiol respectively, with most removal associated with the flocculation/sedimentation and filtration. Sorption coefficients were measured for each of the four test chemicals to quantify the extent of sorption to floc and filter material. Preliminary results also suggest that biological degradation likely contributed to the removal of salicylic acid. The addition of GAC treatment was found to significantly enhance the overall removal of caffeine (> 99%), trovaloxacin mesylate (98%), estradiol (95%), but had limited effectiveness for salicyclic acid (56%).
Key words: granular activated carbon, flocculation/sedimentation, filtration, sorption