W5 AM Perfluorochemical Monitoring
Wednesday, 16 November 2005: 8:00 AM - 11:40 AM in 321-323

(SCH-1117-830458) Behavior and fate of fluorochemicals during wastewater treatment.

Schultz, Melissa¹, Higgins, Christopher², Luthy, Richard ², Barofsky, Douglas¹, Field, Jennifer¹, ¹ Oregon State University, Corvallis, OR, USA² Stanford University, Stanford, CA, USA

ABSTRACT- As fluorochemicals are widely used in household and consumer-based products and have many industrial applications, a primary route for this chemical class into aquatic and terrestrial environments is by municipal wastewater treatment disposal. The untreated fluorochemicals may enter the environment via wastewater effluent, septic discharge or land application of biosolids. A field study was conducted at a full-scale municipal wastewater treatment plant to determine the mass flows of selected perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, fluorotelomer sulfonates, and perfluoroalkyl sulfonamides in wastewater and sludge. 24 h composite samples of wastewater (raw influent, primary effluent, trickling filter effluent, secondary effluent, and final effluent) and grab samples of sludge (primary, thickened, activated, anaerobically digested, and storage lagoon) were collected over a duration of 10 days and were analyzed by liquid chromatography (LC), electrospray ionization (ESI) tandem mass spectrometry (MS/MS). To gain further understanding of fluorochemical behavior throughout wastewater treatment, additional studies were performed to look at the solid-water partitioning of fluorochemicals and their daily and diurnal variations. Overall removals and increases of fluorochemical concentrations in wastewater treatment plants were observed when the effluent concentrations were compared to the influent levels. Individual fluorochemical concentrations in the wastewater and sludge ranged from 1.1 ng/L to 32.5 ng/L and 1 ng/g (dry wt) to 737 ng/g (dry wt), respectively. Perfluoroalkyl sulfonates were found to increase significantly (200%) in the plant mass balance (30 days). Fluoroalkyl sulfonamide acetic acids were also found to increase by at least 300% throughout the sludge treatment process with a residence time of a year. Perfluoroalkyl carboxylates were overall removed by the wastewater treatment plant. From this plant, significant quantities of fluorochemicals are discharged with treated wastewater and biosolids, indicating that wastewater treatment plants are point sources of fluorochemicals and must be considered when determining origins and behavior of fluorochemicals in the environment.

Key words: fluorochemicals, wastewater contaminants, PFOS, PFOA