Oil field wastewater—commonly referred to as produced water—is the largest waste stream associated with petroleum production, characterized by high concentrations of hydrocarbons, heavy metals, dissolved salts, and chemical additives. Its complex and variable composition poses significant environmental and regulatory challenges, particularly in sensitive ecosystems like Nigeria’s Niger Delta. This study conducts a comprehensive technical and economic evaluation of three prominent wastewater treatment technologies: chemical coagulation and flocculation, membrane filtration, and constructed wetlands. Each method was assessed based on contaminant removal efficiency, cost per cubic meter, operational sustainability, and financial metrics including Return on Investment (ROI), Net Present Value (NPV), and Payback Period. Results demonstrate that membrane filtration systems, particularly those utilizing reverse osmosis, achieve the highest removal efficiencies (>98%) for suspended solids, hydrocarbons, and salinity. However, their high capital and operational costs ($1.09/m³) limit their viability for large-scale deployment in developing regions. Coagulation and flocculation present a balanced alternative with moderate removal efficiency (~90%) and a lower treatment cost ($0.83/m³), though they generate significant sludge requiring environmentally sound disposal. Constructed wetlands emerge as the most cost-effective and environmentally sustainable option, offering a treatment cost of $0.40/m³, an ROI of 29.67%, a Net Present Value of $764,018, and the shortest payback period (3.37 years). The study concludes that hybrid treatment configurations—such as integrating coagulation with membrane filtration—could enhance cost-efficiency and treatment performance. Recommendations are made for oil field operators to adopt context-specific, scalable, and regulation-compliant treatment strategies that balance environmental stewardship with economic feasibility. This research provides a critical framework for sustainable produced water management in the Niger Delta and similar oil-producing regions globally.