Sustainability in Maritime Sector: Waste Management Alternatives Evaluated in a Circular Carbon Economy Perspective

Sustainability and waste management on board are key issues that need to be addressed by the maritime sector also in terms of greenhouse gas emissions (GHG). With the aim of evaluating waste management alternatives in a circular economy perspective, the study examines a combined system for the optimisation of ship waste management and assesses its possible use for energy purposes. Different systems are analysed in relation to their GHG emission reduction potential regardless of routes and ports of destination. A SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis was carried out on waste management alternatives in order to preliminary identify their potential in terms of GHG emissions reduction, cost, environmental sustainability, methodological coherence, feasibility and replicability. Following this analysis, two case studies of particular interest were identified: 1) the thermo-chemical treatment of waste oils and sludge to obtain fuel oils; 2) the installation of a waste-to-energy plant and subsequent energy recovery on board. UNFCCC (United Nations Framework Convention on Climate Change) methodologies were applied to these two case studies to calculate GHG emission reduction resulting from their implementation. The obtained results are presented with the aim of supporting sustainable waste management strategies on board in a circular carbon economy perspective.