Extraction and Purification of Phosphorus from the Ashes of Incinerated Biological Sewage Sludge

Phosphorus depletion represents a significant problem. Ash of incinerated biological sewage sludge (BSS) contains P, but the presence heavy metals (e.g., Fe and Al) is main issue. Based on chemical characterization by SEM-EDS, ED-XRF ICP-OES techniques, characteristics P content bottom ash (BA) fly (FA) BSS were very similar. On BA, extraction carried out in counter- current with an S:L ratio 1:10 H2SO4 0.5 M led to better yields than those similar test 1 1:5 (93% vs. 86%). Comparing (S:L 1:10), counter-current method gave results crossflow 83.9%), also improving performance obtained HCl 89.3%). The suggest that purification acid extract from pH variation was impractical due metal precipitation as phosphates. Extraction subsequent treatment isoamyl alcohol represented best option purify leading 81% low amounts metals.