Spatial Analysis of Human Fecal Waste in Rural Oromia, Ethiopia: Biomethane and Nutrient Recovery Potential

Abstract

Sanitation remains a critical development and public-health challenge, particularly in rural Ethiopia, where only 7% of the population resides and access to safely managed sanitation. This study models the spatial distribution and resource-recovery potential of human feces in rural Oromia, integrating high-resolution population data with experimentally validated methane yields and nutrient contents. Model-based estimates suggest annual feces production of ~2 million tonnes, corresponding to ~27.9 PJ of biomethane energy and 7,309 t N, 2,206 t P, and 4,511 t K—equivalent to over 2.6 billion birr in synthetic fertilizer. Resource potential is spatially uneven, with northeastern and central highlands offering the greatest opportunities for biogas and nutrient recovery. Biogas digesters are best suited to livestock-rich highlands, urine-diverting dry toilets to peri-urban areas, and composting or container-based systems to low-income, nutrient-depleted communities. Adoption, however, is hindered by socio-cultural perceptions, financial constraints, and institutional gaps. Coordinated action across health, water-energy, agriculture, environmental protection, and infrastructure sectors—supported by strong regulation, targeted financing, community engagement, and public-private partnerships—is essential for scaling. With context-specific deployment and institutional support, Resource-Oriented Sanitation Technologies can convert human waste into a circular resource that enhances rural energy access, soil fertility, environmental sustainability, improves public health, and advances progress toward the Sustainable Development Goals.