Principle and application of hydrogen peroxide based advanced oxidation processes in activated sludge treatment: A review

The disposal of excessive activated sludge by advanced oxidation processes (AOP) to avoid its potential environmental risk has received extensive attention. As an efficient and clean oxidant, hydrogen peroxide (H2O2) has been used widely in AOP. In H2O2 based AOP, strong oxidative hydroxyl radical (HO) produced by different kinds of activation methods plays an important role in sludge treatment for sludge reduction, recycling and risk relief. This review summarizes current studies and breakthroughs of H2O2 based AOP in sludge treatment. Meanwhile, the possible mechanisms of H2O2 based AOP in sludge dewatering, sludge minimization, anaerobic digestion and the removal of pollutants are clarified systemically. Furthermore, the cost estimation of H2O2 based AOP in sludge treatment is materialized. Finally, the possible focus of future study in sludge treatment via H2O2 based AOP is present. This review can provide a theoretical basis for applying H2O2 based AOP in sludge reduction, recycling and risk relief.