Estimação da taxa de consumo de oxigênio com filtro de Kalman e acionamento PWM da aeração em sistemas de lodo ativado

Abstract

The oxygen uptake rate (OUR) is a key variable in activated sludge processes for the biological wastewater treatment. It has been used to model and optimize the process; to monitor the quality and efficiency of the treatment; to indicate toxic elements in the treatment units and to activate alarms; among other applications. The OUR is usually measured by using respirometers, devices based on some technique to measure the rate at which the activated sludge consumes the dissolved oxygen (DO) available in the liquid. In these systems, the DO concentration must be controlled to ensure an adequate level of oxygen to the microorganisms and to avoid energy waste. The objective of this work is to propose and implement a method for the estimation of the OUR, while the DO concentration is maintained around a constant reference value by using aquarium air pumps driven by a PWM control signal. Numerical simulations and experiments conducted in a laboratory scale activated sludge reactor are used to evaluate the proposed method and the results confirm its validity.