Abstract: Biochar was prepared by pyrolysis of waste activated sludge （WAS） from sewage treatment plants. The sludge based biochar （SBC） was utilized to activate peroxymonosulfate （PMS） to treat the WAS， so as to enhance sludge lysis. The physicochemical properties of SBC surface were characterized by scanning electron microscopy， specific surface area and pore size analyzer and EDS. The effects of dosing ratio and dosing amount of SBC and PMS on sludge lysis were investigated， and the mechanism of enhanced lysis was elucidated. The results showed that there were many activation sites of carbonyl catalyzing PMS on the surface of SBC， and the iron element in SBC could catalyze the PMS decomposition to produce [SO-4]·， which had the potential to activate PMS in activating PMS. The combination of SBC and PMS showed a synergistic effect on promoting sludge lysis with a synergistic factor of 1.4. Compared with untreated， SBC alone and PMS alone under the optimal conditions （0.23 g SBC + 0.49 g PMS）， the combined SBC and PMS treatment improved the soluble chemical oxygen demand （SCOD） of sludge by 296%， 280% and 121% ， respectively， compared with the blank， mono-SBC， and mono-PMS treatment. By combining PMS with SBC， the generation of active particles such as [SO-4]·， ·OH and 1O2 were significantly increased， thus promoting the sludge lysis. The results could provide a reference for effectively improving the WAS cytolysis efficiency， realize sludge reduction and facilitate the subsequent disposal efficiency of WAS.

Key words: waste activated sludge , peroxymonosulfate, sludge-based biochar, sludge lysis, free radical mechanism