EPA/832-R-95-005
                                                  September, 1995
Emerging Technology Assessment: Preliminary
Status of Airplane Deicing Fluid Recovery Systems
                 U.S. Environmental Protection Agency

                   Office of Wastewater Management
                     Municipal Support Division
                    Municipal Technology Branch
                        Washington, D. C.

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                             NOTICE

This document has been reviewed in accordance with the U.S. .
Environmental Protection Agency's peer review and administration
review policies and approved for publication.

The material presented is for informational purposes only.  This
information should not be used without first obtaining competent
advice with respect to its suitability to any general or specific
application.  References made in this document to any specific
method, product or process does not constitute or imply an
endorsement, recommendation or warranty by the U.S. Environmental
Protection Agency.

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                           TABLE OF CONTENTS
                                                                      PAGE
EXECUTIVE SUMMARY  	ES-1
SECTION 1 - INTRODUCTION TO AIRPLANE DEICING
            FLUID RECOVERY SYSTEMS

      Background   	1-1
      Environmental Effects of Airplane Deicing Fluids	1-3
      Environmental Regulation of Ethylene Glycol	1-7
      Requirements and Standards for the Reuse of ADF	1-8
      Objectives    	1-8

SECTION 2 - DESCRIPTION OF  COMMERCIALLY AVAILABLE ADF
      RECOVERY PROCESSES

      Description of Commercially Available ADF Recovery Process  	2-1
      Chemicals Required  	2-4
      Design Criteria	2-4
      End-Use Specifications  	2-5

SECTION 3 - TECHNOLOGY ASSESSMENT

      ADF Collection	3-1
      Performance Data	3-2
      Operation & Maintenance	.'	3-2
      Technology Costs	3-4

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                          TABLE OF CONTENTS


                                                                    PAGE

SECTION 4 - ENVIRONMENTAL IMPACTS

      Distillation	4-1
      Residuals Generated  	4-1

SECTION 5 - SUMMARY OF FINDINGS
                                                               •
      Applications   	5-1
      Limitations    	5-1

SECTION 6 - REFERENCES	6-1
APPENDIX A - CASE STUDY AND EVALUATION

      Deicing System Incorporated	A-l
      Canadian Chemical Reclaiming LTD (CCR)	  .... A-l
      Glycol Specialists, Inc. (GSI)  	A-10

ATTACHMENT B - ADF RECOVERY CHECKLIST 	B-l
                            LIST OF FIGURES

Figure 2-1   General Glycol Recovery Process  	2-3

Figure A-l   Deicing Systems' ADR Recovery Process  	A-3

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TABLE OF CONTENTS
                                              PAGE
Table 1 . 1


Table 3 . 1

Table A.I


Table A. 2
                   LIST OF TABLES

Mammalian Toxicity Data For Ethylene Glycol and
Propylene Glycol
ADF Recovery System Performance Data Summary

Airplane Deicing Fluid Recovery System
Performance Data from Munich Airport, Germany

Airplane Deicing Fluid Recovery System
Performance Data from Toronto Airport, Canada
                                                1-5

                                                3-3


                                               A-5


                                               A-9

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                              ACKNOWLEDGMENTS

This manual is the product of the efforts of many individuals.  Gratitude goes to each person
involved in the preparation and  review of the document.

Contributors

Ms. Lauren Fillmore and Ms. Janet Dell

Peer Reviewers

The following individuals peer reviewed this report:
                                                                         •
       Mr. George  Legarreta,  Federal  Aviation Administration,  Design  and Operations
       Division, Washington, D.C.

       Mr. Alan Hais, U.S. EPA, Office of Science and Technology, Washington, D.C.

Technical Direction and Coordination

Mr.  Joseph T.  Mauro, U.S. EPA,  Office of Wastewater Management, Municipal Support
Division, Municipal Technology Branch (4204), 401 M  Street SW, Washington, D.C. 20460,
coordinated the preparation  of this  manual and provided  technical direction  throughout its
development.
                                          IV

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                                                                Executive Summary
                              EXECUTIVE SUMMARY
  PRELIMINARY STATUS OF AIRPLANE DEICING FLUID RECOVERY SYSTEMS
 BACKGROUND
          Section 402  of the Clean Water Act requires the U.S. Environmental Protection
 Agency  (EPA)  to  establish  permit  requirements  under the National  Pollutant Discharge
 Elimination System (NPDES) for storm water discharges  from industrial activity including
 airport operations. As  airport management has applied for storm water permits, the control of
 the release of airplane deicing  fluid (ADF) into the  environment has become of interest to
 airlines,  airport management, air safety specialists and Federal,  state and local environmental
 protection agencies.

         This  document presents  the  results  of a preliminary  technical evaluation  of
 commercially available  ADF recovery processes.  This report explores design-related questions,
 identifying weaknesses  or limitations, provide  cost data and are  beneficial in the investigation
 of operation and  maintenance (O&M) problems.  In addition, the results of the preliminary
 evaluation  identifies a  specific  range of conditions under  which  the process or technology
 demonstrates levels of  performance efficiency.  This preliminary technology  evaluation is an
.essential  first step in disseminating actual data on selected processes or techniques.  This report
 is not intended to establish ADF recovery systems as the preferred approach nor preclude other
 systems or methods for the control of ADF or  ADF contaminated storm water
                                         ES-l

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                                                                Executive Summary
OBJECTIVES
         The primary objective of this report is to evaluate the technologies that are currently
being used to recover  used ADF.  On-site ADF recovery is a new application of proven
technologies: filtration, ion exchange, distillation, and sometimes reverse osmosis. At this time,
ADF recovery technology has had limited application. There is only one on-site application of
ADF recovery in the United States; therefore, this report has  only limited  data on costs, and
operations and maintenance. The associated cost and performance data discussed in this report
was provided by firms marketing on site ADF recovery systems hi North America. Before using
an ADF recovery  system, it is advisable that more data be obtained as it becomes available from
onsite installations within the United States.  Accordingly, along with ADF recovery systems,
other system, technologies or methods should  be investigated before selecting a final approach
for the  control of ADF or ADF  contaminated storm  water.   The  specific ADF recovery
processes that are currently being marketed are described in detail.
FINDINGS AND CONCLUSIONS
         ADF recovery systems are based on a series of proven processes including primary
filtration, ion  exchange or nanofiltration,  distillation, and reverse osmosis.  The purpose of
primary filtration is to remove suspended solids entrained in the ADF.  Ion exchange may be
employed to remove dissolved solids and nanofiltration may be employed to remove polymeric
additives which  were  in  the  glycol-based  ADF- to  meet  deicing/anti-icing  performance
requirements.  Expensive preconcentration steps such as reverse osmosis may be employed to
concentrate  dilute  streams  (<15%  glycol) in advance  of the  distillation process.  The key
process step in  the overall ADF recovery system is distillation.   Distillation is capable of
separating glycol from water with little degradation.  Product with high purity (>90%)  can be
obtained by two stage distillation provided  that the process economics are not prohibitive.  The
product may be sold to chemical manufacturers for use in other glycol based products, such as
automotive anti-freeze, synthetics or reused as ADF.  Before reuse as ADF, the product must
receive certification  for  compliance  with  the  Society  of Automotive Engineers  (SAE)
                                          ES-2

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                                                                  Executive  Summary
 performance based standards.

          Recovery of collected ADF may be cost effective when the glycol concentration is
 15% or greater.   At higher concentrations processes such as reverse  osmosis may not be
 required hi advance of the distillation process. However, storm water permit requirements of
 individual airports may require the collection and recovery of lower concentrations of waste
 glycol solutions due to the oxygen demanding environmental effects of glycol.  One method to
 satisfy such a requirement is to add a preconcentration step such as reverse osmosis to an ADF
 recovery  system.  This additional step may add considerably to the capital and operating  cost
 of an ADF recovery  system.   Centralized deicing on a dedicated collection pad  is another
                                    •>
 method for obtaining spent ADF which exceeds the minimum glycol content.  Centralized
 deicing systems may be impractical for all but the largest airport operations due to the associated
 capital and operation cost, and physical size of the system. However, for established airports,
 a switch to a centralized deicing system may present operational and logistical problems.

          Another significant limitation  of this technology is that a mixture of ethylene  and
 propylene glycols cannot be recovered and separated efficiently hi a single batch process because
 the glycols will not separate easily in the distillation process.  A recovered mixture  consisting
 of ethylene and propylene glycol has  little commercial value.

   Non-uniform application  of  glycols  may result in the ADF recovery  system being cost
prohibitive, because of the requirements for two systems and  segregated application/recovery
areas.  Uniform application of either glycol at one time may allow for a single recovery system
to be utilized by adjusting the distillation temperature. ADF recovery process performance is
uniformly good.  However, individual airport-specific conditions and economic considerations
will  determine the suitability of ADF recovery at any airport, not technology-based issues or
process performance.

          Additional research is  recommended as data becomes available from the  operation of
                                          ES-3

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                                                                Executive Summary
facilities proposed for the St. Lxnris Airport, The new and expanded Denver International Airport
and other airports not discussed in this report that are currently installing recovery processes.
Additional research is  also recommended for studying the effectiveness of alternative collection
systems such as vacuum trucks and roller sponges.

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                                                        Section 1 - Introduction to
                                       Airplane Deicing Fluid Recovery Systems
                                    SECTION 1
     INTRODUCTION TO AIRPLANE DEICING FLUID RECOVERY SYSTEMS
BACKGROUND
       The employment of chemical^ deicers is recognized by the FAA as an effective safety
procedure hi airborne transportation.  However, a result of these airplane deicing/anti-icing
operations is that portions of the chemicals from the chemical deicers will ultimately enter the
storm water system of the airport.  This report considers management practices which will
enable  airport  tenants  to continue  their  deicing  practices  without compromise while
implementing  changes to minimize  the discharge  of deicing chemicals to  surface  or
ground water.

      The most common aircraft  deicing chemicals currently approved by the FAA  are
ethylene glycol  and propylene glycol. The environmental impact of deicers in airport storm
water runoff has been investigated over the last 5 years (Sills and Blakeslee, 1992).  Since EPA
established  NPDES permit application regulations for storm water discharges from airports
(Federal Register, 1990), airport management and operations have directed ADF recovery from
research oriented  efforts  to practical  applications of available technologies.    EPA  and
authorized NPDES States  have, or are  in  the process of writing  permits for point  source
discharges from airports, including discharges containing deicing fluids. Of particular  note is
a general permit  EPA intends  to  issue,  which  specifically  addresses deicing  chemical
management (Federal Register, 1993).
                                         1-1

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                                                       Section 1 - Introduction to
                                       Airplane Deicing Fluid Recovery Systems
       The data collected by Sills and Blakeslee show the following usages of glycol hi airport
operations:

    Application                                   Glycol Used
                                                                        *•
Annual U.S. ADF Usage           11,500,000 gal/yr (McGreevey,  1990; Roberts, 1990)
Annual Detroit Met Airport        780,000 gal/yr (Morse, 1990; McGreevey, 1990;
                                                   Roberts,  1990)
Large Commercial Aircraft         500-1000 gal/plane/flight (Comstock, 1990)

       The amount of deicer required to adequately deice a plane is highly dependent on
applicator variability, plane size and the weather conditions. Several airport operators reported
(AAAE Conference on Aircraft Deicing, August 23, 1993) that the annual volume of ADF
employed by the U.S. airlines has increased three fold since the airplane accident at La Guardia
Airport in 1992 in which icing was a factor.  As implied by this statement by employing a
factor  of three to the  data reported above, nearly 35 million gallons of ADF may be used
annually in the U.S.  Depending on specific site and variable weather conditions, the actual
amount of ADF used  annually can vary. Since safety concerns are paramount in air travel,
minimization of the volumes of ADF employed are not recommended.  However, collection
and recovery of the chemicals must be considered.

       There are two types of ADF formulations:  Type I and Type II. Both formulations are
deicers and anti-icers  which remove ice and remain on the  aircraft  to prevent subsequent
reicing.  Both Type I  and Type II formulations are glycol-based but have different additives
and different glycol concentrations.  Type I fluids have rust and precious  metal  corrosion
                                         1-2

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                                                         Section 1 - Introduction to
                                         Airplane Deicing Fluid Recovery Systems
 inhibitors, surfactants, and wetting agents.  In addition, Type II fluids contain thickening
 agents, usually polymers, which provide improved anti-icing properties and longer holdover
 times than Type I fluids.

       Typically,  Type I fluids are relatively easy to process and recover the glycol present
 in the fluids.  Type II fluids pose more of a challenge as they contain numerous complex
 polymers that are  used to create some of the special characteristics in Type II fluids.  These
 complex polymers present  in Type II fluids pose unique handling problems for filtering and
 processing systems.

       Of the Type I  deicing solution applied to aircraft, almost half will fall  to  the apron
 (Transport Canada,  State  of the Art Report on Aircraft Deicing/anti-icing, AK 75-09-129,
 November,  1985).  Approximately  35 percent of the ADF is  dispersed to the air and the
 remainder is retained on the aircraft.  The diluted product that is applied to aircraft typically
 contains about 58 percent glycols which gives the minimum freezing point of -56.7 °F (FAA,
 AC150/5320-15, 1991). Unless it is captured for recycling, recovery or treatment, this glycol-
 laden solution flows away to be further diluted and possibly mixed with runway runoff, parking
 lot runoff, and  other local sources of storm water. This data coupled  with a possible annual
 usage of  35  million gallons, suggest that  if the storm water runoff from aircraft deicing
 operations are not adequately treated or contained, substantial amounts of deicing chemicals
 may be released to the ground,  and may ultimately contaminate ground *or surface waters.
       The biodegradation of glycols released into the aquatic environment, which is variable
relative to temperature, can be rapid and extremely oxygen demanding.  Glycol contaminated
storm water runoff can deplete dissolved oxygen levels and threaten oxygen-dependent aquatic
                                          1-3

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                                                        Section 1 - Introduction to
                                        Airplane Deicing Fluid Recovery Systems
life in receiving waters.  The BOD5 at 20° C for ethylene glycol has been reported to be in the
range of 400,000 to  800,000 mg O2/l (FAA, AC150/5320-15, 1991), or 0.4 to 0.7  g/g
(Verschueren, 1983).  The BOD5 of-propylene glycol is considerably higher  (about 1 g/g).
Diluted ethylene glycol in storm water runoff, at concentrations qf 1 percent to 0.1 percent,
would  be expected to exert a BOD5 of roughly 5,000 to 500 mg/1.  Based  upon physical
properties, neither ethylene nor propylene glycol released into the environment is expected to
                                                                          *
be retained in the tissue of organisms and increase with continued exposure (bidaccumulate).

Human Health Effects           *

       Ethylene  glycol  exhibits relatively low acute and chronic toxicity to humans and
laboratory  animals.  It has not been found to cause cancer or mutations; however,  it is a
teratogen.  The life time drinking water health advisory for ethylene glycol is 7 mg/1 and the
one day health advisory is 18.86 mg/1 (Health Advisory, 1987). Mammalian toxicity data for
both ethylene glycol and propylene glycol is presented in Table 1.1. The mammalian toxicity
data indicates that propylene glycol is less toxic than ethylene glycol.

       ADF mixtures contain various types of additives in addition to glycols which constitute
the primary component.   These additives include precious metal corrosion  inhibitors, rust
inhibitors, thickening agents, and surfactants. The following contaminants may  also be present
in glycol-based ADF: diethylene glycol, ethylene oxide, dioxane, and acetaldehyde (trace levels
only).  Dioxane  and acetaldehyde are suspected carcinogens or teratogens.

Environmental  Health Effects

       High concentrations of glycols (greater than  10,000 mg/1) are required to cause acute
aquatic toxicological effects (Hartwell, et. al. 1993)  Although the ethylene and propylene
                                          1-4

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                                                Section 1 - Introduction to
                                   Airplane Deicing Fluid Recovery Systems
                                TABLE 1.1

                    MAMMALIAN TOXICITY DATA FOR
              ETHYLENE GLYCOL AND PROPYLENE GLYCOL(1)
                                                    Dose ml/kg
Toxicity Test
Rat:
Guinea pig:
Mouse:
Rabbit:
Dog:
Human:
single oral LD50(2)
single oral LD50
single oral LD5()
single oral LD50
single oral LD50
single lethal oral
Ethylene
Glycol
5.50
7.35
13.1
—
—
1.4
Propylene
Glycol
32.5


18.5
9.6

(1) From Verschueren (1983).
(2)     is the lethal dose for 50% of the exposed organisms.
                                  1-5

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                                                         Section  1  - Introduction to
                                        Airplane Deicing Fluid  Recovery Systems
glycols in ADF have a low potential to exhibit aquatic toxicity, the contaminants and additives
in ADF  pose a greater concern when released  into the environment.  Corrosion and rust
inhibitors are highly reactive which translates into high biological toxicity. Surfactants are also
very toxic to aquatic organisms (Hartwell et. al.  1993).

       The Maryland Department of Natural Resources (Hartwell et. al. 1993) conducted
                                                                         e
aquatic toxicity testing  with both ethylene glycol  deicer solution and propyfene anti-icer
solution.  Test results indicated that the ADF solutions were more toxic than the literature
values for pure glycol substances.  The higher toxicity was concluded to be due to the presence
of additives.  The specific additives in the Type II fluid were significantly more toxic than the
Type I fluids. Type I deicer exhibited acute toxicity to fish at 8.75 ml/L or a 0.87% solution.
Type II deicer exhibited acute toxicity at 0.063 ml/L.  Measurements of ADF concentrations
in Baltimore Washington International  Airport storm runoff detected peak concentrations of
Type I ADF at 89.1  ml/L arid of Type II ADF at 154.5 ml/L (Lubbers, 1993).

       Similar studies conducted at Stapleton Airport, Denver,  Colorado, confirmed that ADF
formulations exhibited significantly more acute  toxicity  than pure glycol products (ENSR
Consulting and Engineering, 1993).  In chronic studies, ENSR found that the concentration that
inhibits growth  and  reproduction  in 25%  of the  exposed organisms  (IC25) of formulated
propylene glycol ADF was 112 mg/L for fathead minnows; while the IQs for pure propylene
glycol was observed  to be 6.,941 mg/L.

       Data concerning the toxic potential of storm water runoff containing ADF at airport is
preliminary  and subject to an  ongoing debate.  Initial  peer  review comments of the data
provided by the two studies, has raised several concerns that need to  be addressed. To address
these concerns, duplicate testing and additional studies, with peer review, are needed before
confirming the toxicity of storm water runoff containing ADF.
                                          1-6

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                                                        Section 1 - Introduction to
                                        Airplane Deicing Fluid Recovery Systems
 ENVIRONMENTAL REGULATION OF ETHYLENE GLYCOL
        Under the 1990 Amendments to the Clean Air Act, national emission standards were
 established for hazardous air pollutants from stationary sources.  Congress established a list
 of 189 hazardous air pollutants.  Ethylene glycol is included on this list, however, propylene
 glycol is not.
       Under the Comprehensive Environmental Response, Compensation and Liability Act
 (CERCLA),  if a substance is regulated under other legislation, such as the Clean Air Act, it
 is included by reference as a CERCLA (Superfund) hazardous substance.  As such, ethylene
 glycol is a  CERCLA  hazardous  substance while propylene  glycol is  not.  All CERCLA
 hazardous substances without specific promulgated reportable release quantities fall under the
 statutory reportable amount of one pound.  The reporting limits on ethylene glycol has been
 raised to 5000 pounds, effective July 12, 1995 (Federal Register, 1995).  Therefore,  there  is
 a requirement to report all releases to the  environment of ethylene glycol that exceed 5000
 pounds unless the release is covered by other environmental protection programs, such as the
 storm water NPDES permit program. This necessitates reporting requirements for releases of
 ethylene glycol, in amounts that exceed 5000 pounds, to the air or to the ground as part of land
 disposal practices or accidental spills.

       Neither ethylene glycol nor propylene  glycol are hazardous  wastes under Resource
Conservation and Recovery Act  (RCRA).   Contaminants  in  ethylene  or  propylene  glycol,
particularly metals, may make still certain bottoms or residues from ADF recovery a hazardous
waste if the waste fails  the toxicity characteristic limits for metals.
                                         1-7

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                                                       Section 1 - Introduction to
                                       Airplane Deicing Fluid Recovery Systems
REQUIREMENTS AND STANDARDS FOR THE REUSE OF ADF
       The Society of Automotive Engineers (SAE) develops standards for deicing and anti-
icing fluids for aircraft  and runways.  Both Type I and Type II ADF have performance
requirements identified in AMS 1424 and AMS 1428. Because of the interest in the recovery
of ADF,  SAE  issued  a  policy  statement that  recycled  fluids  be certified to  original
                                                                        f
specifications (Committee J, SAE, 1993).  Consequently, recycled fluids must meet the same
requirements as virgin glycol. Certification that ADF meets the appropriate standards (AMS
1424 or AMS 1428) is provided by^the chemical industry.  All recovered ADF used in the
U.S. must be certified prior to reuse in the airline industry.  Certification of recovered ADF
fluid at on-site recovery systems is  impractical due to performance testing requirements.
Unless the industrial practices are changed to an ADF composition basis, it  is unlikely the
recovered ADF fluid will be recycled directly to aircraft at the airport. In regards  to runway
deicers, FAA requires certifications to AMS 1426.


OBJECTIVES
       The goal of this study was to evaluate technologies that could be used to recover spent
aircraft deicing fluid for  reuse in aircraft deicing, runway deicing or other applications. This
study had the following critical objectives:

              Evaluate  the  effectiveness  of  commercially available  recycling  units  in
              generating products that may be reused.
              Evaluate the waste reduction potential.
                                         1-8

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                                                         Section 2 - Description of
                                Commercially Available ADF Recovery Processes
                                     SECTION 2
 DESCRIPTION OF COMMERCIALLY AVAILABLE ADF RECOVERY PROCESSES
         There are three companies which are currently marketing ADF recovery systems for
use on-site at airports in North America.  Each of the three processes is briefly described in the
following subsections. A complete description of each process is provided in Section 6.  At this
time, there is only one on-site application of ADF recovery in the United States. This is a pilot-
scale operation located at  Continental Airlines at the Denver Stapleton Airport. The operation
is designed and run by a cooperative effort of Gylcol Specialists, Inc. and Zenon Environmental,
Inc.

         The technology of ethylene or propylene glycol recovery by primary filtration, ion
exchange or nanofiltration,  and  distillation has been proven in other  industries where glycol
recovery is  utilized, such  as the  petroleum industry. Chemical waste  service  companies  have
provided offsite treatment of ethylene glycol for the automotive and gas processing industries.
         Each of the glycol recovery systems is comprised of the three process units:

        Primary Filtration: To remove suspended solids entrained in the ADF from contact
        with the aircraft and asphalt.  Suspended solids must be removed to avoid plugging of
        downstream processes and spray machinery.
        Ion-Exchange:  To remove dissolved solids such as chlorides and sulfates.
                                       and/or

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                                                            Section 2 - Description of
                                 Commercially Available ADF Recovery Processes
         Nanofiltration: To remove polymeric  ADF additives  such as corrosion inhibitors,
         surfactants, and wetting agents.
         Distillation:  To  remove water which has contaminated the ADF due to ice melt and
         storm water dilution.

          Figure 2-1 presents a  schematic of the general glycol recovery process.
                                                                            *
                                                                            *
          The key process step in the overall ADF recycling system is distillation.  Distillation
is defined as the separation of more  volatile materials (in this case, water) from  less  volatile
materials (glycol) be a process of vaporization and condensation. Distillation has been used for
many years for  purification in chemical manufacturing  and  in processes involving  internal
solvent  recycling (Freeman,  1989).  Distillation is capable of recovering volatile species with
little degradation, which  is an  important advantage in this application where the recovered
product can be  sold or recycled:   Product  purity  of any desired level can theoretically be
obtained by distillation, however the cost to the process can become prohibitively expensive.
In the separation of water from the glycol mixture of ADF,  two stages of  distillation are
employed to remove enough water to produce a minimum 50% glycol content in the recovered
ADF. The recovered glycol is a stable material and can theoretically be stored for an entire wet
weather season (6 months).

         The details of  the distillation process that each vendor employs  are proprietary.
Design  variables include  temperature, distillation column design  (number of stages,  type of
packing, size) and reflux ratio (ratio of  their cycle flowrate to the overhead product flowrate).
Batch distillation systems  are employed due to the variation in the composition of the influent
and the irregular supply of the feed.  Reverse osmosis may also be employed to concentrate very
dilute glycol (< 15%) prior to the distillation step.
                                           2-2

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                                                Section 2 - Description of

                         Commercially Available ADF Recovery Processes
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                                                       Section 2 - Description of
                              Commercially Available ADF Recovery Processes
CHEMICALS REQUIRED
         Sodium hydroxide (NaOH) and hydrochloric acid (HC1) are required for regeneration
of the ion exchange process unit.  Anti-foam agents are required in the distillation tower.  Care
should be taken when handling these chemicals to avoid contact with skin.  Eye protection
should be worn.
DESIGN CRITERIA
 Prior to designing an ADF recovery  system, information on several parameters must be
                                 i
collected.  Data in the following areas is required to design an ADF recovery system:

              Deicing Fluid Data
              Type
              Concentration
              Total consumption per season
              Total consumption per peak-day
              Average consumption per aircraft

        Airport Operations Data
              Length of deicing season
              Number of deicing days per season
              Future traffic extension plans

        Spent Fluid Data
              Volume Generated
              Glycol  Concentration
              Contaminants
                                        2-4

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                                                         Section 2 - Description of
                                Commercially Available ADF Recovery Processes
        Reuser Specifications
               Glycol Concentration
               Acceptable Impurities.


END-USE SPECIFICATIONS
                                                                         •
         In Europe, recovered ADF can be reused at the same airport location as the recovery
operations.  Therefore, the glycol content in recovered  Type I ADF is targeted to the 58%
glycol content for direct use on aircraft after the addition of any necessary additives.  In the
U.S. and Canada,  the  recovered  glycol must be returned to  the chemical industry  for
performance-based testing  and reformulation  into ADF.   The end-use  specification in North
America, therefore, is for higher glycol content in order to have a reusable end-product.
                                         2-5

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                                                Section 3 - Technology Assessment
                                      SECTION 3
                            TECHNOLOGY ASSESSMENT
ADF COLLECTION
       In order for the spent ADF to be recovered or regenerated, it must first be collected at
                                                                           •
the airport.  The implementation of ADF7 collection must respond to the unique requirements of
each airport.  The feasibility of recovery glycol is dependent on the ability of the collection
system to contain a relatively concentrated waste  stream without significant contamination by
other storm water components.  It may not be cost-effective to distill and recycle waste glycol
solutions  at low concentrations  (<  15%), because additional expensive processes,  such as
reverse osmosis, may be needed to  concentrate the solutions to a lower concentration before the
distillation step.  However, storm water NPDES permit requirements of individual airports may
require the collection and recovery  of lower concentrations of waste glycol solutions due to the
oxygen demanding environmental effects of glycols in general.

      Remote or centralized deicing with the containment and collection of used glycol is one
method for collecting concentrated  used glycol.  However, centralized deicing systems may be
impractical for all but the largest  airport operations due to  the cost  and  physical size.  For
established airports,  a switch to  centralized  deicing  systems  would present a number  of
operational and logistical problems. In lieu of a centralized facility, used glycol can be collected
via vacuum trucks and fluid collections containers to siphon  glycol from runway  aprons.
Employment of vacuum trucks has  shown good results.  Roller sponge devices were employed
at the Toronto Airport with mixed  results due to uneven frozen surfaces.

      At Denver's Stapleton Airport a centralized collection facility consisting of a sloped pad,
                                          3-1

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                                               Section 3 - Technology Assessment
underground storage tank (UST), storm water diversion and piping and pumps is employed by
Continental Airlines to collect ADF.  The system reportedly captures the used glycol solution
at 25 to 40 percent glycol concentration.

       A centralized  system is proposed for the St. Louis Lambert Airport.  A pad has been
proposed by Findett Engineering that will be capable of holding more than one narrow body
airplane at one time.  The  fluid is collected from  the pad and held hi a storage tank for
processing.  A skid mounted processing unit will reportedly treat the ADF when the system is
                                                                          •
started up.

                                  i
PERFORMANCE DATA
       Performance data was provided by three firms, Deicing System, Canadian Chemical
Recovery (CCR), and Glycol Specialists. Data supplied by Deicing System was from their full-
scale operation in Munich, Germany and by Glycol Specialists from their recovery system at
Continental Airlines at Stapleton Airport. Performance data was provided by CCR from the
pilot recovery system at the Toronto Airport.   The ADF streams prior to recovery had an
average glycol content between 10 to 28%. The recovery systems produced an effluent stream
with an average glycol content of between 55.1 and 98.5 %. The glycol content of the recovered
solution was dictated by the needs of the reuser and does  not reflect performance limitations.
Table 3-1 shows  the average performance data for these three systems.


OPERATION & MAINTENANCE
       Recovery processes  based on distillation tends to be complex operations  due to the
inherent thermodynamic constraints.  Distillation-based processes have a number of practical
limitations on usefulness. Distillation is a batch operation.  Batch operation, because of its
cyclic nature, involves frequent start-ups and shutdowns and must be operated by highly skilled
                                          3-2

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                                            Section 3 - Technology Assessment
                                   TABLE 3.1
          ADF RECOVERY SYSTEM PERFORMANCE DATA SUMMARY
    Process
           Average
           Influent
            Glycol
Location   Content (%)
  Average      Minimum
  Effluent        Glycol
   Glycol      Specification
Content (%)  by End-User (%)
Deicing System, Inc.            Munich      18.6

Canadian Chemical Recovery    Toronto      10-20

Glycol Specialists, Inc.          Denver       28
                          55.1
                           87
                          98.5
                  50
                  80
                90-95
Notes:
    1.    Data supplied by Deicing Systems, Inc., Canadian Chemical Recovery;
        Glycol Specialist, Inc.

    2.    Concentrations measured in laboratory.
                                      3-3

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                                                Section 3 - Technology Assessment
personnel.  Second, distillation equipment is expensive, and capital recovery charges usually
constitute the major portion of the product recovery costs.  Third, recovery by distillation is
energy-intensive, with nominal energy requirements being about S.SlxlO5 to 2.79xl08 J/kg of
feed (250 to 1200 BTU/lb of feed).
TECHNOLOGY COSTS
       ADF recovery is a new application of existing technology.  Due to the limited full-scale
                           . •                                                »
operation of ADF systems  in the country, information on technology costs are limited.  Cost
estimates discussed here have been provided by GSI.  Based on pilot studies performed at the
Denver Stapleton Airport, The total capital cost for the complete project, including deicing/anti-
icing application equipment, collection piping, storage  facilities, and the glycol recovery system
has been estimated to be between six and seven million dollars. The construction cost for the
ADF collection system, storage and handling facilities, piping and recovery system has been
estimated at approximately  $600,00.

       The total capital cost for the new Denver International  Airport, including deicing/anti-
icing application  pads and equipment, drainage and  collection piping,  storage and handling
facilities, and a complete glycol recovery system is currently estimated to be between 20 to 25
million dollars.  These costs are based on a complete  package  including  planning, engineering
design, equipment, construction and installation, start-up services and other contingencies.  The
construction costs for the ADF collection system, storage and handling facilities, piping,  controls
and instrumentation,  and a complete recovery system is currently estimated  at  five million
dollars.

             The GSI cost for recovering  collected  ADF, assuming the used ADF is 28%
glycol, is approximately  35C/gallon. The greatest annual cost with the ADF recovery system
is the cost for the energy used  in the distillation process.

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                                                  Section 4 - Environmental Impacts
        As discussed in Section 1, up to 35 million gallons of ADF may be used in a single year,
 depending upon variable weather conditions.  Based upon this estimate, the percentage of glycol
 typically found in ADF and the percentage of ADF that falls to the pavement during application,
 as much as 75 million pounds of glycol can be released into the environment in a single year.
 Insignificant amounts  of Type II glycol is released to the runway when the airplane takes off.
 The capture and reuse of ADF that occurs as the result of ADF recovery operations will reduce
 the amount that is either released into the environment or captured  for disposal.
 DISTILLATION
       There is a potential for volatile-organic emissions to the air from the distillation process
 through losses from condenser vents, accumulator tank vents, and storage tank vents.  Since the
 amount of glycol which is vaporized during normal operations is small, VOC emissions to the
 air are likely to be insignificant.
RESIDUALS GENERATED
       Ion-exchange flush and spent regenerant are generated by the recovery process and may
be disposed of, if permitted, after neutralization by the addition of acids or bases, to the sanitary
sewer.  Spent filter cartridges, containing dirt, oil and other solids, may be disposed of as non-
hazardous waste.  Only insignificant traces of glycol will be retained in the filtration  solids.
Under CERCLA, Section 103, any wastes containing over 5000 pounds of ethylene glycol have
additional reporting requirements. As of July 12,  1995, the reporting limit on ethylene glycol
was adjusted from one pound to 5000 pounds (Federal Register, 1995). Any release  of ethylene
                                          4-1

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                                                 Section 4 - Environmental Impacts
glycol to the air or ground, as part of land disposal practices or accidental spills, will have
additional reporting requirements.   Propylene glycol, alone as a waste,  does not have any
reporting requirements under CERCLA.   However,  local authorities should be contacted to
determine if any requirements have to be met for the disposal of spent filter cartridges containing
propylene glycol.  Distillation condensate, with less than 1.5% glycol, is also generated and may
be reused in airport operation or  (if permitted) disposed of to the  sanitary sewer.  Local
pretreatment requirements might limit the amount of oxygen demanding wastewater discharged
to a municipal sewer system and wastewater treatment works.
                                          4-2

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                                                  Section 5  - Summary of Findings
                                     SECTIONS
                              SUMMARY OF FINDINGS
       Although the on-site application of ADF recovery is new ADF recovery technology has
been proven in other industries,  such as the automotive industry.  Distillation-based ADF
recovery systems are capable of recovering glycol with little degradation and a high product
                                                                         •
purity.  Product purity, typically with a minimum of 50%, is dictated by the end-user; however,
high  product purity (over  90%)  can  be obtained provided  the process economics  are  not
prohibitive.
APPLICATIONS
       Glycol recovery systems are applicable at any airport that collects ADF with a minimum
concentration of approximately 15% glycol. Collection and recovery of dilute glycol (< 15%)
is driven by the storm water NPDES permit requirements of individual airports.  Since spent
ADF mixtures  with lower glycol content  are impractical to recover via distillation without
expensive preconcentration steps such as reverse osmosis, dilute streams are typically discharged
to POTWs,  subjected to destruction of organics  or removed by jchemical waste companies.
Ultimately, the  site specific application of on-site ADF recovery will be based on local permit
requirements and economic  considerations including spent ADF collection costs, recovery
economics, end-product  purity  and disposal or treatment costs.


LIMITATIONS
       In order for the ADF to be recovered or regenerated, it must first be collected at the
airport. The implementation of ADF collection must respond to the unique requirements of each
airport. The feasibility of recovery glycol  is dependent on the ability of the collection system
                                         5-1

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                                                    Section 5 - Summary of Findings
to contain a relatively  concentrated waste  stream without significant contamination be  other
storm  water components.  It may  not be cost-effective  to distill and recycle waste glycol
solutions at low concentrations «  15%).  Remote or centralized deicing with the containment
and collection of used glycol  is one method for collecting  concentrated used glycol. However,
centralized deicing systems may be impractical for all but  the largest airport operations due to
the cost and physical size. For established airports, a switch to centralized deicing systems
would present a number of operational and logistical problems.
                                                                             *
       In lieu of a centralized facility, used glycol can be collected via vacuum trucks and fluid
collections containers to siphon glycol from runway aprons. Roller sponge devices may also be
employed.  However, previous experiences with roller sponge devices at the Toronto Airport
have had limited success do to uneven frozen surfaces.

       Glycol recovery systems are designed specifically for ethylene or propylene - type deicing
fluids. Mixtures of ethylene and propylene glycols cannot be recovered and separated effectively
in.a single batch process because the glycols will not separate easily hi the distillation systems.
Processing of a mixture of both glycols through a typical two tower distillation-based recovery
system will result in a recovered, concentrated mixture of ethylene and propylene glycol with
little commercial value.  A prohibitively expensive and elaborate distillation system would be
required to separate ethylene and propylene glycol from each other'because of the closeness of
their boiling points. Airports  which desire to recover their spent ADF must use only one type
of solution or segregate application and runoff areas if both types  of solutions are employed.
The SAE performance-based standards for ADF indirectly  limit the on-site application of ADF
recovery since all recovered product must be returned to glycol suppliers for performance-based
recertification.

       Studies into the effectiveness of these alternative collection systems should be considered
in the future.  These studies should also investigate both cost and environmental benefit.
                                           5-2

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                                                            Section 6 - References
                                    SECTION 6
                                   REFERENCES
American Association of Airport Executives, Conference on Aircraft Deicing, August 23, 1993,
       Washington, D.C.    .

Comstock,  C. 1990. as cited in Sills, R.D. and Blakeslee, P.A.,  1992.  "The Environmental
       Impact of Deicers  in  Airport  Storm Water Runoff",  in Chemical  Deicers  in  the
       Environment, ed. Frank M. D'ltri, Lewis Publishers, Inc. Chelsea, MI.

ENSR Consulting and Engineering. 1993. Evaluation of the Biotic Communities and Chemistry
       of the Water and Sediments in Sand Creek near Stapleton International Airport. Prepared
       for Stapleton International  Airport.  Document No. 6321-002.

Freeman, H.M., 1989. Standard Handbook of Hazardous Waste Treatment  and Disposal,
       McGraw-Hill,  New  York,  1989.

Federal Aviation Administration. 1991.  Advisory Circular (150/5320-15): Management of
      Airport Industrial Waste. U.S. Department of Transportation, Washington, D.C.

Federal  Register. November 16, 1990  EPA Administered Permit Programs; the National
      Pollutant Discharge  Elimination System. Vol. 55, No. 222.  page 48062.
       (Available - OWRC)

Federal  Register.  November 19,  1993.  Fact Sheet for the Multi-Sector Stormwater General
      Permit (Proposed).  Vol. 58, No. 222. page 491587. (Available -  OWRC)
                                        6-1

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                                                              Section 6 - References
 Federal Register.  June 12,  1995.  Hazardous Waste:  Reportable Quality Adjustments.  Vol.
       60, No. 112. pages 30926-30962 (Available - OWRC).

 Hartwell, S.I., D.M. Jordahl, E.B.  May.   1993.  Toxicity of Aircraft Deicer and Anti-icer
       Solutions to Aquatic  Organisms.  Chesapeake Bay Research and Monitoring Division,
                                                             \
       Annapolis, Maryland. CBRM-TX-93-1.

 Health Advisory,  1987. Ethylene Glycol.  Office  of  Drinking  Water, U.S.  Environmental
       Protection Agency. PB87-235578. (Available - NTIS - PB87-235578)

 Kaldeway, J. 1993. Director of Airport  Operations.   L.B.  Pearson International Airport,
       Toronto, Canada. Personal communications with Lauren Fillmore, Engineering-Science,
       Inc.

 Legarreta, G. 1993. Civil Engineer, Design and Operations Criteria Division, Federal Aviation
       Administration.  Personal.communication with Lauren Fillmore, Engineering-Science,
       Inc.

 Lubbers L.   1993.  Laboratory and Field Studies of the Toxicity of Aircraft Deicing Fluids.
       Presentation to the SAE Aircraft Ground Deicing Conference, Salt Lake City, Utah, June
       15-17, 1993.

 McGreevey, T. 1990. as cited in Sills, R.D. and Blakeslee, P.A., 1992. 'The Environmental
       Impact of Deicers in Airport Storm Water Runoff",  in  Chemical Deicers  in  the
       Environment, ed. Frank M. D'ltri, Lewis Publishers, Inc. Chelsea, MI.

 Morse, C. 1990. as cited in Sills, R.D. and Blakeslee, P.A., 1992. "The Environmental Impact
       of Deicers in Airport Storm Water Runoff", in Chemical Deicers in the Environment,  ed.
       Frank M. D'ltri, Lewis Publishers,  Inc. Chelsea, MI.

NIOSHTIC"1 Search Results  - Ethylene Glycol, Propylene Glycol
                                         6-2

-------
                                                            Section 6 - References
Roberts,  D. 1990.  as cited in Sills, R.D. and Blakeslee, P.A., 1992. The Environmental
       Impact of Deicers in Airport Storm Water Runoff",  in Chemical Deicers  in  the
       Environment, ed. Frank M. D'ltri, Lewis Publishers, Inc. Chelsea, MI.

SAE International.  May 17,  1993.  Unconfirmed Minutes of Meeting No.  37 of AMS
       Committee, Rome, Italy.

Sills, R.D. and Blakeslee, P.A., 1992. "The Environmental Impact of Deicers in Airport Storm
       Water Runoff", in Chemical Deicers in the Environment, ed. Frank M. D'ltri, Lewis
       Publishers, Inc. Chelsea, MI.

Transport Canada. 1985. State-of-the-Art Report of Aircraft Deicing/Anti-icing. Professional and
       Technical Services, Airports and Construction, Airport Facilities Branch, Facilities and
       Environment Management. AK-75-09-129.  (Type I Fluid Only)

Verschueren, K.  1983. Handbook of Environmental Data on Organic Chemicals.  2nd Edition.
       Van Nostrand Reinhold Co., New York,  N.Y.
                                         6-3

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                                                          Section 6 - References
Sources for information for Section 6:
      U. S. Dept. of Commerce
      National 'fechnical Information Services (NTIS)
      5285 Port Royal Road
      Springfield, Virginia 22161

      Telephone:           .     (703) 487-4650
      (Rush Orders Only)        1-800-553-6847
      FAX                     (703) 321-8547
      Education Resources Information Center/Clearinghouse for Science, Mathematics and
      Environmental Education (ERIC/CSMEE)
      1929 Kenny Road
      Columbus, Ohio  43210-1015

      Telephone:   (614) 292-6717
      FAX:        (614)292-0263
      Office of Water Resource Center (OWRC)
      RC4100
      401 M Street, SW
      Washington, D. C.  20460

      Telephone:    (202) 260-7786
      FAX:        (202) 260-4383

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                                     Appendix A - Case Studies and Evaluation
                                  APPENDIX A

                       CASE STUDIES AND EVALUATION
 The following section presents specific information on the ADF recovery processes evaluated
for this report.  The information is provided in a checklist format.
DEICING SYSTEM INCORPORATED

1.   Company Address:


       North America Office:
       8737 Red Deer Circle
       Louisville, Kentucky, 40220

       Head Office:
       S-951 84 Lulea
       Sweden

2.   Contact Name:  Mr. Bernt Lidstrom

       Phone: (502) 499-8609
       Fax: (502) 491 7881


3.   Current Status of Applications


       Deicing System has provided large ADF recovery systems in three locations in Europe:



Location                                  Capacity                Start-up Date

Lulea, Sweden                            80 gal/hr                   1984
Oslo, Norway                            530 gal/hr                   1989
Munich New Airport, Germany            1,320 gal/hr                   1992
                                       A-i

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                                         Appendix A - Case Studies and Evaluation
 Process data for the Munich Airport system has been obtained and is presented below.

  For the North American market, Deicing System has developed a mobile recovery plant for
 deicing aircraft fluid.  The mobile recovery plant has the capacity to recover deicing fluid from
 one airport or several  smaller airports.  All processing equipment is contained in a semitrailer,
 easily hitched to a truck.  Once the mobile recovery plant is positioned, it is connected to the
 available energy  supply at the airport, and  to holding tanks for collected and recovered deicing
 fluid.  The processing equipment is similar to that of the large plants for fluid recovery that
 Deicing System has developed and installed at the airports in Europe.

         To date, Deicing System does riot  have any North American field applications of their
 recovery system.

 4.    Process Description

         The glycol recovery plant employed  by Deicing System in Europe consists of a three-
 stage process shown in Figure A.I.  The recovery process was constructed in a building with
 a floor area of 6,000 sq ft and is 30 ft high.  The building has a steel framework and has a
 cladding of double steel sheeting with an insulation in between the sheetings. The steam-boiler,
 control room, electrical distribution  and chemical  storage are  each located in separate rooms.

         The first stage of the recovery process is filtration to remove suspended solids, such as
sand, from the fluid.   Filters F-01  and  F-02  have  a  mesh width of 50 and 10 microns,
respectively. Duty and standby filters are provided for continuous operation of the process.

        The second step  of the process is an ion exchange system (DM-01) where positive and
negative  ions, e.g. chlorides and sulfates, are removed.  The conductivity of the effluent from
                                          A-2

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Appendix A - Case Studies and Evaluation
                                  i
                                  >
                                  I
                                  CD

                                  I
                                  Cfl

                                  O

                                  u
                                   o
 A-3

-------
                                         Appendix A - Case Studies and Evaluation
 the ion exchange columns is measured.  When it reaches a predetermined value, a regeneration
 of the columns is initiated.  The columns are regenerated by flushing with water, followed by
 NaOH in the first column and HC1 in the second column, and a final flush with water prior to
 going back  on-line.   The flush waters  and  spent regeneration chemicals are collected in a
 neutralization tank prior to discharge to the sanitary sewer.

         The effluent from the ion-exchange columns is stored in Tank T-2.  From Tank T-2 the
 fluid is fed through heat exchanges  H-01 and H-05 and then sprayed into distillation tower D-01.
 A portion of the water is removed from the fluid in this tower.  The fluid is thertr sprayed into
 distillation tower D-02 for further removal of water. The concentration of the effluent product
 is measured with  a densiometer.   When the  concentration  of  the  fluid has  reached  the
 predetermined  value, the fluid is fed to the ready tank T-04.

         The water content of the distillation effluent can be guaranteed at a minimum of 50%.
 The glycol content  in the condensate is guaranteed to not exceed 1.5%.

         In Europe, a wetting agent and a corrosion inhibitor must be added to the recovered
 product prior to reuse as airplane  deicing fluid.  The whole process is fully controlled by a
 process computer and PLC.

 5.    Performance Data

        Performance data was provided by Deicing System from the recovery system  at the
Munich Airport.  Table A.I shows that the influent stream had an average glycol content of
 18.6%.   The recovery  system produced an effluent stream with an average glycol content of
55.1%.
                                          A-4

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                                 Appendix A - Case Studies and Evaluation
                               TABLE A.I

              AIRPLANE DEICING FLUID RECOVERY SYSTEM
         PERFORMANCE DATA FROM MUNICH AIRPORT, GERMANY
Time
Hours
1
2
3
4
5
6
7
8
9
10
Average
Influent
Glycol
Concentration %
20.4
20.7
20.9
20.9
20.9
20.8
20.4
20.2
11.3
9.8
18.6
Effluent
Glycol
Concentration %
56.5
55.4
55.4
55.4
56.1
55.1
54.6
55.4
54.0
53.0
55.1
Notes:
           Data supplied by Deicing Systems Inc.
           Concentrations measured in the laboratory.
                                  A-5

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                                        Appendix A - Case Studies and Evaluation
 6.      Process Reliability

        In the data provided for the Munich Airport, the process reliably produced an effluent
with a glycol content over 50%.


7.   Maintenance and Energy Requirements

        Steam is required by. the recovery system.  The system has been designed to employ
excess  heat from the distillation columns in other  units.  In the system shown in Figure A.I,
steam is produced in boiler B-01. The heating media can be oil or gas.
                                        A-6

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                                       Appendix A - Case Studies and Evaluation
CANADIAN CHEMICAL RECLAIMING LTD. (CCR)
  1.    Company Address:
       610 Prairie Meadows Close
       Brooks, Alberta, T1R OC9

 2.    Contact Name:
       Mr. Howard Ames
       Phone: (403) 362-6229
       Fax: (403) 362-6202

 3.    Current Status of Applications

        CCR provided a mobile treatment and recovery system at the L.B. Pearson International
Airport in Toronto, Canada in the winter of 1992. CCR's patented technology was developed
with the assistance of the Canadian National Research Council, Alberta Research Council, and
Environment Canada.

        CCR has provided chemical refining services to the gas processing and petrochemical
refining industries for 15 years.  Ethylene glycol recovery systems,  based on the distillation
process, have been provided  by CCR in these industries.  CCR is transferring the  technology
they have gained in ethylene  glycol  recovery to ADF recycling.

4.   Process Description

        At the Toronto Airport, the ADF was collected from the ramp and deicing  areas, used
by various carriers, with vacuum or roller sponge devices and  delivered to the storage facility
built by  CCR.   In  certain  designated  areas  where significant deicing occurs, a simple
containment system has  been used with pump out and  temporary storage capabilities.  This
                                         A-7

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                                         Appendix A - Case Studies and Evaluation
 material is then transferred to the tank farm for processing. When volumes dictate, the collected
 fluid is processed by CCR's refining equipment.


         The recovery system  is a  three stage process of filtration, ion exchange, and vacuum
 distillation.  The unit's production capacity is 1200  Imperial Gallons per hour.  The refined
 glycol product is resold for reuse in automotive antifreeze. The water condensate is disposed
 to the sanitary sewer.
                                                                           *
                                                                            *
 5.    Performance Data

        Performance data was provided by CCR from the recovery system at the Toronto
 Airport.  Table A.2 shows that the  influent stream had an average glycol content of between 10
 to 20%.  The recovery system produced an effluent stream with an average glycol content of
 87%.


 6.    Process Reliability

        In the data provided for the Toronto Airport,  the process reliably produced an effluent
 with a glycol content over 80% as  required by the reuser.

 7.    Maintenance and Energy Requirements

        Steam is  required by the recovery system. The system has been'designed to employ
excess heat from the  distillation columns in other units.
                                          A-8

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                               •  Appendix A - Case Studies and Evaluation
Sample
                              TABLE A.2

              AIRPLANE DEICING FLUID RECOVERY SYSTEM
        PERFORMANCE DATA FROM TORONTO AIRPORT, CANADA
    Influent
    Glycol
Concentration (%)
    Effluent
    Glycol
Concentration (%)
1
2
3
4
5
Average
Notes:
1.
2.
,10
10
10
10
10
10

-20
-20
-20
-20
-20
-20

89.7
86.1
79.0
90.4
91.5
87.3

Data supplied by Canadian Chemical Reclaiming Ltd.
Concentrations measured in the laboratory.
                                 A-9

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                                         Appendix A - Case Studies and Evaluation
  GLYCOL SPECIALISTS, INC. (GSI)
  1.    Company Address:
       5915 North Broadway
       Denver, CO  80216
  2.    Contact Name:
       Mr.  Jim Hamilton
       Phone:  (303) 292-2000
       Fax:   (303) 292-0429 •
 3.    Current Status of Applications

         GSI owns and operates a glycol recovery system in Denver, CO. GSI has accepted and
 treated the glycol contaminated runoff from 25% to 35% of the deicing fluid volume generated
 at the Denver Stapleton Airport for the last 4 years.  The area collected from at the airport is
 Continental Airline's terminal. The collected runoff is stored in aboveground tanks adjacent to
 the airport property and is transported to the glycol recovery  facility.  The tanks  have a total
 capacity  of 160,000 gallons.  It is estimated that  a heavy storm generates between 30,000  to
 100,000  gallons  of contaminated runoff.

        The recovery system is located 5 miles away and operates year round.  GSI accepts
glycol contaminated liquids from sources other than the airport.  Approximately 450,000 gallons
per season  of glycol contaminated runoff from the airport are treated at the  recovery facility.
The 1993 season continued until June of that year due to the deicing requirements of the MD80
airplane.
        GSI will treat the runoff from 80% of the new Denver International Airport (DIA) when
it opens.
                                        A-10

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                                         Appendix A - Case Studies and Evaluation
 4.    Process Description

         The recovery system is a three stage process of primary filtration, nanofiltration, and
 distillation. Oils, greases, grit and suspended solids are removed during the primary filtration
 stage using a disposable cartridge filter. The filter is rated for removal of solids to 0.1 micron.

         Polymeric additives,  such as corrosion inhibitors and surfactants,  are removed in the
 nanofiltration stage.   Only  those additives with a molecular  weight greater $ian 500 are
 removed.  Typically, additives make up 1% -2% by weight  of the glycol that is used on
 airplanes.  The filtration membranes were supplied by Zenon Environmental.

         The effluent stream from the  nanofilter is  fed  through heat exchanges and  then
 discharged to a distillation tower.  There are three distillations towers in series at the  recovery
 facility.  During the distillation stage, water is removed from the liquid stream.  The GSI facility
 operates at 5,000 gpd.  Antifoaming agents are  added  to the glycol solution at the  inlet to the
 distillation tower because of the surfactants in the glycol.  Dissolved salts have not been detected
 in the spent ADF collected at Stapleton, so the removal of ionic species has not been required
 by an ion exchange unit.

 5.    Performance Data

         Typically, the contaminated runoff from Stapleton Airport has an average glycol content
of 28%.  The recovery system produced an effluent stream with an average  glycol content of
98.5%, with the remaining portion being water.
                                          A-ll

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  6.    Process Reliability
                                          Appendix A - Case Studies and Evaluation
         The recovery system must produce an effluent that meets performance specifications set
 by the reuser.  GSI indicated that the system consistently produces an effluent that meets those
 specifications.

 7.   Maintenance and Energy Requirements
                                                                             f
         No backwashing is required for the filters.  Filter residuals, containing non-toxic solids,
 are landfilled.  Periodic maintenance is required for the pumps and heat exchanges.
                                    i
 8.   Costs

         The greatest cost associated with the recovery system is the cost for the fuel that is used
 in the distillation process.  Therefore,  it is most cost  effective when the contaminated runoff
 contains a high percentage  of glycol.  According to the vendor, the recovery process is  cost
 effective when there is at least 15% glycol in the contaminated runoff.  In addition, the recovery
 system  produces a high glycol percentage (>98%) to reduce transportation costs. Unlike the
 European airports where glycol can be recovered and reused at the  airport at a concentration of
 50%,  the  recovered high  percentage  glycol is transported to  manufacturers in the  US.
 Transportation costs for low percentage recovered glycol are extremely high.

        The complete capital cost for the airplane deicing/anti-icing operations and collection
and processing  of contaminated runoff at the  new Denver Airport is estimated at 20 to 25 million
dollars.  The same complete capital cost for Denver's Stapleton Airport is estimated at 6 to 7
million  dollars.
                                          A-12

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                  Attachment B - Airplane Deicing Fluid Recovery Systems
                                                    Information Checklist
                           ATTACHMENT B

            AIRPLANE DEICING FLUID RECOVERY SYSTEMS

                      INFORMATION CHECKLIST

                                                              *

 1.  Company Name:


 2.  Company Address:


 3.  Contact Name:


          phone

          fax



4.  Current Status of Application


          Locations                Capacity (gal/hr)              Startup Date
5.   Process Description


    (attach process flow diagram if available)
                                 B-l

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                      Attachment B - Airplane Deicing Fluid Recovery Systems

                                                           Information Checklist
   6.  Performance Data






      (provide operating data including influent and effluent glycol content %, and other



contaminant levels if measured)








   7.  Process Reliability
                                                                      r
                                                                       9




   8.  Maintenance and Energy Requirements





      (include information on any wastes produced and disposal requirements)








   9.  Costs                                                             '
                                      B-2

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                  Attachment B - Airplane Deicing Fluid Recovery Systems
                                                   Information Checklist
                           ATTACHMENT B

            AIRPLANE DEICING FLUID RECOVERY SYSTEMS

                      INFORMATION CHECKLIST

                                                             •

 1.  Company Name:


 2.  Company Address:


 3.  Contact Name:


          phone

          fax



4.  Current Status of Application


          Locations                Capacity (gal/hr)              Startup Date
5.   Process Description


    (attach process flow diagram if available)
                                 B-l

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                      Attachment B - Airplane Deicing Fluid Recovery Systems
                                                           Information Checklist
   6.   Performance Data



       (provide operating data including influent and effluent glycol content %, and other

contaminant levels if measured)




   7.   Process Reliability
                                                                       »


   8.   Maintenance and Energy Requirements



       (include information on any wastes produced  and disposal requirements)




   9.  Costs
                                      B-2

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II /I TO
I I/I  I  f1^
I W •  •  i^
 Office of Wastewater Management
 MUNICIPAL TECHNOLOGY  BRANCH
                                              EMERGING TECHNOLOGY REPORT:
                                              Preliminary Status of Airplane Deicing
                                              Fluid Recovery Systems

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      STAPLE HERE
    FOLD HERE
Municipal Technology Branch 4204
United States Environmental Protection Agency
401 M Street SW
Washington, DC  20460
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