The Impact of Cold Weather and Temperatures on the Design of Supplemental Carbon Facilities

Last Modified: Jul 22, 2013


  • Robert Frost - Hazen and Sawyer
  • Amy Gao and Mark L. Supplee - CH2M HILL
  • Sue Liu - NYCDEP

The design of supplemental carbon facilities using glycerol for biological nitrogen removal at wastewater treatment plants (WWTP) has thus far been based on limited published literature values and available vendor viscosity data. The viscosity of glycerol solutions varies significantly with temperature and glycerol concentration (Chemical Engineers’ Handbook, 5th ed). Viscosity data for the lower range of design temperatures, specifically -5°F to 32°F, has not been identified in published literature (Chemical Engineers’ Handbook, 5th ed). High viscosities at cold temperatures can lead to excessive headloss and backpressure in the glycerol feed system.

To determine the impact of winter temperatures on the design of glycerol feed systems at five of NYC Department of Environmental Protection’s (DEP) WWTPs, viscosity was measured as a function of a wide range of temperatures on four commercially available carbon products at several different concentrations. The test results led to design features and operational procedures to keep viscosities manageable during cold weather.

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