This study aims to increase the organic carbon, nitrogen and phosphorus removal efficiencies than the conventional method and meet higher effluent water quality standards by co-culture with bacteria in activated sludge in the aeration tank. By the co-culture in mixotrophic conditions through metabolic characterization of Scenedesmus dimorphus and bacteria in the aeration activated sludge, assessed how the impact on the organic matter, nitrogen and phosphorus removal rate. In addition, the study was to determine if it is possible to supply the oxygen necessary for the bacteria through the photosynthesis of algae without aeration. To test the synergistic effects of the co-culture, we compared co culture with S. dimorphus - only, Bacteria - only as a controls. In the co-culture condition inoculation ratio is based on the TSS concentration S. dimorphus and bacteria 1 : 5 (w / w), 5 : 5 (w / w) at a ratio. The growth rate of S. dimorphus - only condition was higher, which was 10 times and 2 times lower compared to B : A (5 : 1), B : A (5 : 5) respectively. Organic carbon removal rate of S. dimorphus - only condition was lower than other conditions, the remaining conditions were consumed at a similar rate. In the co-culture of Mixed bacteria and S. dimorphus, ammonium and phosphate removal rate has been high. But, nitrate removal rate showed a tendency to decrease compared to the Bacteria-only condition. When considering the Ammonium, nitrate and phosphate removal rate, N, P removal efficiency which is most excellent in terms of bacteria, such as S. dimorphus ratio (5 : 5) were co-cultured in the conditions. DO was maintained at 3 mg/L or more under all conditions. So, implying co-culture has the potential to decrease aeration costs.