Industrial Wastewater Sludge Management: Milestones and Challenges

Industry is a vital sector for mass production to strengthen a large population. At the same time, these industries produce large amounts of wastewater with different characteristics (industrial, commercial, or domestic) that must be treated in wastewater treatment plants (WWTPs), with the consequential generation of large amounts of sludge. Residues from WWTPs could be used as raw materials for construction materials, fertilizers, and adsorbents as well as to produce biogas/biodiesel, diminishing energy supplies, which is the main drawback of the drying sludge process. Moreover, valuable resources, including clean water and nutrients like nitrogen and phosphorous, may contribute to the Sustainable Development Goals (SDGs). However, the presence of pollutants and microorganisms may affect the quality of this raw material type. This chapter presents distinct sludge treatment/valorization methods to obtain various end products that may be economically attractive based on the sludge characteristics under a circular economy (CE) approach.