When he came to Université Laval, Pau was studying industrial engineering at the University of Girona, Spain. He was working on his thesis based on design of wastewater treatment plants.

His project was framed within the ongoing research "Optimising wastewater management during wet weather using an integrated model". He was in charge of developing a dynamic model of the sewer stretch between Saint-Sacrement and the Beauport WWTP (Quebec City). The overall goal of his project was to provide a wider knowledge of the particle sedimentation in the primary treatment in order to optimize the system in terms of pollution removal. Field experimental work in the laboratory was also conducted to characterize the particles before doing the dynamic simulation.