Six Months of Continuous Bench-Scale Testing: Finding a Process for Treatment of Very Cold Stormwater Containing Deicing Chemicals

Twenty-nine weeks of bench-scale testing were performed to assess the feasibility of treating cold water contaminated with aircraft and airfield pavement deicing and anti-icing chemicals. Testing objectives were twofold: (1) determine the minimum temperature at which biological treatment of stormwater with deicing chemicals could be expected to occur and whether it would be possible to meet the preliminary draft permit limit (average monthly CBOD5 limit = 10 mg/L) established by the Pennsylvania Department of Environmental Protection and (2) evaluate the relative efficacy of completely mixed activated sludge and a moving bed biofilm reactor process. Stormwater temperatures were reduced to as low as 2°C/36°F during testing. Testing results show that none of the systems tested could consistently produce an effluent with less than 10 mg/L soluble or total BOD5. However, all three systems were demonstrated to have a limited and periodic capability of producing an effluent with 10 mg/L soluble BOD5, including at temperatures as low as 2°C/36°F.