Control of anaerobic-anoxic-aerobic (A²/O) processes in wastewater treatment: a detailed review

ABSTRACT

This review paper describes different control applications for the A²/O process in sewage wastewater treatment plants. The contents elucidate the research carried out in the literature related to the design of different types of controllers for controlling different variables such as dissolved oxygen, nitrate, total suspended solids, ammonia, etc. that are responsible for the simultaneous removal of both nitrogen and phosphorus. A comprehensive analysis is carried out based on the important factors for the implementation of the control systems with critical discussion and achievements. Control strategies range from simple controllers such as proportional–integral (PI) to the latest (advanced) control approaches such as model-based predictive, fuzzy logic, artificial neural network, and optimal controllers. A distributed control system applied to the A²/O pilot plant is also elucidated. A summary of comparisons between different control systems are assessed and reported in this review.

GRAPHICAL ABSTRACT

KEYWORDS:

• controller design
• nitrogen and phosphorus
• wastewater treatment plant
• A²O process

Data Availability Statement

Data sharing is not applicable to this article as no new data were created or analysed in this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Abdul Gaffar Sheik

Dr. Abdul Gaffar Sheik completed his Ph.D in Chemical Engineering from the Department of Chemical Engineering, NIT Warangal, India, in 2022. There after he is presently working as a Postdoctoral Researcher at Institute for Water and Wastewater Technology, DUT Durban, South Africa. His research interests include wastewater treatment plants modelling and control, water quality estimation, and applications of artificial intelligence in the water sectors. He is a member of international Water Association (IWA). He published more than 14 papers and two book chapters in leading SCI-indexed journals and international conferences.

E.S.S. Tejaswini

Dr. E. S. S. Tejaswini received her doctoral degree from National Institute of Technology, Warangal, India. She worked towards the development of advanced control strategies for biological wastewater treatment plants for improved operability. Her research interests include process control, monitoring, wastewater treatment, artificial intelligence and machine learning applications. She is a Young Water Professional of International Water Association (IWA).

Murali Mohan Seepana

Dr. Murali Mohan Seepana is currently working as an Associate Professor in the Department of Chemical Engineering, National Institute of Technology, Warangal, India. He has over nine years of teaching and research experience. His research areas include Energy Storage & Energy Conversion Technologies, Wastewater treatment and Membrane separations. He has published more than 25 SCI-indexed journal papers. He is an active researcher and has two ongoing international collaborative projects.

Seshagiri Rao Ambati

Dr. Seshagiri Rao Ambati is a Professor at Department of Chemical Engineering, Indian Institute of Petroleum and Energy, Visakhapatnam, India. Prior to this, he worked at National Institute of Technology, Warangal, India. His research interests include Process Control, Wastewater Treatment, Hybrid Energy Systems. He has over 90 publications in peer reviewed journals. His research group carried out many funded research projects which includes Indo-European, India-Canada projects.