The aim of this paper was to study the characterization of sludge affected by different thermal treatment, on selected physical and chemical properties. Sludge incinerated ash has been fired at different temperatures. This material was fired at 1050 °C for 3 h and until a peak of 1010°C. After thermal treatment the ash were screened at 200 mesh. The ash was characterized by X-ray fluorescence and trace elements like Cr, Pb, Zn, Cu, and some oxides like quartz(SiO2), Al2O3, P2O5, Fe2O3 were found. Scanning electron microscopy (SEM) has shown one change of particle between 2μm at 90μm and apparent porosity.