Biodegradation of propylene glycol and associated hydrodynamic effects in sand.

At airports around the world, propylene glycol (PG) based fluids are used to de-ice aircraft for safe operation. PG removal was investigated in 15-cm deep saturated sand columns. Greater than 99% PG biodegradation was achieved for all flow rates and loading conditions tested, which decreased the hydraulic conductivity of the sand by 1-3 orders of magnitude until a steady-state minimum was reached. Under constant loading at 120 mg PG/d for 15-30 d, the hydraulic conductivity (K) decreased by 2-2.5 orders of magnitude when the average linear velocity of the water was 4.9-1.4 cm/h. Variable PG loading in recirculation tests resulted in slower conductivity declines and lower final steady-state conductivity than constant PG feeding. After significant sand plugging, endogenous periods of time without PG resulted in significant but partial recovery of the original conductivity. Biomass growth also increased the dispersivity of the sand.

[1]  David A. Pillard,et al.  Comparative toxicity of formulated glycol deicers and pure ethylene and propylene glycol to Ceriodaphnia dubia and Pimephales promelas , 1995 .

[2]  H. D. Stensel,et al.  Cometabolic Degradation of TCE and DCE Without Intermediate Toxicity , 1995 .

[3]  M. Switzenbaum,et al.  Alcohol and acid formation during the anaerobic decomposition of propylene glycol under methanogenic conditions , 2004, Biodegradation.

[4]  Philippe C. Baveye,et al.  Saturated Hydraulic Conductivity Reduction Caused by Aerobic Bacteria in Sand Columns , 1992 .

[5]  Bruce E. Rittmann,et al.  The significance of biofilms in porous media , 1993 .

[6]  H. D. Stensel,et al.  Evaluation of biodegradation kinetic testing methods and longterm variability in biokinetics for BTEX metabolism , 1999 .

[7]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[8]  Alfred B. Cunningham,et al.  Influence of Biofilm Accumulation on Porous Media Hydrodynamics , 1991 .

[9]  J. Komlos,et al.  Observation of thick biofilm accumulation and structure in porous media and corresponding hydrodynamic and mass transfer effects , 1999 .

[10]  B. E. Jank,et al.  Activated sludge treatment of airport wastewater containing aircraft de-icing fluids , 1974 .

[11]  B. Rittman,et al.  The effect of shear stress on biofilm loss rate. , 1982, Biotechnology and bioengineering.

[12]  Devon A. Cancilla,et al.  Detection of Aircraft Deicing/Antiicing Fluid Additives in a Perched Water Monitoring Well at an International Airport , 1998 .

[13]  Anthony F. Gaudy,et al.  Microbiology for environmental scientists and engineers , 1981 .

[14]  T. Illangasekare,et al.  Hydrodynamic Changes in Sand due to Biogrowth on Naphthalene and Decane , 2002 .

[15]  Stewart W. Taylor,et al.  Biofilm growth and the related changes in the physical properties of a porous medium: 1. Experimental investigation , 1990 .

[16]  Bruce E. Rittmann,et al.  Simplified design of biofilm processes using normalized loading curves , 1990 .