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Steady Analysis of Clarifier Peclet Number Model and Establishment of Dispersed Peclet Number Model

Congress: 2008
Author(s): WEI Anlei, ZENG Guangming; HUANG Guohe
College of Environmental Science & Engineering Hunan University, Changsha 410082, Hunan, China

Keyword(s): clarifiers, wastewater treatment, mathematical model, Peclet number, steady numerical analysis, sweage sludge concentration
AbstractBased on the Peclet (Pe) number mathematical model of clarifiers, the steady results of simulation with one Pe number were analyzed, and the sensitivity of Pe number for the Pe model was further analyzed. Then dispersed Pe number model was established and tested. Sludge blanket height was categorized as for types with the range of height. When the loading conditions changed toward high loading with high Pe number, the changes of SBH type would become sharp, but when with low Pe number, the trend of the changes of SBH type would be flat. Even in the same loading condition, there would be different distributions of sweage sludge concentration in the clarifier when the mathematical model was in computer simulation with different Pe numbers. It was obvious that the Pe number play an important role on clarifier Pe number model. Thus the paper put up the dispersed Pe number model based on the partial chemical potential theory. This model assigned a Pe formula which could give a particular Pe value to every layer when the model was solved with finite difference method. The dispersed Pe model were tested with measured data of sludge concentration under three loading conditions of a full sacle clarifier, with SSRE as 0.14, 0.90, 2.37 respectively, which revealed reasonable results of computer simulations. Comparisons between the new model and former models under the same background also shew the excellent qualities of the dispersed Pe number model. All of the above indicate that the dispersed Pe number model would be helpful for the optimizations of wastewater treatment processes and online control.
2011 IWRA - International Water Resources Association - - Admin