ABSTRACT
Sludge dewatering is an important step in the total sludge processing train and has a serious impact on the effectiveness and cost of subsequent process. Dewatering is a physical unit operation used to reduce the moisture content of sludge for one or more of the following reasons [149]:
The cost of transporting sludge to the ultimate disposal site becomes substantially lower when sludge volume is reduced by dewatering.
Dewatered sludge is generally easier to handle than thickened or liquid sludge. In most cases, dewatered sludge may be shovelled, moved about with tractors filled with buckets and blades and transported by belt conveyors.
Dewatering is normally required prior to the heat drying and incineration of the sludge, to increase the calorific value by removal of excess moisture.
In some cases, removal of the excess moisture may be required to render the sludge totally odourless and non-putrescible. This is especially true for sludges stabilized by processes that create high strength recycle flows.
Sludge dewatering is commonly required prior to land filling to reduce leachate production at the landfill site.
