Wastewater Performance Tracking
One of Maryland's priority strategies in the Chesapeake Bay Watershed Implementation Plan (WIP) for reducing nitrogen and phosphorus pollution - to support healthy living resources - is ensuring wastewater treatment plants (WWTPs) comply with Enhanced Nutrient Reduction (ENR) standards. Maryland has invested over $1.3 billion in ENR upgrades for major WWTPs (engineered flow of 0.5 million gallons per day or greater) and has allocated an additional $315 million for upgrades to minor WWTPs (engineered flow less than 0.5 million gallons per day) along with funding other practices to reduce nutrient pollution in the State. In addition, Maryland has awarded $68.7 million in operation and maintenance (O&M) grants to support WWTPs that optimize their operations to achieve ENR level of treatment or better.
For more information on the Bay Restoration Fund, click here .
Major WWTPs ENR Status
Background
To achieve Maryland's WIP and the Chesapeake Bay Climate Change Goals , the Maryland Department of the Environment (MDE) has set a target average total nitrogen discharge concentration for Chesapeake Bay Significant WWTPs (facilities with a capacity of 0.5 million gallons per day or greater) of 2.85 mg/L.
By early/mid-2020, Maryland was on track to meet its 2.85 mg/L target. However, in 2021, MDE’s compliance inspections at Maryland’s two largest WWTPs (Back River and Patapsco) uncovered significant permit violations. Blue Water Baltimore was also instrumental in identifying these compliance issues.
Numerous actions were taken by MDE, the Maryland Environmental Service (MES), and the Office of the Attorney General to bring the plants back into compliance. Those efforts culminated in a Consent Decree with Baltimore City that includes penalties, enforceable timelines for corrective actions at the Back River and Patapsco WWTPs, and competitive grants for water quality and aquatic habitat improvement projects in the Patapsco and Back River watersheds.
New Wastewater Framework
To prevent future performance problems at the Significant WWTPs, MDE conducted a comprehensive review of its wastewater permitting and compliance process. This review led to Maryland's Updated Strategies to Reduce Nutrients in Wastewater:
MD's Updated Strategies to Reduce Nutrients in Wastewater
Early Detection
The early detection and notification system is a continuous tracking effort where facilities' monthly discharge data are analyzed to detect potential issues in Significant WWTP operations in a timely manner. When wastewater concentrations exceed expected values, MDE reaches out to those facilities to understand the underlying causes and the planned corrective measures, when applicable. This process provides real-time performance feedback and improvement that helps prevent larger system failures.
The graphs below show the yearly performance tracking results at Maryland’s Significant WWTPs. As new monthly data become available, the graphics below are updated. Click on the right arrow to see data from previous years. Please note that MDE uses monthly and quarterly averages solely to identify early signs of declining ENR performance, while permit compliance assessments are based on annual results evaluated after the end of the calendar year. Additionally, considering that low temperatures reduce the efficiency of biological nitrogen removal, it is not uncommon to see higher total nitrogen effluent concentrations during winter months.
Back River and Patapsco WWTPs
Aggregate of All WWTPs with Significant Discharge
Annual Performance Results
Although a few facilities have not met ENR standards in the past couple of calendar years, the volume of their discharge is minimal compared to the total discharge from all of Maryland's Significant WWTPs.
The charts below show how much of the annual monthly average discharge from these WWTPs comes from facilities not meeting ENR performance standards. Use the right arrow to navigate to previous years.
Maryland achieved its WIP target in the wastewater sector in 2023 and 2024. By the end of both years, Baltimore City also met its annual nutrient permit limits for the Back River and Patapsco WWTPs.
Annual Average Total Nitrogen Concentrations in 2023 and 2024
With the establishment of Early Detection and Performance Tracking in 2023, attentive oversight by MDE in response to early signs of performance issues is expected to contribute to significant improvements in total nitrogen concentrations in Maryland's Significant WWTP discharges. This proactive approach, involving the collaboration of many MDE programs, ensures that facilities address concerns before they escalate, supporting long-term compliance with water quality goals.
MDE continues to monitor Baltimore City's WWTPs' performance closely. Upon detecting concentrations above trigger values, MDE promptly contacts facilities to understand and help resolve any existing challenges.
