Multicriteria control strategy for cost/quality compromise in Wastewater Treatment Plants

Abstract Because of their complex behavior, activated sludge processes are very difficult to control. A comparative study of control performances, based on modifications of the Benchmark reference control scheme, shows that these have limited effect on the treatment efficiency. For this reason, a new strategy has been studied: the choice of the manipulated and measured variables is based on a sensitivity analysis on an accurately reduced model. The effluent quality is strongly improved, though the global cost is increased. Finally, a multicriteria control strategy is proposed to decrease the global cost although keeping good performances with a Takagi–Sugeno fuzzy supervisor being developed in order to smooth the switching. As expected this strategy provides good performances, and in addition this control would be very simple to implement on a real process.

[1]  M. Lakrori.  Control of a Continuous Bioprocess by Simple Algorithms of "Ρ" and "L/A" Type , 1989 .

[2]  Stephen Yurkovich,et al.  Fuzzy Control , 1997 .

[3]  S. Weijers.  Modelling, identification and control of activated sludge plants for nitrogen removal , 2000 .

[4]  Edgar N. Sánchez,et al.  Hierarchical fuzzy control for a wastewater anaerobic treatment plant , 2001, 2001 IEEE International Conference on Systems, Man and Cybernetics. e-Systems and e-Man for Cybernetics in Cyberspace (Cat.No.01CH37236).

[5]  J. Alex,et al.  PREDICTIVE CONTROL OF NITROGEN REMOVAL IN WWTPS USING PARSIMONIOUS MODELS , 2002 .

[6]  P. Daoutidis,et al.  Nonlinear Dynamics and Control of Process Systems with Recycle , 2000 .

[7]  W. Gujer,et al.  Activated sludge model No. 3 , 1995 .

[8]  B Carlsson,et al.  Control of an activated sludge process with nitrogen removal--a benchmark study. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[9]  Jean-F. Beteau,et al.  Hierarchical fuzzy control of an activated sludge wastewater treatment plant , 2003, Proceedings of the 2003 American Control Conference, 2003..

[10]  M. N. Pons,et al.  Benchmark for evaluating control strategies in wastewater treatment plants , 1999, 1999 European Control Conference (ECC).

[11]  Jean-François Béteau,et al.  NEW CONTROL STRATEGY DESIGN TO IMPROVE EFFLUENT QUALITY IN WASTEWATER TREATMENT PLANTS , 2002 .

[12]  Sylvie Gillot,et al.  The COST Simulation Benchmark: Description and Simulator Manual , 2001 .

[13]  J. F. Beteau,et al.  Bioprocess Control: An Original Approach Taking into Account Some Bioprocess Constraints , 1991, 1991 American Control Conference.

[14]  Bengt Carlsson,et al.  Iterative design of a nitrate controller using an external carbon source in an activated sludge process , 1998 .

[15]  P A Vanrolleghem,et al.  On-line monitoring equipment for wastewater treatment processes: state of the art. , 2003, Water science and technology : a journal of the International Association on Water Pollution Research.

[16]  I. Takács.  A dynamic model of the clarification-thickening process , 1991 .