No abstract

BACKGROUND The possibility of reusing treated refinery wastewater in the cooling water system (CWS) of the refinery itself is investigated. The contaminant levels in the treated wastewater typically fluctuate around or slightly above the threshold values for recycling to the CWS and this motivates the need for an additional purification unit. To this end, the performance of reverse osmosis (RO) is experimentally investigated through a flat‐sheet RO pilot plant installed directly in the refinery (on the treated wastewater streamline). RESULTS In the pilot plant, two different RO membranes are tested: seawater (SWM) and brackish water (BWM) membranes. In both cases, the permeate water at the outlet of the RO pilot plant had conductivity below 100 μS cm–1, total hardness (TH) below 8 ppm, chemical oxygen demand (COD) below 45 ppm, Fe below 0.04 ppm, and total ammonia nitrogen (TAN) below 1.1 ppm. The concentration of hydrocarbons (HCs) is a few ppm in the treated wastewater both at the inlet of the RO pilot plant and in the RO permeate. All these data are well below the thresholds for reuse in the CWS. The results were stable and no evidence of degradation was found over the experimentation period (3 days and 6 days, respectively, for the SWMs and the BWMs). CONCLUSION The RO permeate water can be reused in the CWS of the refinery. The proposed reuse strategy is expected to make a significant reduction (20–25 t h–1) in refinery primary water withdrawal possible. © 2021 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).