Water Resources Research Act Program

Details for Project ID 2018FL333B

Computational fluid dynamics as a tool for urban water sediment transport and fate during clarification

Institute: Florida
Year Established: 2018 Start Date: 2018-03-01 End Date: 2019-02-28
Total Federal Funds: $16,000 Total Non-Federal Funds: $32,000

Principal Investigators: John Sansalone

Abstract: A primary and historical consideration of urban drainage (whether rainfall-runoff, wastewater and combined sewer overflows, CSOs) unit operation behavior is the transport/fate (control) of particulate matter (PM). This consideration has a strong foundation given that PM is the primary source and sink for chemicals (metal elements, organics, nutrients), the primary habitat as well as vehicle for pathogens, and PM has a significant role in reducing disinfection efficacy. However the control of PM is challenging; in part due to the hetero-disperse and temporally variable size gradation, complex geometries of many unit operations and highly variable and episodic flow rates. The clarification and management of PM has led to a spectrum of unit operations from fine particulate and pathogen filtration, to hydrodynamic separation (HS) for coarse particulate and gross detritus separation that do not provide hydrologic control, to large clarification systems such as wet or dry storage systems that provide a much wider clarification response and potential hydrologic control. The objective of this study is to apply the principles of computational fluid dynamics (CFD) to demonstrate the PM transport/fate of a clarification system subject to dilute multiphase flows (< 2% PM), typical of urban drainage. For many disciplines such as mechanical and chemical engineering, CFD has been used for decades, but is relative new to the field of water resources and water treatment despite the understanding that existing models of transport/fate are not robust for complex urban water loadings. In this study a CFD model will be developed and applied to illustrate PM transport/fate for clarification that is otherwise difficult, at best, for conventional analytical models. In this study CFD will be applied to demonstrate the potential as an analysis and visualization tool for forecasting urban drainage unit operation clarification behavior. In the proposed CFD methodology, a standard turbulence model will be used to resolve flow, and a discrete phase model (DPM) based on characterization of the particle size distribution (PSD) will be utilized to examine PM clarification response. A unique aspect of what is proposed is the coupling of the continuous and discrete phases in CFD to resolve the transport/fate of particles across the entire PSD.