Implications of Glycerol Addition on Nitrogen Removal Mechanisms


  • R. Sharp, A. Brace - Manhattan College
  • S. Dailey Galst, P. Pitt - Hazen and Sawyer
  • A. Deur, K. Beckmann - NYCDEP
  • V. Rubino - CH2M-Hill

The glycerol AT-3 demonstration took place at the ACEC award-winning 26th Ward WWTP, where the AT-3 process was originally developed.

The need for an effective, safe and sustainable supplemental carbon source has become increasingly important as more municipalities are required to meet stringent total nitrogen effluent standards. Glycerol-based carbon sources have gained a lot of attention from the wastewater industry because they are a sustainable alternative (waste product of biodiesel production), do not pose health and safety risks like methanol and ethanol, do not have kinetic limitations in cold weather, and have proven to be effective at pilot and full-scale.

In January 2012, the New York City Department of Environmental Protection began a full-scale demonstration of an AT-3 Separate Centrate Treatment process with glycerol as the added carbon source. During the evaluation of the process, a series of denitrification batch tests were carried out to better understand the kinetics of glycerol acclimated biomass (GAB). The initial batch tests indicated that the GAB carried out denitratation (NO3 to NO2) at a very high rate, while nitrite accumulated until almost all of the nitrate was converted, then denitritation (NO2 to N2(g)) began at rates that were equivalent to over-all denitrification rates observed in previous studies using glycerol. Subsequent batch tests were carried out to better understand this kinetic phenomena, and to investigate potential operational changes that could be made to reduce possible impacts of the initial nitrite accumulation.

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