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Volume II, Number 12

April, 2007

Status of Wastewater Treatment Plant Enhanced Nutrient Removal  (ENR) Upgrades

 By Rajiv Chawla, Water Management Administration


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The Chesapeake Bay is Maryland’s greatest economic and environmental treasure. The last fifty years has shown a drastic decline in water quality due to unwanted nutrient loading from phosphorus and nitrogen. The major contributors to nutrient discharge in the bay are wastewater effluent, urban and agricultural runoff, and air deposition.

Small Fee Provides Large Enhancements
The Bay Restoration Fund (BRF), created in 2004 by the Bay Restoration Act, was a critical turning point for the state in its efforts to restore the Bay. The fund is financed by a $2.50 monthly fee paid by wastewater treatment plant (WWTP) users to upgrade the 66 largest WWTPs that serve county or municipally designated growth areas. These facilities represent approximately 95 percent of the total sewage flow to the Bay and its tributaries. The Bay Restoration Act also specifies a fee on owners of septic systems to be used to fund nutrient removal upgrades for these systems.

BRF Helps Enhanced Nutrient Removal
The Maryland Department of the Environment (MDE) manages the BRF and provides financial assistance to local governments to upgrade their WWTPs. The upgrades involve installing Enhanced Nutrient Removal (ENR) technology to enable the plants to achieve lower levels of nitrogen and phosphorus discharged to the Bay.

As of February 28, 2007, the Board of Public Works has approved over $72.3 million in Bay Restoration Grant awards for the ENR upgrade of 28 of the 66 targeted wastewater treatment plants.

To date, the Board of Public Works has approved BRF funding to implement ENR technology at 28 plants representing 26 jurisdictions. In just over two years since Bay Restoration Funds first became available, ENR upgrades have been completed and are in operation at two plants (Celanese and Hurlock). Another 11 upgrades are under construction, final project designs are underway at 12 facilities, 23 facilities are in the planning stage and the remaining 18 facilities are in pre-planning. For the facilities in the pre-planning phase, ENR agreements will be executed with the facility owners, or evaluations will be conducted to determine if further improvements are needed to achieve ENR.

The Results
Once upgraded, these plants are expected to reduce nitrogen and phosphorus in the wastewater down to 3 milligrams per liter (mg/l) total nitrogen and 0.3-mg/l total phosphorus resulting in 7.5 million-pound annual reductions in nitrogen and 260,000-pound annual reduction in phosphorus. Reducing these nutrients is a significant step in addressing the water quality impairments in the Chesapeake Bay. Other conventional pollutants such as biochemical oxygen demand and total suspended solids will continue to be reduced by more than 90 percent. ENR upgrades typically result in 70-90 percent nutrient reductions in nitrogen or phosphorous discharges from WWTPs.

In our ongoing commitment to assure service to Marylanders and our environment, the Bay Restoration Fund will continue to fund projects that reduce nutrient loads to the Bay.

Click here to learn more about the Bay Restoration Fund or call 410-537-4195.

:: This Issue's Featured Articles :: Enforcement and Compliance Notes :: For the Record



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Maryland Department of the Environment
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