The International Society of Bioprocess and Sustainability (ISBS) organized an internship to the Lake Kasumigaura Purification Center and the Kandachi Resource Recycle Center (Hitachi Cement Co., Ltd.) on 29th November 2024. The participants learned about wastewater treatment through staff presentations, discussions, and on-site observations. At the Recycle Center, they experienced the full-cycle chain of anaerobic digestion of food waste, biogas-based electricity generation, heat recovery and exchange, and biofertilizer production from the digestate. This internship deepens the participants’ understanding of the real-world wastewater treatment and biomass recycling, providing valuable insights and guidance for their future research.