Sewage sludge treatment using microwave-enhanced advanced oxidation process

A microwave-enhanced advanced oxidation process using hydrogen peroxide (MW/H2O2-AOP) was used for the release of nutrients and the destruction of solids from secondary municipal sewage sludge in this study. Using a computer statistical software package for designing experiments and for data analyses, four factors including microwave heating temperature, heating time, hydrogen peroxide dosage, and sludge solids content were examined. Experiments were performed at sludge solids content of 0.5, 1.5 and 2.5%, heating temperature of 80, 100 and 120 degrees C, heating time of 1.5, 3 and 9 minutes, and hydrogen peroxide dosage of 0, 1 and 2 wt %, respectively. Overall, the maximum solubilization of nutrients was obtained at 2.5% of total solids content, 2 wt % of hydrogen peroxide, 5 min. of microwave heating and at 120 degrees C. The most significant factor for the solubilization of nutrients using the microwave enhanced advanced oxidation process was the initial sludge concentration. Hydrogen peroxide dosage was also a very significant factor. The maximum yield occurred at an extended heating period of five minutes in this study. Nevertheless, the results indicated that the nutrient release and disintegration of solids were also very substantial over heating periods of 1.5 and 3 minutes. Even with a heating period of 1.5 minutes, the yield was estimated to be about 70% that of the 5 minute heating.