Archbald Treatment Plant Solids Handling Improvements
The project will replace aging sludge thickening and dewatering equipment at the end of their useful service lives. The upgrades will improve operational efficiency and increase reliability of the solids handling processes.
Sludge Thickening - The existing dissolved air floatation thickener is legacy equipment installed with the plant’s original construction circa 1970. The thickener will be replaced with a modern gravity belt thickener that will produce more concentrated solids with a higher solids capture rate. The ability to concentrate solids reduces the volume of sludge that needs to be processed thereby reducing operating costs.
Sludge Dewatering - Sludge dewatering at the Archbald treatment plant is currently provided using a belt filter press installed in 1991. This unit, which removes water from treated sludge by compressing it between two (2) belts and a series of rollers, will be replaced by a new dewatering centrifuge. A centrifuge works by spinning the sludge at high speeds and separating the water from the solids similar to the spin cycle in a laundry washing machine. The centrifuge will be capable of producing dewatered biosolids that are 50% or more dryer than the existing belt press. The dryer solids will be lighter in weight, which translates to lower disposal cost for the LRBSA and its rate payers.
Aerobic Digestion - Waste sludge generated by the wastewater treatment process is initially treated in aerobic digestion tanks. Air is bubbled through the tanks to provide oxygen that allows natural biological activity to consume the organic material in the sludge. The system of pipes and air diffusers that allow the air to be distributed throughout the digesters will be replaced to enhance mixing and improve their performance.
In addition to the above major process upgrades, supporting systems such as polymer feed (these are chemicals used to enhance sludge thickening and dewatering), sludge pumping equipment and electrical controls will be replaced and improved.
The project is being funded by a low-interest loan from the Pennsylvania Infrastructure Investment Authority (PENNVEST).
The project is expected to be complete by July 2018.
Construction Cost: $2,821,497