Estimation of oxygen uptake rate in an activated sludge reactor using Kalman filter and PWM control of the dissolved oxygen concentration.
Oxygen uptake rate, activated sludge, dissolved oxygen, Kalman filter, PWM control,
wastewater treatment.
The availability of real-time information about the biological activity is a valuable
matter in wastewater treatment employing activated sludge processes, and this is
represented by the oxygen uptake rate (OUR). In these processes, the OUR has been
used as a fast indicator of changes in waste influent organic load or inflow of toxic
organic compounds that could adversely affect the process. Furthermore, it can be used
for monitoring of the quality and efficiency of the process and for system control. 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. The objective of this work is to proposed a method for OUR
estimation by using the Kalman filter and PWM control of the dissolved oxygen
concentration in an activated sludge reactor. The proposed method presents a shorter
response time and a lower measurement uncertainty when compared to the standard
online procedure and a similar method, respectively. 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.