Tuesday, June 23, 2009

Sludge Drying Beds

Sludge drying bed is used as the last step of dewatering system. Sludge of the system is dewatered on these beds by evaporation and drainage. Moreover, cationic polymer can be added to get faster and easier dewatering process. The polymer accelerates the particle agglomeration, increasing the total amount of water that can be drained and reducing the amount of water that needs to be evaporated.

Close sand sludge drying bed is used in this dewatering process. This type of beds includes gravel, sand and sludge layers. Also, at the bottom part, under the gravel layer, there are plastic pipes for the under drainage. Closed sand drying bed is chosen do to EPA.