Comparative Study on Drying Characteristics of Sewage Sludge in Two Kinds of Indirect Heat Drying Equipment

Sludge samples are taken from Qige Waste Water Treatment Plant in Hangzhou. The drying characteristics of sludge are determined by self-made small batch type drying machine. The paddle dryer and disc dryer are used in the drying tests to explore the effect of blade form on the sludge drying viscosity zone. Different heat source temperature and drying machine speed are set up for the same kind of drying machine to research on the effect of working conditions on the drying characteristics of sewage sludge. It is discovered that the paddle dryer has a better ability to overcome the sludge viscosity zone. High speed and drying temperature can speed up the sludge drying and improve the dry deterioration in the sludge viscosity zone. But it is necessary to consider the factors of equipment stability and safe operation at the same time.