### MEMORANDUM

TO: Brian D’Amico, EPA/EAD

FROM: Mary Willett, ERG

DATE: June 30, 2009

SUBJECT: Evaluation of Proposed Compliance Al ternative Ammonia Limitations with respect to Airport Deicing Stormw ater Typical Ammonia Discharges

Purpose

The purpose of this memorandum is to compare the proposed compliance alternative ammonia limitation and standard for airport deicing operations to airport deic ing stormwater discharges of ammonia at airports that use urea-b ased airfield deic ing chemicals.

Basis of EPA’s Proposed BAT for Airfield Deicing

As part of the proposed rule, EPA wants to reduc e discharges associated with the use of ureabased airfield deicing chemicals. As a result , EPA proposed BAT for airfield deicing to be product substitution and required an airport to cer tify (in the absence of compliance monitoring) that it is not using urea-based airfield deicing fluids. Howeve r, EPA also proposed a compliance

alternative that would allow an airport to choose to meet an a lternative ammonia limitation rather than provide a certification. 1 Because EPA estimated costs for the collection and treatment of airfield stormwaters and found the costs to be pr ohibitively high for most airports and because airfield deicing wastewater monitoring is ex tremely complex, EPA anticipates that airports subject to the proposed rule would chose to repla ce urea-based airfield de icing chemicals with a non-urea product and simply certify-- thus elim inating the necessity of monitoring and complying with the proposed compliance alternative ammonia discharge limitation.

Basis of EPA’s Proposed Compliance Alt ernative Ammonia Discharge Limitation

Because the proposed BAT for airfield de icing is product substitution, any compliance

alternative ammonia limit would appropriately reflect non-use of urea. However, EPA also proposed a COD limit that would a pply to all airport deicing stor mwater discharges based on the long-term treatment performance data provided by Albany International Airport (ALB) which characterizes the treatment of deicing stormw aters through an Anaerobic Fluidized Bed (AFB) treatment system. A by-product of this treatment process is ammonia generation. As a result, the Agency evaluated ammonia c oncentrations resulting from the ALB wastewater treatment system and found that AFB discharges may have higher ammonia concentrations than background ammonia levels found in airfield runoff at airports w ithout urea. As a result, EPA

1 Ammonia is a breakdown product of urea-based deicing fluidsMemorandum
June 30, 2009 Page 2

based its compliance alternative ammonia as N limitation on discharge concentrations from the

AFB wastewater treatment system. See Table 1.

Table 1. EPA’s Proposed BAT Compliance Al ternative Ammonia as N Limitation and

Standard

Pollutant Daily Maximum (mg/L)

Ammonia as N 14.7

Using ammonia concentrations from the ALB effluent results in a proposed compliance alternative ammonia limitation which is higher th an airfield runoff ammonia concentrations where no urea-based deicers are used. However, as described in more detail below, EPA concludes that the proposed compliance alternat ive limitation is lower than airfield runoff

ammonia concentrations where urea -based deicers are used.

Typical Ammonia Concentrations in Airport De icing Stormwaters from Airports That Use Urea-Based Airfield Deicing Chemicals

To evaluate whether airports wh ich use urea-based airfield deicers in the absence of treatment are likely to discharge deici ng stormwaters with ammonia as N (or ammonia) concentrations higher than the proposed ammonia- N complian ce alternative limitati on, ERG reviewed data from the following sources:

 The Preliminary Data Study for the Air port Deicing Operations industry;

 Several airport deicing st ormwater studies; and

 Industry-supplied data from Detroit Metr opolitan Airport co vering a timeframe prior to the airport’s discontinuation of urea airfield deicing chemical use.

Table 2 presents a summary of the information identified representing typical ammonia as N (or ammonia) concentrations and concentration ranges from these sources. Review of Table 2 shows that in general deicing stormwater samples collec ted at airports with ur ea use reach ammonia as N (or ammonia) concentrations that exceed th e proposed compliance alternative limitation (in some cases, by an order-of-magnitude). Of the 11 U.S. airports included in the table with either active urea use or suspected urea use, all but one showed maximum ammo nia as N or ammonia concentrations above the proposed complia nce alternative limitation, with maximum concentrations ranging from 1.1 mg/l to 171 mg/l. Additionally, studies for several non-U.S. airports in Canada and Europe using urea airfield deicing chemi cals also demonstrate stormwater discharge ammonia concentrations above the pr oposed compliance alte rnative limitation, with maximum concentrations ranging from 17 mg/l to 124 mg/l.

Typical Ammonia Concentrations in Airport Deicing Stormwaters from Airports that

Discontinued Use of Urea-based Airfield Deicing Chemicals

Both the Detroit Metropolitan Airport (DTW) a nd Pittsburgh International Airport (PIT) used urea deicers for airfield deicing in the past but have discontinued the practice. These airports provided long-term ammonia data for selected co llection ponds and outfalls. Table 3 presents the range of ammonia concentrations measured in Ponds 4 and 6 at DTW since the airport stoppedMemorandum
June 30, 2009 Page 3

using urea. Table 4 presents th e range of ammonia as N concen trations measured in runway

related outfalls at the PIT since the airport stopped using urea. Th ese data indicate that deicing stormwaters generated at airports that di scontinue urea use typi cally have ammonia concentrations in their deicing stormwaters be low 1 mg/L. None of th e samples exceeded the proposed daily maximum complia nce alternative limitation.

Conclusion

This analysis documents that EPA’s proposed compliance alternative ammonia-N limitation would likely be exceeded by airports using urea as a deicing chemical on their airfields in the absence of treatment; requiring airport’s subject to the regulation to modify airfield deicing urea use or to provide treatment. On the other hand, this analysis also documents that airports that have discontinued urea airfield deicing chemical would be able to comply with the proposed compliance alternative ammonia-N limitation.MemorandumJune 30, 2009Page 4Table 2. Typical Ammonia Concentrations in Airport Deicing StormwatersAirportSourceIndication ofUrea UseAmmonia as NConcentration/ConcentrationRange (mg/L)Deicing Stormwater DescriptionGreater Rockford 1 Yes ND (0.5) – 82 Airport submitted data (average was 24 mg/l), 1999Albany 1 Yes 88 Contents of the small lagoon, EPA sampling, airport reported thisconcentration was an anomaly and they usually see < 45 mg/LAlbany 1 Yes 84 Composite of large lagoon and tank, EPA sampling, 1999Bradley 1 Yes 1.1 Stormwater Outfall, EPA sampling, 1999Chicago O’Hare 1 Not specified 0.2 – 50 PCS data pull, NW drainage, avg. effluent = 10.8 mg/L, 1997/1998Chicago O’Hare 1 Not specified 0.2 – 50 PCS data pull, N drainage, avg. effluent = 11.2 mg/L, 1997/1998Chicago O’Hare 1 Not specified 0.6 – 10 PCS data pull, NE drainage, avg. effluent = 3.4 mg/L, 1997/1998Chicago O’Hare 1 Not specified 2.6 – 85 PCS data pull, SE drainage, avg. effluent = 35.1 mg/L, 1997/1998Chicago O’Hare 1 Not specified 0.7 – 37.5 PCS data pull, SW drainage, avg. effluent = 8.28 mg/L, 1997/1998Chicago O’Hare 1 Not specified 50 PCS data pull, drainage from deicing, 1997/1998Louisville StandifordField1 Not specified <0.03 – 171 Stormwater/deicing fluid runoff, PCS data pull, avg. effluent = <17.2,1997/1998NewcastleInternational Airport(United Kingdom)2 Yes 105.7 (ammonia) Measured at airport tributary, mean total ammonia concentrations fromsamples taken duringfreezing conditionsNine Canadian airports 3 Yes Max up to 124 mg/L (ammonia) Stormwater runoffTwo European airports 3 Yes Max of 105 and 89.7 mg/L(ammonia)Stormwater runoff, mean values of 8.73 and 15.9 mg/L (ammonia)Dayton International 4 Yes Max of 161 mg/L Dayton airport self-monitoring data reported for 1994 at the retentionbasin.Dayton International 5 Yes 11.3 – 13.7 Sampling results from the Dayton airport northwest retention basinspillway overflow, Ohio EPA sampling in February and April 1995.Greater CincinnatiInternational7 Not specified 39.1 (ammonia) High value at Station 4. Downstream of box culvert location drainingrunoff from the taxi lane and runway in the DHL Airlines area.BWI 8 Yes 32 (ammonia) Stormwater discharge pipe prior to discharge to Kitten Branch, peaksample was 32 mg/L; composite sample was 40 mg/L ammonia. Samplingoccurred 2/26/93 during deicing event at the airport.General MitchellInternational Airport9 Yes Max of 25.4 (ammonia) Sampled at Wilson Park Creek at the airport outfall 7 , sampled April 12,1997MemorandumJune 30, 2009Page 5Table 2. Typical Ammonia Concentrations in Airport Deicing StormwatersAirportSourceIndication ofUrea UseAmmonia as NConcentration/ConcentrationRange (mg/L)Deicing Stormwater DescriptionGeneral MitchellInternational Airport10 Yes 16 (ammonia) Sampled at Wilson Park Creek at the airport outfall 7, sampled April 28,1997Western Pennsylvaniaairport (unnamed)11 Yes 53.3 Concentrations as high as 53.3 mg/L ammonia as N from breakdown ofurea reported in airport runoff samplesCanadian airports 12 Not specified 0.11 – 17 (total ammonia)Chemical analyses for environmental samples (runoff water)Detroit Metropolitan 14 Yes 0.01 – 13.7 (ammonia) Pond 3 concentration range for submitted data prior to urea banDetroit Metropolitan 14 Yes 0.02 – 15.9 (ammonia) Pond 4 concentration range for submitted data prior to urea banDetroit Metropolitan 14 Yes 0.01 – 26.9 (ammonia) Pond 6 concentration range for submitted data prior to urea banConcentrations reported are for ammonia as N unless otherwise indicated.MemorandumJune 30, 2009Page 6Table 3. Detroit Metropolitan Airport Ammonia Concentrationsfor Post-Urea Ban TimeframesAirportSourceUrea UseAmmonia ConcentrationRange (mg/L)Deicing Stormwater DescriptionDetroit Metropolitan 14 No 0 – 1.5 (0.25 avg.) Pond 4 – flow from Pond 3E discharge to Frank and Poet Drains (includesrunway/taxiway runoff) (# samples = 52)Detroit Metropolitan 14 No 0 – 2 (0.14 avg.) Pond 6 – runway/taxiway drainage from 3R/21L; portion 3L/21R; portion4R/22L; 4L/22R; and 9R/27L (# samples = 122)Table 4. Pittsburgh Airport Ammonia as N Concentrations for Post-Urea Ban TimeframesAirportSourceUrea UseYearMinimum AmmoniaConcentration (mg/L)Maximum AmmoniaConcentration (mg/L)Average AmmoniaConcentration (mg/L)OutfallPittsburgh 15 No 2000 0.05 0.45 0.23 E100Pittsburgh 15 No 2001 0.05 0.41 0.2 E100Pittsburgh 15 No 2002 0.06 0.07 0.065 E100Pittsburgh 15 No 2003 0.05 0.06 0.055 E100Pittsburgh 15 No 2004 0.05 0.06 0.055 E100Pittsburgh 15 No 2005 0.08 0.08 0.08 E100Pittsburgh 15 No 2006 0.05 0.06 0.055 E100Pittsburgh 15 No 2007 0.06 0.12 0.09 E100Pittsburgh 15 No 2000 0.05 0.53 0.33 21Pittsburgh 15 No 2001 0.23 0.44 0.33 21Pittsburgh 15 No 2002 0.3 0.39 0.34 21Pittsburgh 15 No 2003 0.23 0.33 0.28 21Pittsburgh 15 No 2004 0.15 0.23 0.19 21Pittsburgh 15 No 2005 0.12 0.3 0.21 21Pittsburgh 15 No 2006 0.09 0.15 0.12 21Pittsburgh 15 No 2007 0.12 0.23 0.17 21Pittsburgh 15 No 2000 0.05 0.51 0.16 21BPittsburgh 15 No 2001 0.05 0.2 0.125 21BPittsburgh 15 No 2002 0.06 0.09 0.075 21BMemorandumJune 30, 2009Page 7Table 4. Pittsburgh Airport Ammonia as N Concentrations for Post-Urea Ban TimeframesAirportSourceUrea UseYearMinimum AmmoniaConcentration (mg/L)Maximum AmmoniaConcentration (mg/L)Average AmmoniaConcentration (mg/L)OutfallPittsburgh 15 No 2003 0.05 0.05 0.05 21BPittsburgh 15 No 2004 0.05 0.06 0.055 21BPittsburgh 15 No 2005 0.05 0.14 0.095 21BPittsburgh 15 No 2006 0.05 0.1 0.075 21BPittsburgh 15 No 2007 0.05 0.11 0.08 21BPittsburgh 15 No 2000 0.12 0.71 0.33 22Pittsburgh 15 No 2001 0.41 1.03 0.72 22Pittsburgh 15 No 2002 0.3 1.29 0.795 22Pittsburgh 15 No 2003 0.61 0.92 0.765 22Pittsburgh 15 No 2004 0.19 0.46 0.325 22Pittsburgh 15 No 2005 0.06 0.14 0.1 22Pittsburgh 15 No 2006 0.15 0.25 0.2 22Pittsburgh 15 No 2007 0.07 0.18 0.125 22Pittsburgh 15 No 2000 1.61 3.99 3.06 063Pittsburgh 15 No 2001 1.2 1.2 1.2 063Pittsburgh 15 No 2002 0.82 6.54 2.56 063Pittsburgh 15 No 2003 0.3 6.86 2.23 063Pittsburgh 15 No 2004 0.05 3.13 1.65 063Pittsburgh 15 No 2005 0.34 5.18 1.25 063Pittsburgh 15 No 2006 0.28 3.88 1.5 063Pittsburgh 15 No 2007 0.16 4 1.19 063Outfall E100: Airfield stormwaterto east tributary of Enlow Run.Outfall 21 and 21B: Airfield stormwater to west fork of McClarens Run.Outfall 22: Airfield stormwater toeast tributary of McClarens Run.Outfall 063: Discharge point for the north runway.Memorandum
June 30, 2009 Page 8

Sources

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2. Turnbull, DA, Bevan, JR. “The Impact of Airp ort De-icing on a River: The Case of the Ouseburn, Newcastle Upon Tyne.” Environmental Pollution 88 (1995) 321-332.

3. Sills, Robert D, et. al. The Environmental Impact of Deicers in airport Stormwater

Runoff.

4. Ohio EPA. Biological and Water Quality Study of Mill Creek. Da yton International Airport. February 20, 1995.

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7. Kentucky Department of Environmental Prot ection, Division of Water. Impacts of Deicing Fluids on Elijahs and Gunpow der Creeks Boone County, Kentucky.

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. ” Environmental Toxicology and Chemistry , Vol. 20, No. 7, pp. 1474-1482, 2001.

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14. Detroit Metropolitan International Airpor t. Ammonia self-monitoring data for 1998-2007. Submitted to U.S. EPA/EAD April 3, 2008.

15. Pittsburgh Airport. Ammonia as N self-monitoring data for 1999-2000. Submitted to U.S. EPA/EAD April 3, 2008.