Atie Amirgo - Master of environmental engineering, water and wastewater treatment, faculty of environment, university of Tehran
Nasser Mehrdadi - Professor, faculty of environment, university of Tehran

Weinvestigated the effect of different parameters on the ozonation process for disinfection of excess sludge ofan active sludge system. Ozone dosage and pH werethe main parameters investigated in this study. In order to optimize the ozone dosage and pH, total coliform and E.coli count was done before and after the disinfection process using the MPN method. It was found that because of the great amount of suspended solids in sludge, the satisfactory results could not be obtained unless a filtration step was added to the system. The optimal dose of ozone was found to be 0.2 gO3/gTSS. Furthermore, at the pH value equal to 11, the efficiency of disinfection reached its maximum.

sludge, disinfection, ozonation