MANAGEMENT OF GLYCOL-CONTAMINATED STORMWATER RUNOFF

The Problem During the deicing season, stormwater runoff from the Blue Grass Airport in Lexington, Kentucky, can contain glycol, which results in runoff with high biochemical oxygen demand (BOD) that exceeds their Kentucky Pollutant Discharge Elimination System (KPDES) direct discharge permit. To avoid KPDES violations, the glycol-contaminated runoff must be identified, segregated, and treated prior to discharge. Identifying the Problem Management of stormwater runoff from airport facilities during the deicing season is very challenging due to the presences of aircraft deicing chemicals. Aircraft deicing fluids like ethylene glycol and propylene glycol result in very high in biochemical oxygen demand (BOD) concentration. The quantity and quality of runoff depends on several climatological, operational, and regulatory factors.The Airport's KPDES (direct discharge) permit limits the concentration of BOD that can be direct discharged to a small receiving stream. During storm events when aircraft deicing is needed, the concentration of BOD in the runoff can exceed their discharge permit by several orders of magnitude. Furthermore, it is during these times that Airport staff is focused on Airport snow removal, aircraft deicing, and passenger and personnel safety and the staff necessary to manage stormwater runoff is at a premium. Airport's Goals and ObjectivesImprove the stormwater conveyance systemInstall a continuous, online BODInstall a hydraulic gate system automatically triggered by the BOD analyzerDevelop and implement a stormwater management planDischarge high strength BOD runoff to the publicly owned treatment works (POTW)Determine the quantity and quality of the discharge to the POTWThe Results The Airport concluded its first deicing season using its stormwater management system. Only two exceedances of their KPDES permit occurred and only a minimal quantity of runoff was contained and discharged to the POTW for further treatment. The BOD analyzer has performed very well with a minimal amount of staff support.