Bacterial community and system performance of an aerobic granular sludge reactor treating pharmaceutical wastewater

Pharmaceutical compounds are emerging environmental contaminants that have been detected in various environmental matrices [1]. Their occurrence has been widely reported in domestic and hospital wastewater treatment plants (WWTP) effluents where low removal rates are observed. Even at low levels, they can affect the composition of the microbial communities, and hence disturb the metabolic networks [2]. Aerobic granular sludge (AGS) has been successfully applied for the treatment of industrial and domestic wastewater and the implementation off AGS full-scale facilities has been growing worldwide [3]. The possibility to concomitantly remove carbon, nitrogen and phosphorous in a single unit is one of the attractive aspects of the AGS technology since it greatly reduces the plant footprint. Pharmaceuticals are often present in influent wastewaters, therefore knowledge on their effect on the main biological processes is needed to provide guidance for a stable operation. Moreover, as microorganisms within AGS are key players in removal processes, a better understanding of bacterial composition could be useful to improve wastewater treatment efficiency and to enlarge the knowledge on critical functional groups.