e impact on nutrient removal performance) The functioning of ac

e. impact on nutrient removal performance). The functioning of activated sludge under a pandemic scenario is of

concern, given the projected heavy usage of not only antivirals but also antibiotics (Singer et al., 2008, unpublished data). There is recent evidence that bacterial neuraminidases are important in biofilm formation (Soong et al., 2006; Parker et al., 2009). Consequently, antiviral neuramindase inhibitors themselves may inhibit bacterial neuraminidases, which could prove detrimental to the structure of the suspended biofilms that make up activated sludge. While this is yet to Ganetespib cost be fully investigated, current data indicate that the ecotoxicological risks posed by OC are low (Straub, 2009). In addition to examining the potential evolution of OC degradation in a microbial consortium, we aimed to investigate the effects of OC and antibiotics on activated sludge bacterial community structure and function and activated sludge biofilm structure. We implemented a 56-day,

pandemic-scenario dosing regime of OC and three antibiotics (with different modes of action): amoxicillin (cell-wall-synthesis inhibition), erythromycin (protein-synthesis inhibition) and levofloxacin (DNA-replication inhibition), in a laboratory-scale sequencing batch reactor (SBR) operated for granular enhanced biological phosphorus removal (EBPR). The buy PD-0332991 three antibiotics selected for this study are among the most frequently used antibiotics, within their class, for the treatment

of influenza-associated bacterial pneumonia (Lim et al., 2007). An additional high-OC dosing period without antibiotics was used to examine OC toxicity and WWTP function in the absence of the presumed antibiotic stress. A laboratory-scale Pyruvate dehydrogenase SBR had a working volume of 8 L, with 2 L of treated wastewater removed and replaced with synthetic influent wastewater every 6 h, resulting in a HRT of 24 h. The sludge age was approximately 24 days. The synthetic influent wastewater contained either acetate or propionate as the sole carbon source (alternated on a fortnightly basis; Lu et al., 2006) and orthophosphate (P-PO43−) at concentrations of approximately 1100 mg chemical oxygen demand (COD) L−1 and 23 mg P-PO43− L−1, respectively (see Supporting Information for further details). The SBR was operated for EBPR, an activated sludge process for removing phosphate from wastewater. It is appropriate to investigate because it is commonly used in full-scale WWTPs and the bacterial community and biochemical transformations involved are well characterized (Seviour et al., 2003). The current study used granular activated sludge as the reactor biomass. This is a novel activated sludge technology that selects for aggregates (>200 μm) that are larger than those occurring in conventional floccular activated sludge (de Kreuk et al., 2007).

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