ANALYSIS OF MASS TRANSFER PROCESSES BASED ON NUMERICAL MODELS

Problem statement. Aeration tanks and settling tanks are most commonly used in wastewater treatment processes. An important problem is the development of effective specialized mathematical models for analyzing the efficiency of these wastewater treatment facilities. The purpose of the article. Development of numerical models for calculating mass transfer processes in biological reactors and settling tanks of wastewater systems. Methodology. To describe the processes of mechanical and biological wastewater treatment, fundamental equations of continuum mechanics are used. To model the process of activated sludge, oxygen and substrate transport in a biological reactor, three-dimensional mass transfer equations are used. To describe the movement of a pollutant in a settling tank, a 3D equation of convective-diffusion transport of a significant conservative impurity is used. Hydrodynamics in treatment plants is described by the spatial Laplace equation for the velocity potential. Finite-difference schemes are used for numerical integration of the modeling equations. Scientific novelty. The article considers numerical models for determining the concentration of oxygen, activated sludge, substrate in a bioreactor. Numerical models are proposed for analyzing the efficiency of the wastewater treatment process in settling tanks. Numerical models are built for determining the field of wastewater flow velocity in bioreactors and settling tanks. The proposed mathematical models can be used to assess the efficiency of structures that carry out mechanical and biological wastewater treatment. Practical significance. Numerical models for determining the velocity field in aeration tanks and settling tanks, as well as numerical models for solving problems of assessing the efficiency of wastewater treatment in these structures, are proposed. The developed numerical models allow for quick, on-line, solution of applied problems. Conclusions. The developed numerical model has been implemented in software. The results of the computational experiment are presented.