An ozone/hydrogen peroxide/microwave-enhanced advanced oxidation process for sewage sludge treatment

Solids destruction and nutrients release from sewage sludge were investigated using thermal destruction and/ or oxidation processes. Hydrogen peroxide ( H2O2), ozone ( O-3) and a combination of both were used for the oxidation processes performed at ambient temperature. Thermal destruction using microwave ( MW) alone without an oxidant was also conducted. Microwave enhanced advanced oxidation processes ( MW- AOP), such as MW/O-3, MW/ H2O2 and MW/ H2O2/ O-3, were conducted at 100 degrees C. In terms of nutrients release and solids reduction, the MW/ H2O2/ O-3- AOP yielded the best result; an addition of ozone improved the MW- AOP process. More than 30% of TP and 20% of TKN were released into the solution. About 37% of total COD was also solubilized from sludge mass. Both the conventional oxidation processes and the MW- AOP processes could be used to release nutrients and to reduce solids from sewage sludge; however, the MW- AOP processes were superior in performance. Microwave heating alone also resulted in a substantial amount of ortho- phosphate into the solution.