Several modifications with different construction costs were proposed to enhance the performance in large rectangular sedimentation tanks. A two-dimensional fully mass conservative sedimentation model, based on modern computational fluid dynamics theory, was applied to evaluate proposed tank modifications of the existing and modified sedimentation tanks. The usually unknown and difficult to be measured particle density is found by matching the theoretical to the easily measured experimental total settling efficiency. The proposed strategy is computationally much more efficient than the corresponding strategies used for the simulation of wastewater treatment. It is noteworthy that even small differences in the particle velocity can cause large changes in the percent of settled particles; in this work, the overall solids removal efficiency increased when using the modifications from 84.4 and 98.8%, leading to a reduction of the effluent solids concentration of approximately 85%. The comparison of model predicted results with the field data collected in tanks before and after modifications shows very good agreement.
A CFD methodology for the design of rectangular sedimentation tanks in potable water treatment plants
Ghawi A. Hadi, Jozef Kriš; A CFD methodology for the design of rectangular sedimentation tanks in potable water treatment plants. Journal of Water Supply: Research and Technology-Aqua 1 May 2009; 58 (3): 212–220. doi: https://doi.org/10.2166/aqua.2009.027
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