New York City Environmental Protection (NYCEP) is in the process of upgrading its treatment plants for nitrogen removal and is treating centrate, the side stream emanating from the anaerobic digestion process separately (SCT). The City is currently using a multi prong approach to treat centrate. Currently it uses the conventional nitrification/denitrification process with caustic and carbon addition at some of the plants and has the world's largest SHARON® demonstration facility at one site. In addition, the City is exploring the use of the anammox process as a viable alternative to the above two processes. To this effect, a pilot MBBR partial nitritation/anammox (PNA) reactor was operated in conjunction with the City College of New York (CCNY) at the 26th Ward Waste Water Treatment Plant in Brooklyn, NY. PNA is a nitrogen removal process that has a low carbon footprint and fits a low energy framework exceedingly well with low aeration and no external carbon requirements. Conducting a cost comparison of the PNA process to the conventional SCT and the SHARON® process on a cost per pound of nitrogen removed basis, it is found that the operating costs for the PNA process is only 35% of the SCT and 65% of the SHARON®, thus delivering substantial savings to the City when adopted at full-scale for future decades.
- separate centrate treatment
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