摘要：Oxidation ditch reactor is wastewater treatment unit that based on activated sludge process. Water flow characteristic inside reactor is either completely-mixed reactor or plug flow reactor. Water flow characterization plays important role in wastewater treatment process. To ensure the biological process going well, the water flow in reactor must be completely mixed type. Characterization study of water flow in reactor consume time thus financial, so the simulation using CFD (Computational Fluid Dynamics) becomes a good solution. Based on the calibrated model, the CFD simulation was generate to define the water flow characteristic of the oxidation ditch reactor in longitudinal section. The simulation was conducted using VoF (Volume of Fluid) scheme, an open surface model in unsteady flow with k-ε turbulence model. The simulation result shows that water flow inside the oxidation ditch reactor was plug flow. The role of aeration system is to increase water flow to be more homogen, indicated by higher effective volume inside the reactor. The simulation result shows that the aerator could increase effective volume inside the reactor from 32,94% into 55,5%. The higher effective volume means dead zone inside the reactor is reduced.
