Sustainability Assessment of Waste Sludges Management Options

Report Nº 11/24: This report presents a sustainability assessment of waste oily sludges treatment technologies in refinery operations. It provides further analysis of sources, volumes, pre-treatment and final treatment/disposal options of the most important oily sludges per volume, produced by European refineries in the 2019-2021 period, as reported in the 2023 Concawe Waste Survey Report.

The project involved a literature review of emerging and conventional oily sludges treatment technologies from which a smaller number of technologies were selected for detailed assessment. 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 conventional technologies such as incineration in municipal solid waste incinerators, at cement works and disposal to landfill. However, it is important to note that emerging technologies will need to be analysed in greater detail taking into account local considerations and availability of the technology itself.