Abstract: Two-stage sludge drying process by thin film dryer and linear dryer had features of high dry sludge yield (moisture content 10%~30%), safety (oxygen content<5%), high water evaporation efficiency, low equipment investment, stable operation and so on. The process flow, core equipment, process design and commissioning operation of a large-scale domestic municipal sludge treatment and disposal project with a capacity of 1 442.5 t/d was introduced. The project was equipped with 10 two-stage sludge drying lines, and the moisture content of feeding sludge was 78%~82%, the outgoing sludge moisture content could reach to 20%~33%. All performance assessment index and energy consumption index were up to standard.

Key words: sludge drying, two-stage process, thin film dryer, linear dryer