This project was initiated on June 1, 1995 for the purpose of stimulating efforts towards the reduction of point source nutrient discharges to the waters of the Chesapeake Bay Watershed. Prior to the project, a few engineering firms had developed reports wherein they estimated the total costs for biological nutrient removal (BNR) retrofits at the wastewater treatment plants (WWTP) throughout the Watershed. The estimates indicated that implementation of nutrient removal throughout the Watershed would be very costly. The Virginia Tech BNR research group had been working with several full-scale WWTPs in Virginia and Maryland to demonstrate that BNR processes can be reliably operated, can be more economical to operate than fully nitrifying processes, and that retrofits can be relatively inexpensive to implement. The group had successfully experimented with fixed film media integrated into activated sludge at the Annapolis, Maryland WWTP to reduce the aeration basin and clarifier capacities needed for implementation of nitrogen removal at that facility. The successful demonstration reduced the construction needs from a one-third increase in aeration volume and a 150% increase in clarifier volume to no increase in aeriation volume and a 50% increase in clarifier volume.