The influence of wind in secondary settling tanks for wastewater treatment—A computational fluid dynamics study. Part I: Circular secondary settling tanks

2020 ◽  
Vol 92 (4) ◽  
pp. 541-550 ◽  
Author(s):  
Haiwen Gao ◽  
Michael K. Stenstrom
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Secondary Settling

The Use of Computational Fluid Dynamics for Improving the Design and Operation of Water and Wastewater Treatment Plants

1999 ◽  
Vol 40 (4-5) ◽  
pp. 81-89 ◽  
Author(s):  
C. J. Brouckaert ◽  
C. A. Buckley
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Potable Water ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Outer Wall ◽  
Water And Wastewater Treatment ◽  
Secondary Clarifier

Computational Fluid Dynamics (CFD) studies of a secondary clarifier at Durban's Northern Wastewater Treatment Works, and of a clarifier at the potable water treatment plant at Umzinto, a small town near Durban, have been undertaken with a view to improving their load capacities. In both cases the units are located in relatively old treatment plants, which face continually increasing loads due to population growth. Increasing the capacity of existing equipment, rather than installing new equipment, constitutes an efficient use of development capital. Although the two clarifiers have considerable design differences, the CFD studies indicated remarkably similar circulating flows, which concentrate up-flow near the outer wall of the clarifier in the region of the clarified water overflow weirs. Baffles were designed to disrupt the circulation so as to distribute up-flow over a wider area, thereby reducing the maximum vertical velocities. In the case of the wastewater secondary clarifier, the modification has been implemented, and evaluated in comparative tests involving an otherwise identical unmodified clarifier. In the case of the potable water clarifier, the modification has still to be implemented.

Research Progress of Simulation on the Flow Field in Anaerobic Reactor

2014 ◽  
Vol 955-959 ◽  
pp. 2098-2101
Author(s):  
Qin Zhang ◽  
Qiang Li ◽  
Jia Tang
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Flow Field ◽  
Treatment Effect ◽  
Dynamics Simulation ◽  
Research Progress ◽  
Computational Fluid Dynamics Simulation ◽  
Anaerobic Reactor

The flow field in anaerobic reactor is very complex, but it has been given wide attention because of its important impact to wastewater treatment effect. It is often studied by numerical simulation. The paper explored the research progress of simulation on the flow field in anaerobic reactor by the summary of development of anaerobic reactor and principle and characteristics of computational fluid dynamics simulation and introduction of study and application status on numerical simulation. And then it gave its opinion on the development of simulation on the flow field in anaerobic reactor in future.

Modelling and simulation of the steady-state of secondary settlers in wastewater treatment plants

2001 ◽  
Vol 43 (7) ◽  
pp. 39-46 ◽  
Author(s):  
I. Queinnec ◽  
D. Dochain
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Steady State ◽  
Activated Sludge ◽  
Parameter Identification ◽  
Wastewater Treatment Plants ◽  
Operating Conditions ◽  
Sensitivity Studies ◽  
Activated Sludge Processes

This paper discusses the steady-state modelling of thickening in circular secondary settlers of activated sludge processes. The limitations of the solid flux theory basic models to represent steady-state operating conditions serve as a basis to introduce more sophisticated models derived from computational fluid dynamics. Parameter identification and sensitivity studies have been performed from lab-scale continuous experiments.

scholarly journals Improvement performance of secondary clarifiers by a computational fluid dynamics model

2011 ◽  
Vol 19 (4) ◽  
pp. 1-11 ◽  
Author(s):  
Ali Ghawi ◽  
J. Kriš
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Chemical Oxygen Demand ◽  
Biochemical Oxygen Demand ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Design Parameters ◽  
Dynamics Model ◽  
Computational Fluid Dynamics Model

Improvement performance of secondary clarifiers by a computational fluid dynamics model Secondary clarifier is one of the most commonly used unit operations in wastewater treatment plants. It is customarily designed to achieve the separation of solids from biologically treated effluents through the clarification of biological solids and the thickening of sludge. As treatment plants receive increasingly high wastewater flows, conventional sedimentation tanks suffer from overloading problems, which result in poor performance. Modification of inlet baffles through the use of an energy dissipating inlet (EDI) was proposed to enhance the performance in the circular clarifiers at the Al-Dewanyia wastewater treatment plant. A 3-dimensional fully mass conservative clarifier model, based on modern computational fluid dynamics theory, was applied to evaluate the proposed tank modification and to estimate the maximum capacity of the existing and modified clarifiers. A Computational Fluid Dynamics (CFD) model was formulated to describe the tank is performance, and design parameters were obtained based on the experimental results. The study revealed that velocity and (suspended solids) SS is a better parameter than TS (total solids), (Biochemical Oxygen Demand) BOD, (Chemical Oxygen Demand) COD to evaluate the performance of sedimentation tanks and that the removal efficiencies of the suspended solids, biochemical oxygen demand, and chemical oxygen demand were higher in the baffle.

Modelling of wastewater treatment plants – how far shall we go with sophisticated modelling tools?

2006 ◽  
Vol 53 (3) ◽  
pp. 79-89 ◽  
Author(s):  
G.C. Glover ◽  
C. Printemps ◽  
K. Essemiani ◽  
J. Meinhold
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Full Scale ◽  
Structure Identification ◽  
Oxidation Ditch ◽  
Computational Fluid Dynamics Analysis

Several levels of complexity are available for modelling of wastewater treatment plants. Modelling local effects rely on computational fluid dynamics (CFD) approaches whereas activated sludge models (ASM) represent the global methodology. By applying both modelling approaches to pilot plant and full scale systems, this paper evaluates the value of each method and especially their potential combination. Model structure identification for ASM is discussed based on a full-scale closed loop oxidation ditch modelling. It is illustrated how and for what circumstances information obtained via CFD (computational fluid dynamics) analysis, residence time distribution (RTD) and other experimental means can be used. Furthermore, CFD analysis of the multiphase flow mechanisms is employed to obtain a correct description of the oxygenation capacity of the system studied, including an easy implementation of this information in the classical ASM modelling (e.g. oxygen transfer). The combination of CFD and activated sludge modelling of wastewater treatment processes is applied to three reactor configurations, a perfectly mixed reactor, a pilot scale activated sludge basin (ASB) and a real scale ASB. The application of the biological models to the CFD model is validated against experimentation for the pilot scale ASB and against a classical global ASM model response. A first step in the evaluation of the potential of the combined CFD-ASM model is performed using a full scale oxidation ditch system as testing scenario.

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