Leaching behavior of heavy metals from sewage sludge solidified by cement-based binders

► We investigated the effectiveness of acid-assisted S/S treatment on sewage sludge. ► High De values were always achieved under low pH and high temperature conditions. ► More of the heavy metals were converted to stable fractions in acid-assisted S/S. ► Acid-assisted S/S products had considerably less heavy metals in the leachate.