The study of sewage sludge thermo-drying efficiency

With the population exploding and improvement of urbanization, the sewage sludge production increases rapidly with the increasing of sewage. However, high water content has been a big problem for sewage sludge treatment and disposal. Thermo-heating is one of the mature methods to reduce the water content in sewage sludge, but the promotion of thermo drying is very restricted by its high cost because of abundant consumption of energy and its expensive equipments. In order to save energy and reduce investment for equipments, we studied the low-temperature thermo-drying efficiency by varying the temperature from 100 degrees C to 200 degrees C, and changing the shape of the sewage sludge sample, We tried three shapes (cake, cylindrical and spherical) and three temperature (at 150 degrees C,175 degrees C and 200 degrees C). It is found that cake sludge has the highest drying efficiency and spherical sludge is the lowest in each condition. At 200 degrees C the drying efficiency could get the highest point. (C) 2012 Selection and/or peer-review under responsibility of Basel Convention Coordinating Centre for Asia and the Pacific and National Center of Solid Waste Management, Ministry of Environmental Protection of China.