Characterisation of selected human excreta-derived fertilisers for agricultural use: A scoping review

Abstract

Most countries in Sub-Saharan Africa rely on on-site sanitation systems. Integrating on-site sanitation systems with local food systems by recovering nutrients and materials from human excreta, and reuse in agriculture can promote a sustainable circular bioeconomy, which could improve livelihoods and minimize environmental pollution in low-income communities. Although there are several technologies that can valorise human excreta into valuable waste-based agricultural products the scaling up and adoption of these innovations by societies is limited by several institutional challenges. These include an unclear policy and regulatory environment due to inadequate evidence-based information that can inform policy change, stimulate social acceptance, establish economically viable environment and include active participation of women and youth. Based on previous untreated human excreta characterisation studies, meant to inform treatment technological requirements, a scoping review with metanalyses was done to assess the extent to which selected technologies are meeting the requirements of a sustainable sanitation value chain. The selected technologies were shown to comply with the South African and international regulations for the recovery of nutrients from human excreta and reuse in agriculture. The review shows that there is potential to establish circular bio economies, characterised by safe recovery of nutrients and materials from human excreta and subsequent agricultural use, in South Africa and beyond. However minor modifications to the technologies are required to ensure that the products are safe for unrestricted agricultural use, economically viable, socially acceptable and environmentally sustainable.