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 …