Dissolved oxygen regulation by logarithmic/antilogarithmic control to improve a wastewater treatment process

Abstract

This paper presents the automation of a real activated sludge wastewater treatment plant, which is located at San Antonio Ajijic in Jalisco, Mexico. The main objective is to create an on-line automatic supervision system, and to regulate the dissolved oxygen concentration in order to improve the performances of the process treating municipal wastewater. An approximate mathematical model is determined in order to evaluate via simulations different control strategies: proportional integral (PI), fuzzy PI and PI Logarithm/Antilogarithm (PI L/A). The controlled variable is dissolved oxygen and the control input is the injected oxygen. Based on this evaluation, the PI L/A controller is selected to be implemented in the real process. After that, the implementation, testing and fully operation of the plant automation are described. With this system, the considered wastewater treatment plant save energy and improves the effluent quality; also, the process monitoring is done online and it is easily operated by the plant users.

Design and evaluation of advanced automatic control strategies in a total nitrogen removal activated sludge plant

“…Holenda et al (2008) proposed an MPC controller for DO control. Flores et al (2013) implemented PI logarithmic/anti-logarithmic control for maintaining DO concentration on a realtime activated sludge WWTP by developing an online automatic supervision system. This system consists of sensors, data acquisition and programmable logic controller which plays key role in carrying out the logic calculations and complete automation of the process.…”

Energy benchmarking in wastewater treatment plants: the importance of site operation and layout

“…Email: a.soares@cranfield.ac.uk ifications (power and usage time), [4] power loggers [5] and modelling. [6][7][8] In Europe, the methodologies adopted vary from country to country, with the first energy benchmark manual being developed in Switzerland and later being adopted in Germany and Austria. [9] The limitations of this methodology are related to the need to compare similar wastewater pollutant loads at the influent, including carbon to nitrogen ratios, and effluent consents, that might vary between geographical regions and therefore can be of limited use when comparing sites in different locations.…”