Numerical Study of Input of Primary Settling Tanks in Circular Wastewater Treatment Plants with Flow-3D

Water scarcity is one of the main challenges and constraints in the development of the country. On the other hand, wastewater treatment methods were initially developed as a response to concern about public health and the conditions caused by wastewater disposal in the environment, but now with the expansion of cities and urban life, keeping the environment clean and protecting it is essential for social life. Therefore, the aim of the research is to minimize the cost, optimize and simulate the primary sedimentation tanks in wastewater treatment plants using Flow3D software. In addition to evaluating the accuracy of the model in the simulation, parameters affecting the ratio of inlet through the overflow to the inlet under the valve were determined. The results showed that The Les model had better result in simulating the setting cavitiy in circular-shaped treatment plant tanks in comparison to the other turbulence models. Comparing the effect of settling characteristic parameters on the maximum settling depth, it was concluded that the drag coefficient and static angle parameters had a great effect on the it. According to several simulations performed with Flow3D software, it was found that this software has good accuracy in simulating the flow pattern passing through the circular overflow-valve treatment plant in both solid bed and mobile bed modes. Also, by comparing the effect of deposition characteristic parameters on the maximum deposition depth, it can be seen that the parameters of drag coefficient and static angle have a great effect on the amount of deposition. Also, among different turbulence models, LES model has more acceptable results in simulation. The settling of the refinery tanks indicates a circular Spillway-valve shape.