title: Biological degradation of pharmaceuticals in municipal wastewater treatment: proposing a classification scheme.
abstract: A simple classification scheme is suggested to characterize the biological degradation of micropollutants such as pharmaceuticals, musk fragrances and estrogens during wastewater treatment. The scheme should be a basis for the discussion about potential removal efficiencies. Hence, the biological degradation of 25 pharmaceuticals, hormones and fragrances was studied in batch experiments at typical concentration levels using activated sewage sludge originating from nutrient-eliminating municipal wastewater treatment plants. Since pseudo first-order degradation kinetics was observed for all compounds down to ng L(-1) levels, the removal rates can be predicted for various reactor configurations. Therefore dilution of wastewater (e.g. by extraneous water) is expected to reduce the degree of biological removal. Wastewater segregation and treatment at the source are therefore to be favoured for elimination of persistent micropollutants over centralized end-of-pipe treatment. For reactor configurations typical for nutrient removal in municipal wastewater, the derived formula for predicting removal allows the identification of three groups of micropollutants according to their degradation constant k(biol): compounds with k(biol)<0.1 L g(SS)(-1)d(-1) are not removed to a significant extent (<20%), compounds with k(biol)>10 L g(SS)(-1)d(-1) transformed by >90% and in-between moderate removal is expected. Based on the degradation of a heterogeneous group of 35 compounds (including literature data), state of the art biological treatment schemes for municipal wastewater are not efficient in degrading pharmaceuticals: only 4 out of 35 compounds are degraded by more than 90% while 17 compounds are removed by less than 50%.
authors.affiliation: Swiss Federal Institute of Aquatic Science and Technology, Eawag, 8600 Dübendorf, Switzerland. adriano.joss@eawag.ch
authors.forename: Adriano
authors.initials: A
authors.lastname: Joss
authors.forename: Sebastian
authors.initials: S
authors.lastname: Zabczynski
authors.forename: Anke
authors.initials: A
authors.lastname: Göbel
authors.forename: Burkhard
authors.initials: B
authors.lastname: Hoffmann
authors.forename: Dirk
authors.initials: D
authors.lastname: Löffler
authors.forename: Christa S
authors.initials: CS
authors.lastname: McArdell
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Ternes
authors.forename: Angela
authors.initials: A
authors.lastname: Thomsen
authors.forename: Hansruedi
authors.initials: H
authors.lastname: Siegrist
mesh_terms: D001673:Biodegradation, Environmental; D007700:Kinetics; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity
chemical_list: D004364:Pharmaceutical Preparations; D014874:Water Pollutants, Chemical