As a result of the sedimentation process, settled solids must be removed from the clarifiers at a carefully controlled rate. The settled solids are pumped to an aerobic digester for further thickening. As this biological organic matter (solids) reaches a desired thickness, approximately 65%, they must then be separated from the liquid. This is often the most difficult and most expensive part of the treatment process.
The dewatering process reduces the volume by removing water content to approximately 15-20% via a belt press. By reducing the moisture content, expenses are reduced by decreasing the amount of water within the remaining organic solids. This final product, or sludge, is disposed by trucking to a landfill site. Under certain conditions set by the EPD,
the sludge or biosolids, can be applied to agricultural land as a soil amendment.
Dewatering takes place via a mechanical 'belt press' (shown above). The dry solids are then trucked off site for disposal.