After 8 months of re-sourcing in the field of integrated urban wastewater modelling and control at DTU Environment as Otto Mønsted Guest Professor, Peter Vanrolleghem has moved South to the Basque country in Spain to increase his insights in the modelling of physico-chemical processes by working together with the researchers of the Environmental Engineering Department of CEIT, the Technical Research and Training Centre of Gipuzkoa in San Sebastian. During the last 4 months of his sabbatical he will collaborate with Eduardo Ayesa and Paloma Grau.