Isabelle Liard was a student in water engineering at Université Laval doing an internship under the supervision of Prof Peter Vanrolleghem.

Because wastewater and activated sludge processes affect the oxygen mass balance, respirometry (measurements and interpretation of respiration rates) can be used to characterize these processes. Since the development of the "ultimate" hybrid respirometer concept in the 90s, many attempts have been made to build such a respirometer, but none have succeeded.

The project consisted in modelling an "ultimate" hybrid respirometer using WEST software (MOSTforWATER, Kortrijk, Belgium), and in optimizing the design and operation of the respirometer in preparation for a new implementation attempt enabled by the advent of a new type of dissolved oxygen sensors. A simple and automated methodology for data interpretation has also be developed.