<p>Current treatment methods often fail to meet stringent landfill acceptance criteria for real bilge water sludge, necessitating novel, scalable solutions. Managing bilge water sludge remains a significant concern for port reception facilities, primarily due to its elevated levels of organic pollutants and dissolved salts. Many conventional treatment techniques struggle to meet the stringent requirements of Class 1 landfill acceptance, particularly in parameters such as dissolved organic carbon (DOC), total dissolved solids (TDS), and chloride. Unlike most earlier studies that relied on synthetic waste samples and small-scale laboratory setups, this research directly used real bilge water sludge collected from an operating port reception facility. As a result, the findings carry immediate practical relevance, showing a scalable treatment strategy that can be seamlessly adapted to real-world industrial conditions. To address this, the present work examines a combined method involving ultrasonic pre-treatment followed by coagulation using potassium methoxide. The integrated process achieved a DOC reduction of up to 39.12%, while also successfully lowering TDS and chloride to within Class 1 limits. The use of ultrasonic energy enhanced coagulation efficiency, which may help reduce both sludge volume and overall disposal demands. A preliminary economic evaluation suggests that this technique could cut annual sludge management costs by 10–15%, potentially saving around 22,500 USD per year. Thanks to its modular design, the proposed reactor setup shows strong potential for upscaling to real-world operations, offering a practical and environmentally sound solution for managing port sludge.</p>