Greenhouse Gas and Energy Savings from Integration of Centrate Ammonia Reduction with BNR Operation: Simulation of a New York City WPCP

Simulation studies were conducted for three scenarios at the 26th Ward WPCP in New York City: no side-stream treatment, side stream treatment with an Advanced Biological Treatment (AT3), and side stream treatment with a physical chemical process, ARP. The models incorporated anaerobic sludge digestion and sludge dewatering to simulate the release of ammonia and organic nitrogen related to sludge destruction and their return to the wastewater treatment process. An extensive literature search was performed to find GHG emission factors for each of the processes. Use of the physical/chemical ARP displayed benefits intrinsic to the use of a non-biological method of nitrogen reduction. The model demonstrates that the two categories of side stream treatment have materially different benefits. Very large emissions of GHG were found for AT3. The physical-chemical processes used by ARP lowered GHG emissions relative to the base case as well as relative to AT3. The ARP alternative will produce about one-quarter (3,500 metric tons CO2eq per year) less direct GHG emissions than the Baseline alternative and 48 percent (9,300 MT/yr) less than the AT3. Source: WEFTEC 2009 Proceedings