4% Solids Waste Sludge Application

Application / Industry:  Municipal Wastewater Treatment
Customer Name:  Abington Regional Wastewater Authority
Consulting Engineer:  Gannett Fleming, Harrisburg, PA
Process Fluid:  Municipal Waste Activated Sludge
Process Treatment Method:  Aerobic Digestion


The town of Abington, PA, needed an upgraded waste sludge storage system to increase solids concentration for overall volume reduction, along with decanting and thickening of waste sludge. Design concentration was set at a fairly high level of 4% solids, increasing fluid viscosity, oxygen transfer and mixing energy requirements.  Inadequate mixing and oxygen transfer would cause process fluid to prematurely transition to an anaerobic state, resulting in hydrogen sulfide gas discharge.


Tideflex® Technologies Engineers provided a maintenance free Coarse Bubble Mixing and Oxygen Supply System, modeling the oxygen transfer adjustment by utilization of the alpha transfer reduction curve. The system was modeled for a maximum of 4% solids content.


The Tideflex® system proved an excellent solution as it provides high rate mixing in combination with oxygen transfer even in high solids applications, where complete mixing is critical in obtaining target dissolved oxygen levels. High solids concentrations in waste activated sludge fluids results in the most aggressive and difficult fluid at any wastewater treatment facility and typically is the highest to maintain and operate. 

The Tideflex® Check Valve Diffusers allow operators to shut-off the blower for decanting activities.  When the blower is turned back on, the Tideflex® system provides complete re-suspension of all settled solids, eliminating the potential for pockets forming in anaerobic areas.  The Tideflex® system completed eliminated maintenance costs associated with management of this difficult fluid for Abington’s operations.

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