Enhanced dewaterability of sewage sludge in the presence of Fe(II)-activated persulfate oxidation

► First scientific attempt to apply sulfate radicals to sludge dewatering. ► 88.8% CST reduction efficiency was obtained within 1 min. ► Both soluble EPS and viscosity played negative roles in sludge dewatering. ► No correlation was established between dewaterability and bound EPS. ► Soluble EPS were degraded and flocs were ruptured, inducing the dewaterability improvement.