Effect of mineral elements on phosphorus release from heated sewage sludge

The aim of this work was to examine the influence of mineral elements on phosphorus (P) release from heated waste sludges. Energy dispersive X-ray microanalysis suggested that P was associated with Al, Ca, and Mg on the surface of waste sludge biomass obtained from six wastewater treatment plants. The extent of P release decreased with increasing the total concentrations of Al, Mg, and Ca in waste sludges. The addition of Al2(SO4)3, Ca(OH)2, CaCl2, MgSO4, or NaAlO2 to activated sludges, which were taken from a bench-scale EBPR process, reduced the P release significantly.