Disinfection of Sewage Sludge Using Microwave Enhanced Advanced Oxidation Process

The microwave enhanced advanced oxidation process (MW/H2O2-AOP) was used to treat municipal sewage sludge for pathogen destruction. Two levels of microwave heating temperatures of 55 degrees C and 70 degrees C, and six levels of hydrogen peroxide dosages (0% to 0.1%) were used. Fecal coliform concentrations were found below detection limit (1000 CFU/L) immediately after treatment when sludge was treated at 70 degrees C with more than 0.04% of hydrogen peroxide. Significant regrowth of fecal coliforms was observed after the treated samples were stored at ambient temperature for 72 hours. However, no regrowth was observed with hydrogen peroxide dosages higher than 0.08%, suggesting complete elimination of fecal coliforms. The MW/H2O2-AOP might be a very promising technology in sewage sludge treatment; not only can it solubilize nutrients for subsequent recovery, but also destroy pathogens, for producing Class A sludge.