Environmental Engineering Framework for Managing the Solid Waste Crisis in Nigerian Mid-Size Cities: Original Contributions to Integrated Waste Management Theory

This dissertation develops an original integrated waste management theoretical framework specifically designed for mid-size Nigerian cities between 200,000 and one million population, addressing the critical gap between waste management theories developed for either high-income countries or megacities and the institutional, technical, and financial realities faced by Nigeria's rapidly growing secondary cities. Mid-size Nigerian cities are experiencing waste management crises driven by rapid population growth, inadequate collection infrastructure, absence of treatment and disposal facilities, and limited municipal revenue, yet the waste management literature provides limited guidance tailored to this specific urban scale and institutional context. The theoretical contribution is the Nigerian Mid-Size City Integrated Waste Management Framework, constructed through a synthesis of waste management systems theory, urban environmental governance theory, and development economics principles, grounded in comparative empirical analysis of waste management systems in twelve mid-size Nigerian cities drawn from all six geopolitical zones. The comparative analysis uses a structured assessment of technical performance, financial sustainability, institutional effectiveness, social equity, and environmental outcomes for each city's waste system, identifying the configurations and enabling conditions associated with better performance. Original theoretical concepts introduced include the informal sector integration ladder, a stepwise model for progressively formalising informal waste picker and collector networks; the municipal waste revenue cycle, a theory of the fiscal dynamics connecting waste management service quality, household willingness to pay, municipal revenue, and reinvestment capacity; and the fragmented governance trap, a dynamic theory of why multi-agency waste governance in Nigerian cities tends towards systemic underperformance. Keywords: integrated waste management, mid-size cities, Nigeria, theoretical framework, informal sector.