A picture fuzzy set-based decision support system for treatment technologies prioritization of petroleum refinery effluents: A circular water economy transition towards oil & gas industry

•A novel decision support system based on picture fuzzy set is introduced.•Criteria are sustainability and circularity aspects.•Treatment technologies for petroleum refinery effluents are prioritized.•A circular water economy transition for the oil & gas industry is defined. The navigation of a circular water economy transition towards the oil & gas industry needs for employing appropriate treatment technologies, and ensures the development of environmental, economic, technological, social, and circularity dimensions. Using these technologies for treating effluents produced by petroleum refineries in Iran is considered. The treatment technologies for petroleum refinery effluents can assist local authorities, governments, investors, and developers to reduce climate change and water crisis, reuse treated effluents, mitigate soil, water, and air pollutions, and construct sustainable communities and green industries. With the aim of balance between the issues in the context of sustainability and circularity policies, criteria (principles) including environmental, economic, technological, social, and circularity aspects are assessed. The research takes into consideration the applicability of a novel decision support system (DSS) namely a picture fuzzy set (PFS)-based combined compromise solution (CoCoSo) (PFS-CoCoSo). The proposed DSS can be used to choose the suitable technology considering the principles related to sustainability and circularity pillars. It comprises various technologies for petroleum refinery effluents treatment and prioritizes technologies from the most to least as: MPPE technology, Hydro-cyclone technology, ASP technology, and CPI technology.