City of Baltimore Celebrates Major Environmental Accomplishment to Protect the Chesapeake Bay

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Baltimore City Department of Public Works Director, Rudolph S. Chow, P.E., joined by Mr. Ben Grumbles, Maryland's Secretary of the Environment, today announced the completion of another major milestone in improving the water quality of the Chesapeake Bay. At a ceremony at Canton Waterfront Park, the completion of the Patapsco Wastewater Treatment Plant (WWTP), Enhanced Nutrient Removal (ENR) Project, was celebrated.  

The Patapsco ENR upgrade provides new facilities and processes that support the removal of at least 95 percent of the bio-available nitrogen and phosphorus from the water that we return to the Chesapeake Bay following the wastewater treatment process.

ENR’s advanced processes build on the success of nutrient removal programs already in place. These significantly reduce the amount of these pollutants discharged into the Chesapeake Bay to levels that were unimagined at the start of the 2000s. Improved aquatic conditions will result in fewer algae blooms, which reduce the oxygen content in water and cause fish kills, odors, and unsightly conditions on the Bay and its tributaries. 

"As good stewards we must do everything possible to protect and preserve the Chesapeake Bay,” said Mayor Bernard C. “Jack” Young. “The Enhanced Nutrient Removal project means a healthier environment for fish, plants, and other aquatic life. It is our commitment as a City to improving the Chesapeake Bay, which is essential to our sustainability, health and well-being.”

The Patapsco ENR project was funded in part, about 70 percent, by the State of Maryland. The rest comes from sewer charges to customers in the region. DPW is also completing similar upgrades at the Back River Wastewater Facility.

“This, along with new sewer construction/rehabilitation, Headworks, and other Consent Decree projects, marks a giant step forward for our water quality.  Since the building of our sewer system, and our first treatment plant at Back River 110 years ago, we have not had such a dynamic impact on environmental improvement,”said Director Chow.

Approximate construction cost for ENR upgrades at Patapsco WWTP is $260 million.  The project was completed this month, with a final walk-through on January 14, 2020.  

Work on the Back River ENR facility has an estimated construction cost of $575 million. 


Patapsco Wastewater Treatment Plant

Patapsco WWTP occupies 69 acres in Baltimore City with a treatment capacity of 73 million gallons per day (mgd) increasing to 81 mgd after ENR installation.  The plant was originally constructed in 1940.

Patapsco ENR improvements include installation of 3 new buildings.

  1. Biological Aerated Filters (BAF)

22 BAF Filter Cells (Up-Flow); Process Air Blowers; Instrument Air Compressors

Dissolved Air Flotation Thickeners (DAFT); Mud-well Pumps and Blowers

  1. Tertiary Pumping Station:

500 HP Turbine Pumps; BAF Influent Channel Screens; Screening – Compactors

  1. Tetra De-Nitrification Filters :

Backwash Blowers, Backwash Pumps, Instrument Air Compressors, DAFT Units, Mudwell Blowers; Mudwell Pumps; Chemical Systems

The Patapsco Biological Aerated Filters (BAF) system is the largest installation in the United States, and one of the largest in the world.

Additional Environmental Considerations:

The project uses energy efficient HVAC equipment, lighting and electrical gear and motors, consistent with Baltimore City “Green Building” standards for an industrial classified building.

Rain from the roof of the Biological Aerated Filter (BAF) is collected and conveyed into the process filters in lieu of discharging onto the ground. This process reduces the storm water flow on to the ground and the phosphorus load to Back River.

Open grass swales were used to mitigate pollutants from the impervious pavement spaces from entering the river. Maintenance-free landscaping was installed to enhance the site appearance and provide food and cover for seasonal bird species which inhabit the area.    

During construction, dust and groundwater monitoring were provided 24/7 during all earthwork operations to protect the river, workers on the site, and the general public.

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