News + Publications

In a series of previous posts, we highlighted the benefits of CFD as applied to the design of new wastewater treatment plants (WWTP) or the expansion of existing ones. When planning for retrofits, or making in-situ modifications to a plant, relatively normal operation needs to be maintained. For such instances, CFD predictions of various scenarios with or without temporary installations can be used to predict the continued smooth operation of the plant.

One such occurrence was for an operating plant with seven treatment basins for which partition walls between cells of the basins needed to be altered. The plan was to take two basins off-line at a time and continue operation with five basins, however the flow to the remaining five basins had to be evenly distributed. This required temporary adjustments to the intake weirs of the remaining five basins which were all connected to a common influent channel. Using CFD modeling, the flow through the remaining basins was modeled as well as the required changes to the formerly off-line basins once the new partition walls were installed in those and they were put back in use when the other basin partition walls were being retrofitted. Because the modifications to the basin partition walls changed the resistance through those basins, a series of simulations with both modified and un-modified basins in service were also conducted—to ensure continued balanced flow through the plant. Once all basin partition walls had been modified, the resistance through all the basins was again the same, so the original weirs could be re-installed, and normal operation of the plant resumed.

This illustrates once again the utility of CFD predictions in the water flow analysis for a wide range of applications, including the determination of plant operation sequences when modifications need to be made to existing infrastructure, but relatively normal plant operation needs to be maintained while the alterations are proceeding.