This chapter examines how to treat petroleum industry effluents using membrane processes as standalone methods alongside activated sludge systems. The petroleum industry produces large volumes of wastewater containing various contaminants, including hydrocarbons, heavy metals, and other toxic substances. Traditional treatment methods often need to improve to remove these pollutants effectively. Membrane technologies, known for their ability to separate contaminants at a molecular level, provide a promising solution. This chapter explores various membrane techniques, including microfiltration, Ultrafiltration, Nanofiltration, and reverse osmosis, and highlights their effectiveness in treating petroleum effluents. It also examines the synergistic effects of combining membrane processes with activated sludge treatment, demonstrating improved removal efficiencies and operational benefits. The chapter concludes with recommendations for optimizing treatment strategies to enhance sustainability and ensure environmental compliance in the petroleum industry.