Sludge Processing and Disposal
Sludge is the solid material which settles out of the waste- water during various stages of treatment. It must be processed and dewatered prior to disposal.
Sludge from primary treatment settles in the primary settling tanks (3) and is pumped to the gravity thickeners (8) for thickening. The thickened primary sludge is then pumped to sludge storage tanks(9). Waste activated sludge, which has settled to the bottom of the final settling tanks (5), is drawn out of the tanks and pumped to either the gravity thickeners (8) or to the gravity belt thickeners for thickening. The thickened waste activated sludge is then pumped to sludge storage tanks (9) where it is combined with the thickened primary sludge.
To prepare the thickened sludges for dewatering, polymers are added as the sludge is pumped to each centrifuge for dewatering. The dewatered sludge is then pumped by sludge cake pumps to pug mills where lime can be added. The dewatered sludge is then transported by conveyors to containers and is then hauled oft site for disposal.