This "summary of results" is the product of a citizen science pilot to contribute to the improvement of the separate waste collection system in Mollet del Vallès (Barcelona). The research has involved 60 students from 4 secondary schools in the municipality to explore citizens' preferences towards innovative separate collection systems (smart bins and door-to-door) and the variables that may act as possible facilitators or barriers to their implementation. As a citizen science tool, a digital waste game called "Dilemma R" was created and developed, with great potential for replicability in other municipalities. This citizen science pilot is part of the European project TRANSFORM (grant agreement N.872687). This document reflects the views only of the authors, and neither the European Commission nor the European Research Executive Agency can be held responsible for any use which may be made of the information contained therein.