Application of peroxymonosulfate-ozone advanced oxidation process for simultaneous waste-activated sludge stabilization and dewatering purposes: A comparative study

In this study, the efficiency of the Peroxymonosulfate-ozone (PMS+O3) advanced oxidation process in lab scale by the aim of stabilization and dewatering the biological excess sludge was investigated and the results were compared with persulfate-ozone (PS+O3), hydrogen peroxide-ozone (H2O2+O3) and ozonation (O3) processes. The results show that the PMS+O3 is more effective than other mentioned procedures. Therefore, under optimized conditions (pH = 11, PMS/O3 = 0.06 and Dose O3 = 12.5 mmol), VS (Volatile solids) and fecal coliforms reduced respectively 42% and 89% after 60 min and the stabilized sludge in term of pathogen reduction requirements was class B. Furthermore, time to filter (TTF) of sludge decreased 70% relative to the raw sludge. In order to demonstrate the dewatering conditions' improvement, the variations of particle size distribution, extracellular polymeric substances (EPS) and zeta potential were evaluated. Overall, the results show that the PMS+O3 has the capability of stabilizing and dewatering the sludge simultaneously.