Life Cycle Assessment of Wastewater Treatment in a Refinery with Focus on the Desalting Process

During refining operations, desalting wastewater provides 10-30% of the total wastewater volumes and contains 40-70% of the pollutants in the wastewater treatment unit. Desalting consists of removing impurities from the crude oil with washing water. The discharge of treated water into the receptor environment is controlled according to standards regulation. However, due to human health and environmental risks, a multi-criteria and multi-stage analysis must be carried out. This present study aims to identify critical sources of wastewater treatment impacts from desalting operations. Life cycle assessment (LCA) with LCIA methods namely Recipe, CML-IA, TRACI, and USETOX were used in Gabi Software. According to this study, fossil fuel-based, electricity generation is the major contributor to negative output flows with about 99%. Emissions of CO₂, CO, NOx, SOx, and COV during electricity generation influence the global warming potential through the greenhouse effect, acidification potential that causes acid rains, and photochemical oxidation potential relative to smog. Uncertainty relative to toxicity results does not allow conclusive points to be made. The inclusion of the desalting process in LCA of wastewater treatment is relevant for a comprehensive analysis. The preliminary results obtained during this work will be used in future LCAs in Africa to develop an environmental assessment database.