Bounds estimations for uncertain models of wastewater treatment

Deals with the design of observers for wastewater treatment plants. The objective is to develop estimators under some uncertainty constraints. An activated sludge model is presented with three variables. We suppose that the substrate concentration is measured, and estimate the biomasses. We assume that the growth rate is unknown. The organic concentration in the influent is supposed only known to be within upper and lower varying bounds. Then we build an interval observer, giving sure bounds on the unmeasured variables. By including knowledge of the growth rate, we show how the convergence rate can be improved.