The Who, What, When, Where, and How of BNR
Part II

Summary of Virginia draft regulations-  concentration limits are based on the waste load allocations at the current flow of existing significant dischargers.The requirements of the Chesapeake Bay Agreement and Biological Nutrient Removal (BNR) are explored in this Ampersand two-part series. Wastewater treatment plants located in the Chesapeake Bay Watershed have until 2010 to meet these requirements. In the February edition, explanations of BNR and implementation techniques were examined.

Other Considerations

While the main focus of BNR is to change the biological conditions or environments in the wastewater tanks, implementing BNR will change other aspects of wastewater plant operation as well. There are many factors involved that can affect the current sludge storage and disposal options; land application may become limited, and overall performance of the plant can become more sensitive.

Why is this technique being implemented?

Nutrients in wastewater effluent are attributed to excessive algae growth in water bodies. Algae, like plants, need nitrogen and phosphorous to grow and when there is an abundance of these nutrients algae, blooms can occur. Algae blooms can kill fish directly by the toxins that certain algae release, or indirectly by eutrophication- the consumption of oxygen in the water column when bacteria begin to break down the mats of dead algae. One of the goals of the Chesapeake Bay Agreement is to slow down these algae blooms in the Chesapeake Bay by limiting nutrient pollution.

Is there a deadline for compliance?

In accordance with the Chesapeake Bay Agreement goals, Virginia has drafted regulations that would limit nutrient discharges from wastewater treatment plants located in the Chesapeake Bay Watershed (see table above). Tentative deadlines require existing significant dischargers to reduce discharge by December 31, 2010.

How much will this cost?

Estimates for statewide BNR upgrades for existing significant dischargers range from roughly $764 million to $1.64 billion. The prospect of upgrading wastewater treatment facilities to meet these regulations may be daunting, but many existing plants can be optimized for BNR with sensible planning. Biological nutrient removal likely occurs in every facility to a minor extent and if the plant was designed with flexibility in mind, the cost to upgrade can be relatively minor.

Contact David Inman at 800.763.5596 to learn more about the Chesapeake Bay Agreement and how your facility can meet the guidelines. &



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