Unlocking the Power of Source-Separated Organic Municipal Waste for Fertilizer Production and Sustainable Waste Management in Ethiopia

Purpose This study aims to optimize the process of converting organic municipal solid waste (MSW) into organic fertilizer using a pilot Aerated Static Pile (ASP) composting system. It focuses on identifying the best waste mixing ratios, optimizing operational parameters, and evaluating the quality of the resulting fertilizer to enhance waste management in developing countries like Ethiopia, where resources are limited, and urbanization is increasing. Methods The study tested biodegradable organic MSW, supplemented with cow-dung and sediment inocula, in various compositions. It analyzed key composting parameters such as; pH, carbon to nitrogen (C/N) ratio, moisture content, and electrical conductivity to determine the optimal composting conditions. Additionally, heavy metal concentrations were measured before and after composting to ensure the safety of the final product. Results The study identified optimal composting conditions: a pH of 5.43 to 7.89, a C/N ratio of 23:1 to 42:1, moisture content of 60–66%, and electrical conductivity of 4.10–5.24%. Heavy metal concentrations remained within regulatory limits throughout the process. The optimization results showed that the natural sediment inoculum (Run I) was more efficient than the cow-dung inoculum (Run II) for decomposition. In Run I, Pile P3 (50% food waste, 50%-yard waste) produced the best quality compost, followed by Pile P2 (75% food waste, 25%-yard waste). Pile P4 (25% food waste, 75%-yard waste) had lower temperatures, hindering decomposition. Conclusion This research underscores the importance of optimized composting processes and provides valuable insights into implementing ASP composting technology for organic waste management in Ethiopia and beyond. Graphical Abstract