Modelling the Activated Sludge Flocculation Process Using Population Balance Model (PBM)

Abstract

This paper describes the application of population balance models to activated sludge flocculation process. It presents the development and selection of appropriate expressions for aggregation and breakage kinetics within the population balance framework to describe the evolution of mean size and steady state distribution of flocs under shear conditions. A size and velocity gradient dependent collision efficiency is introduced into the aggregation expression. In the model, only 2 parameters need to be estimated: collision efficiency coefficient and the breakage frequency coefficient. They are obtained by the “best fit” with the experimental data, and keep unchanged under different shear condition for the same flocs. The modelling results indicate that the population balance models coupled with suitable aggregation and breakage kinetics is appropriate for describing activated sludge flocculation dynamics.

Study on microstructure evolution of waxy crude oil emulsions under dynamic cooling conditions

“…49,53 Currently, there are primarily two prevailing models in the existing literature for quantifying the agglomeration efficiency of particles subsequent to collision: linear model and curve model. Among them, the linear model does not consider the van der Waals attraction between particles and the shear force of the ow eld on the particles, and the model thinks that the particles will denitely aggregate once they collide, 54 therefore, the calculation is oen greater than the actual value, and the accuracy is lacking. The curve model will comprehensively incorporate the van der Waals gravitational effect between particles and the shear effect of the ow eld on particles, thereby yielding calculation results that are more representative of reality.…”

Numerical Simulation Study on the Flow Field and Separation Efficiency by Built-In Twisted Tape in the Hydrocyclone

“…Based on relevant experiments, 37 the measured pressure drop was compared with the simulated pressure drop. Figure 5 shows the comparison curves of experimental values and numerical values under different conditions.…”