The work was carried out within the framework of a collaborative project with the Catalan Water Agency (ACA) and ICRA to optimise the design and operation of 7 wastewater treatment plants with membrane bioreactors in Catalonia: La Bisbal d’Empordà, Riells i Viabrea, Vallvidrera, Vacarisses, Sabadell-Riu Sec, Gavà/Viladecans and Terrassa. The work was the basis of LEQUIA researcher Sara Gabarrón doctoral thesis.