Drying The dewatered sludge passes through an indirect primary dryer taking the sludge though the sticky plastic phase, producing a product with a 55% to 65% dry solids content. A secondary disk dryer increases the solids content to in excess of 93%.
Vitrification The dried sludge passes through a grinder to the vitrification unit where it becomes the sole fuel, after auxiliary fueling upon start-up. A vitrification temperature in excess of 1200°C is maintained to melt the sludge, causing it to fuse and flow through the vitrification process. The resultant slag, which drops into a water quench section for cooling, represents a final reduction of 99%.
