Pilot scale reverse osmosis refinery wastewater treatment – a techno-economical and sustainability assessment

Abstract

Technologies for wastewater reclamation and water reuse within oil refineries have been gaining particular attention over the past decade due to legislative pressures associated with the efficient use of water resources and wastewater discharge. Having to constantly rely on access to great amounts of water, the oil and gas industry has been seeking opportunities to reclaim water using sustainable and efficient management procedures. In the present study, an on-site pilot plant treatment study on real refinery stripped sour water using reverse osmosis was conducted with the goal of removing the main pollutant blocking the possibility for water reuse in the refinery cooling tower, phenols. A technical and energy evaluation was performed where 90% of the initial wastewater was recovered without loss of permeate quality with 98% rejection of phenols. The installation of an energy recovery device with the reverse osmosis plant could drop the energy input demand to 1.2 kW h m⁻³, allowing the operating costs to decrease from 1.37 € per m³ to 0.41 € per m³. Treatment on an industrial scale would allow the refinery to save up to about 375 000 m³ per year in water and up to approximately 417 000 m³ per year in wastewater volume discharged, translating into net savings of up to 286 000 € per year and a payback period of down to 4 years. The current treatment proposed showed low carbon footprint and negligible waste generation, based on green metric tools; however careful consideration should be taken in the management and treatment of the concentrate stream.