The proper management and treatment of sludge generated from industrial and municipal processes are crucial for environmental sustainability and resource recovery. This chapter delves into the complexities of sludge treatment and dewatering techniques, with a focus on methods to reduce volume, improve solid–liquid separation and enable responsible disposal or beneficial reuse of sludge. Beginning with an overview of sludge characteristics, the chapter discusses its composition and origin. It highlights the need for effective sludge management due to potential environmental and health risks. The chapter then explores primary treatment methods used to prepare sludge for dewatering. These methods include thickening and conditioning, which concentrate sludge solids and optimize subsequent dewatering processes. The core of the chapter examines different sludge dewatering techniques. Mechanical methods like centrifugation, filter pressing and belt filtration are explained, detailing their principles, operational considerations and efficiency. Thermal techniques like drying and incineration are explored as options to reduce sludge volume and eliminate pathogens. These approaches are evaluated based on energy requirements, environmental impacts and the potential for resource recovery from incinerated sludge. Amid growing sustainability concerns, the chapter emphasizes the importance of exploring eco-friendly sludge management options. It discusses approaches like anaerobic digestion and composting, which not only aid dewatering but also yield biogas and nutrient-rich soil amendments. In conclusion, the chapter provides a comprehensive overview of sludge treatment and dewatering techniques, spanning traditional mechanical methods to state-of-the-art innovations. It underscores the need for efficient, cost-effective and sustainable practices to address sludge management challenges. By equipping readers with a nuanced understanding of these techniques, the chapter aims to guide researchers, practitioners and policymakers toward informed decisions for responsible sludge handling and treatment in line with evolving environmental priorities.