Sustainability Assessment of Traditional and Emerging Treatment Techniques for Refinery Oily Sludges

This study presents the results of a survey of EU refineries waste types production, their sources and management options, with focus on oily sludges and a sustainability assessment of selected traditional versus emerging treatment options for oily sludges wastes. It provides a statistical analysis of waste production by Concawe member company refineries in the years 2019, 2020 and 2021, based on survey data returned from 68 refineries (70.1% response rate) situated in the EU-27 countries + UK, Norway and Switzerland. It includes a breakdown of oily sludge waste tonnage according to its origin and how it was managed. A literature review of emerging and traditional oily sludges treatment technologies provided a selected list of treatment options for detailed assessment of their sustainability. The assessment consisted of a semi-quantitative multi-criteria analysis including criteria assigned to the three main pillars of sustainability: environment, social and economics. A fourth pillar, waste circularity was added to assess technologies based on their preservation of resources and minimisation of waste generation. Each criterion was given a score with a higher score indicating technologies more favourable for each of the selected criteria. The scores were weighted allowing comparison of the assessed technologies for each of the four pillars. The assessment identified overall better sustainability performance for emerging technologies pyrolysis, solvent extraction and biopiles than for more traditional technologies such as incineration in municipal solid waste incinerators, at cement works and disposal to landfill.