More Capacity, Same Footprint: Modifications to the Secondary Clarifiers at the Patapsco WWTP to meet ENR Program Goals

The State of Maryland Enhanced Nutrient Removal (ENR) Program sets effluent goals of 3.0 mg/L total nitrogen (TN) and 0.3 mg/L total phosphorus (TP) for plants that discharge to the Chesapeake Bay tributaries. To meet ENR Program goals, the City of Baltimore will construct new ENR treatment facilities downstream of the existing secondary clarifiers at the 81 MGD Patapsco WWTP. The new ENR facilities include biological aerated flooded filters (BAFF) and denitrification filters. The performance of the ENR processes and the ability of the plant to meet ENR effluent goals will depend directly on the performance of the secondary clarifiers. This paper will discuss the design efforts for modifications to the secondary clarifiers to incorporate energy dissipating inlet (EDI) and will provide step-by-step approach in the evaluation and selection of the design. Construction of this project will begin in 2011.