Sensor-fault tolerance in a wastewater treatment plant by means of ANFIS-based soft sensor and control reconfiguration

  • Carlos Alberto C. Belchior
  • Rui Alexandre M. Araújo
  • Francisco Alexandre A. Souza
  • Jorge Afonso C. Landeck
Original Article


This work presents a sensor-fault-tolerant design applied to a decentralized dissolved oxygen control in an activated sludge process subject to sensor faults such as bias and slow drifts. The core idea is to use a data-driven soft sensor based on adaptive neuro-fuzzy inference system to act as a backup of the joint sensor and controller block, and to exploit the data/analytical correlations existing in the system. After fault detection and isolation, a control reconfiguration technique takes action in order to surmount/counteract the effect of the fault until the faulty sensor is repaired. The approach presented here was applied to the Benchmark Simulation Model n.1 and was able to demonstrate the improvements on the control system dependability.


Sensor-fault-tolerant control Data-driven soft sensor ANFIS Activated sludge process Decentralized dissolved oxygen control 



The authors would like to thank Eng. Paulo Resende that is with Luságua, Serviços Ambientais S.A. for his insight about the wastewater treatment process. This work was supported by the Fundação para a Ciência e a Tecnologia (FCT), and ISA—Intelligent Sensing Anywhere, under Bolsa de Doutoramento em Empresa Fellowship SFRH/BDE/33295/2008.

Compliance with ethical standards

Conflict of interest

We declare that no conflict of interest exits in the submission of this manuscript, and the manuscript is approved by all authors for publication.


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Copyright information

© The Natural Computing Applications Forum 2017

Authors and Affiliations

  • Carlos Alberto C. Belchior
    • 1
  • Rui Alexandre M. Araújo
    • 1
  • Francisco Alexandre A. Souza
    • 1
  • Jorge Afonso C. Landeck
    • 2
  1. 1.Department of Electrical and Computer Engineering, ISR - Institute for Systems and RoboticsUniversity of CoimbraCoimbraPortugal
  2. 2.Instrumentation Center, Department of PhysicsUniversity of CoimbraCoimbraPortugal

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