A combined method to facilitate the high dispersion modeling for wastewater treatment bioreactors with closed boundaries

Abstract

Two tanks in series and axial dispersion models are used frequently for bioreactors flow regime modeling, especially the wastewater treatment reactors. Using the tanks in series model is simple, but the axial dispersion model is dependent on the boundary conditions. In case of high dispersion and closed boundaries, axial dispersion model will be a complicated method. In this paper by combination of tanks in series and axial dispersion models, a new simple model is presented to facilitate the axial dispersion solution for closed boundary condition. For the various studied Peclet numbers, the maximum peak concentration error is calculated by combined method equal to 3% in comparison with the error for open solution that increases progressively and exceeds 14%. Furthermore the combined model peak time errors are zero for all the Peclet numbers while are more than 10% for the open solution.