The treatment of wastewater in sewage treatment plants results in the generation of sewage sludge, which is a muddy residue that can exist in solid, semi-solid, or liquid form. Sewage sludge comprises a complex mixture of proteins, carbohydrates, detergents, phenols, and lipids, as well as harmful and dangerous organic and inorganic contaminants. The production of sewage is a result of the combination of domestic and industrial wastes, which typically contains over 99% water. The production of sewage is a result of contributions from various sources, including residential, institutional, commercial, and industrial facilities. This book chapter provides an overview of sludge in waste treatment plants, focusing on the terminology of wastewater treatment plants (WWTPs), the typical processes used in wastewater treatment, the constituents of sludge, rules and regulations governing WWTPs, and current methodologies employed for handling sewage sludge. The chapter provides insight into the complexities of managing sewage sludge, which is a crucial aspect of wastewater treatment, as it poses environmental and health hazards. The chapter highlights the importance of effective management of sewage sludge, emphasizing the need for sustainable approaches that ensure safe disposal and minimize environmental impact.
