Learning Circular Economy by Hands-on Experiments: A Case-Study on Phosphorus Recovering from Wastewater at School

Circular economy (CE) is now gaining attention in academia and industry as an emerging model for minimizing primary resource depletion, waste and greenhouse gas emissions. In the present work, we present a learning pathway, designed for high schools, useful to introduce some basic concepts of CE among youngsters by starting from a laboratory experience. The path was developed in the framework of the European project Raw Matters Ambassadors at Schools (RM@Schools), an innovative program to make science education attractive for youngsters which and to promote a wide dissemination action on raw material-related themes in Schools and Society. In this context, lab experiments to approach raw materials (RMs) considered critical by EU and the necessity of their recovery were set up for high school students. Phosphate rock (P) is one of the critical RMs for EU, and it is primarily used in agriculture. After 2033 Iit is expected a huge decline in P extraction and consequently, a dramatic decrease in fertilizers, food and feed. The goal of the lab experience presented here is to educate students that P can be recovered from secondary resources such as urine, a component of wastewater. The laboratory activities are planned in a theoretical training under the teacher guidance and another practice where students become the main protagonists of all phases of the work (from design to evaluation). The laboratory activity is composed by three experiments with various levels of difficult. By using the material created for this learning path, students become familiar with the concept of biogeochemical cycles and specifically nitrogen and phosphorous cycling, and learn that in CE end-of-life products are considered as resources for another cycle. In addition, consideration must be given to the interactions between materials to determine the best circular solution. Students can be aware of the benefits of closing material loops in a simple and engaging way.