Full scale implementation of post denitrification at the Blue Plains AWT in Washington DC

The Chesapeake Bay Agreement of 1987 calls for an overall reduction in nutrient loading to the Bay of forty percent of 1985 levels by the year 2000. Signatories to the agreement include the states located in the Bay's watershed and the District of Columbia. The District's 16.2 m(3)/sec (370 mgd) Blue Plains Advanced Wastewater Treatment (AWT) Plant is the single, largest point source of nitrogen load to the Bay, currently discharging approximately 18 metric tons (40,000 Ibs) per day. In an effort toward meeting the nitrogen reduction goal, a post-denitrification demonstration project was recently undertaken to access its potential for long-term implementation. The denitrification demonstration project involved operating half of the nitrification facilities in a nitrification-denitrification mode using methanol as a carbon source for postdenitrification. The remaining half continued operation in a nitrification-only mode as a control. The two-year demonstration project was successful in meeting nitrogen reduction goals while meeting all other permit conditions. The District of Columbia Water and Sewer Authority is now proceeding to voluntarily implement the post denitrification process on a permanent, full-scale basis.