Effect of potassium ferrate on disintegration of waste activated sludge (WAS)

► Potassium ferrate pretreatment was effective to reduce the total solid content by 31%. ► The solubility (SCOD/TCOD) of the sludge increased with the increase of potassium ferrate. ► Nitrogen and phosphorous in the sludge dissolved and released significantly after potassium ferrate treatment. ► Potassium ferrate enhanced the sludge settleability due to the production of Fe(III).