Studies on Effect and Corresponding Technical Characteristics of Excess Sludge Reduction in Pressurized Biological Contact Oxidation Process

The excess sludge of wastewater biological treatment, as refractory compounds, only 25-40% of which could be biodegraded. While much research work has be done about the application of sludge, there were concerns about the application of biosolids due to risks associated with disease, odor, nutrients and the presence of toxic metals. Recently, many studies have focused on sludge reduction technology. In this paper, the sludge yield of pressurized biological contact oxidation process was discussed. The studies showed that the sludge yield was about 0.07-0.14 kgVSS/kgCOD when the volume loading changed within 16.8 kgCOD/(m³-d). The technical characteristics leading to excess sludge reduction in pressurized biological contact oxidation process was discussed based on present research achievement. Three concerned technical characteristics played a significant role in the process, including higher organic loading, higher DO concentration and biofilm formation.