A socio-eco-efficiency analysis of waste-to-energy strategies

The shift to waste-to-energy (WTE) systems is hindered by the massive investments, debated environmental benefits, and unfavorable public perception. Their full-scale adoption in developing countries is challenged by obscured combined sustainability aspects (environmental, economic, and social) throughout their lifecycle. None has conducted a thorough sustainability assessment that considers the synergy and trade-offs among the three elements to date. This study presents an integrated sustainability analysis of WTE systems through a socio-eco-efficiency framework, incorporating an environmental lifecycle assessment, lifecycle costing, and social lifecycle assessment. The strategies were applied to an emerging country based on incineration and anaerobic digestion (AD), including three digestate management scenarios: marketing, incineration, and landfilling. Incineration had the least cradle-to-grave environmental impacts, achieving relative improvements of 110 % in global warming, 80 % in human toxicity, and 53 % in eco-toxicity, compared to conventional disposal. The AD with digestate marketing was the most financially feasible strategy, increasing the net present worth by 55 and 39 % compared to landfilling and incineration, respectively. Moreover, selling digestate achieved the most positive social score (0.735), followed by digestate incineration (0.728), based on expert judgments and multiple impact indicator ratings. The AD strategy with digestate marketing was the most socio-eco-efficient, followed by landfilling with gas utilization.