Computational fluid dynamics (CFD) in the wastewater treatment sector

Computational Fluid Dynamics, or CFD, is a discipline of engineering that deals with modelling, simulating and analysing mainly the so-called thermofluidodynamic phenomena: these involve the motion of fluids, heat transfer and many other phenomena.

Thanks to CFD, engineers and researchers can study the behaviour of fluids in a precise and detailed way, predicting the performance of a system and optimising its operation.

The main objective of CFD is to predict the behaviour of fluids under different conditions, such as flow velocity, pressure, temperature, concentration distribution of a dissolved substance, turbulence and vortex formation.

CFD uses a combination of physics, mathematics, computer science, and numerical simulation techniques to solve differential equations that describe the behaviour of fluids.

The equations that govern the motion of fluids are the Navier-Stokes equations, which describe the behaviour of a viscous fluid in a force field.

To solve the equations, the CFD uses a set of numerical methods, discretising a three-dimensional domain of the problem into a grid of points or cells: this is called a mesh and represents the computational fluid domain in which the problem is solved.

The numerical resolution of the Navier-Stokes equations is then obtained by using numerical analysis, iteration algorithms, and numerical approximation, such as the finite difference method, the finite element method, or the finite volume method.

In particular, for SCM, CFD is a fundamental tool to improve the efficiency of its systems, optimising the profiles of the most complex propellers and hydraulics.

Through the numerical analysis of the flows, it is possible to study the dynamics of the fluids inside the machines, identifying the areas in which turbulence or separation of the flowsoccur.

Thanks to this information, it is possible to improve the design of propellers and hydraulics, increasing their efficiency and reducing their energy consumption.

The implementation of the CFD, therefore, allows SCM to offer its customers increasingly efficient and performing machines, able to meet every need and demand.

Thanks to computational fluid dynamics, SCM can always be at the forefront of technological innovation and the improvement of its products.

Computational fluid dynamics (CFD) in optimal water treatment

Wastewater purification is a crucial process that involves the removal of pollutants, such as pathogens, nutrients and organics, before it is released into the environment.

Computational fluid dynamics (CFD) is becoming increasingly important in the water treatment sector; in fact, engineers can design, analyse and optimise purification plants, improve the efficiency of the purification process, reduce the design and management costs of plants, and minimise the environmental impact of plants.

The wastewater purification process involves a number of physical, chemical and biological processes, such as sedimentation, filtration, disinfection and biodegradation.

CFDs can be used to simulate the flow of wastewater within the sewage treatment plant, improving understanding of reactor behaviour and identifying areas where action is needed to improve performance.

In particular, CFD is used for the design and optimisation of biological reactors, which are the heart of wastewater treatment plants.

Biological reactors are tanks in which bacteria degrade the organic matter present in the water, transforming it into inorganic substances.

The CFD allows the flow of water within the biological reactor and the diffusion of nutrients and degradation productsto be modelled, allowing engineers to understand the behaviour of the reactor and to identify areas where action is needed to improve its performance.

 

The Role of Computational Fluid Dynamics in Aeration Systems, Sedimentators, Biological Filters, Oxidation Reactors and Mixing Systems

Computational fluid dynamics is also used to:

• optimise the aeration systems, which provide the necessary oxygen to the bacteria present in the biological reactor to degrade the organic matter. By modelling the flow of air within the biological reactor, CFD helps engineers understand how air is distributed within the reactor and identify areas where action is needed to improve its distribution.
• to assess the flow distribution and speed of solid particles within settlers, used to separate solids from wastewater;
• design and optimise biological filters that are used to remove organic substances and nutrients from wastewater through biodegradation;
• for the study of air flow within oxidation reactors used to remove organic substances from wastewater through chemical oxidation. The simulation of the air flow inside the reactor allows to optimise the distribution of air and the dispersion of pollutants;
• for the design and optimisation of mixing systems, which are used to keep the contents of the biological reactor homogeneous. By modelling the flow of water within the biological reactor, CFD helps engineers identify areas where action is needed to improve flow distribution and mixing.