Petroleum wastewater and oil field discharges represent a significant and growing environmental challenge, contributing to the pollution of air, water, and ecosystems. These discharges are also associated with adverse effects such as ocean noise, degradation of natural habitats, and disruption of local livelihoods. Petroleum wastewater is primarily generated by industries involved in crude oil refining, fuel production, and lubricant manufacturing, whereas oil field discharges originate from oil and gas extraction processes. Such wastewater typically contains a complex mixture of contaminants, including dissolved and suspended hydrocarbons, heavy metals, dissolved minerals, chemical additives, and gases. To address these pollutants, a range of physical and chemical treatment methods have been developed. Conventional approaches, as well as emerging technologies such as membrane bioreactors, electrochemical coagulation, and membrane filtration, are among the most widely explored. Coagulation–flocculation is a fundamental treatment technique employed to remove colloidal particles and oil by introducing coagulants that facilitate particle aggregation. This method is favored for its operational simplicity, cost-effectiveness, and energy efficiency. As a more advanced alternative, membrane bioreactors integrate biological treatment with membrane filtration to effectively remove dissolved organic and inorganic compounds. Notably, this process operates without the need for chemical additives and achieves high efficiencies in reducing chemical oxygen demand (COD). The integration of coagulation–flocculation with membrane bioreactor systems offers a robust and synergistic approach for the treatment of petroleum wastewater and oil field discharges. This combined methodology shows considerable promise for enhancing environmental protection and enabling water reuse in industrial applications.