ACRP AIRPORT COOPERATIVE RESEARCH PROGRAM FACT SHEETS Sponsored by the Federal Aviation Administration Deicing Practices FACT SHEETS Deicing Practices #1–41 ACRP Report 14 Deicing Planning Guidelines and Practices for Stormwater Management Systems 2009 AIRPORT COOPERATIVE RESEARCH PROGRAM Deicing Fact Sheets These Fact Sheets are prepared for each of the identified deicing practices. They are organized into the five categories mentioned in “Deicing Practice Categories,” Chapter 3: aircraft deicing source reduction; airfield pavement deicing source reduction; deicing runoff containment/collection; deicing runoff treatment/recycling; and deicing runoff system components. Special note on costs: Where available, specific costs of equipment and other well-defined elements are provided in the Fact Sheets to give the reader a sense of the magnitude of costs. These estimated cost numbers should not be used for planning purposes without verifying current local costs. Aircraft Deicing Source Reduction The purpose of these practices is to reduce the amount of pollutants generated by aircraft deicing activities, either by using products with reduced environmental impacts or by reducing the amounts of deicing products required to achieve and maintain safe flight operations. It should be noted that U.S. aircraft operators must obtain FAA Flight Standards approval for certain proposed source reduc- tion Fact Sheets prior to selection and implementation. Fact Sheet 1. Aircraft-Deicing ProductSelection Fact Sheet 2. Storage and Handling of Aircraft-Deicing Materials Fact Sheet 3. Proactive Anti-Icing Fact Sheet 4. Blending to Temperature Fact Sheet 5. ForcedAir/Hybrid Deicing Fact Sheet 6. Infrared Deicing Technology Fact Sheet 7. Physical Removal Fact Sheet 8. Hangared Parking Fact Sheet 9. Hot Water Deicing Fact Sheet 10. Enclosed Deicing Bucket Fact Sheet 11. Enhanced Weather Forecasting Fact Sheet 12. Holdover Time Determination Systems Fact Sheet 13. Aircraft Deicer Use Tracking Fact Sheet 14. Aircraft Reduced Operations Fact Sheet 15. Tempered Steam Technology iii iv DEICING FACT SHEETS Airfield Pavement Deicing Source Reduction The purpose of these Fact Sheets is to reduce the amount of pollutants generated by airfield pavement–deicing activities, either by use of products with reduced environmental impacts or by reduction in the amounts of deicing products required to achieve and maintain safe flight operations. Fact Sheet 16. Airfield Pavement-Deicing Product Selection Fact Sheet 17. Storing and Handling of Airfield Deicing/Anti-Icing Agents Fact Sheet 18. PDM ApplicationTechnology Fact Sheet 19. Heated Pavement Fact Sheet 20. Airfield Deicers—Physical Removal Deicing Runoff Containment/Collection The role of these Fact Sheets is to provide methods for isolating, collecting, and containing storm water runoff from deicing activities. In most instances, these practices are implemented to address aircraft deicing runoff. Fact Sheet 21. Centralized Deicing Facilities Fact Sheet 22. Apron Collection Systems Fact Sheet 23. Glycol Collection Vehicles Fact Sheet 24. Block-and-Pump Systems Fact Sheet 25. Airfield Drainage Planning/Design/Retrofit Fact Sheet 26. Deicer-Laden Snow Management Deicing Runoff System Components These technologies represent components of systems that may be imple- mented in various locations, and serving different purposes, in any given system. Fact Sheet 27. Portable Tanks Fact Sheet 28. Modular Tanks Fact Sheet 29. Ponds Fact Sheet 30. Permanent Tanks Fact Sheet 31. Manual and Automated Diversion Valves Fact Sheet 32. Real-Time Monitoring Technology Fact Sheet 33. Catch Basin Inserts/Valves DEICING FACT SHEETS v Deicing Runoff Treatment/Recycling These practices provide alternatives for disposing of deicing runoff that has been collected and contained, and is not suitable for controlled discharge to receiving waters. Fact Sheet 34. POTW Discharge Fact Sheet 35. Anaerobic Fluidized BedReactor Fact Sheet 36. Reciprocating SubsurfaceTreatment Fact Sheet 37. Moving Bed Bioreactor Treatment System Fact Sheet 38. Sequencing Batch Reactor Fact Sheet 39. NaturalTreatment Systems Fact Sheet 40. Membrane Filtration Fact Sheet 41. Glycol Recovery SOURCE REDUCTION Containment/Collection FACT SHEET 1 System Components Aircraft-Deicing Product Selection Treatment/Recycling 1. Description Purpose This practice considers opportunities to use alternative aircraft-deicing products that have a reduced environmental impact, primarily in terms of the biochemical oxygen demand (BOD) found in the freeze-point depressants and aquatic toxicity associated with additives required to meet certification specifications. Product selection is typically the responsibility of aircraft operators and their contractors. Technology All aircraft deicing and anti-icing fluids (ADFs and AAFs) must be certified as meeting the following Aerospace Materials Specifications published by SAE: • 1424 Deicing/Anti-Icing Fluid, Aircraft, SAE Type I • 1428 Fluid, Aircraft Deicing/Anti-icing, Non-Newtonian, SAE Types II, III, and IV Each manufacturer of aircraft-deicing fluids has its own proprietary formulations, the environmental characteristics of which may vary from others. Currently, only ethylene glycol (EG)–based or propylene glycol (PG)–based aircraft fluids are used at a commercial level. Both of these glycols have a relatively high BOD content, with EG having a somewhat lower BOD than PG. The additive packages, which affect primarily the aquatic toxicity of each product, vary more significantly among the formulations. Guidance on the environmental properties is sometimes provided in manufacturer literature for each product, but it is not always consis- tent or comparable between products. The fluid manufacturers have been steadily improving their products with respect to aquatic toxicity and elimination of toxic components in the additive packages. Therefore, it is important to get the most current product information on the deicers that are being used or considered. There are several ongoing efforts to develop ADFs and AAFs with reduced environmental impacts. The Department of Defense’s Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP) have been funding research into environmentally friendly aircraft deicers for the past decade. To date, three ADFs have come out of these programs, none of which has been fully qualified for use. The goal of ACRP’s ongoing 02-01 research project is to identify the sources of 1 ACRP Report 14 April 2009 2 FACT SHEET 1 toxicity in currently available deicing formulations and develop alternatives with more environmentally friendly profiles. This project is expected to be completed in 2009 and produce several alternative formulations suitable for commercializa- tion. It is uncertain if, or when, any of these fluids will become commercially available. Documented Performance The U.S. military and some airports have mandated the use of only PG-based aircraft fluids. This bias toward PG-based fluids seems counterintuitive given its BOD content, but other environmental considerations have driven the trend. Specifically, in the 1990s, industry and the military moved away from EG- based fluids because of ethylene glycol’s mammalian toxicity and its listing as a hazardous air pollutant subject to release reporting under the Comprehensive Environmental, Response, Compensation, and Liability Act (CERCLA) and the Emergency Planning and Community Right-to-Know Act (EPCRA). In contrast to these industry trends, Dallas/Ft. Worth International Airport reported encour- aging the use of EG-based fluids specifically to reduce BOD loading from air- craft deicing. This facility disposes of all collected runoff, so recycling is not a consideration. At least one airport (Oslo) has taken the step of formally banning the use of ADFs and AAFs containing benzotriazoles because of Norwegian environmen- tal regulations. These chemicals are used as corrosion inhibitors in some fluid formulations and have been implicated as a major source of aquatic toxicity in those fluids. There were no reports identified of North American airports taking similar steps. 2. Implementation Considerations Applicability Assessment The primary key to applicability of this practice is the ability of aircraft operators to purchase and use SAE-certified deicing products based on improved environmental characteristics. Flexibility in this regard will be dependent on site-specific weather and operational conditions, which require specific deicer characteristics, and organizational constraints that may affect procurement practices. Also, any change in deicers must be accompanied by revisions to the aircraft operator’s FAA-approved snow and ice control plan. The potential for benefits from changing aircraft deicers may be evaluated by comparing the environmental characteristics of products currently being used against available alternatives in the context of existing facility-specific environmental concerns. Where glycol recycling is used or planned, there will be a strong economic motivation for using PG-based fluids because the value of recovered glycol from runoff containing only PG-based fluids is significantly greater than that of a mixed waste stream. April 2009 ACRP Report 14 FACT SHEET 1 3 Regulatory Considerations The primary regulatory considerations regarding this practice are: (1) choice of alternatives is constrained to SAE-certified products and (2) any changes in product use must be incorporated in revised FAA- approved snow and ice control plans as well as associated training and operational activities. Planning and Design Considerations Product selection by an aircraft operator begins with identifying certified products that are reliably available in the quantities required and within the time constraints. The identified list of products is then evaluated with respect to operator and industry experience with the product, ground support equip- ment fleet mix and compatibility with the product, and the need for and timing of employee retraining. Other considerations include the following: • Airport policies restricting the type of glycol that can be used at that facility. • Implications to recycling programs that depend on using a PG-based fluid. • Potential for increased management and reporting requirements associated with EG being regulated under Toxic Chemical Release and CERCLA reportable quantity regulations. • The logistics of product substitution, which will include consuming or dis- posing of existing stockpiles of old fluids and cleaning tanks and refilling them with the new product. • Modifying and distributing deicing plans to reflect the new product and train- ing employees on the new plan and product. • The environmental characteristics of the product. Integration with Other Fact Sheets Product selection can be combined with all other practices. There may be oppor- tunities to reduce the need for collection and treatment through use of deicers with improved environmental characteristics (for example, lower BOD or reduced aquatic toxicity). Operation and Maintenance Considerations For this practice to be effective, the aircraft operator should plan on revising deicing plans to reflect the new product and providing product-specific training to deicing personnel. With the exception of changes required to the deicing plans, equipment opera- tion and maintenance requirements should not change significantly. ACRP Report 14 April 2009 4 FACT SHEET 1 3. Costs Capital Costs The only capital costs that might be incurred would be if the new product is not compatible with existing storage and application equipment. Operations and Maintenance Costs The primary source of changes to operational and maintenance costs would be differences in cost of the new product compared to the previously used one. April 2009 ACRP Report 14 FACT SHEET 2 SOURCE REDUCTION Storage and Handling of Containment/Collection System Components Aircraft-Deicing Materials Treatment/Recycling 1. Description Purpose This practice includes protocols or guidelines for the storage and handling of air- craft deicing materials, with the primary purpose of reducing the contamination of stormwater by deicing/anti-icing materials. Aircraft operators or their deicing contractors are normally responsible for implementation of this practice. Transfer operations provide an Technology opportunity for inadvertent spills Specific goals for the storage and handling of deicing/anti-icing materials of deicing or anti-icing fluid. include maintaining product integrity, using and storing products effectively, and minimizing exposure of the materials to stormwater. Personnel responsible for the storage and handling of these materials should be trained in stormwater pollution prevention and follow protocols and procedures consistent with the airport’s stormwater pollution prevention plan (SWPPP) and deicer manage- ment program. To maintain the integrity and effectiveness of deicing/anti-icing materials, they must be stored, handled, and applied in a manner consistent with chemical- specific instructions provided by the manufacturer on the material safety data sheet (MSDS). Materials with reduced effectiveness may require larger appli- cation volumes or frequent reapplication, thus increasing the potential for stormwater pollution. In general, aircraft anti-icing fluid, or AAF (classified as either a Type II or a Type IV fluid by SAE), has more specialized requirements for storage and handling than does aircraft deicing fluid, or ADF (classified as a Type I fluid by SAE). The high viscosity of AAF may be damaged by improper handling or storage methods, which can potentially reduce the holdover time between applications. Thickeners in AAF may be damaged by ultraviolet light and cer- tain metal ions and thus AAF requires storage in opaque tanks constructed of stainless steel, coated steel, polyethylene, or opaque fiberglass. AAF agents also require careful heating to protect fluid viscosity. Any transfer of deicers through dedicated pipes and pumping equipment should be accomplished according to manufacturers’ specifications. Anecdotal information from one airport indicates that piping cannot contain 90°bends because they increase the likelihood of freezing. 1 ACRP Report 14 April 2009