Dynamic simulation of pilot thickener operation using phenomenological model with results validation for continuous and discontinuous tests
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The phenomenological theory of sedimentation-thickening processes predicts the settling behavior of a flocculated suspension in dependence of two functions, the batch flux density function and the effective solid stress. These functions were determined using batch settling tests. The governing equations for sedimentation were then solved numerically for these functions and the predictions were compared to the experimental results from pilot scale thickener tests. Firstly, the continuous tests were performed in the plexiglass pilot thickener at different feed flow rates and discharge rates and the solid volume fraction of discharge, the bed height and the time were recorded for each condition. These tests were also simulated and it was observed that there is a good agreement between the results of continuous tests and the results of dynamic simulation. Secondly, the discontinuous tests were performed in the plexiglass pilot thickener at different feed flow rates with a discharge rate of zero. The bed formation rate was determined for each condition. These tests were also simulated and it was observed that there is a good agreement between the results of discontinuous tests and the results of simulation.
Key wordsdynamic simulation dewatering thickener behavior pilot thickener validation
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- VITASOVIC Z Z. Continuous settler operation: A dynamic model [M]// PATRY G G, CHAPMAN D. Dynamic Modelling and Expert Systems in Wastewater Engineering. USA: Lewis, Chelsea, MI, 1989.Google Scholar
- VACCARI D A, UCHRIN C G. Modeling and simulation of compressive gravity thickening of activated sludge [J]. Journal of Environmental Science and Health A, 1989, 24(6): 645–674.Google Scholar
- OTTERPOHL R, FREUND M. Dynamic models for clarifiers of activated sludge plants with dry and wet weather flows [J]. Water Science and Technology, 1992, 26: 1391–1400.Google Scholar
- HARTEL L, POPEL H J. A dynamic secondary clarifier model including processes of sludge thickening [J]. Water Science and Technology, 1992, 25: 267–284.Google Scholar
- OZINSKY A E, EKAMA G A, REDDY B D. Mathematical simulation of dynamic behaviour of secondary settling tanks [R]. Technical Report W85. South Africa: Dept of Civil Engineering, University of Cape Town, 1994.Google Scholar
- BURGER R, BUSTOS M C, CONCHA F. Settling velocities of particulate systems: 9. Phenomenological theory of sedimentation processes: numerical simulation of the transient behavior of flocculated suspensions in an ideal batch or continuous thickener [J]. International Journal of Mineral Processing, 1999, 55(4): 267–282.CrossRefGoogle Scholar
- GLADMAN B R. The effect of shear on dewatering of flocculated suspensions [D]. Melbourne, Australia: Department of Chemical and Biomolecular Engineering, The University of Melbourne, 2005.Google Scholar
- BUSCALL R, WHITE L R. The consolidation of concentrated suspensions part 1. The theory of sedimentation [J]. Journal of the Chemical Society, 1987, 83: 873–891.Google Scholar