In this study, an innovative synthetic high performance nanofiltration membrane composed of adipate ferroxane nanoparticles is embedded in polyethersulfone (PES) used for desalter effluent treatment. The independent numerical variables of feed concentration, transmembrane pressure, and nanoparticle concentration in the membrane were selected to analyze, model and optimize the process. Experiments were conducted at three feed concentrations (1000-5000 mg/l), transmembrane pressures (3-6 bar) and nanoparticle concentrations (0-1 wt.%). Testing was based on a central composite face-centered design. The dependent parameters of flux, chemical oxygen demand (COD) removal, and effluent turbidity were studied as the process responses. The results showed that a 0.5% (wt) nanoparticle concentration had the best effect on nanofiltration performance for desalter effluent. Decreasing the pressure and increasing the feed concentration increased COD removal and decreased effluent turbidity. The softening experiments for 0.5% (wt) nanoparticles embedded in NF membrane showed performance that was similar to that of reverse osmosis, but at lower operational pressure. (C) 2015 Elsevier B.V. All rights reserved.