The treatment processes used at ASA help to improve conditions in the Bay by reducing nitrogen and phosphorus, two key nutrients that promote algae growth and eutrophication (aging) of our water bodies, and adding oxygen needed by aquatic life.

Nitrogen Removal:

Our current wastewater treatment processes are built to allow a loading of 1,315,650 pounds of nitrogen a year into Hunting Creek, a short distance from its meeting with the Potomac River south of Jones Point. This nitrogen load, along with other loads from within the Potomac and other tributaries, makes its way to the Chesapeake Bay. On average, ASA receives about 10 pounds of nitrogen per year from each of you, the users of our environmental protection system. We remove about 85% of the nitrogen you send us in your dirty water. Over $350 million went into the design and construction of our current facilities for improving our nitrogen removal.

We are constructing even more complex treatment processes over the next 8 years in order to meet newer regulations that require even more nitrogen removal on the part of wastewater treatment plants. These much more stringent limits, known as ‘limit of technology' because no one in the country has consistently achieved any lower removals, will help to offset the fact that reductions are not occurring as rapidly or as easily within the storm water or air deposition realms. These new limits will require us to limit our nitrogen loading to Hunting Creek and therefore the Chesapeake Bay to 493,381 pounds. This is about 3 pounds of nitrogen in every million pounds, or 120,000 gallons, of cleaned water returned to our environment.

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Phosphorus Removal:

ASA continues to be a leader in the metropolitan area in removing phosphorus in the wastewater you send us. We have been meeting ‘limit of technology' requirements for many years. We currently have a maximum phosphorus loading of 29,600 pounds per year. This maximum is in place past 2010.

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Dissolved Oxygen:

This is a measure of oxygen that is freely available in water to sustain aquatic organisms. The Bay's structure is highly complex, with different areas requiring different levels of dissolved oxygen. ASA does its part to keep oxygen flowing, always exceeding our minimum requirement.

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