Effect Of Graphene Oxide Nanoparticles on the Performance of Aerobic Granular Sludge Treatment System

contrast, at 25 mg/L GO NPs, NH 4 -N concentration in the effluent increased marginally after 5.5 day and was 2.39 mg/L after 7 days. In the case of 75 and 95 mg/L GO NPs, the effluent ammonia concentration continuously increased to 13.41 and 21.75 mg/L. The addition of GO NPs showed similar effects on COD removal efficiency than in case of NH 4 -N removal. In contrast, GO NPs influenced negatively the phosphorus removal, even at low concentration. When the SWW contained 15 and 95 mg/L GO NPs, the PO 4 - P concentration was 3.42 and 6.38 mg/L. Similar observations were also reported, wherein ZnO and CuO NPs negatively influenced the phosphorus removal in case of AGS [6,7]. At 15, 25, and 35 mg/L GO NPs, the secretion of polysaccharide (PS) slightly decreased, whereas the concentration of protein (PN) increased considerably ( Figure 1 )