### TO: Brian D’Amico, USEPA/OW/EAD

FROM: Steve Strackbein and Mary Willett, ERG

DATE: July 12, 2011

SUBJECT: Centralized Deicing Pa d ADF Collection Efficiency

Introduction

Collection and control of spent de icing fluid is the primary purpose of most airport deicing control programs. EPA performed a review of airport deicing collection operations to esti mate the efficiency of centralized deicing pads (CDPs) in collecting availabl e spent aircraft deicing a nd anti-icing fluid (ADF). The purpose of this memorandum is to doc ument the results of this review.

Description of CDP Technology

CDPs restrict aircraft deicing activit ies to specified locations designed fo r aircraft deicing. The goal of a CDP is to concentrate aircraft deicing activity to a centralized location such that the containment area can be minimized, ADF contaminated storwmater volum es are collected, and concentrations of deicers in that stormwater are maximized. EPA defines a CDP as a facility on an airfield designed for aircraft deicing operations, constructed with a drainage system separate (or that can be made separate) from the airport main storm drain system. Th e separate drainage system is c onnected to a wastewater storage facility.

CDP Collection Efficiency

EPA used estimates of an airport’s Type I and IV ADF usage 1 

### to calculate the volumes of applied and available ADF at airports that utilize CDPs. Ava ilable ADF refers to the quantity of applied ADF that is available for collection. Not all applied ADF is available for collection due to ADF adherence to aircraft surfaces, evaporation, wind losses, and wh eel tracking. EPA has conservatively estimated available ADF to be 75 percent of applied type I de icing fluid and 10 percent of applied type IV antiicing fluid, excluding applied ADF used for defrosting or deicing for sa fe taxiing. Figure 1 presents a detailed example of how EPA calculated available ADF.

EPA evaluated ADF collection efficien cies at seven airports utilizing CDPs to determine the percentage of available ADF captured by CPDs. All but one of the airpor ts EPA evaluated collected at least 60% of their available ADF.

1 ADF usage estimates can be found in section 9.2.1 of the TDD

### Memorandum July 12, 2011 Page 2 of 4

Table 1 presents CDP collection efficiencies repo rted by seven airports, applied and available ADF estimates using EPA’s assumptions, and the calculated collection percentage of available ADF at each airport.

The deicing practices of the seve n airports evaluated by EPA (and in cluded in Table 1) are described below:

Denver International Airport - All deicing is done on deicing pads, with the exception of low level gate deicing (up to 25 undiluted gallons of ADF) to allow for safe plane movement.

Dayton International Airport - The Dayton airport has instituted a centralized deicing system which is comprised of four deicing aprons.

Philadelphia International Airport – Philadelphia’s Deicing Facility includes two aircraft deicing aprons, a deicing fluid delivery system, a deicing fluid recovery system, and a fully integrated computerized aircraft guidance and deicing control system. The facility can handle three wide-body aircraft and four smaller aircraft simultaneously.

Cincinnati International Airport - Airport management on ly allows the main aircraft deicing and anti-icing operations to be conducted at deicing pads. The airport has 12 deicing pads.

Detroit Metropolitan Wayne County Airport - Aircraft de icing/anti-icing fluids at Detroit Metro are applied at four remote deicing pads located near the runways. Limited deicing is performed at the gates, for morning frost removal and wide-body aircraft. When deicing is performed at the gate, a glycol collection vehicle (GCV) collects deicing fluid from the gate area and transfers the fluid to one of the four deicing pad collection sumps.

Pittsburgh International Airport - Aircraft deicing/anti-icing is performed on dedicated deicing pads. The airlines are not permitted to perform deicing procedur es at the gate areas unde r normal winter conditions. PIT has five deicing pads for commercial and cargo aircraft deicing and there are also two deicing pads for military operations. Two of the five commercial pads, Pads C and E, have fixed, pedestal mounted booms equipped with forced air and each of these pads can accommodate three planes at one time. The airport indicated in comment to the proposed rule that the co llection efficiency includes the use of GCVs at the deicing pads and gates.

Salt Lake City International Airport - All deicing is done on deicing pads, where runoff collection systems are installed, with the exception of low level gate deicing to allow for safe plane movement. The airport has 21 designated deicing spaces. Aircraft movement on the pads is controlled by the airline in charge of the pad and aircraft deicing/anti-icing fluids are applied to aircraft using mobile aircraft deicer trucks.

### Memorandum July 12, 2011 Page 3 of 4

Table 1. Airport CDP Collection Efficiencies and Available ADF Collection Calculations Airport ID Airport Name CDP Collection Efficiency of

Applied ADF (except where noted) Applied ADF 2 Available ADF (Type I Applied x 0.75) + (Type IV Applied x 0.10) Collection Percentage of Available ADF Type I Type IV

1028 Denver International 42% 3 949,256 104,314 722,355 61%

1123 Dayton International 55-60% 4 80,616 9,964 61,458 81-88%

1139 Philadelphia International 85-90% 5 862,385 117,598 658,548 85-90% (see footnote 5) 1113 Cincinnati International 70% 6 608,461 114,534 467,799 70% (see footnote 6) 1138 Detroit Metropolitan Wayne County 49% 7 2,001,632 150,660 1,516,290 70%

1107 Pittsburgh International 60-66 8 830,704 113,278 634,356 60-66% (see footnote 8) 1066 Salt Lake City International 20% 9 125,519 34,232 97,562 33%

2 See Table 9-4 of Technical Development Document for the Final Effluent Limitation Guidelines and Standards for the Airport Deicing Category.
3 Denver reported that they collect 68 percent of their applied AD F; with 42 percent recycled an d identified as collected from the deicing pad system and 26 percent discharged to their POTW and identified as collected from limited deicing areas and taxiway/runway areas. See EPA’s site visit to Denver Internati onal Airport. A copy of the site visit report can be found in the public docket, EPA-HQ-OW-2004-0038-0513.
4 As reported to EPA during EPA’s site visit to Dayton Internati onal Airport. A copy of the site visit report can be found in the public docket, EPA-HQ-OW-2004-0038-0159.
5 As reported in Philadelphia International Airport’s response to EPA’s Airport Deicing Questionnaire (comment to Question 38). Amount represents percentage collection of “used deicing fluid”. Results of the questionnaire can be found in the public docket, EPA-HQ-OW-2004-0038-1091.
6 As reported to EPA during EPA’s site visit to Cincinnati Intern ational Airport. Amount repres ents percentage collection of “spent ADF”. A copy of the site visit report can be found in the public docket, EPA-HQ-OW-2004-0038-0502.
7 As reported to EPA during EPA’s site visit to Detroit Metrop olitan Wayne County Airport. A copy of the site visit report can be found in the public docket, EPA-HQ-OW-2004-0038-0504.
8 As reported to EPA during EPA’s site visit to Pittsburgh Intern ational Airport. Amount repres ents percentage collection of “spent ADF”. A copy of the site visit report can be found in the public docket, EPA-HQ-OW-2004-0038-0509.
9 As reported to EPA in public comment by Salt Lake City Intern ational Airport. A copy of the comment can be found in the public docket, EPA-HQ-OW-2004-0038-1244.1.

### Memorandum July 12, 2011 Page 4 of 4

Constants Percent of Type I Available = 75 Percent of Type IV Available = 10

Calculations Total Amount Applied = Type I + Type IV Total Amount Available = (Type I × Percent of Type I Available) + (Type IV × Percent of Type IV Available) Amount Collected and Controlled = Total Amount Applied × Percent Collection and Control of Available Percent of Available = Amount Collected and Controlled ÷ Total Amount Available

Example – Assume Type I Usage = 90 gallons Assume Type IV Usage = 10 gallons Total Amount Applied = 90 + 10 = 100 gallons Total Amount Available = (90 × 0.75) + (10 × 0.1) = 68.5 gallons Applied Amount Collected and Controlled = 50 gallons Percent of Available Collected = Amount Collected and Controlled ÷ Total Amount Available Percent of Available Collected = 73%



### Figure 1. Example Calculation for Available ADF Collection Percentage