Advanced oxidation-based combined conditioning technologies to improve sludge dewaterability: A mini review

With the acceleration of urbanization, sludge production is increasing significantly. The high moisture content of sludge brings great challenges to subsequent incineration or landfill disposal. The advanced oxidation process (AOP) destroys extracellular polymeric substances (EPS) by generating oxidative hydroxyl radicals or sulfate radicals, thereby improving the sludge dewaterability. Due to the promising treatment efficiency of this process, it has become the research focus of chemical conditioning. However, the relatively high cost of pharmaceuticals and subsequent environmental risks limit the widespread application of advanced oxidation methods. Moreover, in order to compensate for the limitations of single sludge conditioning technology, the sludge conditioning technology is currently being developed in the direction of a combined process. Based on AOP, this paper reviews the improvement of sludge dewaterability by other sludge conditioning methods and their combinations in recent years, analyzes the shortcomings of the current technology, and looks into the future development of this technology.