CFD Application for Wastewater Treatment Plants (WWTP)
In a previous post, we considered how CFD can be of particular benefit to quickly and accurately predict free surface flows through basins and influent/discharge structures in wastewater treatment plants (WWTP). In this post, we provide another example in which a CFD simulation first identified the specific problem of a pump intake structure and then confirmed that a design modification would eliminate the problem.
An existing wetwell structure was being modified to accommodate four pumps, although only one or two would be installed initially. The wetwell had large diameter intake pipes at each end and four individual pump bays, but the strong inlet jets resulted in excessive cross-flow at the individual pump bays, as shown in the first figure. To eliminate the strong cross-flow, a stub-wall was placed along the entire length of the wetwell, behind the individual pump bays. As shown in the second figure, the addition of this simple wall structure caused the inlet jet to break-up and flow over the stub-wall—essentially creating an internal weir—thus eliminating the strong cross-flows in front of the pump bays.
In a future post, we will show how CFD was used to modify the weir sizes in a large influent channel with multiple inlet and outlet weirs.