Advancements on the technologies for municipal wastewater excess sludge

With an increasing emphasis on emission reduction, nutrient recycling, and clean energy generation, extensive efforts are currently underway to develop cost-effective, energy-efficient, and sustainable technologies for managing excess sewage sludge (SS) produced during wastewater treatment. Aligned with sustainable development goals and circular economy principles, these technologies aim to minimize SS and transform it from waste into a renewable resource for energy, nutrient, and material recovery. This chapter delves into recent research and explores promising pathways for the sustainable treatment and utilization of SS, with a particular emphasis on novel sludge-to-energy and sludge-to-resource recovery methods. It discusses key factors and trends shaping future developments and assesses the benefits, limitations, and potential of applicable technologies, paying specific attention to thermochemical conversion, energy and nutrient recovery, and sludge biorefinery. Despite promising development prospects, the technology readiness level (TRL) of these applications remains relatively low for widespread adoption. Hence, continued research, innovation, and validation are imperative to advance these technologies and pave the way for their successful industrial application.