Recovery of phosphorus from sewage sludge ash: Influence of incineration temperature on ash mineralogy and related phosphorus and heavy metal extraction

Phosphorus (P) can be effectively recovered from sewage sludge ash (SSA) by applying wet chemical extraction techniques. However, considerable amounts of heavy metals co-extracted depending on the type liquid used. In this study, influence incineration temperature mineralogy and related P metal using sulfuric acid, hydrochloric oxalic acid sodium hydroxide was studied. Results showed that efficiency with decreased increasing temperature, to a decrease in Al/Fe-phosphates SSA. Furthermore, for acidic liquids reached maximum SSA obtained around 850 °C (> 86% extracted). Heavy co-extraction generally which could linked immobilization matrix. For all considered, lowest found samples at 1000 (< 21% total incorporation into silicate melt agglomerates reduced extraction. As result, an range 800 – offered good trade-off between high low co-extraction. • Sewage incinerated temperatures 550 1100 °C. Incineration affected mineralogy. highest 86%). 21%).