Waste Management Routes for Oil and Gas Decommissioned Flexible Pipelines in Brazil: A Comparative Life Cycle Assessment (LCA)

Decommissioning poses a challenge for decision-makers. As an aspect of decommissioning that is not explicitly outlined in regulations, waste management for decommissioned materials is a special challenge. In Brazil, a large amount of the decommissioned subsea infrastructure is composed of flexible pipelines, with interlocked structures that increase the recycling challenge. This study identified two technological routes to dismantle the pipes. These routes (A and B), consisting of processes centered on the shredding and the manual dismantling of the pipes, respectively, were analyzed through a comparative Life Cycle Assessment (LCA) study. This study offers valuable insight into the waste management of decommissioned subsea infrastructure by quantifying the potential environmental impacts associated to the two main pre-processing strategies for the recycling of decommissioned flexible pipes in Brazil. Each route presented different levels of mechanization, energy consumption, productivity, labor intensity, types and levels of occupational hazards and recycling options for the resulting polymeric materials. The results from this study indicate that Route B is more aligned with the principles of a circular economy, enabling the mechanical recycling of 98% of the polymeric material and presenting substantially lower potential environmental impacts. In particular, Route B represents approximately 9.6% of the global warming impact (kg CO2 eq) associated with Route A. Overall, its impacts vary from 1.47% (marine eutrophication) to 12.18% (ozone formation) of those associated with Route A across the different impact categories.