Combined Oxidation-Gasification system for waste treatment with supercritical water: LCA and performance analysis

In this study the environmental performance of a first of a kind integrated process based on supercritical water gasification and supercritical water oxidation, was evaluated using Life Cycle Assessment (LCA). The process was applied to the treatment of carbon black and used oil as model waste. Mass and energy balances were performed using Aspen Plus, and the environmental assessment was carried out through SimaPro. For the analysis was chosen a “From cradle to grave” approach, considering impact categories like climate change, ozone depletion, human toxicity, particulate matter, land use, resource depletion and others relevant indicators. The environmental profile of SCW-GcO process was compared to other technologies for treatment of dangerous wastes, solvent mixture and exhaust mineral oils by using Ecoinvent database. It is shown that SCW-GcO allows reducing impacts in different category and obtaining a favorable positive life cycle energy balance, achieving a good environmental performance.