Sludge
Treatment
Grit from the preliminary treatment process and the primary settling tanks is washed to reduce
organic content and transported to the Fulton County Landfill
along with debris
from the bar screens. Degritted primary sludge is
 pumped to two gravity
thickener
tanks and waste activated sludge is pumped to the Rotary Drum Thickener
(RDT). The thickened sludge is then pumped to anaerobic digesters which stabilize the sludge.
Most of the stabilization occurs in the primary digester where the thickened sludge is heated and
mixed. The sludge is allowed to settle and thicken in the secondary digester.
The Rotary Drum Thickener thickens sludge from less than one percent solids to approximately
six percent solids. This decreases the volume of the material that needs to be handled by reducing
the amount of liquid content and also reduces the energy requirement associated with heating the
sludge in the digestion process.
Ferrous chloride is added to the
thickened sludge to reduce odors. Polymer is added to digested sludge
to improve its dewatering characteristics then it is pumped to two
belt filter presses for processing.
Dewatered sludge is conveyed to a loading area for
subsequent hauling and disposal at the Fulton County Landfill.
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