Water efficiency solutions for the oil refinery industry.

The water-intensive oil refinery industry generates a high amount of wastewater that has the potential to be treated and reused for industrial and/or other purposes, with the aim of closing the water loop. A four-phase methodology was developed to identify fit-for-purpose technologies for treating wastewater derived from an oil refinery industry. The scope of this study is to simulate and assess the overall performance of five scenarios for the oil refinery wastewater (ORW) treatment in a real industrial oil refinery plant by utilising the existing industrial-scale conventional Ballast Water Treatment Plant (titled plate separator, mixing, coagulation/flocculation, dissolved air flotation) and implementing an advanced pilot-scale unit (aerobic granular sludge, ultrafiltration, reverse osmosis). To this end, process modelling, simulation and life cycle assessment tools were performed. Six performance indicators (Waste Reduction, Water-Eco, Water Sustainability, Improved Water Quality, Digitalisation and Environmental Protection) were defined to compare the performance of all scenarios compared to the existing status (scenario 1). According to the results, scenario 5 (only pilot-scale ORW treatment) proved to be the most efficient and sustainable approach to close the water loop in the oil refinery plant, enabling the reuse of reclaimed water as cooling water, firefighting water, or fed into a biological unit for further treatment.