Properties and Storage of Dried Sludge

The features of dried sludge produced by extruding and back-mixing are presented. The influence of conveying systems on dust generation is described. The danger of self ignition of dried sludge in silos is treated. Conditions for a safe operation of silos for fully dried sludge inclusive inertisation are presented. The application of dried sludge as a fertilizer according to US EPA 503 are described together with the necessary conditions of belt drying. Fully dried sludge can be used in cement industry by exploiting its calorific value and by replacing a portion of the limestone and marlstone demand. Limits for sludge application are discussed and an example for using waste energy of klinker cooling for belt drying is presented. Finally the possible role of dried sludge in mono incineration for recovering of phosphorous out of sludge ash is illuminated.