Recovery of Phosphorus by Acid Extraction from Incinerated Ash of Sewage Sludge

Sewage sludge contains significant amounts of phosphorus, and in order to recover the phosphorus, some extraction method using acid or alkali are under way. The acidic extraction can recover the phosphorus with high recovery rate compared to the alkali method, and investigation of the phosphorus recovery using acid extraction was carried out. Almost all of the phosphorus was recovered from the ash, however, the recovered phosphorus is mainly composed of aluminum phosphate which has few usages, and much more reform of the method is needed, and some ideas for the matter are introduced.