Brenda Vidal, Stormwater&Sewers at Luleå University of Technology, visited Professor Sylvie Barraud at INSA National Institute of Applied Sciences of Lyon, France, for five weeks in spring 2018. Sylvie has a long experience of working with multi-criteria analysis of water solutions and especially the ELECTRE III method. The method was developed in France in the 1960s and has been used to a large extent by the urban water sector, especially in sustainability-related research. The method is based on an outranking system that takes into account uncertainties and makes it possible to combine both quantitative and qualitative criteria. The purpose of the visit was to apply the ELECTRE III method to Brenda's project involving a comparison of various small scale wastewater sewage based on a number of sustainability indicators.
During the same period, even Joel Lönnqvist, Stormwater&Sewers at Luleå University of Technology, visited INSA to meet Professor Jean-Luc Bertrand-Krajewski and PhD student Rémy Bournique who are working with stormwater modelling of green-blue roofs. Various solutions for flow measurement and modeling of flow were demonstrated and methods for field experiments at LTU were discussed. A new type of green roof with a water storage under the vegetation and a flow regulator that releases excess water during heavy rains was shown. With this system the vegetation survives longer periods of drought and it is possible to retain close to 100% of the annual rainfall.