On January 19, 2026, the course Circular Economy and Sustainable Business concluded for AY 2025. Throughout the fall semester, students worked collaboratively with staff from Mitsubishi Kakoki to address environmental challenges associated with hydrogen sulfide in sewer pipes. This issue is serious and can potentially lead to road collapse due to corrosion of sewer infrastructure. Removing the fats that generate hydrogen sulfide from all pipes would incur tremendous costs and would be financially prohibitive for the government. Controlling the source of hydrogen sulfide in these systems is therefore essential. Students devoted significant effort to developing innovative business ideas to mitigate this problem.

The course will be offered again in AY 2026 to continue work on this important issue. We are deeply grateful to Mitsubishi Kakoki for its generous support and hospitality. Through this collaboration, students gained valuable experience working with industry professionals and developing practical business solutions to real-world social challenges.

Note:
The course Circular Economy and Sustainable Business was jointly launched in 2025 by Prof. Tetsuya Horie (Department of Economics) and Mr. Yasuhide Hayashi and Mr. Koichi Yamada of Mitsubishi Kakoki. It represents the first university–industry collaborative course under the Sophia Program for Sustainable Futures (SPSF) and was made possible through Mitsubishi Kakoki’s MKK Project.