Phosphorus Recovery from Incinerated Ash of Sewage Sludge by Heat Treatment

Abstract

The phosphorus recovery from incinerated ash of sewage sludge by a heat treatment method was investigated. The incinerated ash of sewage sludge was mixed with sodium hydroxide or sodium carbonate, and treated at 750 °C to 900 °C in aerobic conditions. The phosphorus was successfully recovered as an alkali metal phosphate from the treated ash through water extraction. The recovery rate of the phosphorus reached about 74% to 78%. The optimal condition of the phosphorus recovery and composition of the recovered phosphorus was investigated.