Sludge is a product of wastewater treatment, and its production is huge and continues to climb. The remaining sludge is a mixture of multi-media, complex composition, and dual properties of pollution and resources. 

Sludge treatment and disposal is an important task in the water industry. The traditional landfill method has caused environmental pollution and resource waste, and the harmless treatment of sludge should be implemented to promote resource utilization. Dai Xiaohu, a specially-appointed expert of National Overseas High-level Talents, Professor of College of Environmental Science and Engineering, Tongji University, and Director of National Engineering Research Center for Urban Pollution Control, made an academic report titled "Progress and Current Research Status of Harmless Sludge Treatment and Resource Utilization Technology" on the 18th WaterTalk, which was held on October 8, 2022. The report mainly explains four aspects of sludge, development history, research hotspots, and development direction, and also introduces the relevant research progress of his scientific research team in the field of safe resource utilization of perishable organic solid waste with sludge as the core:

The lack of technology and equipment for sludge treatment and resource utilization is a difficult problem for China, which urgently needs scientific and technological innovation and breakthrough. At present, the mainstream technical routes for sludge treatment and disposal in China are aerobic fermentation + land utilization, anaerobic digestion + land utilization, drying and incineration + ash landfill/building materials utilization, and deep dewatering + sanitary landfill.

China's sludge treatment and disposal has gone through several policy changes, and during the period of the 12th Five-Year Plan and the 13th Five-Year Plan, the requirements of the indicators for the harmless disposal of urban sludge have been continuously improved, the standard system has been continuously improved, China's international academic influence in the field of sludge and the protection of intellectual property rights have been greatly improved, and the progress of science and technology in the treatment and disposal of sludge has achieved stage-by-stage results.

Research on the safe resource utilization of perishable organic solid wastes, with sludge as the core, has received increasing attention from researchers. In the past three decades, "bioconversion", "thermochemical conversion", "solid-liquid separation" and "resource utilization" have been the research hotspots in the field of sludge. are the research hotspots in the field of sludge; the keywords of resource utilization such as "high solid/co-operative anaerobic digestion", "phosphorus recycling" and "nitrogen recycling" of sludge are gradually increasing in attention.

The cross-fertilization of information, materials, biology and other disciplines, advanced analysis and characterization means, artificial intelligence, big data and other technologies are the breakthroughs of future sludge resource utilization innovation; under the dual-carbon background, sludge treatment and disposal and resource utilization need to break the traditional thinking, and realize the breakthroughs of sludge technological innovation by adhering to the concept of "green, low-carbon and recycling" from the perspective of the whole life cycle.