Abstract. Trace organic compounds from pharmaceutical and personal care products are often not fully removed during wastewater treatment, resulting in discharge of these emerging pollutants to surface and groundwater. Fate and transformation of trace organics has primarily been investigated in larger activated sludge wastewater treatment facilities; almost no research has been done on passively aerated fixed-bed bio-filters that are used in decentralized facilities that serve smaller communities. Four laboratory-scale, packed-bed, recirculating-media filter systems were constructed to evaluate the removal of ibuprofen, naproxen, and triclosan. The media (or packed bed) provided support for the development of the fixed film and the needed porosity for air and water movement. Effluent from a local residential septic tank effluent gravity (STEG) system was used as the wastewater supply. This supply had greater than 100 ppb concentrations of ibuprofen, naproxen, and triclosan. Three of the media filters were spiked (nominal 0.1 ppm) with ibuprofen, naproxen, or triclosan to better represent the wastewater from a rural healthcare facility; the fourth media filter received wastewater as produced by the STEG system and served as a non-spiked control. Overall, the mean removal of ibuprofen, naproxen, and triclosan from the wastewater solution was 94%, 84%, and 83%, respectively. At the end of the study, samples of the fixed film were analyzed to discern whether removal was by sorption or biodegradation. It was determined that sorption of the three trace organic compounds into the biofilm accounted for only 0.12% of the ibuprofen, 0.20% of the naproxen, and 1.41% of the triclosan. These results indicate that biodegradation is the primary removal mechanism for these compounds. Keywords: Ibuprofen, Microbial degradation, Naproxen, PPCPs, Recirculating media filters, Triclosan.
Persistence and removal of trace organic compounds in centralized and decentralized wastewater treatment systems