Municipal and Industrial Water Systems

circular clarifier FLOW-3D CFD simulation

Calculated flow patterns in
a circular clarifier with and
without Stamford baffle
(Analysis: Blue Hill Hydraulics)

In the water & wastewater industries, FLOW-3D is used to design pump stations, treatment plant headworks, primary settling tanks, combined sewer overflows, filter systems, and more.

CFD Municipal Projects

FLOW-3D has been used extensively to aid in the design of upgrades to existing treatment facilities and to design innovative new facilities. For example, FLOW-3D was used to improve the overall design of a wastewater treatment facility in the Bangkok Metropolitan Area. Other work has also been carried out for the DC Water and Sewer Authority and the Passaic Valley Sewerage Commissioners.

FLOW-3D has been used to simulate transient flow conditions in secondary clarifiers to better understand how upstream effects change their performance and to confirm the procedures used to design Stamford baffles.

Using FLOW-3D to Improve Clarifier Performance

FLOW-3D Simulation Helps Prevent Nitrification of Water Storage Reservoir
Read more in our Water and Environmental Engineering Tech Papers

Settling tank performance depends
on uniform flow balance. The results
of this FLOW-3D simulation indicate
residual short-circuiting (Analysis:
Blue Hill Hydraulics)

water storage tank CFD simulation

2D view of water storage tank, flow
colored by disinfectant concentration
(Analysis: Inca Engineering)

reservoir design CFD example

FLOW-3D can help evaluate
storage reservoir circulation.
(Analysis: Blue Hill Hydraulics)

FLOW-3D can be used to study
turbulent mixing and transport.
(Analysis: Blue Hill Hydraulics)

Shear velocity distribution along
feeding tunnel and distributor.

Settling Tanks

Effective separation of solids in settling tanks can require the use of baffles to slow and distribute flow, thus providing the best use of the treatment volume within a tank. If the tank is open to the environment, high winds can generate strong currents that can re-suspend solids and reduce the tank’s capture efficiency. FLOW-3D has the ability to simulate the flow through the tank as it is affected by its shape, the settling of solids and the effects of wind on the water’s surface.

Sediment & Erosion

Sediment transport and deposition are important processes that must be considered in the successful design of treatment facilities. FLOW-3D’s sediment scour model accounts for the erosion of settled material, its re-suspension and transport. In addition to this, FLOW-3D will automatically change the computed region to account for the changing shape of the domain due to deposition or erosion.

Purification

Water storage reservoir systems using chloramines as disinfectants must avoid dead spots in reservoirs so that the disinfectant does not break down into nitrites and nitrates, which encourage the growth of bacteria. FLOW-3D has been used by cities to optimize the mixing systems so that the potential for such dead spots is minimized.

Clearwells

FLOW-3D is an effective, efficient tool which has been used extensively to assist in the design of contact tanks. Complex inlet designs and unusual tank configurations can be modeled in three-dimensions and FLOW-3D can be used to compute Residence Time Distribution curves (RTD or break-through curves), which can be used to assess residence time parameters and to estimate the residual levels of disinfection chemicals required to meet consumer protection standards.

Reservoir Design

Numerical “dye testing” with FLOW-3D can help evaluate the performance of proposed reservoir designs and the degree of enhancement to be expected from modifications made to existing reservoirs.

Diffusers

Diffuser performance is affected by near-field flow patterns and their interaction with diffuser flows. FLOW-3D can be used to study near-field mixing and far-field transport problems. Analyses with FLOW-3D can account for temperature related buoyancy and turbulent mixing.

Grit Chambers

Non-uniform distribution of grit among tanks can have an adverse impact on performance of grit chambers within water reclamation plants. FLOW-3D can be used to study the hydrodynamics of the distribution system and improve the balance of flows to maximize plant performance.