title: Removal of total and antibiotic resistant bacteria in advanced wastewater treatment by ozonation in combination with different filtering techniques.
abstract: Elimination of bacteria by ozonation in combination with charcoal or slow sand filtration for advanced sewage treatment to improve the quality of treated sewage and to reduce the potential risk for human health of receiving surface waters was investigated in pilot scale at the sewage treatment plant Eriskirch, Baden-Wuerttemberg/Germany. To determine the elimination of sewage bacteria, inflowing and leaving wastewater of different treatment processes was analysed in a culture-based approach for its content of Escherichia coli, enterococci and staphylococci and their resistance against selected antibiotics over a period of 17 month. For enterococci, single species and their antibiotic resistances were identified. In comparison to the established flocculation filtration at Eriskirch, ozonation plus charcoal or sand filtration (pilot-scale) reduced the concentrations of total and antibiotic resistant E. coli, enterococci and staphylococci. However, antibiotic resistant E. coli and staphylococci apparently survived ozone treatment better than antibiotic sensitive strains. Neither vancomycin resistant enterococci nor methicillin resistant Staphylococcus aureus (MRSA) were detected. The decreased percentage of antibiotic resistant enterococci after ozonation may be explained by a different ozone sensitivity of species: Enterococcus faecium and Enterococcus faecalis, which determined the resistance-level, seemed to be more sensitive for ozone than other Enterococcus-species. Overall, ozonation followed by charcoal or sand filtration led to 0.8-1.1 log-units less total and antibiotic resistant E. coli, enterococci and staphylococci, as compared to the respective concentrations in treated sewage by only flocculation filtration. Thus, advanced wastewater treatment by ozonation plus charcoal or sand filtration after common sewage treatment is an effective tool for further elimination of microorganisms from sewage before discharge in surface waters.
authors.affiliation: Institute for Lake Research, State Institute for the Environment, Measurements and Conservation in Baden Württemberg, Argenweg 50/1, 88085 Langenargen, Germany. Electronic address: frauke.lueddeke@lubw.bwl.de.
authors.forename: Frauke
authors.initials: F
authors.lastname: Lüddeke
authors.affiliation: Karlsruher Institute of Technology, KIT, Institute of Biology for Engineers and Biotechnology of Wastewater, Am Fasanengarten, 76131 Karlsruhe, Germany. Electronic address: stefanie.hess@kit.edu.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Heß
authors.affiliation: Faculty of Technology, Microbiology - Biotechnology, University of Applied Science Emden/Leer, Constantiaplatz 4, 26723 Emden, Germany. Electronic address: claudia.gallert@hs-emden-leer.de.
authors.forename: Claudia
authors.initials: C
authors.lastname: Gallert
authors.affiliation: Karlsruher Institute of Technology, KIT, Institute of Biology for Engineers and Biotechnology of Wastewater, Am Fasanengarten, 76131 Karlsruhe, Germany. Electronic address: Josef.winter@kit.edu.
authors.forename: Josef
authors.initials: J
authors.lastname: Winter
authors.affiliation: Institute for Lake Research, State Institute for the Environment, Measurements and Conservation in Baden Württemberg, Argenweg 50/1, 88085 Langenargen, Germany. Electronic address: hans.guede@lubw.bwl.de.
authors.forename: Hans
authors.initials: H
authors.lastname: Güde
authors.affiliation: Institute for Lake Research, State Institute for the Environment, Measurements and Conservation in Baden Württemberg, Argenweg 50/1, 88085 Langenargen, Germany. Electronic address: herbert.loeffler@lubw.bwl.de.
authors.forename: Herbert
authors.initials: H
authors.lastname: Löffler
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000302:isolation & purification*; D044822:Biodiversity; D015169:Colony Count, Microbial; D004352:Drug Resistance, Microbial / Q000187:drug effects; D016983:Enterococcus / Q000187:drug effects / Q000302:isolation & purification; D004926:Escherichia coli / Q000187:drug effects / Q000302:isolation & purification; D005374:Filtration / Q000379:methods*; D008826:Microbial Sensitivity Tests; D010126:Ozone / Q000494:pharmacology*; D010865:Pilot Projects; D012722:Sewage / Q000382:microbiology; D013210:Staphylococcus / Q000187:drug effects / Q000302:isolation & purification; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
chemical_list: D010126:Ozone; D012722:Sewage; D062065:Wastewater
keywords: Antibiotic resistance; Fecal indicator bacteria; Ozonation; Staphylococci; Wastewater treatment