Adaptive Model of Wastewater Aeration Tank

The paper discusses the methodology of oxygen transfer virtual simulation in a wastewater biological treatment process, using the MATLAB/SIMULINK technology. A self-tuning adaptive model of a wastewater aeration tank, as a non-stationary object, with variable time dependent sensitivity and inertia indexes, as the functions of input variable - air pneumatic supply capacity L_g(t) (m³/min), output variable - dissolved oxygen concentration C(t) (g/m³) and oxygen expenditure, as a load - q(t) (g/min), required for wastewater complete purification, is expounded. Virtual models, applying Laplace transforms and SIMULINK blocks library, are composed in order to compare the transient processes of dissolved oxygen concentration in the simplified stationary model with constant sensitivity and inertia coefficients, and in the non-stationary model with variable sensitivity and inertia indexes. The simulation block-diagram for non-stationary model adoption to the variable parameters is developed, using informative links from input variable L_g(t), from variable load q(t) and feedback from output variable C(t) as inputs of calculation modulus, allowing to instantly re-calculate the variable indexes during simulation time. Comparison of the simplified stationary model and the non-stationary model shows that the simulation results of oxygen transfer differ up to 50%.