The optimal design and operation control, involving complicated hydraulics and biochemical process, of wastewater biologic treatment project is the frontier research field of current international water science and technology, but there is no generally accepted experiment method about sludge various sedimentation under different hydraulic conditions. Furthermore, the existing water environment modelling software can not simulate the multiphase flow and biological reaction under complex boundary conditions.Based on the image analysis technology, this paper developed a new experiment method and device for the measurement of sludge settling velocity, which is adapted to settling velocity measurement of scattered sludge or flocculated sludge under hydrostatic or turbulent hydraulic conditions.The 2-phase turbulence mixture model was used to discribe the hydraulic characteristics of 2-phase flow, sludge and wastewater. This hydraulic model was coupled with activated sludge model NO.2 (ASM2) to define a model of liquid and solid 2-phase turbulenc and biological recation. A simulation system was developed to model the 3-demention fileds of solid-liquid 2-phase flow and materials concentrations distribution in the reactor, where, Matlab 7.0 was used to to compile the modeling programs.A full-scale carrousel oxidation ditch wastewater treatment plant was investigated with this coupling model. A generalized likelihood uncertainty estimation (GLUE), combined with sensitivity analysis and Latin hypercube sampling (LHS), was used to calibrate the model parameters. The results shown that this calibration method can efficiently reduce the error between modeling values and measured values.
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