Unlocking the potential of anaerobic digestion for tropical communities: The SUZDEE system's approach to biogas and biofertilizer production

• SUZDEE system benefits the environment, economy and society. • Decentralized food waste digestion unit offers waste management at the source. • SUZDEE has microorganisms specialized in food waste digestion. • SUZDEE is implemented in 29 locations across 14 provinces in Thailand. This study presents the implementation of the "SUZDEE ( Su stainable Z ero Waste D igestant for W e ll-B e ing)" anaerobic digestion (AD) system in Thailand, addressing the challenge of food waste (FW) management. Developed using AD technology, the SUZDEE system offers several advantages, including ease of use, effective greenhouse gas emission management, and biofertilizer production. Over the course of one year, the system was implemented in 29 communities across 14 Thai provinces, processing 15,335 kg of FW. It produced 747 m 3 of biogas (equivalent to 15,579 MJ) and 13,941 L of biofertilizer, generating an estimated 8,282 $ for the communities while reducing CO 2 emissions by 10,475 kgCO 2 equivalent. Additionally, the social return on investment (SROI) analysis demonstrated an additional value of 9,979 $, resulting in an SROI ratio of 1.0914. A satisfaction survey was also conducted, and the results indicated that users were satisfied with all aspects of the SUZDEE implementation, with an average satisfaction level of 4 out of 5. The implementation of SUZDEE systems in community settings aligns with the United Nations Sustainable Development Goals (SDGs) 11 and 12, which focus on building sustainable cities and communities and promoting sustainable production and consumption, respectively. The data demonstrate that implementing multiple SUZDEE systems could catalyze a positive shift in Thailand's FW management practices, encouraging sustainable and economically viable approaches. Our results also suggest that AD systems similar to SUZDEE could be developed and applied across tropical countries with low-income populations, offering an opportunity to achieve a circular economy through resource-efficient and waste-to-wealth strategies.