Developing a Circular Economy Model for Solid Waste Valorisation in Nigeria’s Agro-Industrial Sector

This dissertation develops an original circular economy model for the valorisation of solid waste streams in Nigeria's agro-industrial sector, integrating industrial ecology, systems thinking, and resource efficiency principles to create a theoretically rigorous and empirically grounded framework applicable across the country's diverse agro-industrial landscape. Nigerian agro-industrial operations generate enormous quantities of underutilised organic solid wastes including palm fruit residues, cassava peels, rice husks, groundnut shells, and bagasse, representing both an environmental burden and a misallocated resource pool that, if redirected through circular economy principles, could contribute to energy security, soil nutrient cycling, and new industrial value chains. The model is developed through a three-phase research design encompassing systematic waste stream quantification across fourteen agro-industrial subsectors in five geopolitical zones, multi-criteria techno-economic evaluation of forty-one waste valorisation pathways, and agent-based modelling of circular economy network dynamics under different policy and market scenarios. Original contributions include a Nigerian Agro-Industrial Waste Valorisation Atlas, a dynamic resource-technology-market matching algorithm, and an institutional enablement framework specifying the regulatory and financial instruments needed to activate circular economy transitions in the Nigerian context. The model demonstrates economic viability for nine priority valorisation pathways with aggregate annual value creation potential exceeding two-point-four billion naira under conservative market assumptions. Keywords: circular economy, agro-industrial waste, valorisation, industrial ecology, Nigeria