MOULTRIE, GA WRF UPGRADES

SCUM AND SLUDGE MANAGEMENT

Carter & Sloope Consulting Engineers was contracted to upgrade the City of Moultrie WRF using a multi-phase design-bid-build methodology.  One of the phased upgrades involved removing and replacing existing scum skimmers, primary sludge pumps, digester sludge transfer pumps and digester mixing pumps to compliment the upgrade of the existing digesters.

The existing scum skimmers located in the primary clarifiers were constructed of cast iron and had been attacked by corrosion over the life of the units and basically rendered them useless.  The idea was to get away from metallurgical scum skimmers and look at fiberglass scum skimmers that are not subject to corrosion.  Plasti-Fab offered a solution with their fiberglass scum skimmers that could retrofit into the same space as the existing cast iron scum skimmers.

To further the upgrades at the primary clarifiers, the City decided to replace the old piston style primary sludge pumps with new Penn Valley Pump's double disc positive displacement pumps.  The upgrade involved removing the old piston style pump from its remote location from the primary clarifiers and installing the new Penn Valley Pumps nearer to the source of the sludge.  This was done to reduce the amount of buried piping that transferred the primary sludge to the pump suction and thus reduce the potential for the buried lines to clog.  One Penn Valley Sludge pump was dedicated to each primary clarifier in order to allow each of the four primary clarifiers to pump sludge independent of the other clarifiers.  Therefore, a total of 4 Penn Valley pumps and two control panels were delivered to the project site.  A fifth Penn Valley Pump was installed to replace another piston style sludge pump for the waste activated sludge pump application.

Part of the digester upgrade included replacing the existing digester mixing pumps with Vaughan Chopper pumps.  The rugged design of the Vaughan Chopper pump plus the ability for the pump to chop up plastics and rags reduced the amount of down time and maintenance needed for a standard centrifugal pump to perform the task of mixing a digester.