Degradation Rate of Aircraft Deicing Fluid in a Sequential Biological Reactor

Glycol-based fluids are used at northern airports during the winter to deice aircraft prior to takeoff. As a result of these operations, an appreciable amount of deicing fluid mixes with runoff and finds its way into nearby streams and lakes. The research described herein focuses on establishing the reaction rate coefficient (k) for the biological degradation of UCAR ADF-D in a sequential biological reactor under different conditions of temperature and organic bad. The rate of removal of the deicing chemical follows a first-order model. It was found that, at 22°C with a food-to-micrcorganisms ratio (F/M) of less than or equal to 2.8, a fourfold increase in F/M reduces k values by a factor of eight. The organic load is less sensitive when F/M is equal to or greater than 2.8: a seven-fold increase in F/M decreases k by only a fector of three. Temperature is very important since, when F/M ≈ 2, Jc returned values of 1.03, 0.29, and 0.05, respectively, for temperatures of 22°C, 10°C, and 4°C. This study clearly demonstrates that UCAR ADF-D can be treated biologically and that the rate of removal can be significantly affected by organic load and temperature.