Conditioning, filtering, and expressing waste activated sludge

In this study, the applied liquid pressure was used to characterize the rat e and extent of activated sludge dewatering in the expression phase. By cha racterizing the Liquid pressure, three important features of expression pha se dewatering were determined. First, as the depth of sludge cake increased , the ability to express water from the sludge cake was greatly reduced. Se cond, iron and lime were found to be superior to polymer, especially as the applied pressure increased. Third, for either type of conditioner, increas ed pressure resulted in a decreased rate of expression. This was probably d ue to the highly compressible nature of activated sludge, which responds to pressure by becoming less porous.