On November 13, 2024, the European Sustainable Phosphorus Platform (ESPP) organized a workshop in Brussels to address the regulatory status and challenges of using algae grown with inputs like wastewater, animal by-products, or manure in fertilizers, feed, and industrial applications. The event featured the presentation of a legal analysis and discussions among experts, producers, and regulators. Topics included EU "End-of-Waste" criteria and the valorization of algae in sustainable practices.