Development and Application of Smoothed Particle Hydrodynamics for Wastewater Treatment and Water Management

The application of computational fluid dynamics methods plays a major role in design and operation of wastewater treatment (WWT) and water management (WM) facilities. With traditional Eulerian methods like the finite volume method (FVM), the solution of pollutant transport problems and multiphase flows can be challenging and extensions e.g. to track the phase interface are required. As an alternative, the meshless fully Lagrangian smoothed particle hydrodynamics (SPH) method, firstly introduced by Gingold and Monaghan (1977), is recommended. SPH solves the Lagrangian form of the Navier-Stokes equations and replaces the fluid with a set of particles, which act as interpolation points for the calculation of fluid properties. SPH has been widely applied in fluid mechanics with a particular focus on multiphase flows, since the particle-based description allows for a natural description of multiple phases. The first-time application of SPH in WWT was announced at the 2015 IAHR world congress (Meister et al., 2015) and since then the method was developed further to integrate hydrodynamics and pollutant transport (Meister et al., 2017).

The latest developments of SPH for applications in WWT and WM shall be presented at the 2019 IAHR world congress. The simulation capabilities are demonstrated on the example of 3 representative test cases. The sample applications are chosen to discuss the advantages and disadvantages of the meshless SPH method in comparison with the mesh-based FVM. Firstly, pollutant transport and degradation in free surface flows are investigated. This test case provides an insight into the description of surface dynamics and flow dependent transport processes. The second test case is a multiphase dam-break flow to demonstrate the SPH method’s strength in the simulation of highly violent impact flows. As a third example a WWT or WM facility with air-water two-phase flow is studied in detail. In addition to the identification of methodical differences, the aim of the paper is to develop decision criteria to support researchers and engineers in choosing the method which best suits their application. Decision criteria include fidelity and robustness as well as the computational performance for GPU-accelerated simulations.

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MeisterM.,WinklerD.,RezavandM.,RauchW.(2017).Integrating hydrodynamics and biokinetics in wastewater treatment modelling by using smoothed particle hydrodynamics.Comput.Chem.Eng.,99,1–12.