Bioaugmentation to degrade the organic de-icers acetate and monopropylene glycol at low temperatures

Two de-icers, potassium acetate and monopropylene glycol (MPG), used widespread as a runway and wing de-icer respectively, can exert high BOD in the surrounding waters. A bioaugmentation approach to degrade these de-icer compounds in the drainage water prior to discharge has been tested. A microbial consortium originating from soil was enriched at low temperatures (4 degrees C) in order to adapt to wintertime conditions. With 0.05 g CDW/L of biocatalyst, maximum specific removal rates up to 1.46 and 3.33 g acetate/g CDW d at 4 degrees C were achieved with and without biostimulation respectively. An acetate:MPG mixture of 1:3 at a total COD concentration of 0.80 and 1.20 g/L was degraded in 12 days by 83 and 70% respectively. Bioaugmentation in the field over a period of 25 days showed a removal of 88% MPG compared to 46% in the control. These results demonstrate that bioaugmentation of airport runoff water can be successfully applied to prevent organic de-icer compounds from entering the receiving surface waters.