Produced water treatment encompasses the suite of technologies and services that transform wastewater generated alongside oil and gas (known as "produced water") into environmentally safe, reusable water—or facilitate its compliant disposal. This wastewater typically contains contaminants like oil, solids, salts, heavy metals, organic compounds, and sometimes naturally occurring radioactive elements. Treatment is typically staged: Primary treatment uses physical separation techniques—such as gravity settling, hydrocyclones, and flotation—to remove oil, grease, and suspended solids. Secondary treatment applies advanced methods like membrane filtration, adsorption, and biological processes to eliminate dissolved organics, fine particles, and chemical pollutants. Tertiary treatment brings the water closer to reuse or discharge standards through technologies like reverse osmosis, advanced oxidation, ion exchange, and chemical polishing. Innovations include compact flotation units, electrochemical and hybrid treatments, AI-driven dosing systems, forward osmosis, and mobile modular setups for rapid deployment. Goals include safe reuse (for drilling, irrigation, or industrial use), controlled reinjection, or environmentally secure surface discharge—all while minimizing reliance on underground disposal, reducing seismic risks, and conserving freshwater. The market faces barriers like high treatment costs, diverse water compositions, and regulatory complexity but continues advancing toward sustainable water solutions for oilfield operations.