Patapsco Wastewater Treatment Plant, Enhanced Nutrient Removal Project

Client: City of Baltimore

Location: Baltimore, Maryland

Services: Environmental Engineering, Enhanced Nutrient Removal

KCI, in a joint venture, performed the preliminary study and 30% design of an Enhanced Nutrient Removal (or ENR) Upgrade for the Patapsco Wastewater Treatment Plant, Maryland’s largest contributor to nutrient problems in the Chesapeake Bay. Baltimore City undertook this project to comply with the State’s ENR Program to meet new discharge goals by 2010. The JV conducted the study and provided design for the removal of total nitrogen (TN) and total phosphorous (TP) to an annual average level of 3.0 and .3 mg/L, respectively.

During the process evaluation stage, the JV identified two feasible ENR process options. Detailed modeling, pilot testing, concept design development, and O&M cost evaluations were conducted for both processes. The Project Engineers chose fixed-film nitrification filters (biological aerated filter, or BAF), followed by fixed-film denitrification filters and re-aeration.

Although used throughout Europe and Asia, the BAF technology is rare in the United States. In fact, the Patapsco Plant is the most complex United States WWTP design configuration to attempt this technology. As a result, the project team earned recognition at national and regional wastewater conferences and presented seven technical papers.

The design team had to address several challenges, including chrome-contaminated soil, limited site area, and industrial wastewater flows that inhibited nitrification. Each challenge was resolved with innovative, creative and cost-effective solutions, saving the City of Baltimore and the surrounding counties approximately $75 million.



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