“Sarriko Zero Waste” is a Challenge-Based Learning (CBL) experience aimed at equipping students of the Faculty of Economics and Business (University of the Basque Country, EHU) with sustainability competencies, turning them into active agents of change toward a more sustainable faculty.

Starting from an analysis of the waste generated at the Faculty, the collection system, and the recycling habits and attitudes of the university community (teaching staff, students, and technical, administrative, and service personnel), the challenge sought to have students develop solutions to reduce the volume of waste produced and enhance the recycling of unavoidable waste, thereby mitigating the environmental impact of the Faculty’s activities.

The proposed solution was the design of an improved recycling system based on grouping all types of containers into recycling stations distributed across high-traffic areas, using color-coded bags according to the type of waste, and launching awareness-raising campaigns. After implementing these measures, the plan includes integrating objective metrics (periodic weighing of waste and CO2 calculations) to measure their impact.

Keywords: Sustainability competencies, university, Challenge-Based Learning (CBL), recycling, Erronka project.