title: Fate and mass balance of contaminants of emerging concern during wastewater treatment determined using the fractionated approach.
abstract: Contaminants of emerging concern (CECs) are often poorly removed from wastewater using conventional treatment technologies and there is limited understanding of their fate during treatment. Inappropriate sampling strategies lead to inaccuracies in estimating removals of CECs. In this study, we used the "fractionated approach" that accounts for the residence time distribution (RTD) in treatment units to investigate the fate of 26 target CECs in a municipal wastewater treatment plant (WWTP) that includes primary, secondary and tertiary treatment steps. Prior hydraulic calibration of each treatment unit was performed. Wastewater and sludge samples were collected at different locations along the treatment train and the concentrations of target CECs were measured by liquid chromatography mass spectrometry. The most substantial aqueous removal occurred during activated sludge treatment (up to 99%). Removals were <50% in the primary clarifier and tertiary rotating biological contactors (RBCs) and up to 70% by sand filtration. Mass balance calculations demonstrated that (bio)degradation accounted for up to 50% of the removal in the primary clarifier and 100% in activated sludge. Removal by sorption to primary and secondary sludge was minimal for most CECs. Analysis of the selected metabolites demonstrated that negative removals obtained could be explained by transformations between the parent compound and their metabolites. This study contributes to the growing literature by applying the fractionated approach to calculate removal of different types of CECs across each wastewater treatment step. An additional level of understanding of the fate of CECs was provided by mass balance calculations in primary and secondary treatments.
authors.affiliation: Department of Chemical Engineering, McGill University, 3610 University St., Montreal, QC H3A 0C5, Canada.
authors.forename: Zeina
authors.initials: Z
authors.lastname: Baalbaki
authors.affiliation: Water Quality Centre, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada.
authors.forename: Tamanna
authors.initials: T
authors.lastname: Sultana
authors.affiliation: modelEAU, Département de génie civil et de génie des eaux, Université Laval, 1065 Avenue de la médecine, Québec City, QC G1V 0A6, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Maere
authors.affiliation: modelEAU, Département de génie civil et de génie des eaux, Université Laval, 1065 Avenue de la médecine, Québec City, QC G1V 0A6, Canada.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Vanrolleghem
authors.affiliation: Water Quality Centre, Trent University, 1600 West Bank Drive, Peterborough, ON, K9J 7B8, Canada.
authors.forename: Chris D
authors.initials: CD
authors.lastname: Metcalfe
authors.affiliation: Department of Chemical Engineering, McGill University, 3610 University St., Montreal, QC H3A 0C5, Canada. Electronic address: viviane.yargeau@mcgill.ca.
authors.forename: Viviane
authors.initials: V
authors.lastname: Yargeau
mesh_terms: D005591:Chemical Fractionation / Q000379:methods; D002853:Chromatography, Liquid; D004784:Environmental Monitoring / Q000379:methods*; D013058:Mass Spectrometry; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Adsorption; Fractionated approach; Hydraulics; Micropollutants; Pharmaceuticals; Tertiary treatment