A MATHEMATICAL MODEL OF BIOLOGICAL WASTEWATER TREATMENT CONSIDERING HYDRODYNAMIC AND NON-STATIONARY CONDITIONS
The paper deals with mathematical descriptions of hydrodynamic structures of aeration tank flow (mixing, plug flow, plug flow with internal recirculation circuit) together with the ASM 1 kinetic model. To solve the problem using a numerical method the authors propose a system of second order differential equations of matter change in non-stationary conditions, which takes into account mass balance. The essence of equations is in using an analytical diffusion model instead of the traditional “cell” or “section” one for the simultaneous solution with the system of differential equations describing transformations of substances (sorption, oxidation, hydrolysis, growth and decay).