scholarly journals Understanding the coagulation mechanism and floc properties induced by Fe(VI) and FeCl3: population balance modeling

2021 ◽  
Author(s):  
Xinliang Liu ◽  
Hailiang Yin ◽  
Jian Zhao ◽  
Ziqi Guo ◽  
Zhen Liu ◽  
...  
Keyword(s):  
Practical Importance ◽  
Population Balance ◽  
Collision Efficiency ◽  
Population Balance Modeling ◽  
Floc Size ◽  
Coagulation Mechanism ◽  
Coagulation Kinetics ◽  
Floc Strength ◽  
Floc Properties ◽  
Positive Effect

Abstract Coagulation kinetics and floc properties are of great fundamental and practical importance in the field of water treatment. To investigate the performance of Fe(VI) and Fe(III) salt on particle coagulation, Malvern Mastersizer 2000 was employed to continuously and simultaneously monitor the kaolin floc size and structure change, and population balance modeling was used to investigate the coagulation mechanism. The results show dosage increase had positive effect on collision efficiency and floc strength and negative effect on restructure rate. Low shear rate resulted in higher collision efficiency and stronger floc. Low water temperature had a pronounced detrimental effect on coagulation kinetics. Temperature increase showed the most significant positive effect on collision efficiency, floc strength and restructure rate. The optimum pH zone for the coagulation was found to be between 6 and 8. Further pH increase lowered the collision efficiency and floc strength and increased the restructure rate. FeCl3 resulted in a larger ratio of the mass to volume of kaolin flocs (compactness) than those induced by ferrate.

scholarly journals Simulation of Floc Size Distribution in Flocculation of Activated Sludge Using Population Balance Model with Modified Expressions for the Aggregation and Breakage

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Zhenliang Li ◽  
Peili Lu ◽  
Daijun Zhang ◽  
Fuzhong Song
Keyword(s):  
Activated Sludge ◽  
Size Distribution ◽  
Velocity Gradient ◽  
Population Balance ◽  
Balance Model ◽  
Population Balance Model ◽  
Collision Efficiency ◽  
Volume Percentage ◽  
Floc Size ◽  
Breakage Rate

The floc size distribution of activated sludge was simulated successfully by population balance model in the previous study (Population Balance Model and Calibration Method for Simulating the Time Evolution of Floc Size Distribution of Activated Sludge Flocculation. Desalination and Water Treatment, 67, 41-50). However, nonignorable errors exist in the simulation for the volume percentage of large flocs. This paper describes the application of a modified population balance model in the simulation of the time evolution of floc size distribution in activated sludge flocculation process under shear-induced conditions. It was found that the application of modified size dependent collision efficiency, modified breakage rate expression by assuming a maximum value, and binominal daughter-particles distribution function could improve the population balance model for activated sludge flocculation and successfully predict the dynamic changes in volume percentage distribution and mean floc size of activated sludge under different shear conditions. The results demonstrate that the maximum breakage rate was independent on the velocity gradient, and both the collision efficiency and breakage rate coefficient show a power-law relationship with the average velocity gradient; the former decreases while the latter increases with the rise of the average velocity gradient. These findings would help to understand the dynamics of activated sludge flocculation.

Understanding the Precipitated Calcium Carbonate Flocculation Mechanism Induced by Starch through Population Balance Modeling

2011 ◽  
Vol 236-238 ◽  
pp. 1250-1255
Author(s):  
Yi Zhou Sang ◽  
Nayef M. Al Saifi ◽  
Peter Englezos
Keyword(s):  
Calcium Carbonate ◽  
Population Balance ◽  
Energy Dissipation Rate ◽  
Balance Model ◽  
Collision Efficiency ◽  
Precipitated Calcium Carbonate ◽  
Population Balance Modeling ◽  
Flocculation Mechanism ◽  
Effects Of Temperature ◽  
Breakage Mechanism

The precipitated calcium carbonate (PCC) flocculation kinetics and floc structures induced by cationic tapioca starch were recorded by the Malvern Mastersizer 2000 (Malvern Instruments Inc, Malvern, UK). Of particular interest, a population balance model for PCC flocculation was employed to extract the flocculation constants, namely collision efficiency, magnitude of energy dissipation rate and restructuring rate. The model made an attempt to take aggregation, breakage and flocs restructuring into account simultaneously to describe the PCC flocculation by aggregation and breakage mechanism. Through a response surface methodology (RSM) involving a central composite design, the effects of temperature, polymer dosage, ionic strength, and shear rate on flocculation parameters were investigated in this paper.

scholarly journals Modeling of Flocculation and Sedimentation Using Population Balance Equation

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Zhipeng Shi ◽  
Genguang Zhang ◽  
Yuzhuo Zhang ◽  
Tingting He ◽  
Guoliang Pei
Keyword(s):  
Settling Velocity ◽  
Population Balance ◽  
Nonlinear Process ◽  
Fine Sediment ◽  
Population Balance Modeling ◽  
Floc Size ◽  
Bed Topography ◽  
Computational Fluid Dynamics Cfd ◽  
Sediment Particles ◽  
Good Agreement

Flocculation is a special phenomenon for fine sediment or silt in reservoirs and estuaries. Flocculation usually results in changes of size, morphology, and settling velocity of sediment particles and finally changes of bed topography of reservoirs and estuaries. The process of flocculation and sedimentation was simulated based on population balance modeling (PBM) and computational fluid dynamics (CFD); the changes of particle or floc size and their settling velocities over time were examined. The results showed that flocculation is a dynamic and nonlinear process containing aggregation, breakage, reaggregation, and rebreakage between particles, microflocs, and macroflocs. Furthermore, the visual process of flocculation and sedimentation was directly created by the simulation results and is in good agreement with the results of the previous experiments.

scholarly journals Special Issue on “Recent Advances in Population Balance Modeling”

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 122
Author(s):  
Seyed Soheil Mansouri ◽  
Heiko Briesen ◽  
Krist V. Gernaey ◽  
Ingmar Nopens
Keyword(s):  
Population Balance ◽  
Special Issue ◽  
Modeling Framework ◽  
Population Balance Modeling ◽  
Recent Advances

Population Balance Modeling (PBM) is a powerful modeling framework that allows the prediction of the dynamics of distributed properties of a population of individuals at the mesoscale [...]

Modelling the activated sludge flocculation process combining laser light diffraction particle sizing and population balance modelling (PBM)

2002 ◽  
Vol 45 (6) ◽  
pp. 41-49 ◽  
Author(s):  
I. Nopens ◽  
C.A. Biggs ◽  
B. De Clercq ◽  
R. Govoreanu ◽  
B.-M. Wilén ◽  
...  
Keyword(s):  
Experimental Data ◽  
Laser Light ◽  
Population Balance ◽  
Light Diffraction ◽  
Balance Model ◽  
Floc Size ◽  
Shear Rates ◽  
Breakage Rate ◽  
On Line ◽  
Floc Size Distributions

A technique based on laser light diffraction is shown to be successful in collecting on-line experimental data. Time series of floc size distributions (FSD) under different shear rates (G) and calcium additions were collected. The steady state mass mean diameter decreased with increasing shear rate G and increased when calcium additions exceeded 8 mg/l. A so-called population balance model (PBM) was used to describe the experimental data. This kind of model describes both aggregation and breakage through birth and death terms. A discretised PBM was used since analytical solutions of the integro-partial differential equations are non-existing. Despite the complexity of the model, only 2 parameters need to be estimated: the aggregation rate and the breakage rate. The model seems, however, to lack flexibility. Also, the description of the floc size distribution (FSD) in time is not accurate.

Celebrating a milestone in Population Balance Modeling

2009 ◽  
Vol 64 (4) ◽  
pp. 627 ◽  
Author(s):  
Ingmar Nopens ◽  
Heiko Briesen ◽  
Joel Ducoste
Keyword(s):  
Population Balance ◽  
Population Balance Modeling

scholarly journals Population balance modeling of biopolymer production in cellular systems

2014 ◽  
Vol 47 (3) ◽  
pp. 1705-1710 ◽  
Author(s):  
Andre Franz ◽  
Robert Dürr ◽  
Achim Kienle
Keyword(s):  
Population Balance ◽  
Cellular Systems ◽  
Population Balance Modeling

Taylor series expansion scheme applied for solving population balance equation

2018 ◽  
Vol 34 (4) ◽  
pp. 561-594 ◽  
Author(s):  
Mingzhou Yu ◽  
Jianzhong Lin
Keyword(s):  
Series Expansion ◽  
Taylor Series ◽  
Numerical Study ◽  
Rapid Development ◽  
Taylor Series Expansion ◽  
Population Balance ◽  
Population Balance Modeling ◽  
Physicochemical Processes ◽  
Selection Of ◽  
Expansion Scheme

Abstract Population balance equations (PBE) are widely applied to describe many physicochemical processes such as nanoparticle synthesis, chemical processes for particulates, colloid gel, aerosol dynamics, and disease progression. The numerical study for solving the PBE, i.e. population balance modeling, is undergoing rapid development. In this review, the application of the Taylor series expansion scheme in solving the PBE was discussed. The theories, implement criteria, and applications are presented here in a universal form for ease of use. The aforementioned method is mathematically economical and applicable to the combination of fine-particle physicochemical processes and can be used to numerically and pseudo-analytically describe the time evolution of statistical parameters governed by the PBE. This article summarizes the principal details of the method and discusses its application to engineering problems. Four key issues relevant to this method, namely, the optimization of type of moment sequence, selection of Taylor series expansion point, optimization of an order of Taylor series expansion, and selection of terms for Taylor series expansion, are emphasized. The possible direction for the development of this method and its advantages and shortcomings are also discussed.

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