Analysis on Influencing Factors and Mechanism of Sludge Adhering Behavior during Thermal Drying

The influence of sludge type,sludge moisture content,drying method and thermal drying temperature on sludge adhering quantity during thermal drying was investigated through experiment.The results show that sludge moisture content is the most important factor affecting the adhering quantity.In the initial stage,the adhering quantity increases as the moisture content decreases.The adhering quantity reaches maximum when the moisture content is approximately 60%.The adhering quantity then follows a decreasing trend as moisture content decreases.The adhering quantity of undigested sludge is greater than that of digested sludge under the same condition.The adhering quantity of sludge dried indirectly is 1.5 times of that of sludge dried directly.The temperature is not a main factor affecting the adhering quantity.The analysis of sludge adhering mechanism during thermal drying shows that the organic content and water content in sludge are intrinsic factors.