Sludge/Coal Washery Drying System
Sewage sludge is primarily derived from waste water which also consists of a variety of other substances. Prior to drying the sludge, free water is removed by mechanical means such as a belt press or firame preas to achieve around20-35% dry solids.
Then the sludge pases to the Rotary Dryer for removal of remaining water to achieve around 70% dry solids, by conduction drying whereby the sludge is brought into contact with a heated surface and heat is usually provided by waste heat steam.
The Rotary Sludge Dryer consists of a horizontal drum which rotates around its axis, composed of membrane tubes through which the heating medium flows, and the sludge to be dried is moved through the drum by internal fins.