This book contains selected papers presented at the 7th edition of the International Conference Wastes: Solutions, Treatments and Opportunities, that took place on September 3&5, 2025, in Funchal, Isle of Madeira, Portugal. The Wastes conference occurs biennially and is an international forum for sharing innovations, technological developments and sustainable solutions for waste management and recycling sectors, with the participation of experts from academy and industry. The papers included in the present book cover a wide range of topics including: Management of waste streams. Environmental, economic and social aspects in waste management. Waste-to-energy technology. Life cycle assessment and carbon footprint. Biological treatment techniques. Waste treatment and valorization technologies. Circular economy and industrial symbioses. Smart technologies and digital tools in waste management. Recycling of wastes and resources recovery. Wastes refinery. Food wastes management and bioeconomy. Plastic waste impacts, management strategies and solutions. Wastes as critical raw materials resources. This book is aimed at academics and professionals involved in waste management and recycling sectors globally.