title: Monitoring benzotriazoles: a 1 year study on concentrations and removal efficiencies in three different wastewater treatment plants.
abstract: Benzotriazole (BTri), 4- and 5-tolyltriazole (4-TTri, 5-TTri) were monitored over 1 year in three wastewater treatment plants (WWTPs) with a membrane bioreactor (MBR-MH) and two conventional activated sludge systems (CAS-E, CAS-M). The influent/effluent concentrations and treatment stages removal efficiencies were monitored. 5-TTri was removed best (mean removal 80%) in the WWTP mainly by biodegradation followed by BTri (mean removal 45%) and 4-TTri (mean removal 15%) that showed a significant lower elimination. High removal fluctuations for all three benzotriazoles occurred over the four seasons with lowest removal during winter. All three WWTPs constituted a point source for BTs in the aquatic environment as concentration measurements in the receiving rivers upstream and downstream of the WWTP proved. While MBR-MH and CAS-M significantly increased the downstream concentrations, CAS-E only slightly increased the downstream concentrations as the receiving river was already contaminated with benzotriazoles from hydropower. 5-TTri was detected in lowest concentrations due to its good removal compared to BTri and 4-TTri that contribute to high effluent concentrations with the potential to accumulate due to insufficient self-purification.
authors.affiliation: Chair of Urban Water Systems Engineering, Technische Universität München, Am Coulombwall, D-85748 Garching, Germany E-mail: b.herzog@tum.de.
authors.forename: Bastian
authors.initials: B
authors.lastname: Herzog
authors.affiliation: Bavarian Environment Agency, Bürgermeister-Ulrich-Str. 160, D-86179 Augsburg, Germany.
authors.forename: Hilde
authors.initials: H
authors.lastname: Lemmer
authors.affiliation: Chair of Urban Water Systems Engineering, Technische Universität München, Am Coulombwall, D-85748 Garching, Germany E-mail: b.herzog@tum.de.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Helmreich
authors.affiliation: Karlsruhe Institute of Technology, Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, D-76131 Karlsruhe, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Horn
authors.affiliation: Chair of Urban Water Systems Engineering, Technische Universität München, Am Coulombwall, D-85748 Garching, Germany E-mail: b.herzog@tum.de.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Müller
mesh_terms: D019149:Bioreactors; D045483:Rivers / Q000737:chemistry; D012722:Sewage; D013997:Time Factors; D014230:Triazoles / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D012722:Sewage; D014230:Triazoles; D014874:Water Pollutants, Chemical