United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/625/R-93/013
September 1993
Handbook
Approaches for the
Remediation of Federal
Facility Sites
Contaminated with
Explosive or
Radioactive Wastes
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EPA/625/R-93/013
September 1993
HANDBOOK:
APPROACHES FOR THE REMEDIATION OF FEDERAL
FACILITY SITES CONTAMINATED WITH EXPLOSIVE OR
RADIOACTIVE WASTES
OFFICE OF RESEARCH AND DEVELOPMENT
CINCINNATI, OH 45268
Printed on Recycled Paper
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Notice
The information in this document has been funded wholly or in part by the U.S. Environmental Protection Agency
(EPA). This document has been reviewed in accordance with the Agency's peer and administrative review policies
and approved for publication. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
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Acknowledgments
This publication was developed for the Center for Environmental Research Information (CERI), Office of Research
and Development, of the U.S. Environmental Protection Agency (EPA). The information in the document is based
primarily on presentations at two technology transfer seminar series: Technologies for Remediating Sites
Contaminated with Explosive and Radioactive Wastes, sponsored jointly by EPA and the U.S. Department of
Defense (DOD) in spring and summer 1993; and Radioactive Site Remediation, sponsored by EPA and the
Department of Energy (DOE) in summer 1992. Additional information has been provided by technical experts from
EPA, DOD, DOE, academia, and private industry.
Edwin Barth, CERI, Cincinnati, Ohio, served as the Project Director and provided technical direction and review.
The Institute of Makers of Explosives (IME) offered review comments for the sections of the document on explosives
waste. Thomas Andersen, DOE; Harry Craig, U.S. EPA Region 10; and Melanie Barger, U.S. EPA, Office of Federal
Facilities, provided additional comments and input. Individual sections were developed and reviewed by the
following persons:
Chapter 1: Introduction, compiled by Eastern Research Group, Inc. (ERG), Lexington, Massachusetts, based
on information provided by several authors of later chapters
Chapter 2: Safety Concerns When Investigating and Treating Explosives Waste, Jim Arnold, U.S. Army
Environmental Center, Aberdeen Proving Ground, Maryland
Chapter 3: Field Screening Methods for Munitions Residues in Soil, Tom Jenkins, Cold Regions Research and
Engineering Laboratory, U.S. Department of the Army, Hanover, New Hampshire
Characterization of Radioactive Contaminants for Removal Assessments, Jim Neiheisel, Office of
Radiation and Indoor Air, U.S. EPA, Washington, DC
Chapter 4: Overview of Approaches to Detection and Retrieval Operations, Richard Posey, Environmental
Health Research and Testing, Lexington, Kentucky
Detection, Retrieval, and Disposal of Unexploded Ordnance (UXO) at U.S. Military Sites, James
Pastorick, International Technology (IT) Corporation, Washington, DC
Detection and Sampling of White Phosphorus in Sediment, Harry Compton, Environmental
Response Team, U.S. EPA, Edison, New Jersey
Chapter 5: Biological Treatment Technologies, Wet Air Oxidation, Low Temperature Thermal Desorption,
Solvent Extraction, and Volume Reduction, Major Kevin Keehan, U.S. Army Environmental Center,
Aberdeen Proving Ground, Maryland
Incineration of Soils and Sludges, Charles Lechner, U.S. Army Environmental Center, Aberdeen
Proving Ground, Maryland
Open Bum/Open Detonation, Steven Whited, Hercules Incorporated, Rocket Center, West Virginia
Ultraviolet Oxidation and Granular Activated Carbon, Wayne Sisk, U.S. Army Environmental Center,
Aberdeen Proving Ground, Maryland
Compressed Gas Cylinder Handling and Reactive Chemical Handling, Irwin Kraut, Emergency
Technical Services Corporation, Schaumburg, Illinois
Reuse/Recycle Options for Propellants and Explosives, William Munson, Thiokol Corporation,
Brigham City, Utah
in
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Chapter 6: Wet-Based Volume Reduction for Radioactive Soils, Michael Eagle, Office of Radiation and Indoor
Air, U.S. EPA, Washington, IDC
Dry-Based Volume Reduction for Radioactive Soils, Ed Bramlitt, Defense Nuclear Agency, Kirtland
Air Force Base, New Mexico
Treatment of Radioactive Compounds in Water, Thomas Sorg, Drinking Water Research Division,
U.S. EPA, Cincinnati, Ohio
Incineration of Radioactive and Mixed Waste, Patrick Walsh, Scientific Ecology Group, Inc., Oak
Ridge, Tennessee
In Situ Vitrification, Tim Voskuil, Equity Associates, Knoxville, Tennessee, with assistance from
Edwin Barth, CERI, U.S. EPA, Cincinnati, Ohio
Polymer Solidification, Paul Kalb, Brookhaven National Laboratory, Upton, New York
In Situ Grout Injection, Michael Gilliam, Martin Marietta Environmental Systems, Oak Ridge
National Laboratory, Oak Ridge, Tennessee
Electrokinetic Soil Processing, Yalcin Acar, Louisiana State University (LSU), Baton Rouge,
Louisiana, with assistance from Robert Gale, LSU
Appendix A: Search for a White Phosphorus Munitions Disposal Site in Chesapeake Bay, Gary Buchanan, IT
Corporation, Edison, New Jersey; Harry Compton, Environmental Response Team, U.S. EPA,
Edison, New Jersey; John Wrobel, U.S. Army Environmental Center, Aberdeen Proving Ground,
Maryland
Appendix B: Case Study: Remedial Action Implementation, Elizabeth, New Jersey, Norman Abramson, Earth
Resources Corporation, Ocoee, Florida
Susan Richmond and Ivan Rudnicki of Eastern Research Group, Inc. (ERG) provided writing and editorial support
and prepared the document for publication. Karen Ellzey and David Cheda, ERG, provided graphics support in
preparing camera-ready copy, including figures. Equity Associates, Inc., of Knoxville, Tennessee, provided
transcripts of the Radioactive Site Remediation Seminar Series.
iv
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Contents
Page
Chapter One Introduction 1
1.1 Document Overview 1
1.2 Technical Introduction 1
1.2.1 Treatment Technologies for Explosive and Radioactive Waste at Federal Facilities . 1
1.2.2 Explosive Waste 2
1.2.3 Radioactive Waste 4
12.4 References 4
Chapter Two Safety Concerns When Investigating and Treating Explosives Waste 6
2.1 Background 6
2.2 Sensitivity Testing 6
2.3 Sampling and Treatment Precautions 6
2.4 Laboratory Analysis of Explosives-Contaminated Samples 7
Chapter Three Laboratory-Scale Analytical Methods 8
3.1 Field Screening Methods for Munitions Residues in Soil 8
3.1.1 Background 8
3.12 Field Screening Methods 8
3.1.3 Advantages and Limitations of the Methodology 10
3.1.4 TNT and RDX Test Kits 11
3.1.5 References Cited 12
3.2 Characterization of Radioactive Contaminants for Removal Assessments 12
3.2.1 Background 12
3.2.2 Applicability to Military Installations 12
3.2.3 ORIA's Soil Characterization Protocol 12
3.2.4 Case Study: Montclair/Glen Ridge Superfund Site 13
3.2.5 References 14
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Chapter Four Detection and Retrieval of Buried Munitions 16
4.1 Overview of Approaches to Detection and Retrieval Operations 16
4.1.1 Site Assessment and Operations Planning 16
4.1.2 Selection of Detection Equipment 18
4.1.3 Minimizing Hazards in Retrieval Operations 18
4.2 Detection, Retrieval, and Disposal of Unexploded Ordnance (UXO) at U.S. Military Sites ... 19
4.2.1 Background and Definitions 19
4.2.2 Authority and Qualifications for Handling UXO 20
4.2.3 Types of UXO Projects 20
4.2.4 UXO Detection and Excavation 21
4.2.5 Positive Identification 22
4.2.6 UXO Disposal 22
4.3 Detection and Sampling of White Phosphorus in Sediment 24
4.3.1 Background 24
4.3.2 Analytical Methods 24
4.3.3 Case Study: White Phosphorus Munitions Burial Area, Aberdeen Proving
Ground 24
4.3.4 References Cited 25
Chapter Five Treatment Technologies for Explosives Waste 26
5.1 Biological Treatment Technologies 26
5.1.1 Background 26
5.1.2 Treatable Wastes and Media 26
5.1.3 Operation and Maintenance 26
5.1.4 References 30
5.2 Thermal Treatment Technologies 30
5.2.1 Incineration of Soils and Sludges 30
5.2.2 Open Bum/Open Detonation 34
5.2.3 Wet Air Oxidation 36
5.2.4 Low Temperature Thermal Desorption 37
5.3 Physical/Chemical Treatment Technologies 37
5.3.1 Ultraviolet Oxidation 37
5.3.2 Granular Activated Carbon 38
5.3.3 Compressed Gas Cylinder Handling 39
5.3.4 Reactive Chemical Handling 42
5.3.5 Reuse/Recycle Options for Propellants and Explosives 47
5.3.6 Solvent Extraction 51
5.3.7 Volume Reduction for Explosives Waste 51
VI
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Chapter Six Treatment Technologies for Radioactive Waste 52
6.1 Wet-Based Volume Reduction for Radioactive Soils 52
6.1.1 Background 52
6.12 Treatabiltty Studies for Radioactive Soils 52
6.1.3 Advantages of Volume Reduction 53
6.2 Dry-Based Volume Reduction for Radioactive Soils 54
6.2.1 Background 54
62.2 Treatable Wastes and Media 54
6.2.3 Operation and Maintenance 55
6.3 Treatment of Radioactive Compounds in Water 57
6.3.1 Background 57
6.3.2 Treatment Selection 57
6.4 Incineration of Radioactive and Mixed Waste 60
6.4.1 Background 60
6.4.2 SEG's Incinerator, Oak Ridge, Tennessee 60
6.4.3 Incinerator at the Oak Ridge Gaseous Diffusion Plant 63
6.4.4 Advantages and Limitations 64
6.5 In Situ Vitrification 64
6.5.1 Background 64
6.5.2 Treatable Wastes and Media 65
6.5.3 Operation and Maintenance 66
6.5.4 Advantages and Limitations 67
6.5.5 References Cited 69
6.6 Polymer Solidification and Encapsulation 70
6.6.1 Background 70
6.6.2 Treatable Wastes and Media 70
6.6.3 Operation and Maintenance 70
6.6.4 Laboratory-Scale Applications 71
6.6.5 Advantages and Limitations 73
6.7 In Situ Grout Injection 73
6.7.1 Background 73
6.7.2 Treatable Wastes and Media 73
6.7.3 Operation and Maintenance 74
6.7.4 Advantages and Limitations 76
6.8 ElectroWnetic Soil Processing 77
6.8.1 Background 77
6.8.2 Treatable Wastes and Media 78
vii
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6.8.3 Operation and Maintenance 79
6.8.4 Bench- and Pilot-Scale Applications 79
6.8.5 Advantages and Limitations 81
6.8.6 References Cited 82
Appendix A Search for a White Phosphorus Munitions Disposal Site In Chesapeake Bay A-1
Appendix B Case Study: Remedial Action Implementation, Elizabeth, New Jersey B-1
viii
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Figures
Figure Page
1-1 Categories of energetic materials 2
1-2 Chemical structures of common explosive contaminants 3
3-1 Schematic of the Janowsky Reaction (1886) for TNT and 2,4-DNT 8
3-2 Visible absorbance spectrum of the Janowsky Reaction product of TNT 9
3-3 Visible absorbance spectrum of acetone extract of potting soil before and after addition
of Janowsky Reaction reagents 9
3-4 Correlation of TNT and TNB analysis by colorimetric and standard RP-HPLC procedures 9
3-5 RDX reaction sequence, including production of pinkish-colored anion (Azo dye) by
Griess Reaction (1864) 10
3-6 Visible absorbance spectrum of NitriVer 3 reaction product 10
3-7 Visible absorbance spectrum of acetone extract of uncontaminated soil before and after
addition of Griess Reaction reagents 10
3-8 Correlation of RDX analysis by colorimetric and standard HPLC
procedures 11
3-9 Grain size distribution curve and histogram for soil from the Nevada Test Site 13
3-10 Radiochemical analysis showing radioactivity as a function of particle size 13
3-11 Heavy mineral composition of soil from the Wayne and Maywood, New Jersey, sites 13
3-12 SEM and EDX analysis of amorphous silica from the 2.10-2.25 density fraction of
the 10- to 20-u/n grain size of radium-contaminated soil from Glen Ridge, New Jersey 14
3-13 Autoradiograph (SEM) showing radiation etch tracks from radiobarite and EDX of
radiobarite in the heavy fraction of 10- to 20-u.m grain size of radium-contaminated soil
from Glen Ridge, New Jersey 14
3-14 Radium reduction produced by laboratory-scale water washing and wet sieving of soil from
Montclair and Glen Ridge sites 14
4-1 A quality control check to a depth of 6 ft to assure that no ordnance items remain in a
demolished bunker 18
4-2 Track hoe in use as munitions recovery vehicle 19
4-3 Locally modified "armored cab" track hoe 19
4-4 UXO disposal operations 23
5-1 Schematic of lagoon slurry reactor 26
5-2 Schematic of aboveground slurry reactor treatment 27
5-3 Contaminant reductions achieved in laboratory-scale testing of sequencing batch reactor
treatment of soils from Joliet Army Ammunition Plant 27
5-4 Schematic of static-pile composting, showing the compost pile, protective shelter, forced
aeration system, and leachate collection pad 27
5-5 Schematic of in-vessel, static-pile composting equipment 28
5-6 Schematic of a mechanical composter 28
5-7 TNT, RDX, and HMX reductions achieved in windrow composting demonstration study at
Louisiana Army Ammunition Plant 28
5-8 Comparison of costs for windrow composting; mechanically agitated, in-vessel
composting (MAIV); and incineration of Umatilla Army Depot soils as a function of total soil
volume treated 29
5-9 Schematic of rotary kiln incineration system employed at Cornhusker Army Ammunition Plant.... 32
5-10 Range of expected incineration costs as a function of total volume of soils treated 34
ix
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Figures (Continued)
Figure Page
5-11 Flow diagram of hydromining process 49
5-12 Flow diagram of ammonium perchlorate reclamation process 50
6-1 General flow diagram for bench-scale testing 52
6-2 General flow diagram of the soil separation process 55
6-3 Percent of feed soil recovered as oversize rocks 56
6-4 Percent of feed soil recovered as clean soil 56
6-5 Specific activity of clean soil recovered on a weekly basis 57
6-6 Cumulative radioactivity recovered over first 40 weeks of operation 57
6-7 Effect of pH on removal of uranium by iron coagulation 59
6-8 Schematic of ISV by joule heating 67
6-9 Maximum waste loading of sodium sulfate, boric acid, bottom ash, and incinerator fly ash in
modified sulfur cement and Portland cement waste forms 70
6-10 Drawing of full-scale extruder with 4.5-in. diameter screw 71
6-11 Schematic of PE encapsulation process showing two feed hoppers 71
6-12 Photograph of PE waste form 72
6-13 Effect of water immersion on compressive strength of PE waste forms 72
6-14 Effect of exposure to 108 rad on compressive strength of PE waste forms ."". 73
6-15 ANS 16.1 teachability indices of PE waste forms containing sodium nitrate 73
6-16 Maximum percent waste loadings of sodium nitrate, sodium sulfate, boric acid, incinerator
ash, and ion exchange resins in PE and Portland cement waste forms 74
6-17 Economic analysis of encapsulating sodium nitrate at Rocky Flats Plant 74
6-18 Portland cement and modified sulfur cement waste forms after 2-week exposure to a
solution of 10 percent hydrochloric acid 74
6-19 Grout injection apparatus 75
6-20 Flow of grout from bottom of grout injection pipe 75
6-21 Grout injection system with in situ mixer 75
6-22 Monolith formed by overlapping grout columns 75
6-23 General chemistry of cement formation, showing growth and collapse of ettringite structure,
followed by growth of CSH structure 76
6-24 Flow behavior of grout at two different densities 76
6-25 Releases over time from structures with ANS 16.1 teachability indices of 11 and 13 76
6-26 Releases per year from structures with ANS 16.1 teachability indices of 11 and 13 76
6-27 Electroosmotic flow of pore fluid in saturated soil 77
6-28 Electrophoresis of negatively charged particles toward the anode 78
6-29 Diagram of advection by electroosmosis, depicting the excess cations at the clay surface
and the resulting velocity profile across the soil capillary 78
6-30 Migration of ionic species and colloids under an electric field 78
6-31 Schematic of protons displacing lead from the soil surface and the transport of both protons
and lead toward the anode compartment 79
6-32 Schematic of electrokinetic soil processing, showing the migration of ionic species
and the transport of the acid front and/or pore fluid across the processed medium 79
6-33 Lead removal across the specimens 80
6-34 Cadmium removal in spiked kaolinite specimens 80
6-35 Uranyl removal in uranyl nitrate-spiked kaolinite specimens 80
6-36 Phenol concentration profile in the effluent in spiked kaolinite specimens 81
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Tables
Table Page
1-1 Nitroaromatics and Nitramines Detected by CRREL and MRD in Explosives-Contaminated
Soils from Army Sites 3
1-2 Nuclear Weapons Site Contaminants and Contaminant Mixtures 5
3-1 Comparison of TNT and TNB Concentrations as Determined by Field and Laboratory Procedures . 9
3-2 Comparison of Colorimetric and HPLC Results from Umatilla Army Depot 10
3-3 Comparison of Colorimetric and HPLC Results for Several U.S. Army Sites 11
3-4 Comparison of Colorimetric and HPLC Results for Newport Army Ammunition Plant 11
3-5 Linear Density Gradient Analysis of 10- to 20-u.m Size Fraction of Soil from Glen Ridge,
New Jersey, Site 14
4-1 Checklist for a Site-Specific Detection/Retrieval Plan 17
5-1 Actual and Percent Contaminant Reductions Achieved in Windrow Composting Demonstration
Study at Louisiana Army Ammunition Plant 28
5-2 Cleanup Criteria for Cornhusker Army Ammunition Plant 32
5-3 Cleanup Criteria for Louisiana Army Ammunition Plant 32
5-4 Cleanup Criteria for Savanna Army Depot 33
5-5 Cleanup Criteria for Alabama Army Ammunition Plant 33
5-6 Definitions of Compressed Gas Cylinder Terms 40
5-7 Explosive Properties of Picric Acid 42
5-8 Compounds That May Form Peroxides During Storage 45
5-9 Compounds That Readily Form Peroxides in Storage Through Evaporation or Distillation 46
5-10 Compounds That Pose Hazards Due to Peroxide Initiation of Polymerization 47
5-11 Overview of Items and Uses 48
5-12 Types of Munitions That Have Been Cryofractured 50
5-13 Application Summary 51
6-1 Particle Separation Techniques 53
6-2 Particle Liberation Techniques 53
6-3 Dewatering Techniques 54
6-4 Goals Versus Results for Volume Reduction Treatability Study at Radium-Contaminated
Site in Montclair, New Jersey 54
6-5 Current and Proposed MCLs for Radium, Uranium, and Radon 58
6-6 Current and Proposed MCLs for Emitters of Alpha Particles, Beta Particles, and Photons 58
6-7 Range of Removal of Cesium-137, lodine-131, and Strontium-89 by Reverse
Osmosis and Ion Exchange 59
6-8 Range of Removal Rates for Each BAT-Contaminant Combination 59
6-9 Effect of Magnesium and Lime Dose on Uranium Removal by
Lime Softening (Percent Removal) 60
6-10 Effect of Sulfate on Uranium Removal by Anion Exchange 60
6-11 Types of Residual Waste Produced by Drinking Water Treatments 60
6-12 Radioactive and Mixed Waste Incinerators in the United States 61
6-13 Metals Contamination Limits for Oak Ridge Gaseous Diffusion Plant Incinerator 63
6-14 Required Lower Limits of Detection (LLD) for Radionuclides in the Oak Ridge Gaseous
Diffusion Plant Incinerator 64
6-15 Metals Retention Efficiencies for ISV 65
6-16 ISV Organic Destruction and Removal Efficiencies 66
xi
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Tables (Continued)
Table Page
6-17 Organic Destruction Efficiencies for Vitrification Systems 67
6-18 TCLP Leach Data for Selected Processes and Selected Metals 68
xit
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Chapter One
Introduction
1.1 Document Overview
The information in this publication is based primarily on
presentations at two technology transfer seminar series
sponsored by the U.S. Environmental Protection
Agency (EPA), the Department of Defense (DOD), and
the Department of Energy (DOE): the Seminar Series
on Technologies for Remediating Sites Contaminated
with Explosive and Radioactive Wastes, and the
Radioactive Site Remediation Seminar Series.
Additional information has been provided by technical
experts from EPA, DOD, DOE, academia, and private
industry. The reader is cautioned not to infer that there
is a connection between explosive waste and
radioactive waste. Both topics have been combined
because of the possibility of finding both types of waste
at federal facility sites. In addition to explosive and
radioactive wastes, reactive chemical and compressed
gas cylinder handling also are discussed in the
document.
This document provides an overview of technical issues
related to remediating soil and ground water
contaminated with explosive and radioactive wastes at
federal facility sites. The document covers a range of
sampling approaches and treatment technologies, both
those that have been successfully demonstrated and
applied and those that have not yet been successfully
implemented. For successfully demonstrated
technologies, the document provides background
information, and information on treatable wastes and
media; operation of the technology; applications at the
laboratory, bench, pilot, or field scale; and advantages
and limitations of the technology.
The document is intended to assist remediation
contractors considering technical issues and sampling
and treatment options at federal facility sites, but it
should not be used as a detailed manual for undertaking
remedial activities. The document presents a sampling
of techniques used for remediating explosive and
radioactive wastes, but is not a comprehensive
presentation of all available techniques and
technologies. In addition, although the document
provides previously published cost data from
applications of certain technologies, the reader is
cautioned against using these data to compare specific
technologies, because of the different costing
assumptions used in each study.
Section 1.2 in this chapter outlines the technologies
available for treating explosive and radioactive waste,
the types of explosive and radioactive waste typically
encountered at federal facility sites, and common
sources of these wastes. Chapter 2 covers safety
concerns associated with investigating and treating
explosive waste. Chapter 3 focuses on laboratory-scale
methods for developing detailed characterizations of
explosives-contaminated sites. Chapter 4 covers
detection and retrieval of buried munitions, both over
large fields of operation overseas and at military
installations in the United States. Chapter 5 describes
the biological, thermal, and physical/chemical
technologies available for remediating explosive waste,
and Chapter 6 covers treatment technologies for
radioactive waste sites.
1.2 Technical Introduction
1.2.1 Treatment Technologies for Explosive
and Radioactive Waste at Federal
Facilities
Most of the treatment technologies for explosive waste
discussed in this document currently are being
developed or implemented. These include biological
technologies, incineration, ultraviolet oxidation, granular
activated carbon treatment, and reuse/recycle options.
Similarly, all of the radioactive waste treatment
technologies discussed in Chapter 6, including volume
reduction, polymer solidification and encapsulation,
incineration, in situ vitrification, in situ grout injection,
and electrokinetic soil processing, have been
successfully demonstrated. This document also
discusses four treatment technologies that have not
been successfully implemented for explosive waste: wet
air oxidation, low temperature thermal desorption,
solvent extraction, and volume reduction. For additional
information on treatment technologies for 2,4,6-
trinitrotoluene (TNT) explosive waste, please see
Installation Restoration and Hazardous Waste Control
Technologies (U.S. ATHAMA, 1992).
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1.2.2 Explosive Waste
1.2.2.1 Types of Explosive Waste
The term explosive waste commonly is used to refer to
propellants, explosives, and pyrotechnics (PEP), which
technically fall into the more general category of
energetic materials. These materials are susceptible to
initiation, or self-sustained energy release, when
exposed to stimuli such as heat, shock, friction,
chemical incompatibility, or electrostatic discharge.
Each of these materials reacts differently to the
aforementioned stimuli; all will burn, but explosives and
propellants can detonate under certain conditions (e.g.,
confinement). Figure 1-1 outlines the various categories
of energetic materials. The emphasis of this document
is on soil and ground water contaminated with
explosives rather than propellants or pyrotechnics.
Explosives
Explosives are classified as primary or secondary
based on their susceptibility to initiation. Primary
explosives, which include lead azide and lead
styphnate, are highly susceptible to initiation. Primary
explosives often are referred to as initiating explosives,
because they can be used to ignite secondary
explosives.
Secondary explosives, which include TNT,
cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX or
cyclonite), High Melting Explosives (HMX), and tetryl,
are much more prevalent at military sites than are
primary explosives. Since they are formulated to
detonate only under specific circumstances, secondary
explosives often are used as main charge or boostering
explosives. Secondary explosives can be loosely
categorized into melt-pour explosives, which are based
on TNT, and plastic-bonded explosives (PBX), which
are based on a binder and a crystalline explosive such
as RDX. Secondary explosives also can be classified
according to their chemical structure as nitroaromatics,
which include TNT, and nitramines, which include RDX.
Figure 1-2 shows the chemical structure of TNT and
RDX. In the TNT molecule, NO2 groups are bonded to
the aromatic ring; in the RDX molecule, NO2 groups are
bonded to nitrogen.
Table 1-1 shows how frequently various nitroaromatics
and nitramines occur at explosives-contaminated sites
with which the U.S. Army Cold Regions Research and
Engineering Laboratory (CRREL) and the Missouri
River Division (MRD) have been involved. TNT is the
most common contaminant, occurring in approximately
80 percent of the soil samples found to be contaminated
with explosives. Trinitrobenzene (TNB), which is a
photochemical decomposition product of TNT, was
found in between 40 and 50 percent of these soils.
Dinitrobenzene (DNB), 2,4-dinitrotoluene (2,4-DNT),
and 2,6-DNT, which are impurities in production-grade
TNT, were found in less than 40 percent of the soils.
Figure 1-2 shows the chemical structures of common
explosive contaminants.
Propellants
Propellants include both rocket and gun propellants.
Most rocket propellants are either (1) Hazard Class 1.3
composites, which are based on a rubber binder, an
ammonium perchlorate (AP) oxidizer, and a powdered
aluminum (Al) fuel; or (2) Hazard Class 1.1 composites,
I
1
Propellants
I
Gun
(Single Base,
Double Base,
Triple Base)
1
Rocket
Energetic Material (PEP)
Explosives
1 1
Primary
Secondary
Pyrotechnics
1
Illuminating
Flare
1
Signal
Flare
Other
Hazard
Class 1 .3
Composite
Hazard
Class 1.1
Nitrate Ester
Figure 1-1. Categories of energetic materials.
-------
H, ฃ__
OJH NT*-!! NO, 0,N -"ฐ
NO,
H.C
NO,
2,4,6-Trlnltrotoluene
(TNT)
?"ป
^ ^ _NO,
NO, Jo, ""
Cyclo-1,3,5- Cyclo-1,3,5,7-
trlmethylene- tetramethylene-
2,4,6-trlnltramlne (RDX) 2,4,6,8-tetranltramlne (HMX)
,NO,
0,N
1NO,
N02
2,4-Dinltrotoluene
(DNT)
* ซ m ป. *i Trlnltro-2,4,6-
2,6-Dlnftrotoluene phenylmethyl,;ft'ramlne
(DNT)
(Tetryl)
Figure 1-2. Chemical strueturee of common explosive contaminants.
Table 1-1. Nltroaromatlcs and NItramlnes Detected by
CRREL and MRO In Explosives-Contaminated
Soils from Army Sites
Frequency (%)
Category
Contaminant
CRREL
MRD
Nltroaromatlcs
NItramlnes
TNT
TNB
DNB
2,4-DNT
2,6-DNT
4-Amlno-DNT
2-Amino-DNT
3,5-DNA
RDX
HMX
Tetryt
85
53
25
41
*
6
27
**
44
27
8
76
38
19
17
*
3
11
**
28
4
14
"Often not separated from 2,4-DNT.
"Peak often observed but only recently Identified.
Source: U.S. Army CRREL, 1993.
which are based on a nitrate ester (usually
nitroglycerine [NG]), nitrocellulose (NC), HMX, AP, and
Al.1 The nitrate ester propellants can be plastisol-bound
(high NC) or polymer-bound (low NC). If a binder is
used, it usually is an isocyanate-cured polyester or
polyether. Some propellants contain combustion
modifiers, such as lead oxide. Gun propellants usually
are single base (NC), double base (NC and NG), or
triple base (NC, NG, and nitroguanidine [NQ]). Some of
the newer, lower vulnerability gun propellants contain
binders and crystalline explosives and thus are similar
to PBX.
Pyrotechnics
Pyrotechnics include illuminating flares, signaling flares,
colored and white smoke generators, tracers,
incendiary delays, fuzes, and photo-flash compounds.
Pyrotechnics usually are composed of an inorganic
oxidizerand metal powder in a binder. Illuminating flares
contain sodium nitrate, magnesium, and a binder.
Signaling flares contain barium, strontium, or other
metal nitrates.
1 Hazard Class (HC) is a designation given to energetic materials by
the defining documents for military explosives (U.S. Army, U.S.
Navy, U.S. Air Force, and U.S. Defense Logistics Agency, 1989;
United Nations, 1992). HC 1.1 materials will mass detonate; HC
1.3 materials will mass deflagrate. The distinction Is made through
a series of tests defined In the document test protocol.
-------
1.2.2.2 Sources of Explosive Waste
Many DOD sites are contaminated with explosive waste
as a result of explosives manufacturing; munitions load,
assemble, and pack operations; explosives machining,
casting, and curing; open burn and open detonation
operations; and laboratory testing of munitions. Based
on the experience of the U.S. Army Environmental
Center (AEC) of DOD, one of the major explosive
wastes of concern at DOD sites are residues from land
disposal of explosives-contaminated process water.
Explosives-contaminated waters are subdivided into
two categories: red water, which comes strictly from the
manufacture of TNT; and pink water, which includes any
washwater associated with load, assemble, and pack
operations or with the demilitarization of munitions
involving contact with finished TNT. Despite their
names, red and pink water cannot be identified by color.
Both are clear when they emerge from their respective
processes and subsequently turn pink, light red, dark
red, or black when exposed to light. The chemical
composition of pink water varies depending on the
process from which it is derived; red water has a
more-defined chemical composition. For this reason, it
is difficult to simulate either red or pink water in the
laboratory.
The United States stopped production of TNT in the
mid-1980s, so no red water has been generated in this
country since that date (Hercules Aerospace Company,
1991). Most process waters found in the field are pink
waters that were generated by demilitarization
operations conducted in the 1970s. In these operations,
munitions were placed on racks with their fuzes and
tops removed. Jets of hot water then were used to mine
the explosives out of the munitions. The residual waters
were placed in settling basins so that solid explosive
particles could be removed, and the remaining water
was siphoned into lagoons. Contaminants often present
in these lagoon waters and the surrounding soils include
TNT; RDX; HMX; tetryl; 2,4-DNT; 2,6-DNT; 1,3-DNB;
1,3,5-TNB; and nitrobenzene.
1.2.3 Radioactive Waste
Several radioactive elements, including uranium,
radium, and radon, occur naturally in soil and ground
water. Radioactive contamination also can result
from processes associated with the production of
nuclear energy and nuclear weapons. Common
radioactive-contaminated materials include dry active
wastes, such as paper, plastic, wood, cloth, rubber,
canvas, fiberglass, and charcoal; ion exchange resins
used to polish condensate from nuclear power plants;
sewer sludges and lubricating oils contaminated with
radioactive materials; and air pollution control
equipment. For the purposes of this document,
radionuclides should be considered to have properties
similar to those of other heavy metals.
The Nuclear Weapons Complex (NWC) is a collection
of enormous factories devoted to metal fabrication,
chemical separation processes, and electronic
assembly associated with the production of nuclear
weapons. In approximately 50 years of nuclear
weapons production, these factories have released vast
quantities of hazardous chemicals and radionuclides to
the environment. Evidence exists that air, ground water,
surface water, sediment, and soil, as well as vegetation
and wildlife, have been contaminated at most, if not all,
nuclear weapons production facilities. Table 1-2 shows
the types of wastes often found at NWC sites.
Contamination of soil, sediments, surface water, and
ground water is widespread at the NWC, and
contamination of ground water with radionuclides or
hazardous chemicals has been confirmed at almost
every facility. Most sites in nonarid locations have
surface water contamination as well. Almost 4,000 solid
waste management units (SWMUs) have been
identified throughout the NWC, and many of these units
require some form of remedial action. Substantial
quantities of waste have been buried at the NWC, often
with inadequate records of the burial location or
composition of the waste buried. DOE estimates that a
total of about 0.2 million m3 of transuranic waste and
about 2.5 million m3 of low-level radioactive waste have
been buried in the complex. Most of this buried waste
is "mixed waste," meaning that it is mixed with Resource
Conservation and Recovery Act (RCRA) hazardous
wastes. For additional information on radioactive waste
sites, refer to Complex Cleanup: The Environmental
Legacy of Nuclear Weapons Production (U.S.
Congress, 1991).
1.2.4 References
References Cited
Hercules Aerospace Company. 1991. A petition for the
reclassification of TNT process red water to a
secondary material. January 14,1991. Radford Army
Ammunition Plant. Radford, Virginia.
United Nations. 1992. Transport of dangerous goods:
Tests and criteria. U.N. Publication ISBN 92-1-1,
39021-4. Chicago, Illinois.
U.S. Army, U.S. Navy, U.S. Air Force, and U.S. Defense
Logistics Agency. 1989. Department of Defense
explosives hazard classification procedures.
TB-700-2. NAVSEAINST 8020.8A. DLAR 8220.1.
U.S. Army CRREL. 1993. U.S. Army Cold Regions
Research and Engineering Laboratory. Evaluation of
analytical requirements associated with sites
potentially contaminated with residues of high
-------
Table 1-2. Nuclear Weapons Site Contaminants and Contaminant Mixtures*
Inorganic Contaminants
Radlonuclldes Metals Other Organic Contaminants Organic Facilitators1* Mixtures of Contaminants0
Americium-241
Cesium- 134, -137
Cobalt-60
Plutonium-238, -239
Radium-224, -226
Strontium-90
Technetium-99
Thorium-228, -232
Uranium-234, -238
Chromium Cyanide Benzene
Copper Chlorinated hydrocarbons
Lead Methylethyl ketone,
Mercury cyclohexanone, acetone
Nickel Polychlorinated biphenyls
and select polycyclic
aromatic hydrocarbons
Tetraphenyiboron
Toluene
Tributylphosphate
Aliphatic acids
Aromatic acids
Chelating agents
Solvents, diluents, and
chelate radiolysis
fragments
Radionuclides and metal ions
Radionuclides, metals, and organic
acids
Radionuclides, metals, and natural
organic substances
Radionuclides and synthetic Chelating
agents
Radionuclides and solvents
Radionuclides, metal ions, and
organophosphates
Radionuclides, metal ions, and
petroleum hydrocarbons
Radionuclides, chlorinated solvents,
and petroleum hydrocarbons
Petroleum hydrocarbons and
polychlorinated biphenyls
Complex solvent mixtures
Complex solvent and petroleum
hydrocarbon mixtures
* This contaminant list is being updated as new information becomes available.
Facilitators are organic compounds that interact with and modify metal or radionuclide geochemical behavior.
0 Information on mixture types is sparse, and concentration data are limited.
Source: U.S. DOE, 1990.
explosives. CRREL Report 93-5. Hanover, New
Hampshire.
U.S. ATHAMA. 1992. U.S. Army Toxic and Hazardous
Materials Agency. Installation restoration and
hazardous waste control technologies.
CETHA-TS-CR-92053. Aberdeen Proving Ground,
Maryland.
U.S. Congress. 1991. Office of Technology
Assessment. Complex cleanup: The environmental
legacy of nuclear weapons production. OTA-O-484.
Washington, DC.
U.S. DOE. 1990. U.S. Department of Energy. Office of
Health and Environmental Research, Subsurface
Science Program. Draft strategy document.
Additional References
U.S. Army. 1984. Military explosives. Department of the
Army Technical Manual. TM 9-1300-214.
U.S. Navy. 1988. Navy explosives handbook. Explosion
effects and properties, part III: Properties of
explosives and explosive compositions. Office of
Naval Technology. Naval Surface Warfare Center.
NSWCMP88-116.
-------
Chapter Two
Safety Concerns When Investigating and Treating Explosives Waste
2.1 Background
Safety precautions must be taken at sites contaminated
with explosives wastes. AEC, which has been involved
in sampling and treating explosives waste sites since
the early 1980s, has developed protocols for identifying
sites that require explosives safety precautions and for
handling explosives wastes at these sites. This section
discusses AEC's sensitivity testing protocol, specific
precautions required for sampling and treating
explosives wastes, and some laboratory safety issues
associated with analyzing explosives-contaminated
samples. The section does not cover statistical site
characterization or the work and health and safety plans
suggested by the Occupational Safety and Health
Administration (OSHA).
2.2 Sensitivity Testing
When AEC began to investigate explosives waste sites
in the early 1980s, the only available guidance on
sampling and treating explosives-contaminated soils
was 40 CFR 261.23, which vaguely specifies waste
identification. Consequently, AEC developed its own
protocol for determining whether soils contaminated
with explosives wastes are susceptible to initiation and
propagation, and, if so, how best to handle them. This
original protocol involved many tests, including impact
tests, friction tests, and shock gap tests. AEC quickly
determined that the original protocol was too expensive
and unwieldy, due to the variety of available tests, and
developed a two-test protocol. This protocol involved (1)
the deflagration-to-detonation test (DDT), which
measures an explosive material's reaction to flame; and
(2) the Bureau of Mines' zero gap test, which measures
an explosive material's reaction to shock. Both of these
tests are extremely conservative, rendering additional
tests unnecessary. The drawback to this protocol was
that both tests required relatively large volumes of soil
to be excavated and shipped, often at great expense,
to specially qualified laboratories.
AEC eventually developed its current protocol, which
involves chemical compositional analysis. By analyzing
the composition of samples from a site, AEC can
determine quickly and inexpensively whether materials
at the site are susceptible to initiation and propagation.
According to the DDT, soils containing more than 12
percent secondary explosives by weight are susceptible
to initiation by flame; according to the shock gap test,
soils containing more than 15 percent secondary
explosives by weight are susceptible to initiation by
shock. As a conservative limit, AEC considers all soils
containing more than 10 percent secondary explosives
by weight to be susceptible to initiation and propagation
and exercises a number of safety precautions when
sampling and treating these soils. Sampling and
treatment precautions are exercised when handling
soils that contain even minute quantities of primary
explosives.
The reliability of compositional analysis depends on
obtaining enough samples to generate a statistically
valid characterization of the site. CRREL has developed
field screening methods to reduce the number of
samples that must be analyzed in the laboratory (see
section 3.1). If contamination is in the parts per million
(ppm) or parts per billion (ppb) range by weight, the
samples could be shipped off site for analysis; if
contamination is in the percent range, special analytical
arrangements must be made.
2.3 Sampling and Treatment Precautions
Work, sampling, and health and safety plans for
explosives waste sites should incorporate safety
provisions that normally would not be included in work
and sampling plans for other sites. AEC works with
other laboratories such as the Bureau of Mines to
conduct site-specific hazards analyses for every
proposed operation at explosives waste sites, including
remedial investigation, remedial design, and remedial
action. These analyses include hazards identification,
hazards evaluation, risk assessment, and risk
management.
The most important safety precaution is to minimize
exposure, which involves minimizing the number of
workers exposed to hazardous situations, the duration
of exposure, and the degree of hazard. To reduce the
degree of hazard at explosives wastes sites, operations
usually are conducted on materials that have been
-------
diluted to a wet slurry. If necessary, distilled water can
be added to the soil to achieve the desired moisture
content. Water desensitizes the explosives and reduces
the effects of heat and friction. Water, however, also can
cause a localized detonation to propagate throughout a
soil mass, so moisture content should be adjusted on a
site-by-site basis. As another safety precaution,
nonsparking tools, conductive and grounded plastic,
and no-screw tops, which were developed for
manufacturing explosives, are standard equipment at
explosives waste sites. For example, nonsparking
beryllium tools are used instead of ferrous tools.
If contamination is above the 10 percent limit in some
areas of a site, the contaminated material could be
blended and screened to dilute the contamination and
produce a homogenous mixture below the 10 percent
limit. This blending is not by itself a remedial action but
a safety precaution; soils containing less than 10
percent secondary explosives by weight occasionally
experience localized detonations but generally resist
widespread propagation. Foreign objects and
unexploded ordnance within the contaminated soil often
impede the blending process and require unexploded
ordnance contractors (see section 4.2).
Once blending is completed, soil treatments such as
incineration and bioremediation can proceed.
Equipment used in treatment must have sealed
bearings and shielded electrical junction box.es,
Equipment also must be decontaminated frequently to
prevent the buildup of explosive dust.
AEC conducts periodic safety audits to ensure that
proper safety procedures are being followed. Field
operations must have DOD approval from the
Explosives Safety Board and corporate approve! from
any private contractors involved.
2.4 Laboratory Analysis of
Although TNT and RDX are the most common
contaminants at explosives waste sites, many sites steo
are contaminated with impurities in production-grade
TNT, such as DNB, 2,4-DNT, 2,6-DNT, and products of
photochemical decomposition of TNT, such as TNB.
These impurities and decomposition product are
thermally labile and hydrophilic and consequently
should not be analyzed using certain tests and solvents,
For example, gas chromatography (GC), in particular, Is,
not the best choice to screen for these chemicals,
because thermally labile compounds decompose in GC
equipment. High-performance liquid chromatography
(HPLC) (SW846 method 8330) has been selected for
routine laboratory analysis of soils from military sites.
-------
Chapter Three
Laboratory-Scale Analytical Methods
3.1 Field Screening Methods for
Munitions Residues in Soil
3.1.1 Background
Laboratory analysis of samples from sites contaminated
with explosives wastes is expensive and time
consuming. Due to heterogeneous waste distribution at
many sites, it would not be unusual for 80 to 90 percent
of the soil samples from a given site to contain no
contamination. As a result, developing a site
characterization with good spatial resolution is
extremely expensive. Field screening methods
determine quickly and less expensively which samples
are contaminated with explosives residues, thereby
reducing total analytical costs. For example, field
screening was found to be acceptable for determining
soil contamination areas at a military site (Craig et al.,
1993). This section discusses the field screening
procedures developed by CRREL and advantages and
limitations of CRREL's procedure. The section does not
cover soil sampling procedures.
3.1.2 Field Screening Methods
In developing the field screening methodology, CRREL
considered several design criteria. The method needed
to detect contaminants that were present at most
military sites. Based on data from sites investigated by
CRREL and MRD, CRREL determined that most sites
could be adequately assessed by methods that screen
first for TNT and RDX, and secondarily for 2,4-DNT,
TNB, DNB, and tetryl. The equipment needed to be
portable, so it could be shipped easily to sites, and
simple to operate, because field operators would not
necessarily have experience in analytical chemistry.
Field screening procedures also needed to use only low
toxicity solvents and have a quick turnaround time, a
large analytical range, a linear calibration scale, and a
sufficiently low detection limit. In addition, the results of
the procedure needed to correlate well with results from
standard laboratory methods.
CRREL's methodology has three steps: extraction, TNT
screening, and RDX screening.
3.1.2.1 Extraction
CRREL's procedure begins with a simple extraction
process. A 20-g sample of undried soil from the site Is
mixed with 100 mL of acetone. The sample is shaken
for at least 3 minutes, allowed to settle, and filtered with
a syringe filter. Very heavy clays might require longer
extraction periods, but 3 minutes is often sufficient for
most sandy and loamy soils. The efficiency of acetone
extraction is 95 percent that of standard laboratory
methods. The filtered extract then is subjected to
CRREL's TNT and RDX screening procedures. For
more detailed information on these procedures, see
U.S. Army CRREL, 1990, and U.S. Army CRREL, 1991.
3.1.2.2 TNT Screening
In the TNT screening procedure, the initial absorbance
of the acetone extract at 540 nanometers (nm) is
obtained using a portable spectrophotometer. The
extract is amended with potassium hydroxide and
sodium sulfite, agitated for 3 minutes, and filtered again.
The extract then can be analyzed visually. If it has a
reddish or pinkish color, it contains TNT; if it has a bluish
color, it contains 2,4-DNT. Figure 3-1 shows the
reactionknown as the Janowsky Reaction
o
O
ฎCH2CCH,+ H,O
CHjC CH,
N02
Blue-Colored Anlon
Figure 3-1. Schematic of the Janowsky Reaction (1886) for
TNT and 2,4-DNT.
-------
(1886)that produces the reddish-colored anion from
TNT and the bluish-colored anion from 2,4-DNT.
Absorbance measurements can be used to obtain
quantitative results. Figure 3-2 illustrates the visible
absorbance spectrum of the Janowsky Reaction
product of TNT, showing the maximum absorbance at
460 and 540 nm. CRREL uses the peak at 540 nm to
verify the presence of TNT, even though the absorbance
at 460 nm is greater, because of the potential for
interference from humic substances at 460 nm. Figure
3-3 illustrates the visible absorbance spectrum of an
acetone extract of uncontaminated potting soil before
and after Janowsky Reaction reagents are added,
showing the greater absorbance near the 460-nm as
opposed to the 540-nm wavelength.
The results of TNT screening, which reflect the sum of
the TNT and TNB concentrations, correlate well with
results obtained in the laboratory. Table 3-1 compares
the sum of the TNT and TNB concentrations as
determined by colorimetric analysis with the
sum of the TNT and TNB concentrations as
determined by laboratory analysis for homogenized,
field-contaminated (i.e., not spiked) soil samples from
seven sites. Figure 3-4 shows the strong correlation (R2
= 0.985) between results of colorimetric analysis and
the standard HPLC laboratory procedures for
homogenized soil samples. Table 3-2 compares
colorimetric and HPLC results from the Umatilla Army
Depot site in Oregon, showing a slightly lower
correlation due to the high concentrations of TNT at the
site. At the Savanna Army Depot site in Illinois, Dames
and Moore, Inc., reported a correlation of 0.959
between the results of laboratory and field analyses. At
the Seneca Army Depot site in New York, Aquatec
reported that colorimetric analysis identified 15
contaminated and 46 uncontaminated samples.
Laboratory analysis revealed only 2 false positives and
confirmed all 46 negative results.
3.1.2.3 RDX Screening
Field screening for RDX is similar to, but slightly more
complicated than, field screening for TNT. As in the
i 500
3 400
ฃ 300
| 200
H 100
? 0
Y .2.614 +0.858 [X]
R* .0.985
N o16
0 200 400 600
"> TNT Concentration by Colorimetric Method (jig/g)
Figure 3-4. Correlation of TNT and TNB analysis by
colorimetric and standard RP-HPLC procedures.
^ Ut5
K
io.4
!0.3
0.2
0.1
0
* * '
Reddish-Colored Solution* .
"'e
, i i I <
400
450
500 550
Wavelength (nm)
600
650
Figure 3-2. Visible absorbance spectrum of the Janowsky
Reaction product of TNT.
2.0
I"
0.8
0.4
Before Reagents Added
e After
^e Extract Visually Yellow -
"'
400 450 500 550 600
Wavelength (nm)
Figure 3-3. Visible absorbance spectrum of acetone extract
of potting soil before and after addition of
Janowsky Reaction reagents.
Table 3-1. Comparison of TNT and TNB Concentrations as
Determined by Reid and Laboratory Procedures
Sample Origin
Vigo Chemical Plant (IN)
Hawthorne Army
Ammunition Plant (NV)
Nebraska Ordnance
Works (NE)
Nebraska Ordnance
Works (NE)
Hastings Ind. Pk. (NE)
Hawthorne Army
Ammunition Plant (NV)
Nebraska Ordnance
Works (NE)
Lexington-Bluegrass
Depot (KY)
Sangamon Ordnance
Plant (IL)
Raritan Arsenal (NJ)
Colorimetric
(Ml/9)
TNT+TNB
14
6
2
592
85
1
146
15
33
85
HPLC
TNT
12
5
0
340
68
1
64
6
22
72
(ng/g)
TNB
-------
procedure for TNT, acetone is used to extract
contaminants from soil samples. The extract then is
passed through an anion exchange resin to remove
nitrate and nitrite. Zinc and acetic acid are added to the
extract, thereby converting RDX to nitrous acid. The
extract then is filtered and placed in a vial with a Hach
NitriVer 3 Powder Pillow. If the extract has a pinkish
color, it contains RDX. Figure 3-5 shows the reaction
sequence, including the Griess Reaction (1864), that
produces the pinkish-colored molecule (Azo dye) from
RDX.
Table 3-2. Comparison of Colorlmetrlc and HPLC Results
from Umatilla Army Depot
TNT Concentration Estimate
Sample #
Colorlmetrlc
Method
Standard
HPLC
Method
1b
2a
3b
3a
4a
5a
6a
8a
9a
11a
12a
1,060
3,560
704
3,180
4,490
2,530
64
102,000
6,610
716
109
2,250
7,430
1,180
4,030
8,520
3,990
131
38,600
7,690
1,300
183
a = Surface soil
b = Soil from 18 in. depth
Source: Jenkins and Walsh, 1992.
N02
Acetic Acid
+ Zn *- 3 HN02
V
O2N NO2 Frgncnimont Reaction (1897)
RDX .... ฉ
HNO2*
I VN=N-(/ YNR-,
Griess Reaction (1864) **o Dye
Figure 3-5. RDX reaction sequence, Including production of
pinkish-colored anlon (Azo dye) by Griess
Reaction (1864).
As in the TNT detection procedure, quantitative analysis
of the extract can be obtained from absorbance
measurements. Figure 3-6 is the visible absorbance
spectrum of the NitriVer 3 reaction product, showing the
absorbance maximum at 507 nm. Colorimetric analysis
of uncontaminated soil after acidification and addition of
the Griess Reaction reagents shows no background
absorbance (see Figure 3-7).
The results of RDX screening, which reflect the sum of
the concentrations of RDX and HMX, correlate well with
results obtained in the laboratory. Table 3-3 compares
RDX and HMX concentration estimates from field and
laboratory analysis of soil samples from three sites.
Figure 3-8 shows the strong correlation (R2 = 0.986)
between these field and laboratory results. Table 3-4
also shows a strong correlation between RDX
concentration estimates from field and laboratory
analysis of homogenized, field-contaminated soil
samples collected from the Newport Army Ammunition
Plant site in Indiana.
3.1.3 Advantages and Limitations of the
Methodology
CRREL's methodology has several advantages,
including:
Speed. The TNT and RDX detection procedures take
about 30 minutes per sample, including the
400
500 600 700
Wavelength (nm)
Figure 3-6. Visible absorbance spectrum of NitriVer 3
reaction product.
0.7
5 0.6
iO.5
!0.4
0.3
0.2
0.1
0'
4(
" " Before Reduction, Filtration, and
" Grlett Reagent
.
" ซ
" " " ซ
After ซ
10 450 500 550
-
-
-
-
. m~,
60
Wavelength (nm)
Figure 3-7. Visible absorbance spectrum of acetone extract
of uncontamlnated soil before and after addition
of Griess Reaction reagents.
10
-------
Table 3-3. Comparison of Colorimetric and HPLC Results for
Several U.S. Army Sites
Table 3-4. Comparison of Colorlmetrlc and HPLC Results for
Newport Army Ammunition Plant
Colorlmetrlc
RDX Concentration Estimate Oig/g)
(Hfl/g, HPLCGig/g) ,s* -
Sample Origin
Nebraska Ordnance
Works (NE)
Hawthorne Army
Ammunition Plant (NV)
Rarltan Arsenal (NJ)
Nebraska Ordnance
Works (NE)
Nebraska Ordnance
Works (NE)
Nebraska Ordnance
Works (NE)
Hawthorne Army
Ammunition Plant (NV)
Nebraska Ordnance
Works (NE)
Nebraska Ordnance
Works (NE)
Nebraska Ordnance
Works (NE)
Nebraska Ordnance
Works (NE)
RDX+HMX ROX
1,060 1.250
233 127
11 4
3 4
1,100 1,140
10 19
6 3
129 104
16 14
21 60
2 > 0.068
* 1000 - N .11
&
!*u\n - *
wUU ^4
I -*ซ
iii i^^
ป 1.1 M ป^r
1 1 1 1
HMX Sample # Method HPLC Method
115 1 0.55 0.05
2 2.86 1.31
56 3 4.55 3.15
4 6.62 15.5
5 5.87 8.45
6 253 299
105 7 17.4 38.6
8 45.4 258
3
9 674 1 ,800
-------
3.1.5 References Cited
Craig, H.D., A. Markos, H. Lewis, and C. Thompson.
1993. Remedial investigation of site D at Naval
Submarine Base, Bangor, Washington. In:
Proceedings of the 1993 Federal Environmental
Restoration Conference, Washington, DC.
Jenkins, T.F. and M.E. Walsh. 1992. Development of
field screening methods for TNT, 2,4-DNT, and RDX
in soil. Talanta 39(4): 419-428.
U.S. Army CRREL. 1991. U.S. Army Cold Regions
Research and Engineering Laboratory. Development
of a field screening method for RDX in soil. Walsh,
M.E. and T.F. Jenkins. CRREL Special Report 91-7.
Hanover, New Hampshire.
U.S. Army CRREL 1990. U.S. Army Cold Regions
Research and Engineering Laboratory. Development
of a simplified field method for the determination of
TNT in soil. T.F. Jenkins. CRREL Special Report
90-38. Hanover, New Hampshire.
3.2 Characterization of Radioactive
Contaminants for Removal
Assessments
3.2.1 Background
In 1987, EPA's Office of Radiation and Indoor Air (ORIA)
developed a characterization protocol for determining
the feasibility of reducing the volume of soils
contaminated with radioactive wastes at Superfund
sites. ORIA's protocol is more extensive than standard
protocols, which require only gamma spectroscopy of
bulk samples to determine the levels of radioactive
constituents. In ORIA's protocol, sieving and
sedimentation techniques are used to separate soils
into size fractions. Each fraction then undergoes
petrographic and radiochemical analysis to determine
the values of certain parameters, such as grain size
distribution, mineral composition and percentages, and
physical properties of radioactive contaminants, that
affect the feasibility of volume reduction. This section
discusses the potential applicability of ORIA's protocol
to radioactive soils at federal facilities, examines the two
tiers of the protocol, and presents a case study of a
radium-contaminated site where the protocol was
applied.
3.2.2 Applicability to Military Installations
ORIA's protocol potentially could be used to
characterize soils at military sites contaminated with
radioactive wastes. For example, at an Air Force base
in California, it was speculated that radium paint buried
in a bunker was contributing to elevated uranium levels
in the well water of a nearby field. Radiochemical
analysis would have indicated that radium paint does
not contain the parent compound, uranium-238, so
uranium at the site could not have been derived from
radium paint in the bunker. Similarly, at an Air Force
base in New Mexico, researchers conducted an
analysis for radium contamination near a particular
bunker where radium paint also might have been
buried. This analysis found radium only at background
levels. A petrographic analysis of the soil would have
revealed natural radioactive minerals and led to the
same conclusion.
ORIA's protocol is relatively inexpensive. Petrographic
analysis of five representative soil samples takes a
petrographer about one week and costs about $5,000.
Radiochemical analysis takes three times as long and
costs about $15,000. Thus the total cost to develop a
detailed characterization of soil from a military
installation, as a feasibility study for remediation
considerations, would be approximately $20,000.
3.2.3 ORIA's Soil Characterization Protocol
ORIA's methodology was developed based on
investigations at thorium-contaminated sites in Wayne
and Maywood, New Jersey; radium-contaminated sites
in Montclair and Glen Ridge, New Jersey; and
Plutonium surrogate host soil at the Nevada Test Site.
These investigations led to the development of a
two-tiered protocol: Tier 1 is a feasibility study; Tier 2 is
an optimization study.
3.2.3.1 Tier 1: Feasibility Study
The Tier 1 feasibility study has two stages: fractioning
and analysis.
Fractioning
Bulk samples are dried at 60ฐC and examined by high
resolution gamma spectroscopy. Samples then are split
into representative 300-gram portions by prescribed
separation methods, and each portion to be tested is
placed in a beaker to create a slurry of five parts
deionized water to one part solids. After 24 hours, the
slurry is stirred and poured through a nest of
increasingly fine sieves to separate the bulk sample into
size fractions of coarse, medium, and fine sand and silt.
Analysis
The fractions obtained by sieving undergo three
separate analyses. First, the fractions are analyzed to
obtain the sample's grain size distribution curve, which
identifies each size fraction's contribution to the total
weight of the sample. Figure 3-9 is a grain size
distribution curve for soils from the Nevada Test Site.
Second, the fractions are analyzed for radioactivity as
a function of particle size. Figure 3-10 is a graph of
radioactivity versus particle size for radium-, thorium-,
12
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CLAY
GRAVEL
0.001
0.01 at 1
OnlnSta(mm)
Figure 3-9.
Grain size distribution curve and histogram for
soil from the Nevada Test Site.
w
!"
5
!*>
!>
!
I 10
|
0
-
p
1
INI
i
r
m
i
ii
Opaque
Arnpnlboto
-Qarnct
-EpMot*
-Zircon
< MonazK*
g Other
Wiyn. WayiwSItt Mtywood MiywoodSItt
Fin* Sand RIM Sind
SlaCbni
Figure 3-11. Heavy mineral composition of soil from the
Wayne and Maywood, Now Jersey, sites.
40
30
20
10
f
1
1
u
i
|
ฐ\\
4.
_~S
r.T'.""
i
--*
0.01 0.1
Ra-228
Th-232
Ra-226
U-238
Th-230
10
Sitt '" Sand Graval
PartictoSize(mm)
Figure 3-10. Radlochemlcal analysis showing radioactivity
as a function of particle size.
and uranium-contaminated soils, from Maywood, New
Jersey, showing increased radioactivity in the silt-size
fraction. Third, the size fractions undergo petrographic
analyses, which generate precise statistical counts of
the various particles in the soil. Coarse-size materials,
which are greater than 0.6 mm, are analyzed visually.
Medium-size materials, which are between 0.038 and
0.60 mm, are immersed in index oil and examined under
petrographic and binocular microscopes. Fine-size
materials, which are less than 0.038 mm, are examined
by X-ray diffraction. Finally, medium-size materials
undergo a second petrographic analysis in which a
separatory funnel containing sodium polytungstate is
used to extract minerals with specific gravities greater
than 3.0. These minerals, which usually represent a
small percentage of the total sample, contain
disproportionately high levels of radioactive materials.
Figure 3-11 shows the heavy mineral composition of soil
from the Wayne and Maywood, New Jersey, sites. The
heavy mineral fraction of the soil from this site contains
all of the radiation contaminants. Monazite, which
contains almost all of the radioactivity, represents only
about 10 percent of the heavy mineral fraction and
comprises less than 1 percent of the total sample.
Zircon, which can contain up to 4 percent substitution
of thorium or uranium in the crystal lattice, constitutes
the remainder of the radioactive material at this site.
3.2.3.2 Tier 2: Optimization Study
If Tier 1 suggests that volume reduction is feasible,
further analyses can be performed to characterize the
contaminated soil. Size fractions can be broken down
into more precise increments by hydroclassification and
centrifuge. In addition, chemical assays can be used to
quantify the mineral analysis if a chemical element is
known to be solely associated with a particular
contaminant. For example, at one of the
radium-contaminated sites, the ore minerals for radium
include a uranal vanadinate. Since vanadium is rare, it
can be used as a "chemical signature" to determine the
weight percentage of this ore mineral of radium.
Instruments such as the scanning electron microscope
(SEM) and energy dispersive X-ray spectrometer (EDX)
also can be useful in identifying the morphology and
elements of specific particles in the submicroscopic size
range.
3.2.4 Case Study: Montclalr/Glen Ridge
Superfund Site
From 1915 to 1926, acid leach tailings from the
manufacture of radium were deposited in open field pits
in Montclair and Glen Ridge, New Jersey. After
operation ceased in 1926, residential housing was
developed in the area. Most of the contamination, which
consists primarily of precipitates and coprecipitates
from the acid leach process, is within 8 ft of the surface.
Ground water contamination is confined to areas
directly surrounding the dump areas, and there is no
ground water contamination in the bedrock, which is 20
ft below the surface. Consolidated glacial till, along with
13
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other materials that were dumped in the pits, is the host
material for the radium-contaminated tailings. The cost
to remove, transport, and dispose of all 300,000 yd3 of
soil from the site is estimated at close to $300 million,
making volume reduction an attractive option.
Tier 1 analyses indicated that the contaminated material
consists of 15 percent ores, such as carnotite and
uraninite, and 85 percent anthropogenic materials.
Within the latter group, most of the radioactivity is
located in the fine silt and clay fractions, particularly
in the 10- to 20-u.m fraction. A linear density gradient
analysis was used to separate the 10- to 20-ujn
fraction into light, medium, and heavy particles (see
Table 3-5). These three groups of particles then
underwent Tier 2 analyses, including gamma
spectroscopy, X-ray diffraction analysis, SEM/EDX
analysis, photomicrography, and autoradiography.
Figures 3-12 and 3-13 illustrate the results of some of
these analyses. The light particles, which are mostly
amorphous silica, were found to contain about 25
percent of the radium; the heavy particles, which are
mostly radiobarite, were found to contain about 50
percent of the radium.
Table 3-5. Linear Density Gradient Analysis of 10- to 20-nm
Size Fraction of Soli from Glen Ridge, New Jersey,
Site
Density
Weight
Ra-226 Activity
%Ra
Ught
2.10-2.25
32.20
Medium
2.25-2.71
Heavy
2.71
55.69
12.01
1,040pCi/g
8,270 pCi/g
27.55
47.24
Source: U.S. EPA, 1989.
LT. 100 sees
10,000
ซ,ooo
Al
Fป Cu
10.000
Energy k*V
Figure 3-12. SEM (Inset) and EDX analysis of amorphous
silica from the 2.10-2.25 density fraction of the
10- to 20-|im grain size of radium-contaminated
soil from Glen Ridge, New Jersey.
Based on the results of the characterization, site
engineers decided to remove the fine silt particles from
the site and wash the remaining sand-size particles of
any residual clay. In laboratory testing, these
procedures reduced 30 to 40 percent of the material to
a target level of 12 to 15 picocuries per gram of radium
226 (see Figure 3-14).
3.2.5 References
References Cited
U.S. EPA. 1989. U.S. Environmental Protection Agency.
Characterization of contaminated soil from the
Montclair/Glen Ridge, New Jersey, Superfund sites.
LT'100Sซl
aooo
7000
WS10104 ORD -1
10.000
Eimgy kซV
Figure 3-13.
Autoradlograph (SEM) showing radiation etch
tracks from radiobarite (Inset) and EDX of
radiobarite In the heavy fraction of 10- to
20-nm grain size of radium-contaminated soil
from Glen Ridge, New Jersey.
Separation Technique
Dry Screen
Wet Sieve
VORCE1
Vigorous
Wash
Clay
Particle Size (mm)
1 Volume Reduction/Chemical Extraction.
Gravel
Figure 3-14. Radium reduction produced by laboratory-scale
water washing and wet sieving of soil from
Montclair and Glen Ridge sites.
14
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EPA/520/1-89/012. U.S. EPA, Office of Radiation U.S. EPA. 1992. U.S. Environmental Protection Agency.
Programs. Characterization protocol for radioactive
Additional References STS?* Sf o^' l?".9380^1"1,:0^ U>8'
EPA, Office of Solid Waste and Emergency
Neiheisel, J. 1992. Petrographic methods in Response.
characterization of radioactive and mixed waste.
Proceedings of HMC/Superfund 1992, December
1-3, Washington, DC, 192-195.
15
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Chapter Four
Detection and Retrieval of Buried Munitions
This chapter covers several aspects of detection and
retrieval of buried munitions. Section 4.1 is an overview
of approaches to munitions detection and retrieval,
primarily in large fields of operation, such as large firing
ranges or war-ravaged countries. Section 4.2 discusses
retrieval and management of unexploded ordnance at
military sites in the United States, and section 4.3
examines detection and sampling of white phosphorus
munitions.
4.1 Overview of Approaches to
Detection and Retrieval Operations
This section examines various approaches for planning
activities related to detection and retrieval of buried
munitions, while emphasizing the importance of the
site-specific operations planning document, which is
designed to anticipate procedural problems and ensure
the procurement of equipment compatible with specified
tasks. This section also considers the means of
anticipating hazards and potential problems and
provides an operations planning checklist.
4.1.1 Site Assessment and Operations
Planning
The factors to consider when assessing a site for
detection and retrieval of munitions can be as varied as
the types of explosives waste that can be encountered.
Along with the instability and unpredictability of the
munitions themselves, however, a comprehensive
assessment also must take into account several other
site-specific factors. These factors include:
Proximity of population centers, which introduces the
possibility of evacuation and can restrict open
burning or detonation.
Particular terrain, which can be inaccessible or
saturated with metal and thus influence the detection
equipment used.
Seasonal weather, particularly temperature, which
determines the type of protective clothing and
detection equipment used.
Breadth and depth of contamination, and the
presence of underground obstacles, such as water
lines and electric power cables, which influence the
selection of detection equipment.
Potential environmental impact of retrieval.
Based on these considerations, retrieval operations at
a munitions firing site would be carried out quite
differently than retrieval of an explosive encountered
during excavations for an addition to a local hospital.
Ultimately, the extent of any operation will be
determined by constraints on time, technology, and
financial resources.
When assessing the nature of the munitions buried at
a site, the operations planner must be fully aware of the
challenges associated with specific types of explosives.
The following items are particularly problematic in terms
of safety and procedural planning:
Dud-fired munitions, which are fuzed and armed.
White phosphorus munitions, which, if damaged or
leaking, ignite on contact with air and pose problems
in recovery, handling, transportation, and disposal.
Chemically filled and depleted-uranium munitions,
which require several safety precautions, such as
protective clothing, decontamination lines for
personnel and equipment, and downwind hazard
areas.
Table 4-1 presents a checklist of factors to consider in
operations planning. While not intended to be
comprehensive, it covers major categories of issues
regarding buried munitions sites and is intended to be
used in the planning stages of a site-specific document.
Using a think-tank approach with subject matter
experts, each applicable section should be reviewed for
problem areas and the development of the operations
plan. Consideration of the factors listed in Table 4-1 will
make it possible to answer several questions that are
key to the planning effort:
What type of munitions are likely to be encountered?
1 The approaches described in Section 4.1 are based on experience
in foreign countries and might not be applicable to operations con-
ducted in the United States.
16
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Table 4-1. Checklist for a Site-Specific Detection/Retrieval Plan
L Background
A. Site history
1. Abstracts (e.g., old records, aerials, archives)
2. Range history
3.,
4. Ammunition Supply Point (ASP) records/storage
facilities and dumps (e.g., anticipated munitions and
degree of deterioration)
B. Level-one assessment
1. Current aerials/satellite photographs
2. Recent surveys (boundaries/borders, both physical and
political)
3. Utility company records (e.g., wires, cable, piping)
4. Environment
a. Climatic conditions/restrictions
b. Sensitive floral and fauna! species
5. Topography
6. Subsurface/surface soils and stratigraphy
a. Ground water Interference (also impact of
retrieval operations on local water and mineral
resources from chemical munitions)
b. Limitations on detection and retrieval equipment
7. Walk-Through
a. Evidence of dispensers and other delivery
systems
b. Presence of physical obstacles not readily
apparent
c. Craters or other physical evidence not apparent
from aerials or surveys
d. Surfldal evidence of buried munitions/chemical
leaks, high explosives, or ordnance components
C. Regulatory restrictions
1. National
2. Regional
3. State
4. Local
5. Political (foreign restraints)
6. Sociological
7. Rerouting of utilities
8. ฃconomic (e.g., Interruption of businesses or access to
natural resources)
II. Scope of Work
A. Geographic extent
B. Quantity of contamination anticipated/types of contamination
C. Time for completion
0. Quality controls
1. Determination of completeness
2. Internal/external controls/monitoring
E. Remediation required (e.g., reclamation)
III. Equipment Requirements
A. Mine detector
B. Computerized subterranean visual location
C. Ferrous ordnance locators (deep)
D. Mass detectors
E. Retrieval equipment (manual or remote)
F. Heavy equipment (e.g., modified heavy equipment)
1. Soil handling
2. Gaining access to ordnance Items
3. Removal of ordnance items
IV. Personnel Requirements
A. Explosive ordnance dlsposal/unexploded ordnance
(EOD/UXO) specialists
B. Support personnel
1. Administration
2. Safety/medical support
3. Laborers
4. Heavy equipment operators
5. Technical support (e.g., instrument personnel)
6. Maintenance
C. Political agents/liaisons
D. Trainers
V. Safety Requirements
A. Remote retrieval equipment
B. Chemical/Hazardous materials protection
1. Communications
2. Medical monitoring
3. Decontamination of personnel and equipment
C. Environmental protection
D. Contingency Plan/Accident Prevention Plan
E. Training program
VI. Financial/Budgetary Restraints
A. Cost vs. operational size
B. Quality of detected Information vs. cost and utility
C. Time allotted for completion
17
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e What is the required end result?
c What is the scope of the project?
4.1.2 of Detection Equipment
Wher> selecting munitions detection equipment, the
operations planner must weigh the advantages and
disadvantages of various technologies in relation to the
particular site. For example, munitions detection
equipment used in the remediation of a 5-acre military
storage facility might not be appropriate for a larger
seals operation, such as the removal of land mines from
100 square miles of a former militarized zone.
Equipment used for the larger scale operation would
have to be portable and could not require long setup
and operation times.
High-end munitions detection equipment is quite
sophisticated. A recently developed computer
technology has made it possible to generate a
three-dimensional, enhanced "snapshot" of as much as
an acre of subsurface contamination. Selected views of
the area can be generated that eliminate such
obstructions as utility lines in order to portray
subsurface contamination with great accuracy. A
limitation of this technology is that it detects only
metal!ic objects; also, certain soil compositions can
undermine the accuracy of such equipment. Moreover,
because it takes most of a day to generate a readout,
such equipment is best suited to relatively small-scale
operations,
Or, the other end of the detection technology spectrum
is the conventional metal detector (i.e., the mine
detector). Metal detectors vary in sensitivity and signal
type. Some detectors have a depth range of up to 60 ft;
others have a range of only 1 ft. Relatively unsensitive
detectors might be appropriate for clearing an artillery
impact area where large amounts of ordnance
fragments are within 6 ft of the ground surface. Figure
4-1 shows a metal detector being used to perform a
quality control check for ordnance in a demolished
bunker, A more sensitive detector would be required to
locate an unexploded bomb dropped from an airplane,
sines ordnance dropped from a high altitude can
penetrate deep into the ground surfacein loose soil,
to as deep as 60 ft.
So ths past, mass detectors were used to search for
non-ferrous materials. These detectors were sensitive to
variation in density and thus capable of detecting
explosive materials containing no metal. At present,
however, mass detectors are considered to be an
antiquated technology.
Figure 4-1. A quality control check to a depth of 6 ft to
assure that no ordnance items remain In a
demolished bunker.
4.1.3 Minimizing Hazards in Retrieval
Operations
Personnel safety with chemicals and explosives is the
primary consideration when carrying out a buried
munitions retrieval operation. Indeed, although the
dangers inherent in certain aspects of munitions
retrieval operations cannot be eliminated, thorough
planning can reasonably minimize hazards. A "least
hazardous" method for a particular procedure usually
can be developed through hazard analysis studies, the
application of modern loss-control techniques, and
adherence to safety recommendations and regulations.
Most cases of "failure" in munitions retrieval operations
can be traced to insufficient site-specific safety
planning.
A general approach to follow in munitions retrieval
operations is to expose a minimum number of personnel
to hazards for a minimum amount of time. This
approach suggests that remote retrieval procedures
should be used whenever possible. Remote procedures
can be as unsophisticated as attaching a line to a piece
of buried ordnance and retrieving it from a safฎ
distance. Or they can involve elaborate technologies
such as remote-controlled tools and computer-operated
robots. Since using remote retrieval procedures is not
always practical, the operations planner must determine
which approaches can be used with minimum risk. Type
of ordnance is the determining factor in most cases.
Remote initial movement would be advisable, for
instance, when retrieving either antitank munitions
fuzed with piezoelectric crystals and a dud-fired,
graze-sensitive feature or extensively damaged white
phosphorus munitions. Conversely, manual retrieval
might be reasonable for either a dud-fired illumination
round with a powder-train time fuze or an unarmed and
undamaged explosive projectile.
18
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For some situations, readily available equipment can be
modified to fulfill operational requirements. For
example, an area saturated with small-blast or
blast-and-fragmentation munitions might be cleaned up
with a conventional D-8 bulldozer after a "rake" has
been added and the operator's cab has been armored.
For other situations, it might be feasible to enhance
such a bulldozer with the addition of remote controls or
to use the heavy equipment itself as a barrier between
the ordnance and the operator. Figures 4-2 and 4-3
show examples of modified vehicles used in munitions
recovery. The operations planner should be prepared to
use whatever will accomplish the task without posing an
unacceptable risk of injury to personnel.
When retrieving munitions that pose a respiratory
hazard, such as chemical ordnance, personnel must
wear protective clothing. In such cases, the operations
planner needs to consider several questions in regard
to equipment use, including:
Can the equipment controls be manipulated by
personnel wearing protective clothing?
Figure 4-2. Track hoe In use as munitions recovery vehicle.
Will climate and fatigue limit the length of time
personnel can operate equipment?
Can the equipment be decontaminated after the
operation?
After all logical attempts have been made to limit
exposure of personnel to operational hazards, certain
aspects of an operation still might need to be performed
manually. For such cases, the operations planner will
face difficult decisions concerning acceptable risks. The
basis of any such decision-making has to be a
recognition of the dangers that are inherent to the task
of clearing weapons of destructionsome only partially
detonatedfrom a site. Operations often require that
procedures be developed at the site and then
implemented without benefit of thorough testing. Only
through careful planning can an operation be designed
to minimize hazards and the threat of injury.
4.2 Detection, Retrieval, and Disposal of
Unexploded Ordnance (UXO) at U.S.
Military Sites
4.2.1 Background and Definitions
Ordnance and explosive waste (OEW) is technically
defined as:
anything related to ordnance designed to cause
damage to personnel or materiel through
explosive force, incendiary action, or toxic
effects. OEW includes bombs and warheads;
guided and ballistic missiles; artillery, mortar,
and rocket ammunition; small arms ammunition;
antipersonnel and antitank land mines; demolition
charges; pyrotechnics; grenades; torpedoes and
depth charges; containerized and uncontainerized
high explosives and propellants; depleted
uranium rounds; military chemical agents; and all
other related components, explosive in nature
or otherwise designed to cause damage to
personnel or materiel (e.g., fuzes, boosters,
bursters, rocket motors). Uncontainerized high
explosives/propellents or soils with explosive
constituents are considered explosive waste if
their concentration is sufficient to be reactive and
present an imminent safety hazard.2
One component of OEW is unexploded ordnance
(UXO), technically defined as:
explosive ordnance which has been primed,
fused [sic], armed, or otherwise prepared for
action, and which has been fired, dropped,
Figure 4-3. Locally modified "armored cab" track hoe.
This definition of OEW was developed by the Huntsville Mandatory
Center of Expertise (MCX) and is used frequently in their state-
ments of work to contractors.
19
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launched, projected, or placed in such a manner
as to constitute a hazard to operations,
installations, personnel, or materiel, and remains
unexploded either by malfunction or design or for
any other cause.3
This section discusses the authority and qualifications
for handling UXO projects, types of UXO projects, UXO
detection and excavation tools and techniques, and
UXO identification and disposal.
4.2.2 Authority and Qualifications for
Handling UXO
4.2.2.1 Authorities and Programs
In 1986, Congress established the Defense
Environmental Restoration Program (DERP) under
Public Laws 99-190 and 99-499 to investigate and
remediate OEW. The two subprograms established
under DERP are the Installation Restoration Program
(IRP), which deals with active DOD installations, and
the Formerly Used Defense Sites (FUDS) Program,
which deals with sites formerly owned or used by DOD,
but no longer under DOD control.
The Huntsville Division of the U.S. Army Corps of
Engineers (COE) was designated on April 5, 1990, as
the Mandatory Center of Expertise (MCX) and Design
Center for UXO. As the UXO MCX, Huntsville is
responsible for investigating and remediating OEW
under the IRP and the FUDS program. The Huntsville
Division MCX works in cooperation with local COE
districts, local officials, and interested citizens to
examine and remediate OEW contamination.
4.2.2.2 UXO Personnel
Specialized training in ordnance disposal for personnel
from all four branches of the armed forces has been
standardized at the U.S. Naval School of Explosive
Ordnance Disposal (EOD), at the Naval Ordnance
Station in Indian Head, Maryland. This site has been the
main EOD training center for the U.S. armed services
since World War II. In the future, a recently opened
satellite facility of the U.S. Naval School of EOD at Eglin
Air Force Base, Florida, might assume a larger role in
EOD training.
While civilian- and military-trained specialists are
distinguished by titleUXO specialists and EOD
technicians, respectivelyskill classifications in this
field are roughly equivalent. Civilian skill classifications
of UXO Specialist, UXO Supervisor, and Senior UXO
Supervisor generally correspond to the military
3 Definition of UXO from the "Department of Defense Dictionary of
Military and Associated Terms," Joint Publication 1-02, December
1, 1989.
designations of Basic EOD Technician, Senior EOD
Technician, and Master EOD Technician (also known in
the military as "Master Blaster"). All UXO specialists
working for contractors under contract to the Huntsville
MCX must be former EOD technicians who have
attended and graduated from the U.S. Naval School of
Explosive Ordnance Disposal.
4.2.3 Types of UXO Projects
UXO projects fall into two main categories: UXO
remediation/investigation and UXO support services.
These two types of projects are described below.
4.2.3.1 UXO Remediation/Investigation
UXO remediation/investigation involves the location and
disposal of UXO. The explosive hazard presented by
UXO is the overriding safety concern in UXO
remediation/investigation.
While the organization of a UXO remediation project
varies depending on the project's size and the site
conditions, UXO work crews generally work most
efficiently when divided into distinct teams to
accomplish specific objectives. A field work team
typically is staffed by a group of 3 to 10 UXO specialists,
assistants, and skilled laborers under the direction of a
UXO supervisor. The exact number and type of
personnel depend on the project's work objective. A
large surface survey team, for example, could have
several skilled laborers trained as magnetometer
operators. UXO work crews performing intrusive
operations, such as UXO excavation, will consist
entirely of UXO specialists because a high level of
training is required to perform that operation safely.
4.2.3.2 UXO Support Operations
In contrast to the goal of removing and disposing of
UXO in remediation/investigation, UXO support
operations focus on protecting site personnel who are
not EOD trained from the hazards presented by UXO in
their work area.
An example of a UXO support operation is any remedial
investigation/feasibility study (RI/FS) that requires the
generation of field data from an active or formerly used
DOD installation. Whenever an installation has been
used by DOD, the possible presence of UXO or
explosives should be considered. If the site history
indicates that UXO was used or disposed of near project
sampling activities, the project management authority
typically requires that the work plan and safety plan
consider UXO hazards and requests Huntsville MCX
oversight of UXO operations.
During environmental sampling efforts, UXO specialists
might be employed to remove UXO hazards to allow
access to well drilling sites, or to perform downhole
20
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magnetometer checks during well drilling operations to
preclude contact with UXO. UXO specialists also might
escort field sampling teams to locate potentially
hazardous UXO and ensure that such items are
avoided.
UXO support operations usually are staffed with the
minimum number of UXO specialists required to ensure
the safety of field sampling personnel. Generally, the
level of UXO staffing required is one UXO specialist for
each individual field operation to be simultaneously
conducted. For example, if two well drilling rigs and one
soil gas sampling team are working simultaneously in
areas that could contain UXO, a total of three UXO
specialists would be used to ensure the safety of the
three sampling teams. Each sampling team should have
an assigned UXO specialist responsible for the
detection and avoidance of UXO.
Because UXO disposal typically is net included in the
statement of work for UXO support operations, UXO
discovered during such operations should be reported
to the area's military EOD team. Planning for UXO
support operations always should include deciding who
would have custody of and responsibility for UXO that
might be discovered during the project. The group or
agency responsible for disposal of the UXO also should
ensure adequate security to prevent unauthorized
access to the hazardous UXO.
The disposal of UXO hazards usually is not possible
during a UXO support project, because sufficient UXO
personnel are not available. Intrusive activities, such as
excavation of suspected UXO items, require at least two
UXO specialists, with additional support personnel
available in case of emergency. This staffing level is
rarely available on a UXO support project, which has
other field priorities and usually involves only the
minimum number of UXO specialists to escort the
sampling teams. As a result, disposing of UXO
discovered during a support operation takes a long time,
because the contracting authority must shift from the
UXO support staff to the Huntsville MCX.
4.2.4 UXO Detection and Excavation
The equipment and techniques commonly used for
UXO detection and excavation are described below.
4.2.4.1 Geophysical Detection Equipment
While locating UXO by sight is sometimes possible,
most UXO is extremely difficult to locate without the aid
of detection equipment, because UXO usually is
deteriorated and camouflaged by soil, grasses, and
leaves. Geophysical instruments are used to locate
potential UXO anomalies. The most common types of
geophysical instruments used on UXO projects are the
low-sensitivity magnetometer, the high-sensitivity
magnetometer, and the metal detector.
Low-Sensitivity Magnetometer (LSM). The LSM is
the most commonly used instrument for UXO location
because it is inexpensive, effective, and easy to use.
LSMs used for UXO detection typically are the dual-
fluxgate type originally developed for the detection of
underground utilities. Completely nonintrusive, LSMs
do not emit any electromagnetic radiation, which is a
potential source of initiation for some electrically initi-
ated UXO. A minor disadvantage of LSMs is that they
detect only ferrous items; nonferrous UXO, however, is
fairly rare. LSMs are used most frequently to supple-
ment visual observation during surface and near-sur-
face UXO searches and during safety escort
operations.
High-Sensitivity Magnetometer (HSM). While operat-
ing on the same principle as the LSM, the HSM also
can be calibrated and has a greater detection capability.
Some HSMs are designed specifically for subsurface
UXO detection and are so used by military EOD teams.
Some specific models have been tested extensively by
the U.S. Naval EOD Technology Center and can locate
large UXO up to 20 ft underground. Some HSMs are
equipped with a fluxgate sensor probe, which can be
detached from the electronics package to perform un-
derwater and downhole investigations. The HSM's pri-
mary disadvantages are cost ($17,000 compared to
$650 for the LSM) and increased weight and bulk. An
HSM, therefore, is used only when additional sensitive
detection capabilities are required or as a quality control
tool to check areas previously searched by the less
capable LSMs.
Metal Detector. Metal detectors, similar to
commercially available treasure finders, are useful for
projects requiring a second method of UXO detection.
These inexpensive instruments can locate nonferrous
metallic objects. They emit low-frequency radiation,
however, which presents the remote possibility of
initiating certain UXO under ideal conditions.
Underwater versions also are available for use by
divers.
4.2.4.2 Geophysical Detection Techniques
UXO specialists surveying an area for UXO typically
begin by marking the site boundaries with stakes. They
then divide the area into 5-ft-wide search lanes by
stringing surveyors' lines across the site to stakes at
each end of the survey area. The UXO survey team
then uses the low-sensitivity magnetometer to examine
each survey lane.
Upon detecting a possible subsurface UXO, the UXO
specialist will mark the spot with a pin flag or spot of
spray paint. A team of two UXO specialists then will
21
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excavate the marked items when the magnetometer
survey team has advanced beyond the area that would
be hazardous in the event of an accidental detonation
caused by the excavation team.
4.2.4.3 UXO Excavation Tools and Techniques
Anomalies suspected to be UXO can be positively
identified by a trained UXO specialist only after
excavation, which allows access to the item. Excavation
does not involve removal or movement of the item;
these activities would be considered part of the disposal
process. At most UXO sites, the vast majority of UXO
are located within 2 ft of the surface. Various common
hand tools are used to excavate such relatively shallow
UXO. For large projectiles and bombs that can be
imbedded from 10 to 20 ft underground, a backhoe can
be used by a skilled UXO specialist/equipment operator.
Upon locating and unearthing the suspected item,
excavation team members attempt to classify it. First,
they will determine if the item is UXO. If it is not UXO
and is not hazardous, such as a scrap of metal, the
nonhazardous metallic item may be removed and the
hole backfilled. If the item is identified as UXO, the
excavation team next will attempt to positively identify
it. All excavation results should be recorded in a field
excavation log.
4.2,5 Positive Identification
UXO is discovered most often in a deteriorated
condition after years of exposure, which can make
positive identification difficult or impossible. Positive
identification is even more difficult for UXO specialists,
since, unlike EOD technicians, they do not have ready
access to EOD 60 Series publications, reference
documents with detailed information on the
identification and functioning of specific ordnance.
These publications are frequently classified and
available to UXO specialists only on an as-needed basis
from the Huntsville MCX. UXO specialists are not
authorized to maintain EOD 60 Series libraries, which
would have to be guarded with the proper security and
updated when the publications are changed by the EOD
Technology Center in Indian Head, Maryland.
UXO specialists, therefore, frequently are required to
identify UXO based on their experience alone. Required
to err on the side of safety, specialists must consider a
UXO not positively identified unless it is a common UXO
with characteristics and operation that are thoroughly
familiar to them. If a UXO cannot be positively identified,
it must be considered unsafe to move. Unidentified UXO
potentially could have been exposed to a number of
stresses, including being buried for a long time, being
fired downrange and failing to function as designed, or
being kicked out of an improperly constructed disposal
detonation by the force of the detonation rather than
being consumed by the detonation. It often is impossible
to determine how the UXO was affected by such
stresses.
4.2.6 UXO Disposal
Once a UXO has been positively identified, the decision
to move a UXO is based on the UXO's fuzing and
condition, i.e., whether the UXO fuze has been armed.
Fuze arming is designed to occur when the ordnance is
fired or otherwise deployed. Therefore, UXO that has
been deployed, but failed to function, is considered to
be armed.
While the general rule of thumb is that unarmed UXO
is safe to move and armed UXO is not, some exceptions
exist. Although armed UXO usually is disposed of
without being removed, some specific UXO is safe to
move even if armed. Knowledge of the specific UXO is
required to move any UXO safely. Conversely, even if
a UXO is considered to be unarmed, the UXO specialist
may decide based on its appearance that it is not safe
to move. The UXO specialist should always err on the
side of safety and opt not to move any questionable
UXO.
The ideal method of handling UXO that is positively
identified as armed and unsafe to move is to dispose of
it where it is found. For UXO that is unarmed and safe
to move, disposal by detonation in a prepared disposal
area is a feasible option. Since transporting UXO can
be extremely problematic, time consuming, and costly,
transportation to an offsite disposal area should be
considered only if the UXO's current location cannot
withstand a high-order detonation, thereby precluding
onsite disposal methods.
The following sections discuss the accepted methods of
UXO disposal and the critical factors that must be
considered when designing a safe and efficient UXO
disposal operation. Figure 4-4 is a logic diagram
illustrating the rationale and logic for the proper handling
and disposal of UXO.
4.2.6.1 Onsite Disposal and Handling
UXO that is positively identified as armed and unsafe to
move commonly is disposed of using the blow-in-place
(BIP) method, which involves detonating UXO where it
is found. In BIP, a small initiation charge of explosives
is placed in contact with, or very near to, the UXO.
When neither BIP nor movement of the UXO is possible,
a render safe procedure (RSP) is a viable option.
Huntsville MCX, however, allows only EOD technicians,
not UXO specialists, to perform this operation because
needed information on particular RSPs is available only
from classified EOD 60 Series publications, to which
civilian UXO specialists do not have easy and routine
access. The RSP disrupts the UXO's explosive train,
22
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Support
Operation
1
i
Is Goal to Remove and Dispose of UXO
(Remediation/Investigation} or to Protect
Site Personnel That Are Not EOD Trained
(Support Operation)?
One Technician Can Escort Each Sampling
Team
i
!
Remediation/
Investigation
F
Team of at Least Two Technicians Required
for Intrusive Operations
UXO Is Located
1
UXO Is Located
Mark UXO with Ragging Tape
Can UXO Be Positively Identified?
V Yes
I
Report Type and Location to Military EOD | | ,a uxo Sflfa .'o Mova?
* Blow in Place
** Render Safe Procedure
- 1 *
Move to Secure Storage
Area for Later Disposal
No
BIP* or RSP" (RSP by
Military EOD)
iNo
Assume Not Safe to
Move. BIP* or RSP"
(RSP by Military EOD)
Figure 4-4. UXO disposal operations.
which is the series of events that causes an armed UXO
to detonate. This procedure is extremely time
consuming and possibly hazardous, so it is most
efficient to BIP these armed items and transport only
those that are safe to move in the condition in which
they were found.
RSPs are designed to eliminate the possibility of UXO
detonation, typically through fuze removal or
disablement. Since performing an RSP is inherently
hazardous, preparations should be made in advance for
a high-order detonation in case the RSP is not
successful. EOD technicians frequently perform RSPs
remotely to ensure their safety in case of accidental
detonation. Since performing RSPs is time consuming
and costly, the process should be used only when BIP
or movement of the UXO for disposal in a prepared
disposal area is not possible.
4.2.6.2 Disposal in a Prepared Disposal Area
Disposal in a prepared disposal area is most efficient
for larger projects where a secure onsite storage area
is constructed and maintained to collect UXO and store
working explosives. In any UXO disposal operation, the
goal is to minimize shock and fragmentation associated
with the operation, thereby avoiding excessive
disturbance of the surrounding area. Large disposal
detonation is more efficient than a series of BIP
operations and has less of a lasting environmental
impact.
For consolidation, however, UXO must be moved to the
disposal site and possibly stored until enough UXO is
amassed for an efficient disposal detonation. For large
disposal detonation, the disposal site is chosen, rather
than being dictated by where the UXO was found, as in
BIP. Previously disturbed sites can be selected for the
UXO disposal area, thereby limiting unnecessary
additional environmental impact to other areas. The
environmental impacts are contained in the selected
area, which can be completely remediated after UXO
disposal operations.
Large disposal detonation is much more efficient than
performing a series of BIPs. While setting up one large
disposal detonation takes slightly longer than preparing
a BIP, a much larger quantity of UXO can be disposed
of simultaneously in such a detonation area. In contrast,
a BIP is effective only for disposal of a single UXO, or
a cluster of UXO found together.
4.2.6.3 Considerations for UXO Disposal
Points to consider in any UXO disposal detonation are
discussed below.
Security
UXO disposal areas should be easily accessible to UXO
personnel and also easily secured when UXO disposal
operations are being conducted. If UXO is going to be
stored until sufficient quantities are amassed for
disposal, a secure storage area also must be provided.
23
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Tamping
Common methods for reducing blast and fragmentation
effects are to tamp each disposal shot by covering it
with earth or sandbags. At a prepared UXO disposal
site, the effects of blast and fragmentation can be
minimized by tamping the disposal detonation. To tamp
a disposal detonation, the UXO is placed in a hole and
covered by at least 3 ft of earth, which helps contain the
detonation and reduce the amount of blast and
fragmentation, if the site is in or near a residential area,
the amount of earth used to tamp the disposal
detonation may be increased to further decrease the
effect of the blast.
Monitoring
A seismometer can be used to record the amount of
blast and shock produced by the detonation. This record
of the audio and seismic effects of each disposal
detonation can be used to confirm or dispute property
damage claims from nearby residents.
Safe Distance
The safe distance from disposal detonations depends
on site-specific conditions. For more information on safe
distances for disposal detonations, see section 5.2.2.4.
4.3 Detection and Sampling of White
Phosphorus in Sediment
4.3.1 Background
White phosphorus, a tetrahedral molecule with four
phosphorus atoms, burns rapidly in air to form
phosphoric oxide (P4O10) powder, which has had
several military applications. In the past, munitions
makers produced phosphorus shells for artillery use.
These shells also were effective weapons, because
small particles of burning phosphorus stuck to clothing
and skin.
Shells disposed of under water can release phosphorus
into the environment, resulting in environmental
damage due to the toxicity of white phosphorus.
A major factor controlling the rate of disappearance of
white phosphorus is whether it is dissolved or
suspended. Dispersed white phosphorus could be
quickly covered with sediment. Other potential problems
with white phosphorus are that decomposition products
are poorly defined and that white phosphorus has the
potential to bioaccumulate in organisms higher in the
food chain.
4.3.2 Analytical Methods
Elemental phosphorus can be extracted and analyzed
using the method, Direct Determination of Elemental
Phosphorus by Gas-Liquid Chromatography (Addison
and Ackman, 1970). In this method, sediment and water
samples are extracted with toluene and analyzed by
gas chromatography/mass spectrometry. The mass
spectrometer is used as the detector because it can
be programmed to scan specifically for the P4
molecule of elemental phosphorus. This eliminates the
misidentification of phosphorus due to coeluting peaks
or any interferences in the matrix.
4.3.3 Case Study: White Phosphorus
Munitions Burial Area, Aberdeen
Proving Ground
The White Phosphorus Munitions Burial Area (WPMBA)
is located near Chesapeake Bay within the confines of
the restricted waters of the U.S. Army Base at Aberdeen
Proving Ground (APG), Maryland. An investigation of
this site was conducted to determine the exact location
of the WPMBA and the impacts of the area upon the
surrounding ecosystem. This investigation is
summarized below. For a more detailed description of
this case study, see Appendix A, "Search for a White
Phosphorus Munitions Disposal Site in Chesapeake
Bay" (Buchanan et al., 1989).
4.3.3.1 Detection and Sampling
Several techniques were used during the investigation
to determine the location of the WPMBA. A search was
conducted to locate related information concerning the
disposal, storage, and handling of white phosphorus. In
addition, an initial geophysical survey was conducted
during October 1988. The transects were completed in
two phases because of safety constraints imposed by
the nearby firing range.
In conducting the survey, a coarse grid was developed
to screen the area with an underwater proton
magnetometer. The magnetometer was used to detect
the assumed large mass of ferrous material in the
disposal area. Discrete areas exhibiting numerous or
extremely large gamma changes were investigated in a
second survey.
Based on the geophysical data, five areas were
selected for sediment core analysis to determine if a
burial site existed. Cores were collected off Black Point,
in the channel, north of Gull Island; east of the channel;
and west of the channel. In addition, cores were
collected in the adjacent APG channel to assist in
decision-making concerning future dredging. A
reference area also was selected north of the site in
Spesutie Narrows. The coring was conducted during
August 1989 in each of the five areas. Because of safety
concerns in dealing with the burial area and the known
presence of unexploded ordnance on APG, a remote
coring operation was necessary.
24
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4.3.3.2 Sample Analysis
A total of 60 cores was obtained, ranging in depth from
1 to approximately 9 ft. Cores were screened on site for
explosives using a portable gas chromatograph, and
composite samples were collected for analysis. All
samples were analyzed for elemental phosphorus,
explosives, and RCRA characteristics. Select samples
were analyzed for total organic carbon, grain size, and
toxicity. Core liners (6-ft butyrate plastic tubes) were
used throughout the investigation to collect, transport,
store, and maintain the integrity of the cores.
Water samples also were collected at each of the areas,
cored, and analyzed for elemental phosphorus and
explosives. Water quality measurements were recorded
in each area and included temperature, pH,
conductivity, salinity, oxidation-reduction potential, and
dissolved oxygen.
4.3.3.3 Safety Considerations
Steps were taken to prevent personnel from coming into
contact with white phosphorus and white phosphorus
munitions. The hazards posed to sampling personnel
from white phosphorus included the potential for fire and
explosion, and the inhalation of toxic fumes produced
during its burning. The following contingencies were
established to minimize this hazard.
A 55-gallon drum filled with water was placed in close
proximity to all core handling operations so that cores
could be submerged in the event of an isolated flare-up.
A pressurized hose also was available to douse any
core that could not be isolated and submerged. In the
event of an incipient fire, personnel were instructed to
don emergency respiratory equipment (self-contained
breathing apparatus) and evacuate the area
immediately. As a back-up to the water systems, wet
mud also was available.
In addition, to control incidental skin contact with white
phosphorus or other contaminants that may have been
contained in sediments, personnel involved with sample
handling wore butyl aprons, rubber boots, Nomex
coveralls, and long sleeve butyl gloves. Hard hats
equipped with face shields prevented sediments or
contaminants from splashing into eyes. Frequent
breaks between sampling events, construction of
shaded areas, and an ample supply of fluids eliminated
the hazards associated with the sun and hot
weather conditions and reduced the potential for
heat-stress-related injuries associated with the use of
protective clothing.
4.3.3.4 Results
White phosphorus was detected in 11 of the 60 core
samples at concentrations less than 6 u.g/kg. No white
phosphorus was detected in the water column. No
explosive compounds were detected in the water or
sediment samples. RCRA analyses indicated that the
sediment cores would not be considered hazardous
waste. Definitive boundaries for the WPMBA could not
be determined because of the diffuse, isolated nature
of the contamination. No impacts upon the aquatic
ecosystem are expected. Release of white phosphorus
is not expected unless the sediments are disturbed.
4.3.3.5 Further Investigation
The possibility of another location for the WPMBA was
suggested by historical references. One reference
alluded to munitions disposal in a tidal marsh near Black
Point, an area currently covered with 2 ft of sediment.
The Maryland Department of the Environment (MDE)
requested that this site be investigated as a possible
land disposal site. The survey location was selected
based on MDE's review of historical references and
aerial photographs.
The location identified by MDE was inaccessible by
water or land, so the subsequent magnetometry survey
was performed by a helicopter. The helicopter was
equipped with a helium magnetometer in a towed "bird"
configuration (an aerial tow). Navigation control was
accomplished with a range-range positioning and global
positioning system. The survey encompassed a
1,400-m by 1,600-m area.
The range-range and global positioning system with
video display provided accurate navigation control. The
aeromagnetic survey successfully identified the location
of several magnetic anomalies the size of the target.
Also detected was a single anomaly with a magnitude
that correlated well with that predicted by a
computer-generated model.
Ground investigation of the anomaly identified it as an
old metallic residuals burial area. The location of the
WPMBA remains undiscovered.
4,3.4 References Cited
Addison, R.F. and R.G. Ackman. 1970. Direct
determination of elemental phosphorus by gas-liquid
chromatography. Journal of Chromatography (47):
421-426.
Buchanan, G.A., H.R. Compton, and J. Wrobel. 1989.
Search for a white phosphorus munitions disposal
site in Chesapeake Bay. Proceedings of the U.S.
EPA's Forum on Remediation of Superfund Sites
Where Explosives Are Present. December 5-6,1989.
San Antonio, Texas.
25
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Chapter Five
Treatment Technologies for Explosives Waste
5.1 Biological Treatment Technologies 5.1.3 Operation and Maintenance
5.1.1 Background
Biological treatment, or bioremediation, is a developing
technology that uses microorganisms to degrade
organic contaminants into less hazardous compounds.
Compared to conventional technologies, bioremediation
has several advantages: (1) it actually degrades target
compounds, rather than just transferring them from one
medium to another; (2) it is publicly accepted, because
it is a natural process; and (3) it is probably less
expensive than incineration, especially for small
volumes of contaminated soil.
Although the two terms occasionally are interchanged,
biodegradation is not synonymous with mineralization.
Mineralization, which is the process by which
compounds are transformed into carbon dioxide and
water, is only one of several fates of contaminants in
biological treatment systems. Contaminants also may
be volatilized, bind to organic materials, be assimilated
into an active biomass, or be transformed into
compounds other than carbon dioxide and water.
Mineralization of contaminants is a desired, but rarely
achieved, outcome of bioremediation. This section
discusses the types of explosives that can be
bioremediated and highlights five specific biological
treatment technologies: aqueous-phase bioreactor
treatment, composting, landfarming, white rot fungus
treatment, and in situ biological treatment.
5.1.2 Treatable Wastes and Media
Bioremediation is most effective for dilute solutions of
explosives and propellants. TNT in the crystalline form
is difficult to treat biologically.
TNT degrades under aerobic conditions into
monoamino-, diamino-, and hydroxylamino-DNT, and
tetranitro-azoxynitrotoluenes. RDX and HMX degrade
into carbon dioxide and water under anaerobic
conditions. Researchers have not identified any specific
organisms that are particularly effective for degrading
explosives waste; a consortium of organisms usually
effects the degradation.
DOD currently is developing or implementing five
biological treatments for explosives-contaminated soils:
aqueous-phase bioreactor treatment; composting, land
farming, and white rot fungus treatment, which are
solid-phase treatments; and in situ biological treatment.
5.1.3.1 Aqueous-Phase Bioreactor Treatment
DOD is considering two types of aqueous-phase
bioreactors for the treatment of explosive contaminants.
The first is the lagoon slurry reactor, which allows
contaminants to remain in a lagoon, be mixed with
nutrients and water, and degrade under anaerobic
conditions. Figure 5-1 is a schematic of a lagoon slurry
reactor. The second is the aboveground slurry reactor,
which is either a concrete activated sludge basin or a
commercially available bioreactor. Figure 5-2 is a
schematic of aboveground bioreactor treatment,
showing the excavation and screening of soils prior to
treatment, dewatering of the treated soil, and recycling
of the extracted water to the reactor.
Aqueous-phase bioreactors provide good process
control, can be configured in several treatment trains to
treat a variety of wastes, and potentially can achieve
very low contaminant concentrations. A drawback of
bioreactor treatment is that, unlike composting systems
which bind contaminants to humic material, bioreactors
accumulate the products of biotransformation. In
addition, bioreactors have been shown to remediate
explosives only at laboratory scale, so the cost of
Nutrients
Aeration
Microorganisms
Mixer
Mixer
Figure 5-1. Schematic of lagoon slurry reactor.
26
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full-scale bioreactor treatment is unknown. Full-scale
bioreactors will have to incorporate a variety of safety
features that will add to their total cost.
The Army is conducting a demonstration study to examine
the effectiveness of treating explosives-contaminated
soils from the Joliet Army Ammunition Plant (JAAP) in
an aboveground sequencing batch bioreactor. The goal
of this study is to determine the extent of degradation,
byproducts, and total costs of full-scale bioreactor
treatment. Soils will be excavated from the site,
screened, and pumped into the reactor. Indigenous
microorganisms from the site will be isolated and added
to the reactor. Either malate or molasses will be used
as a substrate. After processing in the reactor, soils will
be drawn into a filter bed, where process waters will be
removed. These process waters will be recycled back
to the reactor, and any remaining discharges will be
treated to meet National Pollutant Discharge Elimination
System (NPDES) requirements. Initial laboratory testing
of this system produced greater than 99 percent
contaminant reductions within 14 days (see Figure 5-3).
5.1.3.2 Composting
DOD has been evaluating composting systems to treat
explosives waste since 1982. To date, composting has
been shown to degrade TNT, RDX, HMX, DNT, tetryl,
and nitrocellulose in soils and sludges. The main
advantage of this technology is that, unlike incineration,
composting generates an enriched product that can
sustain vegetation. After cleanup levels are achieved,
the compost material can be returned to the site and
covered with a soil cap. Another advantage is that
composting provides both aerobic and anaerobic
treatment, so it is effective for a range of wastes. The
feasibility of composting can be limited, however, by the
level of indigenous organisms ซn contaminated soil and
the local availability 01 amendment mixtures. In addition,
composting requires long treatment periods for some
Excavation
Soil Screening
Water Recycle
Nutrients
I Aeration
Dewatered
Slurry
II
c
Microorganisms
1
a
1
1
Dewatering
Slurry Bioreactors
waste streams, and composting of unfamiliar
contaminants potentially can generate toxic byproducts.
Composting methods fall into four categories: (1)
static-pile composting; (2) in-vessel, static-pile
composting; (3) mechanically agitated, in-vessel
composting; and (4) windrow composting. In static-pile
composting, contaminated material is excavated,
placed in a pile under a protective shelter, and mixed
with readily degradable carbon sources. The pile
undergoes forced aeration to maintain aerobic and
thermophilic (55 to 60ฐC) conditions, which foster the
growth of microorganisms. Bulking agents, such as cow
manure and vegetable waste, can be added to enhance
biodegradation. Figure 5-4 is a schematic of static-pile
composting. In-vessel, static-pile composting is similar
to static-pile composting except the compost pile is
placed in a vessel. Figure 5-5 is a schematic of an
in-vessel, static-pile composting device. In mechanically
agitated, in-vessel composting, contaminated material
is aerated and blended with carbon-source materials in
a mechanical composter. These devices have been
used at municipal sewage treatment facilities and
JAAP Consortium
Aerobfc+Malate
Anoxic+Succinate
Anoxlc+Malate
Figure 5-3. Contaminant reductions achieved in
laboratory-scale testing of sequencing batch
reactor treatment of soils from Joliet Army
Ammunition Plant.
Roof
Leachate
Collection
Woodchlp
Cover and Base
Figure 5-4.
Figure 5-2. Schematic of aboveground slurry reactor
treatment.
Ventilation Pipe
Concrete Pad (18' x 30' x 8" thick)
Schematic of static-pile composting, showing
the compost pile, protective shelter, forced
aeration system, and leachate collection pad.
27
-------
applied to explosives waste. Figure 5-6 is a schematic
of a mechanical composter. Windrow composting is
similar to static-pile composting except that compost is
aerated by a mechanical mixing vehicle, rather than a
forced air system.
In 1988, the Army began a series of demonstration studies
at the Louisiana Army Ammunition Plant to determine the
effectiveness of composting explosives-contaminated
soils. In the initial study, static-pile composting required
153 days to remediate soils contaminated with just 3
percent explosive waste by volume. Based on these
results, the Army determined that static-pile composting
would not be cost effective for remediating large
volumes of explosives waste.
The Army conducted a second study to optimize the
cost effectiveness of composting. This study used a less
expensive carbon-source material, thereby cutting
amendment costs from over $200 per ton to less than
Deflector
To Blower
Insulation
/
To Blower
Wood Chips
Figure 5-5. Schematic of in-vessel, static-pile composting
equipment.
Totally
Enclosed
Reactor
$50 per ton, and used a commercially available
mechanically agitated composter rather than a static
pile. These conditions led to more rapid and extensive
degradation of the explosives, achieving cleanup levels
of 10 to 20 ppm of TNT and RDX within 20 days.
Nevertheless, this method also was determined to be
economically infeasible, due to the initial cost of the
commercial composter.
Finally, the Army conducted a study to examine the
effectiveness of windrow composting. This study used
cow manure, sawdust, and potato waste amendments
and required the construction of a concrete pad
leachate collection system. Temperatures were
maintained at 55ฐC and the compost was turned once
a day. This process produced 98 percent reductions of
explosives contamination within 20 days, and degraded
HMX, which formerly had resisted degradation (see
Figure 5-7 and Table 5-1). Toxicological data from this
study indicated that composting achieved 90 to 98
percent toxicity reductions, consumption of the compost
material would not have been toxic to rats, the leachates
exhibited no mutagenicity, and some of the TNT had
been mineralized. Radiolabeled TNT studies indicated
that strong binding had occurred between TNT and the
humic compost. Since the initial costs were relatively
40
Figure 5-7. TNT, RDX, and HMX reductions achieved In
windrow composting demonstration study at
Louisiana Army Ammunition Plant.
Table 5-1. Actual and Percent Contaminant Reductions
Achieved in Windrow Composting Demonstration
Study at Louisiana Army Ammunition Plant
Contaminant Level
Figure 5-6. Schematic of a mechanical composter.
Da*/
0
5
10
15
20
40
TNT
1563
101
23
19
11
4
(ns/g)
RDX
953
1124
623
88
5
2
Reduction (%)
HMX
156
158
119
118
2
5
TNT
0.0
93.5
98.5
98.8
99.3
99.7
RDX
0.0
0.0
34.6
90.7
99.5
99.8
HMX
0.0
0.0
23.7
24.4
98.7
96.8
28
-------
low, windrow composting was determined to be an
economically feasible alternative to incineration.
Composting methods were evaluated in a feasibility
study at the Umatilla Army Depot TNT washout lagoons.
In initial testing, composting compared well to
incineration in terms of treatment performance but not
in terms of cost. The Army then analyzed the factors
affecting the cost of composting, including the specific
composting method, volume of contaminated soil, soil
throughput, amendment costs, and treatment time. This
analysis suggested that for treating less than 10,000
tons of contaminated material, the cost would be $740
per ton for incineration, $651 per ton for mechanically
agitated composting, and $386 per ton for windrow
composting. Figure 5-8 shows estimated composting
and incineration costs as a function of total soil volume
treated. Based on these estimates, the Army elected to
use windrow composting as the remedial action at the
Umatilla site for 300 tons per day.
5.1.3.3 Land Farming
Land farming has been used extensively to treat
soils contaminated with petroleum hydrocarbons,
pentachlorophenol (PGP), and polycyclic aromatic
hydrocarbons (PAHs), and potentially could be used to
treat low to medium concentrations of explosives as
well. In land farming, soils are excavated to treatment
plots and periodically rototilled to mix in nutrients,
moisture, and bacteria. Land farming typically achieves
very slow degradation rates and can take many years
to reach target cleanup levels.
In one pilot study at an explosives waste site in
Hercules, California, soils contaminated with TNT and
DNT were excavated to 1-yd3 bins, inoculated with
organisms indigenous to the site, and amended with
brain/heart infusion agar, which is a common laboratory
agar. This procedure failed to achieve the target
cleanup levels of 30 ppm TNT, 5 ppm DNT, and 5 ppm
800
S600
I
I 400
I
200
0 Windrow Composting
o MA IV Composting
A incineration
2 4
10 12 14 16 16 20 22 24 26 23 30
Thousands of Tone (K)
Figure 5-8. Comparison of costs for windrow composting;
mechanically agitated, in-vessel composting
(MAIV); and incineration of Umatilla Army Depot
soils as a function of total soil volume treated.
DNB, achieving instead a 30 to 40 percent contaminant
degradation.
5.1.3.4 White Rot Fungus Treatment
White rot fungus has been evaluated more extensively
than any other fungal species for remediating explosives
waste. Although white rot fungus degradation of TNT
has been reported in laboratory-scale settings using
pure cultures (Berry and Boyd, 1985; Fernando et al.,
1990), a number of factors increase the difficulty
of using this technology for full-scale remediation.
These factors include competition from native bacterial
populations, toxicity inhibition, chemical sorption, and
the inability to meet risk-based cleanup levels.
In bench-scale studies of mixed fungai and bacterial
systems, most of the reported degradation of TNT is
attributable to native bacterial populations (Lohr, 1993;
McFarland et al., 1992). High TNT concentrations in soil
also can inhibit growth of white rot fungus. One study
suggested that Phanerochaete chrysosporium was
incapable of growing in soils contaminated with 20 ppm
or more of TNT. In addition, some reports indicate that
TNT losses reported in white rot fungus studies can be
attributed to adsorption of TNT onto the fungus and soil
amendments, such as corn cobs and straw (Spiker et
al., 1992).
A pilot-scale treatability study was conducted using
white rot fungus at a former ordnance open burn/open
detonation area at Site D, Naval Submarine Base,
Bangor, Washington. Initial TNT concentrations of 1,844
ppm were degraded to 1,267 ppm in 30 days and 1,087
in 120 days. The overall degradation was 41 percent,
and final TNT soil levels were well above the proposed
cleanup level of 30 ppm (Spectrum Sciences &
Software, Inc., and Utah State University, no date).
5.1.3.5 In Situ Biological Treatment
In situ treatments can be less expensive than other
technologies and produce low contaminant concentrations.
The available data suggest, however, that in situ
treatment may not be effective for explosives waste. In
situ treatment of explosives might create more mobile
intermediates during biodegradation. In addition,
biodegradation of explosive contaminants typically
involves cometabolism with another nutrient source,
which is difficult to deliver in an in situ environment.
Mixing often affects the rate and performance of
explosives degradation. Finally, because in situ
remediation takes place beneath the surface, the
effectiveness of in situ treatment is difficult to verify both
during and after treatment.
29
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5.1.4 References
References Cited
Berry, D.F. and S.A. Boyd. 1985. Decontamination of soil
through enhanced formation of bound residues.
Environmental Science and Technology 19:1132-1133.
Fernando, T., J.A. Bumpus, and S.D. Aust. 1990.
Biodegradation of TNT (2,4,6-trinitrotoluene) by
Phanerochaete chrysosporium. Applied Environmental
Microbiology 56:1667-1671.
Lohr, J.T. 1993. Bioremediation of TNT and RDX using
white rot fungus Phanerochaete chrysosporium. Utah
State University. Prepared for Naval Civil Engineering
Laboratory, Port Hueneme, California. Contract No.
DAAL-03-86-D-0001.
McFarland, M.J., S, Kalaskar, and E. Baiden. 1992.
Composting of explosives-contaminated soil using
the white rot fungus Phanerochaete chrysosporium.
Utah State University. Prepared for the U.S. Army
Research Office, Research Triangle Park, North
Carolina. Contract No. DAAL-03-91-C-0034.
Spectrum Sciences & Software, Inc., and Utah State
University. No date. White rot remediation of
ordnance-contaminated media. Prepared for Naval
Civil Engineering Laboratory, Port Hueneme,
California. Contract No. F49650-90-D5001/DO 5013.
Spiker, J.K., D.L Crawford, and R.L. Crawford. 1992.
Influence of 2,4,6-trinitrotoluene (TNT) concentration
on the degradation of TNT in explosive-contaminated
soils by the white rot fungus Phanerochaete
chrysosporium. Applied Environmental Microbiology
58:3199-3202.
Additional References
CH2M Hill and Morrison Knudsen Environmental
Services. 1992. Feasibility study for the explosives
washout lagoons (site 4) soils operable unit at the
Urnatilla Army Depot Activity (UMDA), Hermiston,
Oregon. CH2M Hill, Seattle, Washington.
Weston, R.F. 1993. Windrow composting demonstration
for explosives-contaminated soils at the Urnatilla
Depot Activity, Hermiston, Oregon. Prepared for the
U.S. Army Environmental Center. Report No.
CETHA-TS-CR-93043.
Weston, R.F. 1991. Optimization of composting of
explosives-contaminated soils. Prepared for the U.S.
Army Toxic and Hazardous Materials Agency.
CETH-TE-CR-89061.
Weston, R.F. 1988. Field demonstration: composting of
explosives-contaminated sediments at the Louisiana
Army Ammunition Plant (LAAP). Prepared for the
U.S. Army Toxic and Hazardous Materials Agency.
Report No. AMXTH-IR-TE-88242.
5.2 Thermal Treatment Technologies
5.2.1 Incineration of Soils and Sludges
5.2.1.1 Background
AEC of DOD at Aberdeen Proving Ground, Maryland,
oversees large-scale incineration of munitions,
explosives waste, and explosives-contaminated soils as
part of remedial actions at Army sites. This section
discusses the types of wastes and media that can be
incinerated, looks at various devices used to incinerate
explosives waste, presents case studies of four sites
where incineration has been applied to
explosives-contaminated soils, and examines the
advantages and disadvantages of incineration.
5.2.1.2 Treatable Wastes and Media
Incineration processes can be used to treat the
following waste streams: explosives-contaminated soil
and debris, explosives with other organics or metals,
initiating explosives, bulk explosives, unexploded
ordnance, bulky radioactive waste, and pyrophoric
waste. In addition, incineration can be applied to sites
with a mixture of media, such as concrete, sand, clay,
water, and sludge, provided the media can be fed to the
incinerator and heated for a sufficient period of time.
With the approval of the DOD Explosives Safety Board,
the Army considers incineration of materials containing
less than 10 percent explosives by weight to be a
nonexplosive operation. Soil with less than 10 percent
explosives by weight has been shown by AEC to be
nonreactive, that is, not to propagate a detonation
throughout the mass of soil. (The military explosives to
which this limit applies are secondary explosives such
as TNT and RDX, and their manufacturing byproducts.)
The Army's first pilot-scale use of rotary kiln incineration
utilized soil well above the 10 percent limit (up to 40
percent) with approval from the DOD Explosives Safety
Board. A consideration in conducting the test was the
fact that the kiln was not actually sealed and hence not
thought to provide confinement for the small amount of
explosives fed. Another consideration was a previous
successful Army incineration of pure TNT without
detonation in a deactivation furnace. Though the
pilot-scale test experienced no detonation problems, the
Army's full-scale incineration projects have incorporated
a blending step to reduce the explosives concentrations
below the 10 percent limit prior to feeding. The blending
step is considered to be an explosives operation that
requires the preparation and approval by the Army and
DOD safety offices of a site plan/safety submission,
which must include an explosives hazard analysis.
Finally, even at explosives concentrations below 10
percent, each explosives project has unique elements,
and a thorough safety review is a necessity.
30
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The Army also has developed and tested a feed system
capable of feeding reactive levels of explosives (up to
20 percent). The system includes multiple units with
breaks in between to prevent propagation of a possible
detonation throughout the system. Metai-to-metal
contact also is minimized in the system to reduce the
chances of detonation by friction or spark.
5.2.1.3 Operation and Maintenance
The Army primarily uses three types of incineration
devices: the rotary kiln incinerator, deactivation furnace,
and contaminated waste processor.
Rotary Kiln Incinerator
The rotary kiln incinerator is used primarily to treat
explosives-contaminated soils. In rotary kiln
incineration, soils are fed into a primary combustion
chamber, or rotary kiln, where organic constituents are
destroyed. The temperature of gases in the primary
chamber ranges from 800 to 1,200ฐF, and the
temperature of soils ranges from 600 to 800ฐF.
Retention time in the primary chamber, which is varied
by changing the rotation speed of the kiln, is
approximately 30 minutes. Off gases from the primary
chamber pass into a secondary combustion chamber,
which destroys any residual organics. Gases from the
secondary combustion chamber pass into a quench
tank where they are cooled from approximately 2,000ฐC
to 200ฐC. From the quench tank, gases pass through a
Venturi scrubber and a series of baghouse filters, which
remove acid gases and particulates prior to release
from the stack. The treated product of rotary kiln
incineration is ash (or treated soil), which drops from the
primary combustion chamber after organic
contaminants have been destroyed. This product is
routed into a wet quench or a water spray to
remoisturize it, then transported to an interim storage
area pending receipt of chemical analytical results.
Deactivation Furnace
The deactivation furnace also is referred to as Army
Peculiar Equipment (APE) 1236, because it is used
almost exclusively by the Army to deactivate large
quantities of small arms cartridges, 50-caliber machine
gun ammunition, mines, and grenades. The
deactivation furnace is similar to the rotary kiln
incinerator, except that it is equipped with a thick-walled
primary combustion chamber capable of withstanding
small detonations. Deactivation furnaces do not have
secondary combustion chambers, because they are
intended not to completely destroy the vaporized
explosives but to render the munitions unreactive. Most
deactivation furnaces are equipped with air pollution
control equipment to limit lead emissions. The operating
temperature of deactivation furnaces is approximately
1,200 to 1,500ฐF.
Contaminated Waste Processor
The contaminated waste processor handles materials,
such as surface-contaminated debris, that are lighter
and less reactive than those processed in the
deactivation furnace. Contaminated waste processors
are thin-walled, stationary ovens that heat contaminated
materials to about 600ฐC for 3 to 4 hours. The purpose
of this process is not to destroy contaminated debris but
to lower contaminant levels to meet Army safety
standards. AEC currently is helping to develop
standardized time and temperature processing
requirements to meet these safety standards.
5.2.1.4 Case Studies
Cornhusker Army Ammunition Plant
The Cornhusker Army Ammunition Plant (CAAP) in
Grand Island, Nebraska, was the site of 58 explosives
wastewater washout cesspools and leaching pits.
Explosives residues from these 10-ft deep pits created
a contaminated ground water plume that extended into
nearby residential areas. To prevent further ground
water contamination, the Army opted to incinerate
contaminated soils and sludges from the cesspools and
leaching pits. For each contaminant, the Army
established two cleanup criteria: (1) an excavation
criterion, which was health risk based and determined
the depth to which soils were excavated, and (2) an
incineration criterion, which equaled the nondetection
level for each contaminant. Table 5-2 shows the cleanup
criteria for contaminants from the CAAP site.
Figure 5-9 is a schematic of the rotary kiln incineration
system employed at the CMP site. A three-stage feed
system with a live bottom hopper, belt conveyor, and
gravity tube was used to feed contaminated material to
the incinerator. Ash from the incinerator was loaded into
ash bins and subjected to compositional analysis. Once
the ash was determined to be clean (i.e., to contain no
detectable explosives), it was backfilled at a single
location on the CAAP site. The CAAP project was
completed successfully in 1988, after incinerating
40,000 tons at an average total cost of $260 per ton.
Some of the difficulties encountered included (1)
clogging of the quench tank by slag that fell from the
walls of the secondary combustion chamber, (2)
unwanted air infiltration through the air lock in the feed
system, and (3) the need to winterize the unit for cold
weather operations.
Louisiana Army Ammunition Plant
Over the years, wastewaters from ammunition load,
assemble, and pack operations at the Louisiana Army
Ammunition Plant (LAAP) in Shreveport, Louisiana,
were shipped by truck to 16 leaching/evaporation
lagoons at Area P in south-central LAAP. Explosives
residues from these Isgoons leached info the underlying
31
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ground water, creating plumes of TNT and RDX. As at
the CAAP site, the Army opted to incinerate soils and
sludges from the LAAP lagoons and set the incineration
cleanup criterion equal to the nondetection limit for each
contaminant. Rather than assign each contaminant a
specific excavation criterion, the Army specified that the
concentrations of all contaminants total less than 100
ppm after 1 foot of lagoon material had been excavated.
Table 5-3 shows the cleanup criteria for the LAAP
lagoons.
The incineration system used at CAAP was transported
to LAAP with a significant modification to the quench to
allow workers to clean it without entering the tank. While
operating at LAAP, some other modifications were made
to correct the following difficulties: (1) clayey wet feed
soil plugged and jammed the feed system and (2)
buildup of soil on the secondary combustion chamber
fell into the quench tank causing a steam overpressure.
To remedy the first problem, the feed system was
strengthened and a high-speed slinger belt conveyor
was used as the final stage to throw the soil into the
Table 5-2. Cleanup Criteria for Cornhusker Army Ammunition
Plant
Excavation Criteria
Analyte (ppm)
Incineration Criteria
(Method Detection
Limits [ppm]}
RDX
2,4,6-TNT
1.3,5-TNB
2,4-DNT
2,6-DNT
HMX
1,3-DNB
NB
Tetryl
2A.4.6-DNT
<10
<5
<15
<0.5
<0.4
NA
NA
NA
NA
NA
<2.2
<1.3
<1.25
<0.24
<1.26
<2.9
<1.2
<1.26
<2.2
<1.25
Air Pollution Control
llutlon Control Q
j
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of 1993. The estimated quantity of soil to be incinerated
is approximately 60,000 tons.
Alabama Army Ammunition Plant
In 1986, explosives- and lead-contaminated soils from
the Alabama Army Ammunition Plant in Childersburg,
Alabama, were excavated and placed on a concrete
slab and in two containment buildings. These soils,
totalling approximately 35,000 tons, are slated to
undergo incineration over the next 2 years. Table 5-5
shows the excavation and incineration criteria for the
site. The excavation criteria, which are health risk
based, governed the initial excavation in 1986. The
incineration criteria al! are equal to nondetection limits.
The Army anticipates two problems. First, the soils
contain large amounts of debris and possibly pieces of
explosive, which will have to be removed manually prior
to incineration. Second, the soils contain lead, so the
ash product may have to be stabilized prior to disposal.
Table 5-4. Cleanup Criteria for Savanna Army Depot
Incineration Criteria
Excavation Criteria (Method Detection
Analyte
RDX
2,4,6-TNT
1,3,5-TNB
2,4-DNT
2,6-DNT
HMX
1,3-DNB
NB
Telryl
2A.4.6-DNT
(ppm) Limits [ppm])
<5.75 <1
<21.1 <1
<3.7 <1
<9.3 <1
<4.3 <1
<3,722 <1
<7.4 <1
<37.2 <1
<112 <1
<1,191 <1
Table 5-5. Cleanup Criteria for Alabama Army Ammunition
Plant
Excavation Criteria
Incineration Criteria
(Method Detection
Analyte
RDX
2,4,6-TNT
1,3,5-TNB
2,4-DNT
2,6-DNT
HMX
1,3-DNB
NB
Tetryl
2A,4,6-DNT
(ppm) Limits [ppm])
None <1
<1.92 <1
<5.5 <1
<0.42 <1
<0.40 <1
None <1
<1.1 <1
None <1
<1.7 <1
None <1
5.2.1.5 Advantages and Disadvantages
Incineration has many advantages, including:
Effectiveness. With sufficiently long residence time
and a sufficiently high temperature, incineration
usually reduces levels of organics to below
nondetection levels, which simplifies handling of
treated soil and reduces overall site cleanup levels.
Demonstrated success. Incineration is a proven
technology; the literature on successful applications
is extensive; many vendors offer incineration
services, thereby driving down prices; and
incineration equipment comes in many sizes to fit the
needs of any site.
Regulatory requirements. EPA's Land Disposal
Restrictions (LDRs) specify incineration as a best
demonstrated available technology (BOAT) for many
types of wastes, meaning that these wastes must be
incinerated prior to land disposal. Also, incineration
results were used to set concentration-based BOAT
standards for many contaminants and incineration
probably has the best chance of continuing to meet
these standards.
Incineration of TNT also has many disadvantages,
including:
Safety concerns. The foremost safety concern stems
from exposing explosive materials to open flame, but
this can be addressed through routine safety
measures. Secondarily, hazards also are associated
with erecting and operating the incinerator, which is
a large piece of industrial equipment with moving
parts and high temperature areas. For any explosives
operation, DOD must approve the incineration work
plan and may require a hazards analysis and site
safety plan.
Noise. The incinerator is driven by up to a 400 to 500
hp fan, which can generate substantial noise.
Residents neighboring the Savanna Army Depot and
the Louisiana Army Ammunition Plant have
complained about the noise from incineration activity
at these sites.
Air emissions. Emissions from the stack may contain
nitrous oxides (NOX); volatile metals, such as lead;
and products of incomplete combustion (PICs).
Modeling may need to be conducted to predict the
distribution of emissions.
Capital costs. The capital mobilization and
demobilization costs associated with incineration
typically range from $1 to $2 million. Over time, for
a large facility, incineration becomes more cost
effective. Figure 5-10 shows the range of estimated
incineration costs as a function of site size.
33
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1,600-
A - CAAP
B - LAAP
C - 3VAD
D - AAAP
Very Small Small Medium Large
<5,000 5,000- 15,000- >30,000
15,000 30,000
Site Size-Tons
Figure 5-10. Range of expected Incineration costs as a
function of total volume of soils treated (U.S.
EPA, 1990).
Public perception. The public usually is wary of
hazardous waste incineration. There may be public
concern that a mobile incinerator will be established
at a site and subsequently used to incinerate waste
from other sites. The public must be assured that,
most often, mobile incinerators are used only for
single site cleanups and that incineration can be an
effective way to treat explosives waste.
Required tests. Before an incinerator can be used to
treat a large volume of hazardous waste, it must pass
a trial burn demonstrating that it can achieve a 99.99
percent organic destruction efficiency. If the soil at the
site does not contain enough contamination to
demonstrate the 99.99 percent destruction and removal
efficiency, explosives might have to be shipped to the
site to spike the feed soil for the trial bum.
Ash product. Incineration of combustible materials
produces a volume reduction, which can lead to
higher concentrations of inorganic contaminants in
the ash product and create teachability problems.
Incineration of most contaminated soils produces
only modest volume reductions, so inorganics are not
significantly concentrated in the treated soil.
Materials handling. Some soils can be difficult to feed
to the incinerator, which has a small feed opening.
Feeding sticky, high clay content soils can be
particularly difficult. These soils require pretreatment
by aeration and tilling to reduce moisture levels and
decrease viscosity.
Electricity and water requirements. Incineration
operations require large supplies of electricity and
water, both of which can be limited in rural areas.
5.2.1.6 Reference Cited
U.S. EPA. 1990. U.S. Environmental Protection
Agency. Engineering bulletin: Mobile/transportable
incineration treatment. EPA/540/2-90/014. Office of
Emergency and Remedial Response, Washington,
DC. Office of Research and Development, Cincinnati,
Ohio.
5.2.2 Open Burn/Open Detonation
5.2.2.1 Background
Open burn (OB) and open detonation (OD) operations
are conducted by DOD and some private companies to
destroy unserviceable, unstable, or unusable munitions
and explosive materials. In OB operations, explosives
or munitions are destroyed by self-sustained
combustion, which is ignited by an external source,
such as flame, heat, or a detonation wave (that does
not result in a detonation). In OD operations, detonable
explosives and munitions are destroyed by a
detonation, which is initiated by the detonation of a
disposal charge. This section discusses types of wastes
and media that can be destroyed in OB/OD operations,
OB/OD procedures currently being used, safety
precautions associated with OB/OD operations, and a
method recently developed for quantifying the level of
hazardous emissions from OB/OD operations.
5.2.2.2 Treatable Wastes and Media
OB/OD operations can destroy many types of
explosives, pyrotechnics, and propellants. OB areas
must be able to withstand accidental detonation of any
or all explosives being destroyed, unless the
responsible OB technicians used recognize that the
characteristics of the materials involved are such that
orderly burning without detonation can be ensured.
Personnel with this type of knowledge must be
consulted before any attempt is made at OB disposal,
especially if primary explosives are present in any
quantity.
5.2.2.3 Operation
OB and OD can be initiated either by electric or burning
ignition systems. In general, electric systems are
preferable, because they provide better control over the
timing of the initiation. In an electric system, electric
current heats a bridge wire, which ignites a primary
explosive or pyrotechnic, which, in turn, ignites or
detonates the material slated to be burned or detonated.
If necessary, safety fuzes, which consist of propellants
wrapped in plastic weather stripping, are used to initiate
the burn or detonation.
The following design and procedural specifications for
OB/OD operations are taken from paragraph 27-16d of
the Army Materiel Command Explosives Safety Manual
(U.S. AMC, 1985) and paragraph 8-44 of Air Force
Regulation 127-100 on explosives safety standards
(U.S. Air Force, 1990). OB of nonfragmenting
explosives is conducted in burning trays, which are
34
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designed without cracks or angular corners to prevent
the buildup of explosive residues. The depth of
explosive material in a tray may not exceed 3 in., and
the net explosive weight of materials in a tray may not
exceed 1,000 Ib. The distance between the trays for
explosive devices is determined by hazards analysis,
but, in the absence of such analysis, trays are placed
parallel to one another and separated by at least 150 ft.
These distances may vary for OB of bare explosives or
explosives-contaminated soils. When wet explosives
are being burned, trays may be lined with nonexplosive
combustible materials, such as scrap wood, to ensure
complete combustion. An OB tray may not be inspected
until 12 hours after the conclusion of the burn, and a
tray may not be reused until 24 hours after the
conclusion of the burn or until all ash and residues have
been removed from the tray.
If there is a significant risk of fragmentation, OB
operations are conducted in open pits, which must be
at least 4 ft deep and have sloped sides to prevent cave
in. The length and width of the pit is determined by the
quantity of waste being burned. If necessary,
nonexplosive combustible materials and fuel may be
added to ensure complete combustion of explosive
materials. As with burning trays, OB pits may not be
inspected until 12 hours after the conclusion of the burn.
Facilities engineered specifically for OD operations are
rare in practice. Consequently, almost all OD operations
are conducted in pits that are at least 4 ft deep and
covered with 2 ft of soil to minimize the risks associated
with fragmentation. Detonating cords, which are plastic
cords filled with RDX, are used to initiate buried disposal
charges. Explosive components are arranged in the pits
to be in close contact with the disposal charge.
To prevent partial or incomplete destruction, site
personnel must ensure that the disposal charge is
sufficiently powerful to propagate a detonation
throughout the explosive material. High brisance
explosives and shaped charges, which cut through
metal casings, are very effective at propagating
detonations. If a misfire occurs, personnel are required
to wait at least 30 minutes before inspecting the point
of initiation. The misfire may be inspected by no more
than two personnel, who must follow specific operating
procedures.
After each detonation, the surrounding area is searched
for unexploded materials. Lumps of explosive material
and unfuzed munitions are returned to the detonation
pit; fuzed ordnance or munitions that may have
damaged internal components are detonated in place.
5.2.2.4 Safety Precautions
During OB operations, munitions may rupture and
produce fragments that travel relatively short distances,
and explosive materials may detonate. OD operations
always produce dangerous overpressures and various
types of fragments, depending on the type of explosives
being detonated. DOD has developed specific safety
precautions for OB/OD operations, designed to expose
the fewest individuals to the least degree of hazard for
the shortest period of time. These precautions include
minimum setbacks from OB/OD sites, provisions for
the layout of OB/OD sites, optimum weather
conditions for conducting OB/OD operations, and
training requirements for OB/OD personnel.
Minimum Safety Distances
As a basic precaution, personnel are required to
maintain a minimum distance from the OB/OD
operation. This distance depends on the type of material
being burned or detonated. The following minimum
safety distances are outlined in paragraph 8-44 of Air
Force Regulation 127-100 on explosives safety
standards (U.S. Air Force, 1990). (Various Armed
Services manuals contain distances that provide
varying degrees of safety for exposure to the
detonation.) For nonfragmenting explosive material, the
minimum distance is either 1,250 ft or the explosive's
actual maximum debris and fragment throw range, if
known. For fragment-producing materials, the minimum
distance is 2,500 ft. For bombs and projectiles with a
caliber greater than 5 in., the minimum distance is 4,000
ft. For heavier case munitions, the minimum distance
can be calculated by the following formula:
D = 300 x (NEW)1/3
where D is the minimum distance and NEW is the net
explosive weight of the munitions in pounds. This
distance is the radius in which most hazardous
fragments will fall.
Even at the minimum distances, personnel may be
exposed to some fragments. To minimize this exposure,
the base plates and suspension lugs of bombs and
projectiles should be pointed away from personnel prior
to OB/OD.
Layout of the OB/OD Site
The following site layout specifications are taken from
paragraphs 27-10 to 27-16 of the Army Materiel
Command Explosives Safety Manual (U.S. AMC, 1985)
and paragraph 8-44 of Air Force Regulation 127-100 on
explosives safety standards (U.S. Air Force, 1990).
(Specifications from other Armed Services manuals
may vary.) The center of the OB/OD site typically
consists of several burning trays, burning pits, and
detonation pits. All combustible materials and loose
stones are cleared within a 200-ft radius of the center
of the site. Personnel shelters are located a minimum
of 300 ft from the site, and holding areas for explosives
35
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awaiting detonation are located a minimum of 1,250 ft
from the site. Roadblocks are established at the
perimeter of the site to restrict entry during the
operation.
Weather Conditions
Weather conditions affect both the location and timing
of OB/OD operations. OB/OD operations are sited so
that prevailing winds carry sparks, flame, smoke, and
toxic fumes away from neighboring facilities. The
optimum wind speed for an OB/OD is 4 to 15 mph,
because winds at these speeds tend not to change
direction and, as a result, dissipate smoke relatively
rapidly. OB/OD operations are never conducted during
sand, snow, or electrical storms strong enough to
produce static electricity, which might cause premature
detonation.
Personnel Training
All OB/OD operations are supervised by a minimum of
two experienced personnel with training in general
OB/OD safety procedures and the handling of the
specific materials being burned or detonated.
5.2.2.5 Emissions from OB/OD Operations
Quantifying the level of pollutants in the emissions from
OB/OD operations is a difficult undertaking. Results
from laboratory-scale studies translate poorly to the
field, because only very small quantities of explosives
can be tested. At this scale, the initiator or blasting cap
contributes significantly to the total amount of pollutants
in the system. Emissions from field-scale operations
also are difficult to measure, because contaminants
usually are not distributed homogeneously within the
plume, and the plume dissipates quickly.
Personnel at Dugway Proving Ground in Utah recently
developed a facility that is large enough to provide
reliable, field-scale results while allowing the plume to
be captured and analyzed by precise laboratory
methods (Jeer et al., 1993). The facility is a 1,000-m3
enclosed hemisphere known as the bangbox.
Preliminary studies conducted in the bangbox indicate
that OB/OD operations emit traces of organics and
small quantities of soot in addition to CO2, N2, and H2O.
Based on data generated from bangbox studies,
modeling was conducted to estimate the health risks
associated with emissions of benzo(a)pyrene from
OB/OD of TNT. The modeling assumed a cancer
potency of 1.7 x 10"3 for benzo(a)pyrene and an
emission factor of 3.01 x 10"6the highest factor
calculated in any bangbox trial (and an order of
magnitude higher than that of the second highest trial).
It was determined that 500 tons of TNT would have to
be destroyed in OB/OD operations to produce a 1 in
100,000 cancer risk from benzo(a)pyrene emissions.
Since the assumed emission factor was very
conservative, the health risks associated with emissions
from OB/OD operations probably are minimal (Teer et
al., 1993). Future bangbox studies will examine different
waste compositions to target other specific analytes,
such as benzidine, that pose particularly acute threats
to human health.
5.2.2.6 References Cited
Teer, R.G., R.E. Brown, and H.E. Sarvis. 1993. Status
of RCRA permitting of open burning and open
detonation of explosive wastes. Presented at Air and
Waste Management Association Conference, 86th
Annual Meeting and Exposition. June 1993. Denver,
Colorado.
U.S. Air Force. 1990. Air Force Regulation 127-100,
Explosives Safety Standards.
U.S. AMC. 1985. U.S. Army Materiel Command.
Explosives Safety Manual, AMC-R, 385-100.
5.2.3 Wet Air Oxidation
5.2.3.1 Background
Wet air oxidation is a high-temperature, high-pressure,
liquid-phase oxidation process. The technology is used
in municipal wastewater treatment, typically for treating
dilute solutions of 5 to 10 percent solids or organic
matter. Wet air oxidation also has been tested but not
used on a large scale for treating explosives waste. In
a typical wet air oxidation system, contaminated slurries
are pumped into a heat exchanger, where they are
heated to temperatures of 177 to 300ฐC, then into a
reactor, where they are treated at pressures of 1,000 to
1,800psi.
5.2.3.2 Laboratory-Scale Applications
In 1982, the Army conducted a series of
laboratory-scale studies on technologies, including wet
air oxidation, that formerly had been identified as
technically or economically infeasible for treating
explosives waste. Wet air oxidation was applied to
lagoon slurries containing 10 percent explosive
contamination with added chemical catalysts. Although
the technology was found to be very effective for
treating RDX, several disadvantages were noted. First,
the treatment produced hazardous byproducts from
TNT. Second, the technology had high capital costs.
Third, lagoon slurries had to be diluted prior to
treatment. Fourth, gaseous effluents from the oxidation
process, such as carbon monoxide (CO), CO2, and
NOX, needed to be treated by another technology.
Finally, the laboratory-scale system was found to have
a 5 to 10 percent down time, because clays blocked the
pump system and heat exchange lines, and solids built
36
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up in some of the reactors. The Army still is evaluating
wet air oxidation treatment for TNT-contaminated red
water (U.S. ATHAMA, 1992).
5.2.3.3 Reference Cited
U.S. ATHAMA. 1992. U.S. Army Toxic and Hazardous
Materials Agency. Installation restoration and
hazardous waste control technologies.
CETHA-TS-CR-92053. Aberdeen Proving Ground,
Maryland.
5.2.4 Low Temperature Thermal Desorption
Low temperature thermal desorption (LTTD) technology
originally was developed for treating aqueous slurries
contaminated with volatile organic compounds (VOCs).
The technology also has been tested for treating
explosives-contaminated slurries.
In LTTD, contaminated slurries are fed into the system,
heated to 200 to 300ฐC by a hot oil heating chamber,
and treated under elevated pressures. Emissions from
the system are treated in an afterburner.
The Army conducted a laboratory-scale study on low
temperature thermal desorption of explosives waste
in 1982, as part of a series of studies on technologies
that previously had been demonstrated as
unsuccessful for treating explosives waste. LTTD
was shown to achieve a 95 percent destruction
and removal efficiency (ORE) in 20 minutes, but
two degradation products3,5-dinitroanaline and
3,5-dinitrophenolwere found to be recalcitrant
regardless of treatment time and temperature. The
reactivity and toxicity of these products were unknown
at the time, meaning that the product of thermal
desorption might have to be treated as a hazardous
waste. Pilot-scale engineering and cost analyses of this
technology have been delayed, pending further testing
of the degradation products.
5.3 Physical/Chemical Treatment
Technologies
5.3.1 Ultraviolet Oxidation
5.3.1.1 Background
Ultraviolet (UV) oxidation has not been used
extensively for remediating water contaminated with
explosives, because of the widespread use of
granular activated carbon (GAC) treatment.
Nevertheless, UV oxidation can be an effective
treatment for explosives-contaminated water and,
unlike carbon treatment, actually destroys target
compounds, rather than just transferring them to a more
easily disposable medium. This section discusses the
types of explosives-contaminated water that can be
treated by UV oxidation, examines some pilot-scale
tests of UV oxidation, and provides a detailed
discussion of a treatability study of UV oxidation
recently conducted at Milan Army Ammunition Plant
(AAP).
5.3.1.2 Treatable Wastes and Media
UV oxidation can be used to treat many types of organic
explosives-contaminated water, including process
waters from the demilitarization of munitions (pink
water) and ground water contaminated from disposal of
these process waters.
5.3.1.3 Pilot-Scale Applications
In 1981, the Army conducted a pilot-scale study of UV
oxidation for treating waters from the Kansas AAP
contaminated with RDX (U.S. AARRDC, 1982). RDX
concentrations in the process water ranged from 0.8 to
21.0 mg/L. The UV oxidation system consisted of thirty
40-watt, UV lamps, and an ozone generator, which
provided ozone to the treatment process. Treatment
times in this system ranged from 37 to 375 minutes at
flow rates of 0.2 to 2.0 gpm. Final RDX concentrations
in the effluent ranged from 0.1 to 1.7 mg/L, which would
not have met current regulatory criteria.
Similar studies have been conducted at Crane AAP,
Iowa AAP, Holston AAP, and Picatinny Arsenal. It is
difficult to compare performance data from these
studies, however, because each study operated under
different treatment conditions. Some used 40-watt, low
pressure, UV bulbs; others used 65-watt, medium
pressure, UV bulbs. Some amended the water with
hydrogen peroxide (H2O2); others did not. The studies
also used different concentrations and species of
contaminant, different total residence times, and
different concentrations of ozone. In addition, some of
the studies used simulated pink water, which usually
lacks many of the constituents of real pink water.
UV oxidation is being considered at Picatinny Arsenal
for the treatment of ground water containing 6.0 ppb of
RDX. The Waterways Experiment Station in Vicksburg,
Mississippi, currently is running a pilot test on the
proposed UV oxidation system and a parallel test of an
activated carbon system to compare the economic
feasibility of the two.
5.3.1.4 Treatability Study at Milan AAP
In the 1970s, Milan AAP was the site of munitions
washout operations. Process waters from these
operations were placed in lagoons until the early-1980s,
when the waters were drained and the lagoons were
capped. A contaminated ground water plume is
migrating from the site. The Army has conducted a
study to determine whether the contaminated ground
37
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water could be treated by UV oxidation (U.S. ATHAMA,
1992). The treatability study focused on how to optimize
the performance of a full-scale UV oxidation system,
should UV oxidation be selected as the final remedial
technology at the site. The treatability study consisted
of bench- and pilot-scale tests.
Bench-Scale Tests
Bench-scale UV oxidation tests were conducted on 15
gallons of contaminated water from a site. The
bench-scale system consisted of a 2.4-L reactor with a
single 40-watt UV bulb. Ozone was diffused through the
reactor at rates ranging from 2.8 to 15.0 (mo/L)/s, and
a solution of 35 percent H2O2 by volume was used in
the tests. The pH in the system ranged from 4.0 to 8.5,
and the pH of the water was found to drop due to the
production of organic acids during treatment. The
concentration of all explosives in the influent was
57,500 ng/L, with TNT, RDX, HMX, and tetryl present in
the highest concentrations. Residence times varied
from 40 to 200 minutes per treatment batch. These tests
indicated that UV radiation degraded explosive
contaminants and that longer UV exposure times
yielded better contaminant removals. H2O2 levels were
found not to affect contaminant degradation, and UV
oxidation was found to be most effective at pHs of 7 or
greater. The level of 1,3,5-TNB, which is a product of
the UV oxidation of TNT, was the rate-limiting factor in
each test; 1,3,5-TNB concentrations actually increased
after 40 minutes of UV exposure.
Pilot-Scale Tests
The pilot-scale tests had two purposes: (1) to obtain
design data for a full-scale, 500-gpm, UV oxidation
system; and (2) to estimate the cost of operating a
full-scale UV oxidation system.
Pilot-scale UV oxidation tests were conducted in a
650-gallon Ultrox P-650 system, consisting of six
reaction chambers, each containing twelve 65-watt,
low-pressure, UV lamps, and a cooling system to
prevent temperature increases during long exposure
times. The treatment system was operated in recycle
batch mode, meaning that each 650-gallon batch was
recycled through the system seven or eight times. The
total concentration of explosives in the influent was
about 20,656 u.g/L, and the pH of the water was
maintained at 7 to 11 during treatment. Tests were
conducted at ozone doses ranging from 1.11 to 3.33
(mg/L)/minute and with residence times ranging from 40
to 210 minutes. The pilot-scale study indicated that UV
oxidation was most effective at a pH of 9 and an ozone
dosage of 3.3 (mg/L)/minute. Residence times greater
than 180 minutes coupled with high ozone doses
destroyed all of the explosives, including 1,3,5-TNB.
Biotoxicity tests indicated that the effluent from the UV
oxidation system was toxic, due to leaching of metals
from bronze impellers within the equipment.
5.3.1.5 References Cried
U.S. AARRDC. 1982. U.S. Army Armament Research
and Development Command. Ultraviolet ozone
treatment of RDX (cyclonite) contaminated
wastewater. ARLCD-CR-83034. Dover, New Jersey.
U.S. ATHAMA. 1992. U.S. Army Toxic and Hazardous
Materials Agency. Milan Army Ammunition Plant
O-line ponds area treatability study report for ground
water treatment alternatives. Draft final document.
CETHA-IR-B. Aberdeen Proving Ground, Maryland.
5.3.2 Granular Activated Carbon
5.3.2.1 Background
In the 1980s, the Army discontinued the practice of
disposing of untreated process waters from the
production of munitions in open lagoons. Every Army
ammunition plant currently employs some type of
granular activated carbon system to treat process
waters as they are generated. GAC is very effective at
removing a wide range of explosive contaminants from
water. GAC is a transfer technology only, however, and
carbon adsorption media can only be partially
regenerated. This section outlines the types of
explosives-contaminated water that can be treated by
GAC, discusses isotherm tests, and looks at two studies
of continuous flow column GAC equipment conducted
at Badger and Milan AAPs.
5.3.2.2 Treatable Wastes and Media
GAC can be used to treat explosives-contaminated
water, Including process waters from the manufacture
and demilitarization of munitions (pink water) and
ground water contaminated from disposal of these
process waters. GAC is not used to treat red water
produced during the manufacture of TNT.
5.3.2.3 Isotherm Tests
Isotherm testing is a simple laboratory technique for
initial screening of a particular wastewater prior to GAC
treatment. From 6 to 10 aliquots of wastewater are
measured into containers that can be stirred or shaken
for a period of time. Into each container is introduced a
known quantity of pulverized carbon with a different
amount of carbon for each container. After stirring the
mixture for a period of time, the mixture is filtered and
the filtrate analyzed. The results of the tests indicate the
relative adsorbability of explosives, the adsorption
capacity and exhaustion rate of the carbon, the
maximum degree of removal achievable, and whether
there is preferential adsorption of any explosives.
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5.3.2.4 Continuous Flow Column Studies
The Army conducted pilot-scale studies of continuous
flow column GAG equipment at Badger AAP and Milan
AAP. At both sites, GAC treatment was found to be
effective for removing every type of explosive from the
water and removing 2,4- and 2,6-DNT to below
detection levels.
Badger AAP
At Badger AAP, residues from the open burning of
rocket paste contaminated ground water beneath the
burning ground with 2,4- and 2,6-DNT. A pilot-scale
GAC system consisting of eight, 4.25-in. diameter
columns was tested at the site. The first column, which
was the test column, operated in series with the second
column, which was a back-up column used to remove
contaminants when contaminant breakthrough occurred
in the first column (i.e., when contaminants began to
appear in the effluent from the first column). The fill
depth in each column varied from 2 to 4 ft, a range that
generally provides good data. Fill depths of greater than
4 ft require as much as 70,000 to 80,000 gallons of
water to be pumped through the system to get
breakthrough.
Based on the data obtained in an isotherm test, two
types of commercially available carbon filters were
selected for pilot-scale testing at Badger AAP: Calgon
Filter Sorb 300 and Hydrodarco 4000. Flow rates were
maintained at 0.3,0.5, and 0.7 gpm, and a total of about
20,000 gallons of water were used in each test. Influent
concentrations ranged from 200 to 600 \ig/L of 2,4- and
2,6-DNT. A packed-column air stripper was used prior
to GAC treatment to remove trichloroethylene from the
water. All laboratory analyses were conducted using
HPLC equipment, rather than GC.
The data obtained at Badger AAP were used to design
a full-scale treatment system that currently is being
implemented.
Milan AAP
Ground water at Milan AAP was contaminated with
seven types of explosives. The GAC system tested at
Milan AAP was similar to that tested at Badger AAP,
except that Atakim 830 carbon was substituted for the
Hydrodarco 4000. Tests were conducted at four flow
rates ranging from 0.2 to 1.0 gpm, and as many as
56,000 gallons of water were used in each test. The
concentration of total explosives in the influent ranged
from 600 to 900 ug/L.
The data from the pilot-scale GAC study are being
evaluated concurrently with data from a pilot-scale
study of ultraviolet oxidation (see section 5.3.1.4).
5.3.3 Compressed Gas
5.3.3.1 Background
Compressed gas cylinders exhibit a wide range of
hazardous characteristics. The chemicals contained
within compressed gas cylinders may be flammac'te:
corrosive, pyrophoric, or poisonous, or they may be
oxidizers (definitions of these and other terms appear
in Table 5-6). In addition, these chemicals are contained
within the cylinders by valves that are relatively small
and vulnerable. Left unattended, cylinders becom-;
more hazardous. Labels fall off and stenciling corrocte-,
making it difficult to identify the contents of the cyiind.-;!!.;
valves fail due to corrosion; ieaks develop: wi
emergency situations occur that demand immedtal;
attention. Many of the serious injuries and deativ;
attributed to hazardous materials result from accident:.,
involving liquefied or compressed gases.
Technologies now are available for safely managing
compressed gas cylinders. New recycling and
EPA-permitted treatment facilities are in operation, aic1
antiquated disposal procedures have been replaced by
sophisticated systems designed to protect the
environment.
The Compressed Gas Association (CGA) advises EPA
and the Department of Transportation (DOT) on
technical matters directly affecting the compressed gas
industry. CGA members include gas manufacturers;
suppliers, and distributors; chemical manufacturers;
valve and cylinder manufacturers; consultants; and
environmental contractors. CGA provides to the public
numerous pamphlets and videos that are useful as
guidance and technical resources.
This section discusses criteria for inspecting
compressed cylinders; systems for handling anc!
transporting unstable cylinders; options for treating,
disposing of, and recycling cylinders; and some
methods that have proven unsuccessful for disposing of
compressed cylinders. Appendix B presents a case
study of compressed gas cylinder handling at a
Superfund site.
5.3.3.2 Cylinder Inspections
Before a compressed cylinder can be transport'/' ,
treated, a detailed inspection and evaluation <-* "
cylinder, including its valve, must be conouc-o,
Cylinders should be inspected for the following:
Leaks. All valves and fittings must be tested for leate
with recognized CGA procedures, -which might
include the use of a soap or suitable solution to dsteei
the escape of gas, or a hand-held direct reading
instrument.
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Table 5-6. Definitions of Compressed Gas Cylinder Terms
A formless fluid that fills the space of Its enclosure and changes to the liquid or solid state under
increased pressure or decreased temperature.
Gas pressure commonly is designated in pounds per square inch (psl); the analogous metric unit Is the
kilopascal (kPa); 1 psl equals 6.895 KPa. The term psla refers to absolute pressure. Absolute pressure
is based on a zero reference point, a perfect vacuum. Measured from this reference point, atmospheric
pressure at sea level Is 14.7 psi. Gauge pressure (pslg) has local atmospheric pressure as a reference
point. As such, psla minus local atmospheric pressure equals psig.
Any material or mixture contained at an absolute pressure exceeding 40 psl at 70ฐF or exceeding 104
psl at 100ฐF; or any flammable liquid having a vapor pressure exceeding 40 psi at 100ฐF as determined
by the American National Standard Method of Testing for Vapor Pressure of Petroleum Products,
ANSI/ASTM D323-79.
A gas contained at a pressure of 500 psig (3448 kPa) or higher at 70ฐF (21.1ฐC).
A gas that, under the charged pressure, is partially liquid at a temperature of 70ฐF.
A gas other than a gas in solution, that, under the charged pressure, is entirely gaseous at 70ฐF.
Inert gases, which Include argon, carbon dioxide, helium, krypton, neon, nitrogen, and xenon, are simple
asphyxiates which can displace the oxygen in air necessary to sustain life and thus cause suffocation.
A liquid or gas that destroys living tissue by chemical action.
A noncorrosive liquid or gas that, on Immediate or prolonged contact, induces a local inflammatory
reaction in living tissue.
A gas or liquid that creates an immediate hazard to health when inhaled, ingested, or absorbed through
the skin, and can be fatal In low concentrations.
A gas that will ignite spontaneously in dry or moist air at a temperature of 130ฐF or below.
A gas or liquid that accelerates combustion and that, on contact with combustible material, may cause
fire or explosion.
A temperature- or pressure-activated device that functions to prevent the rupturing of a charged cylinder
by releasing pressure above a predetermined point.
Source: CGA, 1981.
Gas
Gas Pressure
Compressed Gas
High Pressure Gas
Liquefied Compressed Gas
Nonliquefied Compressed
Gas
Inert Gases
Corrosive Gas/Liquid
Irritant
Poison
Pyrophoric Gas
Oxidizer
Pressure Relief Device
<ป Dents. Guidelines mandate that a dent at a weld be
no deeper than 0.64 cm. If a weld is not involved,
dents may be no deeper than 10 percent of the
cylinder's greatest dimension. Dents are measured
using a ruler and a dial caliper.
ฎ Gouges and cuts. Gouges and cuts reduce the
thickness of cylinder walls. Thickness gauging is
required to determine whether cylinders with gouges
or cuts have structural weaknesses that constitute a
safety hazard. Ultrasonic thickness gauges often are
used to measure cylinder wall thickness.
Bulges. Bulging weakens a cylinder. Cylinders with
bulges must be evaluated by trained personnel to
determine if the cylinders maintain their structural
integrity.
ซ Corrosion. While corrosion may be limited to surface
rust, corroded cylinders should be inspected using
thickness gauging to evaluate the integrity of their
walls and to ensure that continued handling and
transportation of the cylinders will be safe.
ซ Fire damage. The following is evidence of fire
damage: charring of paint or protective coatings;
burning or melting of fuze plugs, valves, and pressure
relief devices; scarring or burning of metal surfaces;
and disfiguring of the cylinder. DOT regulations
mandate that a cylinder showing evidence of fire
damage may not be placed into service or
transported until it has been reconditioned, unless a
proper inspection reveals that the cylinder is only
discolored or smudged and is in serviceable
condition.
Improper backfilling. Cylinders sometimes are
backfilled with materials that they were not designed
to contain. This can cause many problems, including
corrosion of the interior walls.
Retrofitted valves. Gas cylinders occasionally are
retrofitted with valves or fittings that are not designed
for the cylinder or its contents. Proper inspections
should reveal if these conditions exist.
Cylinder labels and stenciling also should be inspected
to determine the contents of the cylinder. A cylinder is
considered to be "unknown" under any of the following
circumstances:
The cylinder has no original label or stenciling
identifying its contents.
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The cylinder is labeled, but the inspection reveals that
its fittings and/or pressure relief device is inconsistent
with the labeled gas.
The cylinder's contents are suspected to have been
contaminated with other materials, which can alter
the chemistry of the original contents.
The contents of an unknown cylinder must be identified
through laboratory analytical procedures, not by
examining the cylinder's color, valve outlet, or other
markings. Applicable analytical procedures include
mass spectrometry, as well as Fourier transform
infrared (FTIR) and GC. An unknown cylinder cannot be
shipped off site for disposal or recycling or treated on
site until its contents have been identified. An unknown
cylinder that is shipped off site for laboratory analysis
must be given a tentative shipping description (Hazard
Class) as defined in 49 CFR 172.101(c)(11).
5.3.3.3 Handling Techniques
DOT regulations and CGA guidelines ensure that safe
handling and transportation procedures are being
followed. Generators of compressed cylinders must use
hazardous waste manifests and licensed waste
transporters. Each generator also must have an EPA
identification number as a small or large generator
unless exempt.
Two handling procedures are available: hot tapping/
controlled access and overpacking.
Hot Tapping/Controlled Access
The management of a cylinder with an inoperable valve
requires state-of-the-art hot-tapping equipment, which
performs one of three operations:
Drilling into the cylinder at a predetermined location,
thereby allowing the contents of the defective cylinder
to flow into a primary containment vessel.
Shearing the valve from the cylinder or shearing the
cylinder in half and capturing the gas or liquid in a
primary containment vessel.
Drilling into the cylinder while maintaining a tight seal
and introducing a new valve into the cylinder without
releasing gas into a primary containment system.
Secondary containment may be used during this
procedure depending on the known or suspected gas
involved.
The first two operations are followed either by onsite
treatment of the gas in the primary containment vessel
or the recontainerization of this gas into a
DOT-approved cylinder for offsite treatment or
recycling. All three operations are identified as the
current BDATs for managing compressed cylinders with
inoperable valves and essentially are the only methods
in use today.
Overpacking
Salvage cylinder overpacks can be used to contain a
compressed gas cylinder that is being transported to an
offsite facility or is leaking. An overpack is an oversized
cylinder fabricated to accept a smaller cylinder into
itself. Once closed, the overpack contains any release
from the defective cylinder. Valves and pressure gauges
on the overpack allow its internal pressure to be
monitored so that the defective cylinder can be removed
safely. Cylinder overpacks are similar to the 85- or
110-gallon salvage overpacks used to transport
55-gallon drums.
5.3.3.4 Treatment, Disposal, and Recycling
Options
Compressed cylinders may be sent to a treatment or
recycling facility, or treated on site.
Offsite Treatment
Discarded and abandoned cylinders must be disposed
of in EPA-permitted treatment, storage, and disposal
facilities (TSDFs). TSDFs use two systems to treat the
contents of cylinders. In one system, vapor or gas is
drawn from the cylinder through a manifold directly into
an incinerator. In the other system, vapor or gas is
drawn from the cylinder into a chemical scrubbing
medium. In both systems, the remaining empty cylinder
then is purged, cleaned, devalved, and landfilled or
recovered for scrap.
Recycling
If the contents of a cylinder are known, generators may
send cylinders to a recycling facility. At the recycling
facility, the cylinder's contents are removed from the
cylinder through a manifold system and introduced back
into the manufacturing process as a raw material. The
empty cylinder then is either cleaned, devalved, and
sent for steel scrap recycling, or, if in suitable condition,
cleaned, painted, restamped, and hydrostatically tested
for reentry into the market as a filled and usable
cylinder.
Onsite Treatment
In onsite treatment, cylinders of liquified or
compressed gases are treated, neutralized, or
otherwise disposed of at their location, without the
use of an offsite TSDF or recycling facility. Onsite
treatment involves chemical scrubbing, incineration,
flaring, or controlled atmospheric venting of cylinder
contents. Onsite treatment may be used under any of
the following conditions:
There are no available offsite management options.
The cylinder is in a non-DOT transportable condition
and cannot be removed from the site or
recontainerized into another vessel.
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The cylinder is leaking and must be treated
expeditiously.
Regulatory authorities mandate onsite treatment only.
Onsite treatment of cylinders containing RCRA
hazardous substances requires permit approval by
federal or local authorities.
5.3.3.5 Unsuccessful Treatment Approaches
Several techniques have been tested for the treatment
and recycling of compressed gas cylinders. Most of these
techniques are no longer used because they do not
adequately protect human health or the environment.
Nevertheless, these methods occasionally are used by
contractors or regulators unaware of the current BDATs.
Detonation (Uncontrolled Release)
A pressurized cylinder can be destroyed by the
detonation of a disposal charge that breaches the
cylinder body or its valve. Chemicals contained in the
cylinder also might be destroyed during the explosion.
In the past, this practice was used to dispose of
cylinders with inoperable valves, for which detonation
was more cost effective than more sophisticated
treatments or recycling. Today, detonation is considered
to have several drawbacks, including fragmentation
from the cylinder body. In addition, the cylinder can
rocket away from the detonation site.
Projectile Method (Uncontrolled Release)
In the projectile method, a high-caliber projectile is fired
from a rifle into a cylinder, releasing gas' from the
cylinder through the vent holes produced by the impact.
As with detonation, this procedure releases untreated
gases to the environment. In addition, the cylinder may
rocket from the site or detonate.
Valve Release (Controlled or Uncontrolled Release)
In valve release, the cylinder's valve is opened, and the
cylinder is allowed to vent until empty. Like detonation
and the projectile method, this procedure releases
potentially toxic or ozone-depleting substances
untreated into the environment. Valve release should be
used only for atmospheric gases and must be employed
using both a regulator to control flow and a stack to
prevent the formation of an oxygen-deficient work area
for the operator.
5.3.3.6 Reference Cited
CGA. 1981. Compressed Gas Association. Handbook
of Compressed Gases, Third Edition.
5.3.4 Reactive Chemical Handling
5.3.4.1 Picric Acid
Background
Picric acid is a yellow crystalline substance that was
discovered in 1771 by the British chemist Peter Woulfe.
Picric acid's name is derived from the Greek word
pikros, meaning bitter, due to the intensely bitter and
persistent taste of its yellow aqueous solution. In the
past, this strong acid was used as a fast dye for silk and
wool and in aqueous solutions to reduce the pain of
burns and scalds.
When dry, picric acid has explosive characteristics
similar to those of TNT. Table 5-7 summarizes the
explosive characteristics of picric acid. The first
experiments to use picric acid as an explosive bursting
charge were conducted in the town of Lydd, England,
in 1 885, and picric acid was adopted by the British as
a military explosive in 1888 under the name Lyddite.
Since that time picric acid has been used by many
countries as a bursting charge under the names
Shimose (Japan), Granatfullung 88 (Germany), Pertite
(Italy), Melinite (France), and trinitrophenol (United
States). Today, the use of picric acid as a military
explosive has been largely discontinued, because picric
acid was found to have several disadvantages:
It is prone to sympathetic detonation, wherein the
detonation of a nearby charge would cause it to
detonate without a priming charge.
Table 5-7. Explosive Properties of Picric Acid
Gross formula
Melting point
Autoignition temperature
Molecular weight
Oxygen balance
Heat of explosion
Density
Lead block test
Detonation velocity (when confined)
Deflagration point
CAS
United Nations (dry or wetted with less than
30 percent water by weight)
United Nations (with 30 percent or more
water, by weight)
Source: Adapted from DOD, no date; Material Safety Data Sheet,
1985; Meyer, 1981; NSC, 1981.
122.5ฐC
572ฐF
229.1
-45.4%
1 ,080 kcal/kg
1 .767 g/cm3
315 cm/10 g
7350 nVs
570ฐF (300ฐC)
88-89-1
0154
1344
42
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When it contacts metals, such as mercury, copper,
lead, or zinc, it forms explosive salts that are sensitive
to friction, heat, and impact. Special precautions also
are required if picric acid falls on concrete floors,
because this causes the formation of sensitive
calcium salts.
Metal and cement shells that contain picric acid must
be sealed with a protective varnish to prevent contact
between the picric acid and the shell lining.
In addition to its explosive properties, picric acid also is
highly toxic. Like many trinitrocompounds, picric acid is
absorbed through the skin and through inhalation. Acute
picric acid exposure can depress the central nervous
system and reduce the body's ability to carry oxygen
through the blood stream. Prolonged exposure may
result in chronic kidney and liver damage. Percutaneous
absorption may cause vomiting, nausea, abdominal
pain, staining of the skin, convulsions, or death. The
Occupational Safety and Health Administration's
(OSHA's) permissible exposure level (PEL) for picric
acid is a time weighted average (TWA) of 100 u,g/m3,
with a "skin" notation to indicate the possibility of dermal
absorption, and the American Conference of Governmental
Industrial Hygienists (ACGIH) recommends a threshold limit
value (TLV)-TWA of 0.1 mg/m3.
Proper personal protective equipment, such as gloves,
respirators, and self-contained breathing apparatus
(SCBA), including Level B attire, should be worn when
handling picric acid outside of an established laboratory
environment. The use of advanced personal protective
equipment should be commensurate with the activity of
the individual. Individuals responding to a spill of picric
acid or handling spilled material, should wear SCBA,
including Level B attire. On the other hand, chemists
and technicians working in a laboratory setting should
wear gloves and work under a fume hood to ensure safe
handling of picric acid.
The following sections discuss handling procedures and
disposal options for picric acid.
Handling Procedures
Picric acid is soluble in water and various solvents.
When hydrated, picric acid becomes nonexplosive and
is safe to transport and incinerate in offsite facilities.
Nevertheless, dry picric acid residues on the outer
surface of containers as well as in threaded container
closures present a significant friction-sensitive hazard.
This hazard prompts many generators to use remote
handling equipment when opening containers of picric
acid, a technique usually reserved for containers of dry
(desiccated) material.
DOT classifies solutions of picric acid containing less
than 10 percent water as explosive materials and
solutions of picric acid containing greater than 10
percent water as flammable solids. This regulatory
distinction dictates the mechanics of preparing picric
acid for shipment, such as packaging, labeling, and
adhering to manifest documentation requirements, it
has little relevance to the facility receiving the picric acid
for treatment.
Disposal Options
Incineration currently is the BOAT for the destruction of
picric acid (40 CFR 261.23(a)(6)). Incineration facilities
have varying acceptance criteria governing the
concentrations of picric acid in water; some require
picric acid concentrations to be as low as 1 percent,
others will accept solutions with picric acid
concentrations as high as 50 percent.
Because of picric acid's history as a commercial and
military explosive, many civilian police bomb squads
and military EOD units formerly accepted picric acid for
disposal through controlled detonation. Detonation was
the disposal method of choice until the mid-1980s, when
it was discovered that picric acid was not, in fact,
destroyed by open air detonation but simply dispersed
by the explosion of the disposal charge. The resulting
dispersal of picric acid over the detonation site caused
finely divided particles of the substance to enter the
surface strata. Testing of surface samples obtained from
picric acid detonation sites often showed trace
quantities of the compound unaffected by the
detonation. In addition, slow motion video of several
picric acid detonations clearly showed a heavy yellow
smoke of finely divided picric acid particles, which
negatively affected localized air quality.
5.3.4.2 Peroxides
Background
Peroxides are shock-sensitive compounds that can
explode if subjected to mechanical shock, intense light,
rapid changes in temperature, or heat. In some cases,
peroxides also can explode through a spontaneous
reaction. Peroxide structures are particularly dangerous
when present in organic solvents, which often are highly
flammable. In testing conducted in the mid-1980s, the
detonation of a sample of a hard peroxide crystal
destroyed a 4-lb lead Trauzl block, a test used to
determine whether or not a substance is explosive.
Similarly, a controlled detonation of pure peroxide
crystals discovered in an evaporated bottle of isopropyl
ether demonstrated that peroxide explosions produce
high levels of destructive fragments.
The following sections discuss the formation of peroxide
compounds, procedures for inspecting and testing for
the presence of peroxides, and options for treating and
disposing of peroxides.
43
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Peroxide Formation/Inhibition
Peroxides form in organic solvents as a result of
autoxidation. Common peroxide-forming solvents can
be divided into the following groups:
Ethers, including open chain and cyclic ethers,
acetals, and ketals (e.g., ethyl ether, isopropyl ether).
Hydrocarbons with allylic, benzylic, or proparglic
hydrogen (e.g., cumene, cyclohexane).
Conjugated dienes, eneynes, and diynes (e.g.,
butadiene, furans).
Most of these solvents are purchased from the
manufacturer with an added inhibitor, such as
hydroquinone or tert-butyl catechol, which chemically
inhibits peroxide formation.
Autoxidation in solvents is facilitated by three factors:
Exposure to oxygen
Exposure to light, including sunlight
Storage time
Oxygen is a necessary ingredient for peroxide
formation. A cap or bung left off a container or drum, or
a loose fitting seal, may supply sufficient oxygen to
support peroxide formation by eliminating the inhibitor
and supporting the initiation of the autoxidation process.
Light, including sunlight, also promotes the elimination
of inhibitors and stimulates the autoxidation process.
Light, however, cannot promote the autoxidation
process unless sufficient oxygen is present in the
container. Once formed, peroxides can, in direct
sunlight, undergo autodetonation. Storage time simply
allows peroxides to develop and form structures. Since
autoxidation is a self-sustaining reaction, the rate of
peroxide formation increases with time.
More than a decade ago, the National Safety Council
(NSC) published easy-to-follow laboratory guidelines
(NSC, 1982) for preventing the formation of peroxides
in solvents; unfortunately, although these guidelines can
be obtained easily from the NSC, they seldom are
followed. The formation of peroxides in an organic
solvent can be inhibited in two ways: (1) by adding an
inhibiting compound to the solvent, or (2) by purging the
oxygen from the free space in the solvent container.
Chemical manufacturers add inhibitors to almost all
solvents, except those used for HPLC. These are
specifically manufactured without inhibitors, because
inhibitors interfere with the UV detection process.
Inhibitors added by the manufacturer, however, are
effective only during shipping and marketing of the
product; once the solvent container is opened and
exposed to oxygen, the autoxidation process begins.
Oxygen is the rate-limiting factor in peroxide formation.
Replacing oxygen in the free space of a solvent
container with an inert gas, such as nitrogen or argon,
prevents autoxidation of the solvent. This method has
proven very successful in inhibiting peroxide formation.
Peroxide Detection
Visual Inspections. Solvents stored in glass bottles can
be inspected for peroxides visually. Bottles containing
organic solvents usually are made from amber or brown
glass, so a soft light source, such as a flashlight, is
helpful for lighting the interior of the bottle to allow a
good view of the liquid. The light source should be
placed behind or to the side of the bottle, because light
shone directly on the glass creates reflections that
obstruct inspection of the bottle's contents.
During the visual inspection, the investigator should
look for two signs of peroxide contamination:
Gross contamination. Hard crystal formations in the
form of chips, ice-like structures, crystals, or solid
masses, or an obscure cloudy medium.
Contamination. Wisp-like structures floating in a clear
liquid suspension.
Peroxide formation may be present anywhere in the
contaifier, including the bottom of the container, the side
walls of the glass, the threaded cap, or even the outside
of the container. Peroxide formation in ppm
concentrations may not be visually observable and must
be identified through appropriate testing procedures.
Metal cans and drums cannot be inspected visually and
must be opened to allow appropriate testing. Opening
containers is a delicate procedure due to the possibility
of peroxide accumulation in the cap threads. While
peroxide contamination tends to occur less frequently
in the cap area than in other container areas, metal cans
and drums should be opened only by trained
individuals, and the application of remote opening
equipment should be considered.
Metal containers are believed to accelerate the rate of
peroxide formation. The scientific documentation
supporting this belief, however, is largely anecdotal.
Laboratory Testing. Several methods are employed to
test for the presence of peroxides. The following two
tests are among the more common:
Commercially available peroxide test strips. These
test strips provide quantitative results and are simple
to use. The test strip is saturated with a
representative sample of the liquid in question. A
section of the strip changes color if peroxides are
present; this color then is compared to a graph, which
indicates the peroxide concentration in ppm. Test
strips typically register as high as 100 ppm.
Potassium iodide (Kl) test. In this test, 100 mg of
potassium iodide is dissolved in 1 mL of glacial acetic
44
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acid. Then 1 ml of suspect solvent is added. A pale
yellow color indicates a low concentration of
peroxides; a bright yellow or brown color indicates a
higher concentration of peroxides. This is the
preferred method for testing di-isopropyl ether.
A peroxide test should be performed each time material
is removed from a container. If the material is removed
on a daily basis, tests should be done every other day.
Containers of peroxide-forming compounds should be
marked with the date the container was first received
and first opened, the results of the first peroxide test,
and the results of the last peroxide test before disposal.
Tables 5-8,5-9, and 5-10 show the testing requirements
for common peroxidizable compounds during storage,
as well as handling and testing requirements for these
compounds while in use.
The results of peroxide testing dictate how the material
should be handled. The following are the general levels
of risk associated with various concentrations of
peroxides:
Between 3 and 30 ppm. Expired compounds testing
within this range pose little or no threat of violent
reaction on the given test date. For compounds
testing in this range, the investigator should consider
adding fresh inhibitor to retard the autoxidation
process, and the container should be tightly sealed
to prevent air and light exposure.
Between 30 and 80 ppm. Expired or mismanaged
compounds that test within this range may pose a
threat to operations in the laboratory or facility.
Several major exothermic reactions have occurred
during the reduction of peroxides within this range.
Table 5-8. Compounds That May Form Peroxides During
Storage8
Compound
Isopropyl ether
Divinyl acetylene
Test Cycle in
Storage
Every 3 months
Every 3 months
Special Handling
and Tests While
In Use
Consume or
discard within 3
days of opening
these containers.
Consume or
discard within 3
days of opening
these containers.
Vinylidene chloride
Potassium metal
Sodium amide
Every 3 months
Every 3 months
Every 3 months
Avoid
oil/hydrocarbons, if
KO2 is present.
a These compounds must be promptly consumed or properly dis-
carded after exposure to air. (Peroxide accumulations in these
containers may explode without even being concentrated!)
Source: National Safety Council, 1982.
Greater than 80 ppm. Any solvent testing in excess
of the maximum quantifiable limits of standard
peroxide test strips must be considered potentially
shock sensitive.
Treatment and Disposal Options
Deactivation. Most, if not all, peroxide-forming
chemicals are regulated as hazardous wastes. The
BOAT for peroxides is deactivation to eliminate the
ignitability characteristic (55 FR 22546). Technologies
that may be used to deactivate peroxide-formers
(classified as D001 oxidizers) include chemical
oxidation, chemical reduction, incineration, and
recovery. Any of these technologies is acceptable,
provided it eliminates the ignitability characteristic. To
be accepted by an offsite, EPA-permitted, treatment and
disposal facility, peroxide containers that no longer are
in use must be peroxide free and present no explosive
hazard.
Stabilization/Reduction. Peroxides within a container
can be chemically stabilized. The following describes
one chemical procedure that has been used
successfully to stabilize peroxides. (The reader is
cautioned that any procedure used to handle a sensitive
chemical or eliminate peroxides should be undertaken
only by very experienced personnel who understand the
potential for uncontrolled exothermic reactions during
the procedure.) The solvent container is accessed
through its cap by a remotely operated titanium-coated
drill. A Teflon catheter then is inserted through the
access point to draw a 1-cm3 sample of solvent for
testing. Three standard peroxide test strips are used to
measure the sample's peroxide concentration. All
negative indications are verified by adding a drop of
sample solvent to a 10 percent potassium iodide
solution for colorimetric evaluation.
If the container is found to contain peroxides, a solution
of ferrous ammonium sulfate is injected into the
container. This produces an oxidation-reduction
reaction that, while often very exothermic, has proven
to be successful in eliminating peroxides. The container
is retested continuously until all peroxides have been
dissolved and peroxide tests are shown to be negative.
Hydroquinone then is added to stabilize the container
and guard against an immediate recurrence of
peroxidation. Finally, the container is resealed with a
silicone sealant and standard sealing tape and placed
in a designated safe area pending offsite disposal.
Open Detonation. Open air detonation or burning of
peroxide-forming compounds formerly was used by
police bomb squads and government explosive
technicians in an effort to assist the private sector. This
practice was found to have two major disadvantages:
Potentially shock-sensitive materials were subjected
to movement prior to disposal.
45
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Table 5-9. Compounds That Readily Form Peroxides In Storage Through Evaporation or Distillation8
Test Cycle In
Compound Storage Special Handling and Tests While in Use
Diethyl ether
Tetrahydrofuran
Dloxane
Acetal
Methyl-isobutyl-ketone
(Isopropylacetone)
Ethylene glycol dimethyl
ether
Every 12 months HPLC grades of these compounds are normally packaged without peroxide
inhibitors. These uninhibited containers should be stored in an inert (oxygen-free)
atmosphere and tested at 3-month intervals. Limit these containers to sizes
appropriate to the application in order to prevent repeated exposures.
Every 12 months Every 3 months, if uninhibited
Every 12 months Every 3 months, if uninhibited
Every 12 months Every 3 months, if uninhibited
Every 12 months Every 3 months, If uninhibited
Every 12 months Every 3 months, if uninhibited
Vinyl ethers
Dicyclopentadlene
Isoprene
Organometallics
(Grignard Reagents)
Diacetylene
Methyl acetylene
Cumene
Tetrahydronaphthalene
Cyclohexene
Methylcyclopentene
t-Butyl alcohol
Acetaldehyde
Every 12 months
Every 12 months
Every 12 months
Every 12 months
Every 12 months
Every 12 months
Every 12 months
Every 3 months, If
uninhibited
Every 12 months
Every 3 months, If
uninhibited
Every 12 months
Every 12 months
Every 3 months, If uninhibited
Every 3 months, if uninhibited
Every 3 months, If uninhibited
Every 3 months, if uninhibited. Do not store in a cold room. These highly reactive
compounds accumulate peroxide at low temperatures because the peroxide
degradation rate is slowed relative to the peroxide formation rate.
Every 3 months, if uninhibited
Every 3 months, if uninhibited
Every 3 months, if uninhibited
Every 12 months
Every 3 months, if uninhibited
Every 12 months
Every 3 months, if uninhibited
Anhydrous acetaldehyde will autoxidize at 0ฐC or below under ultraviolet light
catalysis to form peracetic acid, which may react with more acetaldehyde to
produce the explosive acetaldehyde monoperacetate.
a Concentration processes (evaporation or distillation) defeat the action of most autoxidation inhibitors. Special handling and accountability
are required of those compounds offered as HPLC grade, because HPLC-grade materials are packaged without autoxidation inhibitors.
The compound in question was dispersed untreated
into the surrounding air and soil.
5.3.4.3 Ethers
Ethers are organic compounds with common uses as
both medical anesthesia and solvents. Simple ethers
may be highly volatile and have flammable and
potentially explosive characteristics. The most commonly
used ether is diethyl ethera clear, colorless liquid that
vaporizes readily at room temperature and is highly
flammable. Diethyl ether's flashpoint is -45ฐC and its
flammable range extends from 1.85 to 48 percent by
volume. Aside from their flammability, liquid ethers also
can contain organic peroxides produced by a reaction
between the ether and atmospheric oxygen (Meyer,
1989).
5.3.4.4 References Cited
DOD. No date. Department of Defense. Publication
TM9-1300-214/TO 11A-1-34.
Material Safety Data Sheet. 1985. MSDS #534. Gunium
Publishing Company. Schenectady, New York.
Meyer, E. 1989. The Chemistry of Hazardous Materials,
Second Edition. Prentice Hall, Inc. Englewood Cliffs,
New Jersey. 394-395.
Meyer, R. 1981. Explosives, Second Revised and
Expanded Edition. Weinheim Publications. Deerfield,
Florida.
NSC. 1982. National Safety Council. Industrial Safety
Data Sheet l-655-Rev.82, Stock No. 123.09. Chicago,
Illinois.
46
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Table 5-10. Compounds That Pose Hazards Due to Peroxide
Initiation of Polymerization
Compound
Butadiene
Styrene
Tetrafluoroethylene
Vinyl acetylene
Chlorobutadiene
(Chloroprene)
Vinyl pyridine
Vinyl chloride
Test
Cycle In
Storage
Every 12
months
Every 12
months
Every 12
months
Every 12
months
Every 12
months
Every 12
months
Every 12
months
Special Handling and
Tests While In Use8
Every 3 months, if stored
as liquid
Every 3 months, if stored
as liquid
Every 3 months, if stored
as liquid
Every 3 months, if stored
as liquid
Every 3 months, if stored
as liquid
Every 3 months, if stored
as liquid
Every 3 months, If stored
as liquid
1 When stored in the liquid state, the peroxide-forming potential dra-
matically increases.
Source: Manufacturer warning labels.
NSC. 1979. National Safety Council. Data Sheet
10351-79.
5.3.5 Reuse/Recycle Options for Propellants
and Explosives
5.3.5.1 Background
Recovery and reuse technologies for energetic
materials, including both explosives and propellants,
are available in production-scale facilities capable of
handling quantities greater than 100,000 Ib.
Recovery/reuse options should be considered at
explosives waste sites for several reasons. First, new
recovery methods and potential uses for reclaimed
explosive materials are rapidly developing. Second,
recovery/reuse options reduce overall remediation
costs by eliminating destruction costs and allowing the
value of reclaimed materials to be recovered. Finally,
EPA's treatment hierarchy, which is based on
environmental considerations, favors recovery/reuse
options over destruction technologies.
This section describes the types of explosives waste and
media that can be recovered/reused, the available
recovery/reuse technologies, some leading recovery/reuse
companies and institutions, potential applications for
recovered energetic materials, and advantages and
limitations of recovery/reuse technologies.
5.3.5.2 Treatable Wastes and Media
A detailed knowledge of energetic materials is necessary
to minimize the risks associated with recovery/reuse and
to develop a suitable recovery/reuse plan. For a detailed
description of energetic materials, refer to section 1.2.2.
In addition to pure energetic materials, munitions and
rocket motors and explosives-contaminated soils and
sludges also can be recovered/reused.
Energetic Materials
Propellants that contain combustion modifiers, such as
lead compounds, are difficult to reuse because of the
stringent controls on lead emissions. Reuse of these
propellants as commercial explosive additives is rarely
an option. Primary explosives and initiating explosives,
such as lead azide, generally are not candidates for
recovery/reuse due to their high sensitivity. Very little
has been done on recovering pyrotechnics, probably
due to their highly variable compositions, their
sensitivity, and the low value of their ingredients. This
section does not discuss pyrotechnics in detail.
Munitions and Rocket Motors
Recovery/reuse methods generally are applied only to
munitions and rocket motors that have documented
histories, including documentation of how the item was
manufactured, its energetic fill, and its inert parts. In
addition, the recovered item must be present in
sufficient quantities for the recovery/reuse process to be
economical. These criteria limit the types of munitions
for which recovery/reuse is feasible. Bunkered
ordnance discovered during a remediation effort may
have a documented history and sufficient quantity.
Ordnance encountered during range cleanup often is in
various stages of physical disrepair and does not meet
the criteria for recovery/reuse.
Explosives-Contaminated Soils and Sludges
Soils and sludges contaminated with energetic
materials present handling problems during recovery
and reuse operations. AEC has established a guideline
that soils containing greater than 10 percent energetic
materials by weight should be considered explosive
during handling and transportation. As a general rule,
soils and sludges containing less than 10 percent
energetic materials by weight pass AEC's nonreactivity
tests. Reuse/recycle options are more feasible for
contaminated soils and sludges meeting the
nonreactivity criteria, because they can be removed,
transported, and handled using conventional
equipment, which could provide a substantial cost
savings. Unless diluted with fuel, the material extracted
from contaminated soils and sludges most likely must
be treated as an energetic material.
5.3.5.3 Operation and Maintenance
Recovered munitions and rocket motors either can be
reused "as is," or the energetic materials can be
recovered from these items and reused or recycled. If
an ordnance item is to be reused as is, it is inspected,
47
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recrated, and sold as reconditioned ordnance.
Energetic materials recovered from munitions can be
reused in their original application, or specific
ingredients can be extracted and recycled into energetic
materials. Explosives-contaminated soils and sludges
can be recovered for the fuel value of their
contaminants. Table 5-11 provides an overview of the
potential uses for recovered munitions and energetic
materials.
Energetic Material Extraction
One of the more technically challenging aspects of
energetic material recovery/reuse is the separation of
energetic components from inert components. For
Hazard Class 1.3 composite propellant rocket motors
and items containing plastic-bonded explosives,
high-pressure water washout (hydromining) and
machining are the established separation methods.
Other washout methods that have been demonstrated
at bench scale include liquid nitrogen and liquid
ammonia washout at high pressure. The latter two
methods are scheduled to be demonstrated at prototype
scale in the next year under DOD's Large Rocket Motor
Demilitarization Program.
Thiokol Corporation's washout facility near Brigham
City, Utah, which has been used mainly for rocket motor
case and warhead body recovery, utilizes hydromining
technology (see Figure 5-11). In operation since the
mid-1960s, this facility has been used to remove over
17 million pounds of propellant and recover over 3,000
motor cases. Another major hydromining facility in the
United States is the Aerojet Solid Propulsion Company
facility in Sacramento, California.
Propellant machining is used in final grain shaping to
provide desired ballistics (i.e., propellant burn back
pattern) and recover missile motor cases. All of the
propulsion companies have employed this method, in
which a drill, boring mill, or special tooling is used to cut
propellants from motors under carefully controlled
conditions.
Recovery methods for TNT-based explosives are well
established and involve melt and steam-out processes.
These processes liquify TNT so that it can be poured
out of the munition. TNT melt and steam-out facilities
are located at several Army ammunition plants and
depots, and at the Western Demilitarization Facility in
Hawthorne, Nevada.
Table 5-11. Overview of Hems and Uses8
Hem
Rocket Motor
Energetic Material
Hazard Class 1.3
Propellant
Typical Ingredients Potential Reuse
Binder/AP/AI Original, CEA,
Original, CEA,
IR (AP)
IR (HMX)
Comments
CEA & AP recovery have
been demonstrated full
scale, special additives
such as lead oxide may
require destruction methods
Gun Propellant
Bombs
Warheads
Bomblets
Illuminating Flare
Signal Rare
Mfg. Waste
Hazard Class 1.1
Propellant
Hazard Class 1.1
Propellant
Explosive
Explosive
Explosive
Pyrotechnic
Pyrotechnic
Propellants, Explosives,
Pyrotechnics
NG/NC/HMX/AP/AI/
Binder
NC/NG/NQ
TNT, Al, AN, RDX
Binder, HMX, RDX,
Al
Binder, HMX, RDX,
Al
Binder, NaNO3, Mg
Binder, Metal
Nitrates, Mg
Any of the above
Original, CEA, IR (NC)
Original, CEA
Original, CEA, IR (HMX)
Original, CEA, IR (HMX)
Original
Original, IR (MgNO3)
CEA, IR (HMX, AP)
CEA & HMX recovery
demonstrated prototype
scale
CEA demonstrated full
scale
CEA & IR demonstrated
full scale
CEA demonstrated
prototype scale, IR (HMX)
bench scale
Recovery demonstrated
bench scale
IR not demonstrated
IR not demonstrated
Composition and ingredient
reuse demonstrated bench
to full scale, sludges not
demonstrated
Key: Al = aluminum; AN = ammonium nitrate; AP = ammonium perchlorate; CEA = commercial explosive
explosives; IR = ingredient recovery (most likely ingredient to be recovered); Mg = magnesium; MgNOs =
sodium nitrate; NC = nitrocellulose; NG = nitroglycerine; NO. = nitroguanidine; Original = original intended
explosives, or cyclonite; TNT = trinitrotoluene.
additive; HMX = high melting
magnesium nitrate; NaNOs =
use; RDX = royal demolition
48
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Water
NPOES
Discharge
Figure 5-11. Flow diagram of hydromlnlng process.
Another means of disassembly and separation of
munitions components is called "reverse engineering."
Several systems have been built to reverse engineer
munitions. These systems, which are called ammunition
peculiar equipment (APE), work well for specific munitions
but do not adapt easily to varying configurations. Reverse
engineering methods disassemble munitions down to
the casing that contains the energetic material.
Standard methods for further reducing the size of the
munition include wet saw cutting and high pressure
water jet.
A size reduction method called Cryofracture has been
developed by General Atomics Corporation. It involves
cooling munitions to liquid nitrogen temperatures and
crushing them in a hydraulic press. After being
processed in this manner, the ordnance can be fed to a
specially designed incinerator. Several separation
methods, including solvent, density, magnetic, and melt
and steam-out separation processes, could be applied
to recover the energetic material after fracturing. The
types of items that have been successfully
Cryofractured are shown in Table 5-12. Because
Cryofracture can handle multiple versus individual
munitions, the technology might be most useful in
separating inert and live materials in smaller items, such
as bomblets, for which reverse engineering is less
practical.
Reuse of Energetic Materials
Once energetic materials have been separated from inert
materials, reuse is more straightforward, and many
large-scale reuse applications have been demonstrated.
Ordnance items and rockets routinely are reinspected
and used for training or similar applications. Surplus
explosives also have been purchased from the
government by commercial explosives companies since
before World War II. In addition, the patent literature
reveals many examples of smokeless powders, TNT,
tetryl, HMX, and RDX being added as sensitizing agents
and blast enhancers for slurry and emulsion explosives
used in the mining and quarry industries. According to
the Institute of Manufacturers of Explosives (IME),
hundreds of millions of pounds of slurries and emulsion
explosives are used annually. While the feasibility of
using recovered propellants and explosives in slurries
depends on their availability and cost, this potentially
could be a significant market for recovered energetic
materials. When used in slurries, explosive additives
are generally in the range of 5 to 30 percent, and most
major commercial explosive formulations can be altered
to accommodate military propellants and explosives.
Other smaller scale applications for recovered energetic
materials recently have been demonstrated. For
example, Thiokol Corporation has made 2-lb booster
charges, used to initiate ammonium nitrate/fuel oil
(ANFO) or slurry explosives, from Hazard Class 1.1
rocket propellants. TPL, Inc., has demonstrated using
reclaimed granulated plastic-bonded explosives (PBX)
for explosive-metal bonding and forming applications.
Requirements for this type of application, such as a
detonation velocity of 2.2 km/s with a variation of ฑ 50
m/s, are fairly stringent. The TPL application was
demonstrated under a small business innovative
research (SBIR) contract from the Naval Surface
Weapons Center in Crane, Indiana.
Ingredient Recovery
Ingredient recovery from propellant or explosive
compositions is the least advanced reuse technology.
In theory, ingredient recovery is not difficult, but, until
recently, there has been no economic or environmental
driving force to recover individual ingredients. Moreover,
many military programs have a "no change" policy that
prohibits changes in materials used in ordnance
manufacture. This policy also would distinguish
between recovered materials and virgin materials made
from reactants. The "no change" policy is starting to
change under environmental and economic pressures,
but ingredient recovery probably will continue to meet
resistance from risk-averse program managers.
Three significant efforts are being conducted in the area
of ingredient recovery and reuse. In the first, AP is
recovered from Hazard Class 1.3 composite rocket
propellants. This technology involves leaching of the
soluble AP from size-reduced propellants, recrystallization
at an AP vendor, and reincorporation of AP into rocket
propellant. Over 100,000 Ib of AP have been recovered
and recrystallized using this method, and the
propellants made from the recovered AP cannot be
distinguished from those made with virgin materials, A
schematic of the reclamation process is shown in Figure
5-12. Two companies, Thiokol Corporation and Aerojet
Solid Propulsion Company, are participating in this effort
with support from two AP producers, WECCO & Kerr
McGee, as well as the U.S. Air Force and the Large
Rocket Motor Demilitarization Group.
49
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fcMs &.1S. Typ3S of [Munitions That Have Been Cryofractured*
ฃ,suซ!t!@n iypฎ
M55 Rockets
(1 85-mm)
M23 Land Mines
yso 105-rnm
Cartridges
155-rnm Projectiles
Tested Form
Rocket in firing tube
Steel drum with three mines and packing material
Wood box with two cartridges in fiber tubes
Projectile
Explosive Elements
Comp B burster 3.2 Ib
Doublebase cast propellant 19.3 Ib
Comp B burster 0.8 Ib
Tetrytol burster 0.3 Ib
Tetrytol booster 0.05 Ib
Singlebase grain propellant 2.8 Ib
M-110 and M21A1
Explosive Items
Cryofractured
5
126
72
1,204
8 Al! explosives fractured without explosion.
Source: General Atomics, 3550 General Atomics Court, San Diego, CA 92121-1194.
Ammonium
Perchlorate
(Wet)
Residue (Wat)
E-12. Flow diagram of ammonium perchlorate
reclamation process.
Another ingredient drawing interest for recovery is HMX.
Tiha HMX recovery process involves separation by
dissolving and subsequent recrystallization using
solvents such as acetone or dimethyl sulfoxide (DMSO).
At least two organizations have reported successfully
ii'Kseting material specifications for recovered HMX:
TPL, Inc., which recovers HMX from PBX; and the U.S.
Army Missile Command (MICOM), which recovers HMX
from Hazard Class 1.1 propellants. In addition to reuse
In military applications, HMX might have commercial
applications, such as sen/ing as an oil well perforation
charge.
third ingredient that has been successfully
recovered and recycled is white phosphorus. The Crane
Army Ammunition Activity (CAAA) installation in Crane,
Indiana, has an acid-conversion plant that converts
Atite phosphorus into phosphoric acid. Using this plant,
;he GAAA installation can recover marketable scrap
metal and phosphoric acid from white phosphorus
munitions. The acid-conversion plant processes
;Tii!f!ffiQas from other Army facilities and has sold
thousands of ions of phosphoric acid and scrap metal
from its demilitarization operations.
approach proposed for energetic
contaminants in soils and sludges is solvent extraction
One recovery/i'3us
followed by burning of the extract with other fuels to
provide energy. AEC has demonstrated that low levels
of smokeless powder, RDX, or TNT can be used to
supplement boiler fuel. This energy recovery approach
also could be applied to extracted energetic materials,
using the AEC studies as a guide to the sensitivity and
fuel value of the materials.
5.3.5.4 Applications
Table 5-13 lists a variety of recovery and reuse
applications. Some, such as the Louisiana Army
Ammunition Plant's steam-out facility for TNT-based
explosives, which has been operational for decades,
are well established production-scale methods. These
facilities normally have the infrastructure to handle
wastewaters from the recovery process. Others, such
as the Cryowash process, which uses 12,000 to 30,000
psi liquid nitrogen to remove energetic materials from
cases, are emerging bench-scale technologies. The
Cryowash process has been demonstrated on
hundreds of pounds of energetic materials and is
scheduled to undergo full-scale prototype testing within
the year. Developmental status must be considered
when selecting recovery/reuse technologies for
particular applications.
5.3.5.5 Advantages and Limitations
Recovery and reuse of energetic materials should be a
goal in every remediation effort. EPA places this option
higher than destruction technologies on the preferred
treatment scale. Each situation, however, requires a
cost/risk/benefit assessment. At sites where rocket
motors and ordnance are in sufficient quantity and have
known materials and histories, recovery/reuse should
be seriously considered. At sites where the pedigree
and volume criteria cannot be met, cost/risk/benefit
assessments probably will indicate that destruction
technologies should be used. In each instance, the
safety of the operating personnel must be the highest
priority.
50
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TaWeS-13. Application Summary
Removal Method
Mechanical
Melt/Steanvout
Cryofracture
Cryocycle
Reverse
Engineering
Water Washout
Liquid Ammonia
Washout
Liquid Nitrogen
Washout
Facility
Thlokol, Chemical Systems Division
UTC, U.S. Army Facilities, other
U.S. Army Facilities
General Atomics
Sandia National Labs
U.S. Army Facilities
Thlokol, Aerojet
U.S. Army MICOM
General Atomics
Status
Production
Production
Prototype
Bench
Production
Production
Bench
Bench
Most Likely Use
Commercial
Explosive
Military Explosive
Commercial
Explosive
Commercial
Explosive
Military Explosive
New Propellents
New Explosive
Commercial
Explosive
Status
Prototype
Production
Emerging
Emerging
Production
Prototype
Bench
Emerging
5.3.6 Solvent Extraction
Solvent extraction is a technology that the Army
originally determined to be infeasible for treating
explosives-contaminated soils. The technology,
however, might have potential for treating these soils if
a few lingering technical issues can be resolved.
In 1982, the Army conducted laboratory-scale solvent
extraction on explosives-contaminated lagoon samples
from a number of sites. Each sample was washed with
a solution of 90 percent acetone and 10 percent water.
This process achieved greater than 99 percent
contaminant removals.
In 1985, the Army conducted a pilot-scale engineering
analysis to determine the feasibility of full-scale solvent
extraction. This analysis indicated that, for solvent
extraction to be economically feasible, the number of
required washes would have to be reduced and acetone
would have to be recovered and reused. Currently, the
only available technology for recovering acetone is
distillation, which exposes acetone to heat and
pressure. Exposing a solvent that has been used to
extract explosive contaminants to heat and pressure
raises serious safety considerations. In fact, the
distillation column used to recover acetone often is
referred to as an "acetone rocket." Nevertheless, the
Army believes that full-scale solvent extraction would be
feasible if a safe, efficient, alternative recovery method
were developed.
5.3.7 Volume Reduction for Explosives Waste
A soil washing procedure, termed the Lurgi Process,
currently is being developed in Stadtalendorf, Germany.
Although no data have been published on the
effectiveness of this process, initial reports suggest that
the process can reduce levels of explosive
contamination in soils to low ppm levels. As with all soil
washing technologies, the Lurgi Process produces
secondary wastes, such as washwater and
concentrated explosives.
In the Lurgi Process, contaminated soils are excavated
and processed in an attrition reactor, which detaches
the explosive material from the soil particles. The
mixture of detached particles then undergoes a
separation process to remove large rocks. These rocks
are crushed and returned to the site. The remaining
material undergoes a second separation process, which
separates clean from contaminated particles. Clean
particles are dewatered, separated into heavy and light
materials, and returned to the site. Contaminated
particles undergo a final series of washing, separation,
and chemical extraction processes to remove any
remaining clean particles. Finally, the contaminated
material is clarified and concentrated before being
disposed of or treated.
51
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Chapter Six
Treatment Technologies for Radioactive Waste
6.1 Wet-Based Volume Reduction for
Radioactive Soils
6.1.1 Background
Many sites with radioactive soils have large volumes of
soil contaminated with low concentrations of radioactive
waste. Volume reduction is a promising alternative to
actions that remove and dispose of all the contaminated
soils. Currently, there is no universally applicable
volume reduction technology; the feasibility of volume
reduction must be evaluated on a site-by-site basis.
This section provides general guidelines for conducting
treatability studies to determine the feasibility of
reducing the volume of contaminated soils at
radioactive waste sites.
6.1.2 Treatability Studies for Radioactive
Soils
ORIA has conducted and is conducting treatability
studies for the volume reduction of radioactive soils.
Based on ORIA's experience to date, the recommended
general steps for a treatability study for radioactive soils
are as follows:
Soil characterization
Bench-scale testing
Mini-pilot plant
Pilot plant
6.1.2.1 Soil Characterization
Characterization of representative soil samples
provides the initial information needed to determine if
volume reduction is technically feasible. Soil
characterization also is a valuable aid in planning the
use of plant equipment and greatly enhances the overall
planning and development process. The purpose of
characterization is to identify physical differences in the
soil constituents that can be exploited to separate
contaminated soil particles from clean particles.
Common exploitable differences between contaminated
and clean particles include size, specific gravity, particle
shape, magnetic properties, friability, solubility,
wetability, and radioactivity.
6.1.2.2 Bench-Scale Testing
Bench-scale testing is designed to verify whether a
volume reduction technology can meet the performance
goals for a site. Bench-scale testing employs, on a small
scale and in a batch sequence, the general techniques
of particle liberation, particle separation, and
dewatering. A general flow chart for the sequence of
these techniques is shown in Figure 6-1.
Particle separation processes divide a mixture of soil
particles into two or more volumes (see Table 6-1).
During particle liberation, contaminated soil particles
are released from clean particles, resulting in a mixture
of unattached contaminated and clean particles (see
Table 6-2). Dewatering the contaminated volume
becomes an important unit operation since there are
restrictions on the amount of free water in waste being
disposed of (see Table 6-3).
The flow chart shown in Figure 6-1 is simple, but the
actual volume reduction process grows in complexity
and specificity as the bench-scale testing progresses
toward the design of a pilot plant.
6.1.2.3 Mini-Pilot Plant
A mini-pilot plant can be developed to demonstrate
volume reduction on site at a rate of about 10 kg/hr. The
decision to develop a mini-pilot plant is based on
favorable results from the bench-scale testing. From the
Figure 6-1. General flow diagram for bench-scale testing.
52
-------
Table 6-1. Particle
Common Name
Basic Principle
Major Advantage
Major
Disadvantage
General
Equipment
Lab Test
Equipment
Separation Techniques
Sizing
Screening
Various diameter
openings and
effective particle
size
Inexpensive
Screens can plug,
fine screens are
fragile, dry
screens produce
dust
Screens, sieves
Vacuum
sieve/screen,
trommel screen
Settling Velocity
Classification
Faster vs. slower
settling, particle
density, size,
shape of particles
Continuous
processing, long
history, reliable,
inexpensive
Difficulty with
clayey, sandy, and
humus soils
Mechanical,
non-mechanical
hydrodynamlc
classifiers
Elutriation columns
Technique
Specific Gravity
Gravity separation
Differences in
density, size,
shape, and weight
of particles
Economical,
simple to
Implement, long
history
Ineffective for fines
Jigs, shaking
tables, troughs,
sluices
Jig, shaking table
Magnetic
Properties
Magnetic
Magnetic
susceptibility
Simple to
implement
High operating
costs
Magnetic
separators
Lab magnets
Flotation
Flotation
Suspend fines by
air agitation, add
promoter/collector
agents, skim oil
froth
Very effective for
some particle sizes
Contaminant must
be small fraction
of total volume
Flotation machines
Agitair laboratory
unit
Table 6-2. Particle Liberation Techniques
Basic Principle
General
Equipment
Lab Test
Equipment
Washing
Water action
Trommel, washer,
screw classifier
Stirring units,
trommel,
elutrlation column
Scrubbing
Moderate
particle/particle
action
Trommel, screw
classifier
Trommel
Technique
Attrition
vigorous
particle/particle
action
Trommel, mill
Trommel
Crushing and
Grinding
Size reduction
Crushers, mill
grinders
Crushers, mill
grinders
Surface
De-Bonding
Surfactant action
Trommel, mill
Trommel
batch tests, a continuous process is developed that
begins to simulate a field system. This process
addresses many operational Issues not addressed
during bench-scale testing. The technical necessity of
developing the mini-pilot plant is matched by its
importance in helping to obtain the public's acceptance
of onsite treatment as a viable alternative to complete
removal of contaminated material.
6.1.2.4 Pilot Plant
A pilot plant, which typically processes about 200 kg/hr,
should be developed to demonstrate volume reduction.
The pilot plant is designed to provide detailed cost,
design, and performance data on the volume reduction
process. For example, the pilot plant developed for a
radium-contaminated site in Montclair, New Jersey,
effectively separated over 50 percent of the
contaminated soil, producing a fraction with
approximately 11 picocuries per gram (pCi/g) activity.
Table 6-4 shows the performance goals and actual
results obtained at the Montclair site.
6.1.3 Advantages of Volume Reduction
Physical liberation and separation methods are used
widely in processing ore and coal. These processes are
well characterized, and considerable information is
available on their operation. These methods are
excellent candidates for use in volume reduction of soils
contaminated with low levels of radioactivity and have
been demonstrated to be effective in tests with soil from
53
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Table 6-3. Dawaterlng Techniques
Technique
Filtration
Centrifugation
Sedimentation
Expression
Basic Principle
Major Advantage
Major Disadvantage
General Equipment
Lab Test Equipment
Passage of particles
through porous
medium: particle size
Simple operation,
more selective
separation
Batch nature of
operation, washing
may be poor
Drum, disk, horizontal
(belt) filters
Vacuum filters, filter
press
Artificial gravity
settling: particle size,
shape, density, and
fluid density
Fast, large capacity
Expensive, more
complicated equipment
Solid bowl
sedimentation and
centrifugal, perforated
basket
Bench or floor
centrifuge
Gravity settling:
particle size, shape,
density, and fluid
density; flocculent aided
Simple, less expensive
equipment, large
capacity
Slow
Cylindrical continuous
clarifiers, rakes,
overflow, lamella, deep
cone thickeners
Cylindrical tubes,
beaker, flocculents
Compression with
liquid escape through
porous filter
Handles slurries
difficult to pump, drier
product
High pressures
required, high
resistance to flow In
cases
Batch and continuous
pressure
Filter press, pressure
equipment
Tabb 6-4. Goals Versus Results for Volume Reduction
TrsatabJIity Study at Radium-Contaminated Site in
Rtontelair, New Jersey
ซ3oal
Result
50 percent volume reduction
15 pCi/g in residual soil
Minimal process water
contamination
56 percent volume reduction
11.3 pCi/g in residual soil
Less than 100 pCi/L
Source: U.S. EPA. Office of Radiation and Indoor Air. Unreported
data.
the Montclair site. Physical separation can significantly
lower the cost of remediating sites with radioactive soils
by reducing the volume of soils that must be disposed
of. For this reason, soil separation technologies should
be considered during the feasibility studies for
Superfunti and other sites. Soil characterization will
provide preliminary information on the feasibility of
volume reduction, liberation, separation, and collection
of clean and contaminated fractions. Bench-scale test
results effectively lead to a preliminary design that will
correlate well with field equipment. The equipment,
commonly used in the coal and ore industries, is
commercially available or relatively easy to manufacture
and operate.
6.2 Dry-Based Volume Reduction for
Radioactive Soils
6.2.1 Background
This section discusses a volume reduction system
being operated at Johnston Atoll, a site with large
volumes of plutonium-contaminated soil. The system
combines wet and dry volume reduction. The latter
method is very successful because contamination at
Johnston Atoll is not uniformly distributeda condition
common for most contaminated soils. Contaminated
and uncontaminated soils are interspersed as a result
of nonuniform initial disposition, weather, vegetation,
traffic, or previous cleanup efforts. Excavating only the
contaminated soils from a site is difficult because
excavation equipment, such as bulldozers, is not able
to remove just the contaminated spots, and operators
of the equipment have little experience in soil cleanup.
Site managers also are inclined to excavate large soil
quantities to ensure that all contaminants have been
captured. As a result, large volumes of clean soil
typically are excavated along with contaminated soil.
Volume reduction procedures, which separate or sort
clean soils and contaminated soils to different paths,
reduce the volume of soil requiring wet corrective
action.
6.2.2 Treatable Wastes and Media
Although the volume reduction plant at Johnston Atoll
is set up to process radioactive soils, the technology
theoretically could be applied to soils contaminated
with other heavy metals or organic chemicals, such
as explosives. For example, X-ray fluorescence
detectors, which identify heavy metals, could be
substituted for the radiation detectors used in the
process. Similarly, an organic vapor detector could be
used to identify volatile organic compounds. The key
volume reduction will occur when the large volume of
clean soil is removed from the smaller volume of
contaminated soil.
54
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6.2.3 Operation and Maintenance
6.2.3.1 Analyzing Soils
Two methods typically are used to analyze soils at sites
contaminated with radionuclides: (1) the removal
method, in which samples are drawn at various
locations across the site and analyzed in a laboratory;
and (2) the in situ method, in which a radiation detector
is used to estimate an average contaminant
concentration for an area much larger than the size of
removal samples. The Johnston Atoll cleanup plant
employs a third method, which combines the best
features of the other two methods. This method, known
as the conveyor method, conveys all suspect soil
beneath detectors under well-defined conditions and
automatically sorts clean soil from contaminated soil.
6.2.3.2 Separating Soils
Figure 6-2 is a flow diagram of the separation process
used at the Johnston Atoll cleanup plant. First,
excavated soil is screened to remove large rocks.
These rocks, which have a relatively large volume with
respect to their contaminated surface area, typically are
cleaner than the sand and soil fines. As a result, their
presence lowers the average radioactivity concentration
of the soil. Removal of oversize rocks by screening is
an effective volume reduction technique. The rocks
must be crushed, however, to ensure that they are
fjlean. Once separated out, large rocks pass through a
crusher, which reduces their size and allows
radionuclides on their surfaces to be detected more
easily.
After the screening process, several devices are used
to sort soils based on their levels of radioactivity. These
sorters have an array of radiation detectors on 3-ft wide
conveyors that analyze batches of soil. Each batch is
approximately 4 in. wide, 1 ft long, and 3/4 in. deep, and
is counted for 2 seconds. The detectors trigger gates
Feed
J
M Scrw
_
Sorter
One
1
Sorter < ..
Five ^
t
Sorter
Two
th
t t f-1
Sorter
Three
If - I I
t
Clean
1
K^E
| >
< __
Sorter
Four
1
5
t
Figure 6-2. General flow diagram of the soil separation
process.
that direct each batch of soil either to a contaminated
path or to a clean path.
After soils are separated into clean and contaminated
paths, soils on the contaminated path are subdivided
further to separate uniformly contaminated soil fines
from contaminated particles. Contaminated particles
are defined as those having more than 5,000
becquerels (Bq) of radioactivity, which is equivalent to
a pure plutonium oxide particle about 70 microns in
diameter. As soon as a contaminated particle is
identified, it is diverted to a drum. Contaminated fines
continue on to a washing system, which includes a
spiral classifier and a settling pond. This system
separates the very finest, highly contaminated, soils
from the larger, less-contaminated, fines.
6.2.3.3 Monitoring Plant Performance
The cleanup plant at Johnston Atoll is equipped with
several diagnostic instruments that monitor the
performance of the plant. These instruments include
weigh scales, density gauges, and flow meters, which
assess various properties of the clean and
contaminated soils. The computer equipment used to
operate the plant also generates detailed data on plant
performance, including both daily and weekly
summaries. These data are important for establishing
that soil emerging from the plant actually is clean and
determining contaminant levels in waste soil.
Figures 6-3 through 6-6 show some of the performance
results of the Johnston Atoll cleanup plant over its first
40 weeks of operation. Figure 6-3 shows the percent of
oversize rocks removed and crushed. These materials,
which represent 25 to 30 percent of the soil by weight,
are over 99 percent clean. Figure 6-4 shows the
recovery of clean soils by weight (including oversize
rock), typically around 98 percent from one pass
through the sorters. Figure 6-5 shows the average
specific activity levels of clean soils recovered from the
cleanup plant. These levels generally are 5 times less
than the cleanup standard of 500 Bq/kg. A total of about
25,000 tons of soil met this standard. Figure 6-6 shows
the amount of radioactivity captured by the
plantalmost 2 GBq (equivalent to 0.8 g of plutonium)
after 40 weeks. This activity is concentrated in about
500 tons of soil.
The computer monitoring data can be verified by
conventional analyses, including laboratory analysis of
discrete samples and in situ analysis of the clean pile.
In addition, Johnston Atoll uses an in situ pan method,
in which clean soils from the plant are placed in a 1-m2
pan to a depth of 1 cm and analyzed by a radiation
detector. This method is fast and very accurate,
because particles of contamination have been removed
and the remaining contamination is uniformly
distributed.
55
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Figure 6-3. Percent of feed soil recovered as oversize rocks.
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Figure 6-4. Percent of feed soil recovered as clean soil.
The computer monitoring data can be used not only to
determine the actual contaminant levels achieved by the
plant but also to monitor the performance of the plant in
terms of startup time, down time, productivity, and
estimated date of cleanup completion. Extrapolating from
current productivity rates, the Johnston Atoll project should
be finished in a total of 140 weeks.
6.2.4 Advantages and Limitations
Soil that emerges from the cleanup plant could be a
valuable commodity for construction purposes, because
it has been processed to a uniform size. Over 98
percent of the soils excavated from radioactive waste
sites at Johnston Atoll can be recovered as clean soils
to avoid importing soil at much greater expense than
the cleanup process.
This technology eliminates the cost of conducting a
detailed site characterization. Once the general
boundaries of the contamination have been established,
the soil can be excavated and processed in the cleanup
plant. Similarly, the technology eliminates the need to
conduct additional assays after the cleanup is
completed, because the detectors on the conveyors
continuously monitor contaminant levels of the waste
stream. The 500 Bq/kg guideline allows sites to average
radioactivity over 1 acre, but the cleanup plant actually
accounts for every kilogram of excavated soil.
Compared to stabilizing large volumes of radioactive
soils, the volume reduction process used at Johnston
Atoll is very inexpensive. The cost for the entire volume
reduction project is estimated at $15 million, with a plant
cost of $2,4 million.
56
-------
3 50ฐ
I 400
I 300
o 200
100
10
15
20 25
Process Week
Figure 6-5. Specific activity of clean soil recovered on a weekly basis.
30
35
40
5 10 15 20 25
Process Week
Figure 6-8. Cumulative radioactivity recovered over first 40 weeks of operation.
30
35
40
Many of the potential limitations of the technology can
be eliminated through careful planning. Site managers
must keep track of in-line performance data to verify that
contractors are living up to their claims. This is
especially important since the process combines
technologies from several fields, including computer
programming, mining, and waste disposal. Plant
performance should be evaluated in terms of soil mass,
rather than volume, because density can be highly
variable at various stages of the process. Extensive
computer records should be generated as evidence to
regulators that the process is effective.
6.3 Treatment of Radioactive
Compounds in Water
6.3.1 Background
Radioactive compounds, such as radium, uranium, and
radon, occur naturally in drinking water sources,
particularly in ground water. On July 18, 1991, EPA
proposed final regulations (56 FR 33050) specifying the
limits on radioactive compounds in drinking water. This
section discusses the final regulations; the treatment of
radium, uranium, and radon; the available treatment
methods; and the factors that influence the selection of
particular treatments.
Drinking water treatments fall roughly into five groups:
Precipitation, which includes both coagulation/
filtration and lime softening.
Ion exchange, which includes both anion and cation
exchange processes.
Membrane treatment, which includes reverse
osmosis (RO) and electrodialysis (ED).
Adsorption by various media, such as GAG, which is
a common medium for drinking water treatment;
activated alumina (AA), which can be used for the
treatment of some radioactive compounds; and
selective complexers, which essentially complex the
contaminant and are not regenerable.
Aeration, which is used to remove volatile
compounds, including radon.
6.3.2 Treatment Selection
The factors that influence treatment selection include
removal requirements, best available technologies
57
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(BATs), water quality, water source, cost of treatment,
and the type and quantity of residual wastes.
6.3.2.1 Removal Requirements
The Safe Drinking Water Act (SDWA) requires that EPA
establish primary and secondary drinking water
standards. Primary standards consist of two parts: (1)
a non-enforceable maximum contaminant level goal
(MCLG), and (2) an enforceable maximum contaminant
level (MCL). The MCLG, which is based on health
criteria alone, is zero for all radioactive contaminants
regulated. Because this goal cannot always be
achieved, the SDWA also specifies a companion
enforceable MCL, which is based on health criteria,
available technology, and treatment cost. Secondary
standards (SMCLs) are similar to primary MCLs except
that these regulations set limits for contaminants that
affect aesthetic qualities of drinking water, such as
taste, odor, color, and appearance. These secondary
levels represent reasonable goals for drinking water
quality and are not federally enforceable.
Currently, the MCL for radium-226 and -228 is 5 pCi/L.
Under the proposed regulation, radium-226 and -228
have separate limits, each equal to 20 pCi/L. The
proposed limit for uranium is 20 u.g/L, which corresponds
roughly to 30 pCi/L, and the proposed limit for radon is
300 pCi/L. Table 6-5 presents these current and
proposed limits.
The proposed regulation also has two general
restrictions, which establish MCLs for compounds that
emit alpha particles, beta particles, and photons. These
restrictions are summarized in Table 6-6. The proposed
MCL for alpha emitters (excluding radon, uranium, and
radium) is 15 pCi/L. The proposed MCL for emitters of
beta particles and photons is based on specific radiation
doses. These contaminants cannot exceed levels that
result in a 4 millirem per year dose to an individual who
drinks 2 liters of water per day. The proposed regulation
lists two pages of specific radionuclides with the
drinking water concentrations that yield 4 millirem
annual doses. These vary considerably for different
contaminants; for example, the limit for tritium is 20,000
pCi/L, while the limit for barium-140 is only 90 pCi/L.
6.3.2.2 Best Available Technologies
Under the SDWA, whenever EPA sets an MCL, it also
must identify one or more BATs for achieving that level.
Utilities are free to select any technology that can meet
the MCL. If a non-BAT treatment fails to achieve the
MCL, however, the utility is required to use the BAT. The
proposed regulation (56 FR 33050) identifies the
following BATs for radioactive contaminants:
Table 6-5. Current and Proposed MCLs for Radium, Uranium,
and Radon
Radionuclide
Combined Ra-226
and Ra-228
Ra-226
Ra-228
Rn-222
U (total)
Proposed limit
Current Limit (July 1991)
5pCi/L
20 pCi/L
20pCi/L
300 pCi/L
20 \ig/L (30 pCifl.)
Table 6-6. Current and Proposed MCLs for Emitters of Alpha
Particles, Beta Particles, and Photons
Radionuclide
Gross Alpha
Beta particle and
photon emitters
(manmade
radionuclides)
Current Limit
15pCi/L
(including
Ra-226, but not
U, nor Rn-222)
4 mrem/year
(dose to body
or any internal
organ)
Proposed Limit
(July 1991)
15pCi/L
(excluding
Ra-226, U,
and Rn-222)
4 mrem/year
(dose to body
or any internal
organ)
Radium-226 and -228cation
softening, and reverse osmosis.
exchange, lime
Uraniumcoagulation/filtration, ion exchange, lime
softening, and reverse osmosis.
Radonaeration.
Alpha emittersreverse osmosis.
Beta particle and photon emittersion exchange and
reverse osmosis.
GAC also is used to treat radon in drinking water, and
EPA evaluated it as a potential BAT. It is not listed as a
BAT, however, because it requires a long empty bed
contact time, which renders it economically infeasible
for large systems. Similarly, adsorption by selected
complexers and activated alumina have proven
successful for treating radium and uranium, but
adsorption is not a BAT because these media are not
regenerableonce they become saturated with
contaminant, they must be disposed of. In addition,
although certain beta emitters, such as cesium-137,
strontium-89, and iodine-131, are not specifically
regulated, the regulation identifies reverse osmosis and
ion exchange as effective treatments for these
contaminants (see Table 6-7).
EPA's proposed regulation (56 FR 33050) lists a range
of expected removal rates for each BAT-contaminant
combination (see Table 6-8). For example, coagulation/
filtration typically removes 85 to 95 percent of uranium
from drinking water. The range of removal rates listed
for each BAT depends on the chemistry, concentration,
58
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and solubility of particular contaminants, and on
variation in the quality of the water being treated.
6.3.2.3 Water Quality
Important aspects of water quality include pH and the
presence of anions, cations, and other radioactive
contaminants.
Uranium can be a cation, neutral, or an anion depending
on the pH of the water. In water with a pH less than 5,
uranium is a cation; in water with a pH between 5 and
7, uranium is neutral; in water with a pH greater than 7,
uranium is an anion. As a result, ion exchange for
uranium may involve either cation exchange or anion
exchange. The pH of the water also affects the uranium
removal efficiency of iron coagulation. Iron coagulation
is very efficient at pHs near 6 and near 9; the treatment
is not efficient, however, at pHs between 7 and 8 or
below 5 (see Figure 6-7). When alum is used as a
coagulant, the removal pattern is similar to that of iron
coagulation. The uranium removal efficiency of lime
softening and anion exchange depends on the
presence of naturally occurring elements in the water.
Table 6-9 illustrates the impact of magnesium levels on
the effectiveness of lime softening for uranium removal.
Table 6-10 shows the effect of sulfate levels on uranium
removal by ion exchange.
As with uranium, the effectiveness of ion exchange for
radium removal depends on the presence of other
elements, such as barium, calcium, and magnesium, in
Table 6-7. Range of Removal of Ceslum-137, lodlne-131, and
Strontium-89 by Reverse Osmosis and Ion
Exchange
Beta Emitters% Removal
Treatment Method
Reverse osmosis
Ion exchange
Cesium
137
90-99
95-9P
Iodine
131
90-99
Strontium
89
90-99
95-99
the water being treated. These elements may be
preferred to radium in the resin's selectivity sequence,
shown below:
Ra+2 > Ba+2 > Ca+2 > Mg+2 > Na+ > H*
Even if radium is highly preferred by a particular cation
resin, the final percentage of radium removed will
depend on the selectivity sequence of the resin and
other elements present in the water.
Water with more than one radioactive contaminant may
require more than one treatment process. For example,
radium usually is treated by cation exchange with
sodium, and uranium usually is treated by anion
exchange with chloride. Water contaminated with
radium and uranium can be treated by a mixture of
cation resin and anion resin.
6.3.2.4 Water Source
Treatment efficacy can depend on the source of the
water being treated. A treatment appropriate for
contaminated ground water often will not be appropriate
for contaminated surface water. Surface waters that are
high in turbidity will foul ion exchange media, reverse
osmosis membranes, or GAG. These methods can be
used only if surface water is pretreated to achieve
ground water turbidity levels. Lime softening can be
used for both ground and surface waters without
pretreatment, though it might be more costly for surface
water. Coagulation/filtration treatment is designed to
remove turbidity and therefore is used only on surface
waters.
6.3.2.5 Cost of Treatment
Cost often is a determining factor at large water utilities
that treat enormous quantities of water over extended
periods of time. Cost might not be as important at
cleanup sites, however, where the total volume of water
Table 6-8. Range of Removal Rates for Each
BAT-Contaminant Combination
Contaminant% Removal
Treatment Method
Radium
Uranium
Radon
Coagulation/Filtration 85-95
Lime softening 75-97 85-99
Ion exchange 65-97 65-99
Reverse osmosis 87-98 98-99
Aeration Up to 99
Ferric Sulfate -
25mg/L
U 83 ng/L
Ferric Chloride
30 mg/L
U450M/L
Figure 6-7. Effect of pH on removal of uranium by Iron
coagulation.
59
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Table 6-9. Effect of Magnesium and Lime Dose on Uranium
Removal by Lime Softening (Percent Removal)
Lime Dose -Ca(OH)2 - mg/L
Table 6-11. Types of Residual Waste Produced by Drinking
Water Treatments
Treatment Method
MgCO3 mg/L
10
40
80
120
50
32
9
24
15
150
90
95
93
99
250
89
94
98
99
Residual (Waste)
Table 6-10. Effect of Sulfate on Uranium Removal by Anlon
Exchange
Influent
Field
Site"
1(1)
2(1)
3(1)
4(C)
5(C)
6(C)
U-ng/L
22
30
104
52
35
28
S04-
mg/L
320
9
390
400
3
Bed
Volume
Treated at
Termination
(x 1,000)
9.4
25
7.9
34.5
11.9
62.9
Percent
Uranium
Removal
(total)
99.8
99.8
99.8
73.1
29.8
99.6
* (I) Intermittent flow; (C) continuous flow.
to be treated is limited. Adsorption by GAC, for example,
is a relatively expensive technique. While GAC would
be impractical for a large utility, it might be an
appropriate option for a smaller scale cleanup.
6.3.2.6 Residual Wastes
Different treatments generate different quantities of
residual waste. Uranium treatment by coagulation/filtration
produces 2,100 gallons of waste per million gallons of
treated water; lime softening produces 5,000 gallons;
anion exchange produces 340 gallons; and reverse
osmosis produces 333,000 gallons, assuming two-thirds
treated water and one-third reject water.
Table 6-11 delineates the types of residuals produced
by each drinking water treatment method.
Coagulation/filtration produces a sludge from the
settling basins and a filter backwash water that both
contain the contaminant. Lime softening also produces
a sludge from the settling basins and filter backwash
water wastes. Ion exchange normally creates a brine
waste, but, depending on the type of regeneration
material used, it could produce a caustic or acid
solution. In addition, ion exchange resins themselves
contain residual radionuclides. Adsorption media, such
as GAC, activated alumina, and specific complexers,
Coagulation/Filtration
Lime softening
Ion exchange
Adsorption (GAC/AA)
Membrane processes (RO/ED)
Aeration
Backwash water
Sludge (alum or iron)
Backwash water
Sludge (lime)
Brine
Caustic solution
Acid solution
Resin
GAC
Activated alumina
Reject water
Air
Adsorption media
accumulate contaminants that must be safely disposed
of. If aeration is used to strip radon, the resulting gas
must be passed through an adsorption system, such as
GAC, from which the adsorption medium will become
contaminated. The type and quantity of waste
generated ultimately may drive the selection of
treatments at cleanup sites.
6.4 Incineration of Radioactive and
Mixed Waste
6.4.1 Background
Incineration serves several purposes as a management
strategy for mixed waste: (1) it destroys some
hazardous materials by breaking them down into
simpler chemical forms, (2) it eliminates liquids in waste
that otherwise complicate waste management, (3) it
decreases the volume of waste, and (4) it may generate
usable energy. Incineration currently is a critical
component in DOE's strategy for managing low level
radioactive and mixed wastes.
Table 6-12 lists all of the DOE and commercial
incinerators that handle radioactive and mixed wastes
in the United States. This section focuses on two of
these incinerators: (1) the incinerator operated by
Scientific Ecology Group, Inc. (SEG), in Oak Ridge,
Tennessee; and (2) the incinerator operated at the Oak
Ridge Gaseous Diffusion Plant. This section also
discusses advantages and limitations of incinerating
radioactive and mixed wastes.
6.4.2 SEG's Incinerator, Oak Ridge,
Tennessee
6.4.2.1 Background
SEG operates the world's largest radioactive waste
incinerator and the only incinerator licensed to burn
60
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Table 6-12. Radioactive and Mixed Waste Incinerators In the United States
Commercial
Incinerators
Unit
Location
Current Status
Comments
DOE
Incinerators
Toxic Substances
Control Act (TSCA)
Incinerator
Oak Ridge Gaseous
Diffusion Plant
In full-scale operation
since 1991.
EPA Region 4
responsible for
compliance and
enforcement
Waste Experiment
Reduction Facility
(WERF)
Controlled Air Incinerator
(CAI)
Glass Melter
GIF
Scientific Ecology Group
(SEG)
DSSI
Idaho National
Engineering Laboratory
Los Alamos National
Laboratory
Mound Laboratory
Savannah River Site
Oak Ridge, TN
Kingston, TN
Facility closed since
Feb. 1991. Planned
restart in 1993.
On stand-by since 1987.
On stand-by. Planned
restart in 1993.
Under construction.
Planned operation in
Jan. 1996.
Full-scale operation
began in fourth quarter
of 1989.
In full-scale operation.
Facility closed to update
Operational Safety
Requirements.
Facility closed to
upgrade. Announced
restart in 1993, likely
restart in 1995.
Awaiting RCRA part B
permit from Ohio EPA.
Startup deferred 2 to 3
years while RCRA part B
permit is negotiated.
RCRA part B permit
pending.
System modified to meet
new BIF regulations.
Source: U.S. EPA, 1993.
commercial radioactive waste in the United States.
SEG's incinerator is an automated, controlled-air
incinerator capable of burning 1,000 Ib of waste per
hour.
6.4.2.2 Treatable Wastes
The following radioactive materials are incinerated at
the SEG operation:
Dry active wastes, such as paper, plastic, wood,
cloth, rubber, canvas, fiberglass, and charcoal.
Ion exchange resins used to polish condensate from
nuclear power plants.
Animal carcasses from scientificbut not
medicalresearch.
Sewer sludges and lubricating oils that have become
contaminated with radioactive materials.
High efficiency paniculate air (HEPA) filters
Other materials, including metals, explosives,
flammable liquids, shock-sensitive materials, or
polyvinyl chloride (PVC), might not be suitable for
incineration at SEG. In addition, large pieces of metal,
such as sections of pipe, cannot be incinerated,
because they can jam the augers that slowly propel
ashes from the charging area to the discharge area of
the incinerator. Items smaller than a 10-in. crescent
wrench do not interfere with the action of the augers.
6.4.2.3 Operation and Maintenance
In addition to the actual burning of waste, the
incineration process involves sorting of waste,
packaging of waste, and treatment of incinerator flue
gas emissions to control air pollution. The incinerator
also has several redundant features to ensure safe
operation.
Sorting Waste
Since many materials cannot be incinerated, materials
must be sorted before being fed to the incinerator.
Waste arrives at SEG in sealand containers loaded atop
flatbed trailers. The containers house large plastic bags
of low level dry active waste materials. The bags are
removed from the sealand containers and placed on a
revolving carousel, from which SEG operators manually
sort waste materials. Metals are sent to a metal melt
facility, unidentifiable liquids are sent to be analyzed,
and PVC-bearing materials are shredded and
compacted.
Waste Packaging
Before any waste is burned, it must be packaged
properly. Typically, waste is packaged in plastic bags
that line large feed boxes. The feed boxes, which can
hold up to 300 Ib of waste, have bar codes and tracking
sheets that identify the type of waste they contain, the
customer, the date, and the manifest number. The bar
codes allow waste to be monitored at every stage of the
incineration process. Feed boxes are placed on a
61
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conveyor, which carries them to the incinerator. Each
box has anchors on the bottom so that the contents of
the box can be dumped mechanically through a feeding
sluice and into the primary chamber of the incinerator.
Burning Waste
The incinerator has three chambersthe primary
combustion chamber, secondary combustion chamber,
and retention chambereach with its own burner and
thermostat. The total residence time for gases, from the
dumping of waste materials into the primary combustion
chamber to the emission of flue gases from the retention
chamber, is about 3 seconds.
Primary Combustion Chamber. Waste feeds into the
primary chamber in batches, usually 200 to 300 Ib every
15 minutes. The feed rate is limited by the Btu content
of the waste, the resultant temperatures in the three
chambers, and the quality of the flue gas leaving the
incinerator, Flue gas quality factors include oxygen
concentration, CO concentration, and opacity caused
by particulates in the flue gas line. No waste is fed to
the incinerator while these quality factors exceed certain
limits. Once the flue gas factors return to normal, waste
can be charged again.
The primary combustion chamber operates at about
1,000ฐC. At this temperature, volatile and partially
volatile metals are released as gases or aerosols.
Operating the chamber at too low a temperature results
in elevated concentrations of lead and cadmium in the
hearth ash, requiring costly stabilization of the ash prior
to disposal. Operating the chamber at a higher
temperature ensures that these compounds are
completely volatilized and thus removed from the hearth
ash. Primary chamber temperature is maintained by a
mechanism that sprays water into the chamber at a
desired upper temperature limit. This mechanism not
only cools the chamber, but also can provide an
inexpensive way to dispose of contaminated water.
Contaminated water otherwise would require costly
solidification processes, which would result in increased
burial volumes.
Hearth ash from the primary chamber drops onto two
rotary screw augers located in the bottom of the
chamber. These augers rotate forward for 10 seconds,
pause, then rotate backward for 8 seconds. The net
effect is a slow forward motion. Over a period of 14
hours, the augers turn over the burning waste to
promote even and complete combustion, then grind the
ash into a fine powder and convey it to the end of the
chamber, where it is cooled and dropped into the hearth
ash collection boxes. A typical ash box weighs
approximately 1,200 Ib when full.
Secondary Combustion Chamber. Flue gases and
particulate matter from the primary chamber pass into
a secondary combustion chamber. The temperature in
this chamber ranges from 1,000 to 1,200ฐC, depending
on the amount of CO gas and aerosols emitted from the
primary combustion chamber. There is not enough
oxygen in the primary chamber to allow these gases
and aerosols to burn. As the gases pass from the
primary chamber into the secondary chamber, however,
they are mixed with fresh air and they combust quickly,
heating the secondary chamber. Secondary chamber
temperature usually peaks shortly after each waste
charge and then gradually declines until waste is
charged again.
Retention Chamber. Flue gases from the secondary
chamber pass into a retention chamber, which is a large
thermal fly wheel that provides time for any remaining
hazardous materials to be destroyed. The chamber is
sized to provide an adequate delay or retention time for
the gases. The temperature in this chamber tends to be
very stable due to the volume and mass of refractory in
the chamber. A propane burner in this chamber
maintains a temperature range from 1,000 to 1,300ฐC
to ensure complete combustion of flue gas components.
Treatment of Incinerator Flue Gas Emissions
From the retention chamber, flue gases pass into a
steam boiler, where they are cooled to about 200ฐC.
The boiler generates 70 Ib of saturated steam pressure,
which can be used to dry contaminated resin, evaporate
wastewater from sludge, heat stack gases for plume
suppression, or heat the facility. Flue gases then pass
through a baghouse filter, which removes the particulate
entrained in the gas stream; a HEPA filter and wet
scrubber, which remove nonvolatile radionuclides and
acid gas; and an ID fan, which maintains the entire
system under a negative pressure for contamination
control. Emission gases are monitored at the stack for
radioactive materials. Should such materials be
detected, various notification alarms sound.
Safety Features
Draft fans, air supply fans, gas monitors, opacity
detectors, HEPA filters, negative air-pressure
controllers, and an emergency power source are among
the redundant features that can improve the safety of
an incinerator. The most important feature is an
emergency power source. SEG has a 300-kilowatt
diesel backup generator, capable of carrying the entire
incinerator load when outside power is lost.
Since SEG's incinerator is used to process radioactive
wastes, it must be operated under a vacuum. SEG's
primary combustion chamber is operated at -0.5 in.
H2O, while the vacuum at the suction of the ID fan is
-30.0 in. H2O. The difference between these is the
differential pressure that occurs across the scrubber,
baghouse, boiler, and HEPA systems.
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6.4.3 Incinerator at the Oak Ridge Gaseous
Diffusion Plant
6.4.3.1 Background
The incinerator located at the Oak Ridge Gaseous
Diffusion Plant is a 6-ft diameter by 25-ft long rotary kiln
unit rated at 10 million Btu per hour with a secondary
combustion chamber rated at about 22 million Btu per
hour and a total system maximum heat release of 28
million Btu per hour. The unit, which currently processes
primarily liquid wastes, processed 2.2 million Ib of waste
in fiscal year (FY) 1991 and 2.8 million Ib in FY 1992.
The system is permitted to handle both Toxic
Substances Control Act (TSCA) and RCRA wastes.
6.4.3.2 Treatable Wastes and Media
Although the incinerator is capable of handling a variety
of waste types and forms, the near-term processing
plan is to burn primarily liquid low-level mixed wastes,
because of the concern about the handling and ultimate
disposition of incinerator residuals derived from offsite
wastes. The following restrictions limit the types of
wastes that can be fed to the incinerator:
Waste must be free of dioxin wastes as defined in 40
CFR 268.31 and listed as waste codes F020 through
F023 and F026 through F028 in 40 CFR 261.
Waste must be free of cyanide wastes as defined in
waste codes F007 through F011 listed in 40 CFR 261.
, Waste must be free of explosive material that
detonates on heating or percussion, ignites
spontaneously in dry or moist air, or meets the
definition of reactive waste as defined in 40 CFR 261
or as designated by EPA hazardous waste code
D003.
Waste containing uranium with U-235 enrichment of
less than 1 percent must not exceed 0.08 Ci per
shipment (i.e., per truckload).
Waste containing uranium with U-235 enrichment of
more than 1 percent must have a total uranium
content of less than or equal to 5 ppm.
In general, the waste form must be nonvolatile, such
that it does not rapidly evaporate when the waste
container is opened.
If the boiling point of the waste is less than 100ฐF,
acceptance will be on a case-by-case evaluation.
For liquid organic wastes, the corrosivity must be
limited to less than 6.35 mm/yr.
For aqueous wastes, the pH must be greater than 6
for drummed liquids or between 8 and 10 for bulk
liquids.
The incinerator has metals contamination limits in the
feed waste (see Table 6-13). In addition, the incinerator
has the following restrictions on specific elements:
Total chloride: <89 percent by weight.
Total sulfur: <6 percent by weight (drums); <3 percent
by weight (bulk).
Total fluoride: <85 percent by weight (drums); <25
percent by weight (bulk).
To be fed to the incinerator, solid materials in drums
must be shreddable, which limits rebar, pipe, and
concrete pieces larger than 2 in. in diameter. Wastes
received for processing must be identified by
radionuclide content. Prior to processing, the incinerator
staff analyzes the waste to determine whether
incineration of the waste, along with other wastes, will
exceed the annual committed effective dose equivalent
limits. Required lower limits of detection for specific
radionuclides are listed in Table 6-14. Waste shipping
containers must meet the following requirements:
Maximum dose equivalent rate at contact: 50
mrem/hr.
Maximum dose equivalent rate at 2 ft: 5 mrem/hr.
Transferrable beta/gamma surface contamination:
1,000 disintegrations per minute (dpm)/100 cm2.
Transferrable alpha surface contamination: 200
dpm/100 cm2.
6.4.3.3 Operation and Maintenance
The incinerator uses a wet off-gas treatment system
composed of a quench tower, venturi scrubber,
demister, packed-bed scrubber, two-stage ionizing wet
scrubber, ID fan, and a 100-ft stack. The facility's
maintenance procedures typically include two planned
outages every yearone in the spring for a few weeks
Table 6-13. Metals Contamination Limits for Oak Ridge
Gaseous Diffusion Plant Incinerator
Metal
Aluminum
Beryllium
Cadmium
Chromium
Lead
Mercury
Zinc
Plutonium
Liquid
(Drums)
20,000
10
1,500
6,000
2,500
200
65,000
0.004a
Liquid
(Bulk)
11,000
5
500
3,300
2,000
60
65,000
0.0049
Solids
80,000
5
800
6,000
1,000
120
65,000
0.004a
Sludge
80,000
5
800
6,000
1,000
120
65,000
0.004"
8 Or 246 pCi/g.
Source: U.S. EPA, 1993.
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Table 6-14. Required Lower Limits of Detection (LLD) for
Radlonuclldes In the Oak Ridge Gaseous
Diffusion Plant Incinerator
Radionucllde
H-3
C-14
P-32
Co-57
Co-60
Kr-85
Sr-90
Tc-99
1-131"
Cs-137
Required
LLD
(pCI/g)
60
60
5
0.1
0.5
5
5
20
0.7
1
Radionucllde
Pb-210
Th-228
Th-230
Th-232
Th-234
Pa-234
U-alpha
Np-237
Pu-238
Pu-239
Required
LLD
(pCi/g)
1
1
1
1
1
1
1
1
1
1
Analysis for 1-131 is not required if waste has been stored more
than 6 months.
Source: U.S. EPA, 1993.
and a major one in the fall for 1 to 2 months, depending
on maintenance requirements. Maintenance activities
during these outages include fiberglass repair and
replacement of pumps and deteriorating equipment.
6.4.4 Advantages and Limitations
6.4.4.1 Advantages
Incineration produces a waste form that is dense and
easy to transport, and takes up relatively little space
when buried. Incineration has been shown to yield
varying volume reduction factors (VRFs): commonly 4
to 40 for most types of compressible dry active wastes
and combustible solids, and greater than 100 for liquids
and most plastics. SEG also operates a
supercompactor, which exerts up to 10 million Ib of
pressure on the filled ash box and can produce further
VRFs of 2 to 5.
The annual permissible dose equivalent release limit
from the SEG site is 10 mrem, but actual releases tend
to be much lower. In 1991, the SEG incinerator
processed 5.3 million Ib of radioactive wastes, exposing
the nearest resident to an estimated dose of 0.027
mrem for the year, compared to natural background
levels of approximately 150 mrem/year.
6.4.4.2 Limitations
The primary disadvantage of incineration is that it can
produce toxic ash that requires further processing prior
to disposal. This is a particular concern for incineration
of radioactive waste, which yields waste residues that
have much higher radionuclide concentrations than
does the original waste stream. As a result, containers
or bins of ash from the incineration of radioactive waste
may have high external radiation exposure rates. When
radiation exposure levels are expected to be high,
personnel interaction with equipment and ash bins
should be minimized. Ash collection bins and other ash
handling equipment also might need to be shielded.
Incineration produces three types of ash: hearth ash,
which is discharged from the primary chamber during
combustion; fly ash, which gets stripped from the flue
gas in the baghouse; and boiler ash, which gets stripped
from the flue gas in the boiler. Hearth ash from an
incinerator operated at the proper temperature usually
passes EPA's Toxicity Characteristic Leaching Procedure
(TCLP). Fly and boiler ash always are characteristic
because of the presence of lead which emanates from
the primary chamber and passes from the incinerator in
fine aerosol form.
Ash that passes TCLP testing can be compacted
immediately and shipped for burial, while ash that fails
TCLP testing must be solidified by concrete or epoxy
into a monolithic waste form by mixing it with a hardener
and fixer base material and allowing it to harden. Once
hardened, the waste form is sampled and retested. If
the sample passes, the waste form may be buried; if it
fails, the waste must be reprocessed. To date, SEG has
not experienced a TCLP failure of its stabilized fly ash
waste form.
Another disadvantage to incineration is that the
operation of wet scrubbers generates salt that must be
removed. SEG uses a quick dry dewatering system in
which salt drums are decanted into larger drums that
contain filtering systems. A vacuum then is applied to
draw the water out of the salt mixture. The remaining
salt is not hazardous and can be disposed of
accordingly. SEG currently is developing a spray dryer
to provide a one-step drying process for the salt slurry.
6.5 In Situ Vitrification
6.5.1 Background
Vitrification is the process of converting materials into
glass or glass-like substances at high temperatures.
Vitrification is an attractive option for stabilizing
high-level radioactive contaminants, because vitrified
materials are very durable and exhibit low radionuclide
teachability. In addition, vitrification is applicable to
mixtures of organic and inorganic wastes, because the
technology pyrolyzes organics and immobilizes
inorganics.
Thermally formed glasses are produced by fusing or
melting crystalline materials or previously formed
glasses, which form a network of interlocking silicate
tetrahedra upon cooling. During vitrification, inorganic
contaminants become immobilized in the glass matrix
64
-------
in three ways: (1) as network formers, by replacing
silicon and forming covalent bonds with oxygen atoms
in the network; (2) as network modifiers, by forming
ionic bonds with oxygen atoms that do not bridge
between tetrahedra; or (3) by becoming encapsulated
in vitrified material.
The ability of a vitrification process to immobilize a
particular contaminant is known as the retention
efficiency for that contaminant. Retention efficiencies
vary from metal to metal, because different metal oxides
have different solubility limits in glass. Table 6-15 shows
the retention efficiencies for a number of semivolatile
and nonvolatile metals. The retention efficiency for any
metal also depends on the operating parameters of the
vitrification process. Retention efficiencies can be
increased by reducing the gases generated during
vitrification, allowing a cold cap to increase contact time
between metals and the melt, recycling volatilized
metals, decreasing the melt temperature, or modifying
the melt composition with additives.
Contaminants that are not immobilized in the vitrified
waste form either are destroyed through pyrolysis or
combustion or removed during off-gas treatment. In
general, only organics and asbestos are destroyed
during vitrification. The ability of a vitrification process
to destroy an organic contaminant is known as the
destruction efficiency for that contaminant. Tables 6-16
and 6-17 list the destruction efficiencies of in situ
vitrification (ISV) for common organic contaminants.
Destruction efficiencies can be increased by allowing a
cold cap to increase contact time with the melt, adding
oxygen to enhance secondary combustion of organics
in the area above the melt, or recycling organics back
to the melt.
There are two types of vitrification technologies: electric
process heating and thermal process heating. Electric
process heating includes joule heating, plasma heating,
and microwave heating. Of these processes, only joule
heating, in which a high-voltage electric current is used
to heat soils, can be operated in situ. ISV eliminates the
risk of exposing site workers to excavated contaminants
and thus is potentially the most useful technique for
treating radioactive contaminants. This section focuses
on ISV, examining treatable wastes and media, the
operation of ISV by joule heating, treatment of
off-gases, and advantages and limitations of the
technology.
6.5,2 Treatable Wastes and Media
ISV can be applied to a wide variety of wastes, including
radioactive wastes and sludges, contaminated soils,
contaminated sediments, industrial wastes and sludges,
underground storage tanks, drummed wastes, and
asbestos wastes. Organic contaminants, which are
destroyed during the heating process, and inorganic
Table 6-15 Metals Retention Efficiencies for ISV
Class
Volatile
Semivolatile
Nonvolatile
Metal
Mercury(Hg)
Arsenic(As)
Cadmium(Cd)
Cesium(Cs)
Lead(Pb)
Ruthenlum(Ru)
Antimony(Sb)
TelleriumfTe)
Americium(Am)
Barium(Ba)
Cerium(Ce)
Cobalt(Co)
Copper(Cu)
Chromium(Cr)
Lanthanum(La)
Molybdenum(Mo)
Neodymium(Nd)
Nickel(Ni)
Plutonium(Pu)
Radium(Ra)
Strontium(Sr)
Thorium(Th)
Uranium(Th)
Zinc(Zn)
Retention
Efficiency,
%a
0
70-85
67-75
99-99.9
90-99
99.8
96.7-99.9
50-99
99.99
99.9
98.9-99.9
98.7-99.8
90-99
99.9
98.9-99.98
99.9-99.999
99-99.98
99.9
99.99
99.9
99.9-99.998
99.99
99.99
90-99
Scale"
Engineering
Engineering
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Engineering
Pilot
Pilot
Engineering
Engineering
Pilot
Pilot
Pilot
Engineering
Pilot
Engineering
Pilot
Engineering
Engineering
Engineering
a Percentage of original amount remaining in the melt.
b Engineering-scale tests involve a melt depth of 1 to 2 ft. Pilot-scale
tests involve a melt depth of 3 to 7 ft.
Source: Hansen, 1991.
contaminants, which are immobilized in the vitrified
waste form, both can be treated by ISV. ISV is relatively
expensive to operate, however, so it should be used
primarily to treat highly concentrated hazardous wastes,
wastes with complex mixtures of contaminants, and
wastes that require a high-quality product.
Characteristics of the soil and waste that can affect the
ISV process include:
Moisture content. Moisture content does not
necessarily limit the technical applicability of ISV, but
it does affect the technology's economic feasibility,
because soils with high moisture content require
more energy to drive off excess water. Limits of 20
to 25 percent moisture content by weight have been
identified for some ISV processes (U.S. EPA, 1987;
U.S. EPA, 1988).
65
-------
Table 6-16. ISV Organic Destruction and Removal Efficiencies
Initial Concentration
Contaminant (ppb)
Percent Destruction
Total DRE (Including
off-gas removal)
Aldrin
Chlordane
Dichlorodiphenyl dichloroethane (ODD),
Dtehlorodiphenyl dichloroethylene (DDE),
Dtehlorodiphenyl trtenloroethylene (DDT)
Dleldrin
Dioxins
Fuel oils
Furans
Qlycol
Heptachlor
Methylethyl ketone (MEK)
Polychlorinated biphenyls (PCBs)
Pentachlorophenol
Toluene
Trichloroethane
Xylenes
113
535,000
21-240,000
24,000
>47,000
230-11,000
>9,400
NA
61
NA
19,4000,000
>4,000,000
203,000
106,000
3,533,000
>97
99.95
99.9-99.99
98.0-99.9
99.9-99.99
>99
99.9-99.99
>90
98.7
>99
99.9-99.99
99.995
99.996
99.995
99.996
>99.99
>99.999
>99.999
>99.99
>99.9999
>99.999
>99.9999
>99.99
>99.99
>99.999
>99.9999
>99.99999
>99.99999
>99.99999
>99.99999 ,
Source: In Situ Vitrification Update, 1990.
Soil composition. In order for ISV to be effective, the
soil must contain adequate quantities of
glass-forming materials, such as SiO2 and AI2O3; and
current-carrying alkaline flux agents, such as Na2O,
K2O, and CaO. These materials can be added to soils
to improve the effectiveness of ISV.
Buried debris. ISV might not be appropriate for soils
with substantial buried debris, which can interfere
with current between the electrodes.
Combustible materials. Combustible materials
produce large volumes of off-gas, which must be
treated and can provide a pathway for inorganics to
escape the melt.
Volatile contaminants. ISV of soils with high levels of
volatile contaminants, such as mercury, lead, and
cadmium, can produce secondary contamination.
Metals. High concentrations of metals can short the
electrodes. The effects of shorts can be minimized
by employing an electrode feed system, which
temporarily raises electrodes when a short begins to
occur.
6.5.3 Operation and Maintenance
6.5.3.1 Heating
A schematic of ISV is shown in Figure 6-8. Four
electrodes are inserted into the contaminated soil by an
electrode feed system, which automatically controls the
height of the electrodes. Because unsaturated soil is not
electrically conductive, a conductive mixture of flaked
graphite and glass frit is placed between the electrodes
as a starter path. A current is established between the
electrodes to heat the starter path and surrounding soil
to 2,000ฐCwell above the 1,100 to 1,400ฐC required
to melt the soil. Gradually, the starter path is oxidized,
and the molten soil, which is electrically conductive,
begins to carry the current. As the molten vitrified mass
grows, it incorporates radionuclides and nonvolatile
metals and pyrolyzes organic components. Byproducts
of pyrolysis migrate to the surface where they combust
in the presence of oxygen. A hood placed over the
vitrified area directs the gaseous effluent to an off-gas
treatment system. A full-scale system typically
processes waste at the rate of 3 to 5 tons per hour. The
average processing time required for one setting of the
electrodes is 150 to 200 hours, depending on soil depth
and electrode spacing (Buelt et al., 1989).
6.5.3.2 Off-Gas Control
Off-gas constituents of particular concern include:
Volatile and semivolatile metals and organics, which
are the very contaminants vitrification is designed to
immobilize and destroy.
Inleakage air, which creates convection currents in
the area above the melt that can entrain particles and
contaminants from the cold cap.
-------
Table 6-17. Organic Destruction Efficiencies for Vitrification
Systems
Compound
ฐC for 99%
Destruction In
2 Seconds Measured DE (%)
Hydrocyanic acid
Chlorobenzene
Formic acid
Phosgene
Methylene chloride
Phenol
Acetone
Isodrln
Ethanol
Mustard gas
Nitrogen mustard
Carbon tetrachloride
Aldrin
Dleldrin
SulfoxkJe
Endrin
Dithlane
Sulfone
Xylenes
DIMP
DMMP
ACN
AN
482-866
482-866
318-368
427-479
427-479
374-421
374-421
374-421
374-421
318-368
318-368
318-368
318-368
318-368
218-316
38-160
182-213
NA
NA
NA
NA
NA
NA
NA
99.99986
NA
NA
>99.9995
99.99992
>99.9995
>99.9998
>99.9995
NA
NA
99.99988
99.99994
>99.9995
>99.99
>99.998
>99.9
>99.995
99.99617
>99.8
>99.8
99.99996
99.9994
Sources: Armstrong and Wingler, 1985; U.S. ATHAMA, 1988;
Wlngler and Abellera. 1989.
Byproducts of the combustion of organics, which
provide a pathway for inorganics to escape the melt.
Entrained particles produced by the feed dust or
volatilization of glass components, which also can
serve as carriers for inorganics.
Off-gases are controlled by two mechanisms: emission
reduction and off-gas treatment. Many of the methods
discussed in section 6.5.3.1 for increasing retention of
waste constituents also apply to reducing emissions.
These include allowing a cold cap to increase contact
time between metals and the melt and recycling
contaminants captured in the off-gas system. Other
methods include modifying the soil with additives to
reduce its level of volatile constituents and adding
oxygen to enhance secondary combustion of organics
and products of incomplete combustion. Emission
reduction methods cannot completely eliminate evolved
off-gases, however, and gases that escape the melt
Maximum Extsrit of Men
(Mixture of Soil and Me*
at Surface; Slae Depends
on Elestmde Spacing)
Denser Layer
(Ceramics, Pure Mails)
Figure 6-8. Schematic of ISV by joule heating (from U.S.
EPA, 1989).
must be captured and treated. Components of the
off-gas treatment system include HEPA filters, which
perform the initial and final filtering to remove
particulates; scrubbers, which cool gases and remove
particulates; a condenser, which removes water vapor;
and a heater, which reheats gases above dewpoint. To
ensure containment of off-gases, the entire vitrification
system is operated at a negative pressure. This
precaution protects against the possibility of pressure
surges caused by temperature fluctuations or the rapid
release of large volumes of combustion gases.
6.5.4 Advantages and Limitations
6.5.4.1 Advantages
The advantages of ISV include the technology's ability
to destroy organics, solidify a wide variety of waste
streams, and avoid excavation and reburial of
hazardous contaminants. In addition, the vitrified waste
form resists leaching, has high strength and impact
resistance, exhibits long-term durability, and reduces
the volume and increases the density of solidified
waste.
Chemical Immobilization
Chemical immobilization, or the resistance to leaching
of hazardous constituents, is the most important feature
of vitrified waste. Vitrified waste forms have undergone
numerous tests for leaching of toxics and radionuclides.
These tests generally indicate that vitrified wastes have
leach rates below levels accepted by EPA. Table 6-18
shows the TCLP data for various in situ and ex situ
vitrification processes. Results for partially vitrified or
crystalline waste forms indicate only slightly higher
teachability (Spalding and Jacobs, 1989).
Strength and Impact Resistance
Waste forms produced by ISV have high compressive
and tensile strengthsup to 5 to 20 times those of
67
-------
Table 6-18. TCLP Leach Data for Selected Processes and Selected Metals*
Metal
Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Silver
Glass Melter"
(ppm)
<0.02
<0.05
0.007
0.03
<0.05
<0.0002
<0.01
Klln/Vltrlflcatlon
Process0 (mg/L)
<0.01
0.175
0.015
0.825
0.15
0.00035
0.01
ISV Glass" (mg/L)
<5
0.05
<1
<1
<1
<0.03
<0.1
ISV Metal3
(mgA)
<5
<1
<1
2.7
<1
<0.03
<0.1
TCLP Limits
(mg/L)
5.0
100.0
1.0
5.0
5.0
0.2
5.0
8 As original contaminant concentrations and process DREs were not always supplied, these leach data are not directly comparable. The
data are presented to show that, in general, vitrification products pass TCLP limits.
Penberthy Etectromelt International, Inc., vendor informat'on.
ฐ Harlow et al., 1989.
Farnsworth, Oma, and Bigelow, 1990.
unreinforced concrete. Table 6-19 compares the
compressive and tensile strengths of concrete to those
of ISV and joule-heated ceramic melter (JHCM)
products. The impact resistance of glassy and partially
devitrified waste forms produced by ex situ processes
also has been tested. In these tests, vitrified waste
forms shattered only under extreme conditions, such as
an impact of 80 mph. In addition, shattering increased
the surface area of the waste forms by a factor of only
about 40 and produced few particles smaller than 10 urn,
which could potentially disperse in air currents (Wicks,
1985).
Long-Term Durability
Natural glasses, such as obsidian and basalt, last
millions of years. It is impossible to measure directly the
long-term durability of a synthetic waste form, but kinetic
and thermodynamic modeling can be used to estimate
long-term durability. Kinetic models mathematically
describe the processes, such as ion exchange,
diffusion, and the formation of protective layers, that
affect the leaching behavior of a glass. Kinetic models
indicate that waste glasses should be very durable but
cannot predict which types of glass will be most durable.
The thermodynamic model estimates a glass's
teachability and loss of thickness based on its free
energy of hydration. This model predicts that the
durability of glasses produced by ISV ranges from 1,000
to 1 million years (Jantzen, 1988).
Volume Reduction and Density Increase
During vitrification, void gases and water are
evaporated, and organic materials are destroyed.
These processes decrease the volume and increase the
density of the vitrified waste. Volume reductions depend
on the type of waste and the technology used. For
example, ISV of soil produces a 25 to 45 percent
volume reduction, while microwave melter vitrification of
liquid and sludge wastes produces a 98 to 99.5 percent
Table 6-19. Compressive and Tensile Strengths of
Unreinforced Concrete and Glasses Produced by
ISV
Source of Waste Glass
ISV (50% sludge/50% soil)
ISV (20% sludge/10%
soil/70% liner)
JHCM
Unreinforced concrete
Compressive
Strength (psl)
59,350
43,210
43,210
3,000 - 8,000
Tensile
Strength (psi)
4,410
4,309
4,300
400-600
Source: Koegler et al., 1989.
reduction. The density of vitrified products ranges from
2.3 to 2.65 g/cm3 (Buelt et al., 1987), compared to 0.7
to 2.2 g/cm3 for products of conventional stabilization
technologies (Stegman et al., 1988).
6.5.4.2 Limitations
The effectiveness of ISV can be limited by
characteristics of the soil, such as high moisture content
and inadequate quantities of glass-forming constituents.
In addition, ISV is limited by depth constraints,
susceptibility to chemical attack, and relatively high
cost.
Depth Constraints
ISV has not been demonstrated to be effective at depths
of over 5 meters, and currently, 60 percent of all DOD
sites extend deeper than 5 meters. If ISV capability
could be extended to 9 meters, the technology could be
applied at 90 percent of the existing DOD sites. Depth
limitations result primarily from heterogeneous power
distribution within the melt. During field applications of
ISV, almost half of the power has been delivered to the
upper third of the melt, and less power has been
dissipated in the lower regions of the melt.
68
-------
Several potential methods for increasing the depth of
ISV have been identified, including using hot-tipped
electrodes, passive electrodes, or thermal barriers, and
starting the melt at the bottom of the contaminated area.
Hot-tipped electrodes would have tips made from highly
conductive material, such as molybdenum, or have
insulation covering the upper portion of their shafts.
Passive electrodes would be conductive iron-based
materials placed in the startup layer. When these
iron-based materials melted, they would settle to the
bottom of the system, directing current downward.
Thermal barriers placed next to the site would prevent
lateral dissipation of power and reflect heat downward.
The last option, starting the melt at the lower regions,
might be possible with the use of the electrode feed
system, which could mechanically raise and lower the
electrodes as necessary. The drawback to this method
would be that it could create a subsurface cavity that
might collapse and splash molten glass on the off-gas
treatment hood.
Potential for Devitrification
Devitrification, which is the formation of a nonglassy
crystalline structure in the waste form, can increase the
teachability of hazardous constituents from the waste
form (Spalding and Jacobs, 1989). Devitrification
usually occurs during cooling of the molten glass or after
the glass has cooled if, for some reason, the amorphous
glass structure crystallizes. If a waste form is reheated,
devitrification can occur as the waste form cools for a
second time. This is a concern because certain
radionuclides produce heat as they decay.
Chemical Attack
Vitrified waste forms are highly resistant to chemical
attack, but they can be broken down through matrix
dissolution and interdiffusion. Matrix dissolution is a
form of alkaline attack that begins with hydration of the
silica network and can proceed to dissolution of the
vitreous material. Interdiffusion, which is the primary
mechanism by which contaminants leach from a waste
form, is a form of acid attack. It is an ion exchange
process that preferentially extracts elements present as
network modifiers, leaving the silica structure almost
intact.
A waste form's resistance to chemical attack is
influenced by several factors:
Chemical composition. Waste forms with lower ratios
of oxygen to network formers have more bridging
oxygens and are more durable.
Waste loading. Higher waste loadings can increase
the durability of waste forms, due to the formation of
protective surface layers of waste constituents.
Time. Leachability generally decreases with time.
Temperature. Leachability is lower at lower
temperatures. The mechanism of attack also varies
with temperature: interdiffusion predominates at
ambient temperatures, and matrix dissolution
predominates at temperatures above 100ฐC.
pH. Acid attack decreases at high pHs; alkaline attack
decreases at low pHs.
6.5.5 References Cited
Armstrong, K.M. and L.M. Klingler. 1985. Evaluation of
a unique system for the thermal processing of
radioactive and mixed wastes. MLM-3340. EG&G
Mound Applied Technologies, Miamisburg, Ohio.
Buelt, J.L, C.L Timmerman, K.H. Oma, V.F. Fitzpatrick,
and J.G. Carter. 1987. In situ vitrification of
transuranic waste: an updated systems evaluation
and applications assessment. PNL-4800 Suppl. 1.
Pacific Northwest Laboratory, Richland, Washington.
Buelt, J.L., C.L. Timmerman, and J.H. Westsik, Jr. 1989.
In situ vitrification: test results for a contaminated
soil-melting process. PNL-SA-15767, Suppl. 1.
Pacific Northwest Laboratory, Richland, Washington.
Farnsworth, R.K., K.H. Oma, and C.E. Bigelow. 1990.
Initial tests on in situ vitrification using electrode
feeding technique. PNL-7355. Pacific Northwest
Laboratory, Richland, Washington.
Hansen, J.E. 1991. Treatment of heavy metal
contaminated soils by in situ vitrification. Presented
at the 4th Annual Hazardous Materials Management
Conference, Rosemont, Illinois, April 3-5, 1991.
Harlow, G.L., C.A. Whitehurst, H. Robards, D. Deville,
and B.V. Rao. 1989. Ash vitrificationa technology
ready for transfer. Presented to the American Society
of Mechanical Engineers.
In situ vitrification update. 1990. The Hazardous Waste
Consultant July/August.
Jantzen, C.M. 1988. Prediction of glass durability as a
function of environmental conditions. Materials
Research Society, Mat. Res. Soc. Symp. Proc. Vol.
125.
Klingler, L.M. and P.L. Abellera. 1989. Joule-heated
glass furnace processing of a highly aqueous
hazardous waste stream. MLM-3577. EG&G Mound
Applied Technologies, Miamisburg, Ohio.
Landau Associates. 1991. Report of engineering
consultation vitrification treatability study of
Northwest Transformer (Mission/Pole) Site, Everson,
Washington. Landau Associates, Inc., Edmonds,
Washington. Prepared for Northwest Transformer
Steering Committee.
69
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Plodinec, M.J., G.G. Wicks, and N.E. Bibler. 1982. An
assessment of Savannah River borosilicate glass in
the repository environment. DP-1629. Savannah
River Laboratory, Aiken, South Carolina.
Spalding, B.P. and G.K. Jacobs. 1989. Evaluation of an
in situ vitrification field demonstration of a simulated
radioactive liquid waste disposal trench.
ORNL/TM-10992. Oak Ridge National Laboratory,
Oak Ridge, Tennessee.
Stegman, J., P.L. Cote, and P. Hannak. 1988.
Preliminary results of an international
government/industry cooperative study of waste
stabilization/solidification. In: R. Abbou, ed.
Hazardous Waste: Detection, Control, and
Treatment. Elsevier Science Publishers B.V.,
Amsterdam, The Netherlands, pp. 1539-1548.
U.S. ATHAMA. 1988. U.S. Army Toxic and Hazardous
Materials Agency. Bench-scale glassification test on
Rocky Mountain Arsenal soil. AMXTH-TE-CR-87141.
U.S. ATHAMA, Aberdeen Proving Grounds,
Maryland.
U.S. EPA. 1987. U.S. Environmental Protection Agency.
Technical resource document: treatment
technologies for halogenated organic containing
waste. NTIS PB88-131271. U.S. EPA, Washington,
DC.
U.S. EPA. 1988. U.S. Environmental Protection Agency.
Technology screening guide for treatment of CERCLA
soils and sludges. EPA/540/2-88/004. U.S. EPA,
Washington, DC.
U.S. EPA. 1989. U.S. Environmental Protection Agency.
Stabilization/solidification of CERCLA and RCRA
wastes: physical tests, chemical procedures,
technology screening,
EPA/625/8-89/022. U.S.
Environmental Research
Ohio.
and field activities.
EPA, Center for
Information, Cincinnati,
Volf, M.B. 1984. Chemical Approach to Glass. Elsevier
Science Pub., New York, New York.
Wicks, C.G. 1985. Nuclear waste glasses. Treatise on
Materials Science and Technology, Vol. 26. ISBN
0-12-341826-7. Academic Press, Inc. pp. 57-117.
6.6 Polymer Solidification and
Encapsulation
6.6.1 Background
Many radioactive, hazardous, and mixed wastes are
considered to be "problem" wastes, because they are
difficult to solidify and encapsulate with conventional
technologies. This section describes two processes
conducted at the Brookhaven National Laboratory (BNL)
In Upton, New York, that encapsulate problem wastes in
thermoplastic materials: polyethylene (PE) encapsulation
and modified sulfur cement encapsulation. Both methods
have advantages over conventional hydraulic cement
solidification, which currently is used to solidify the majority
of the problem wastes generated by DOE and the
commercial sector. Waste solidification and encapsulation
methods Involving thermoplastic materials produce
durable waste forms that minimize the release of toxic
contaminants to the environment, comply with all
applicable regulatory criteria, and maintain these
characteristics under long-term storage or disposal
conditions. These methods also are simple to operate,
easy to maintain, and cost effective.
6.6.2 Treatable Wastes and Media
Because thermoplastic materials are inert, they do not
react with waste constituents during the solidification
process. As a result, solidification technologies involving
thermoplastic materials can be applied to a wide range
of waste types, including many radioactive wastes, such
as sodium nitrate, sodium sulfate, boric acid, incinerator
ash, and ion exchange resins.
Modified sulfur cement readily encapsulates certain
wastes that are particularly problematic for hydraulic
cement Mixed waste incinerator fly ash, for example,
typically has relatively high concentrations of metals,
such as zinc and lead, in the chloride form. While the
chemistry of hydraulic cement inhibits the encapsulation
of large quantities of this type of waste, sulfur cement
achieves relatively high waste loadings of these
compounds. Figure 6-9 compares the waste loadings of
several waste streams achieved by modified sulfur
cement and Portland cement.
6.6.3 Operation and Maintenance
During PE encapsulation, PE is mixed with waste
material, heated, and extruded into a waste drum by a
single screw extruder. Figure 6-10 is a drawing of a
Drun LMdtag (kg/M a* drum)
50 100 180
200
odium
Bottom Art
Indnwttor Fly Art
MO
WtHIIHIIHHimiU,
0 100 200 300 400
Drum LMdhtg (fe/H ซ! 4nm)
[Modified Sulfur E3 Hydraulic Cปmซnt
800
Wow MMni Mn nh ป.
Figure 6-9. Maximum waste loading of sodium sulfate, boric
add, bottom ash, and Incinerator fly ash In
modified sulfur cement and Portland cement
waste forms.
70
-------
full-scale PE extruder. The extruder is similar to
extruders used in the plastics industry, with one
modification: it has two dynamic feeders rather than a
single feed hopper. Figure 6-11 is a schematic of the PE
encapsulation process, showing the two hoppers that
feed the extruder. The two feeders allow waste and PE
to be extruded simultaneously. Each feeder can be
calibrated individually, however, to precisely monitor the
proportions of waste and binder. A full-scale extruder
can process 900 kilograms of mixed material per hour.
Once the material cools, the contaminants are
immobilized in a stable, homogenous, monolithic waste
form (see Figure 6-12).
Modified sulfur cement, developed by tie U.S. Bwxc
of Mines, is not a hydraulic cement but a thsmmopla-f:
material composed of 95 percent e'emsnia! suifur.'""
sulfur cement encapsulation process is similar to 1" .
for PE encapsulation. Unlike PE, Siwsver, c<'"
cement is not viscous when rnetec".. so if is
necessary to run the cement through &n extruder lo i
it with the waste. Instead, a double planetary orl-
mixer is used. Sulfur cement and waste are
the mixer, heated by oil bsth cireutelio
rotating blades, and drained by gravity
drum or mold. A hydraulic platen c"fi be
waste mixtures that resist gravity draining i
Upon cooling, the mixture forms >;. stab'
waste form.
":, mixe-
nto s. w-
,;30d to
itoih;? u
Figure 6-10. Drawing of full-scale extruder with 4.5-ln.
diameter screw.
6.6.4 Laboratory-Seal*
BNL has conducted full-scale feesibiiiiy testing -o
predict the long-term integrity of waste forms produced
by PE encapsulation. These tests examined the effect-
of water immersion and thermai eyeiing on tho
compressive strength of PE waste forms an-.-:
determined the radiation stability raclionuc!?o;-i
teachability, toxic teachability, and bioctegradability o?
PE waste forms. The following sections describe ths
results of this testing.
6.6.4.1 Compressive StswiigSih
Compressive strength, which indicates fchs mechanic:-..;
integrity of a waste form, rnay be compromised by
Dry Waste
Storage
Hopper
Polyethylene
Storage
Hopper
Teed Rale:
i.asoib/hr
Feed Rale:
Vent
Vacuum
Pump
Screw
Speed:
120 rpm
i i Extruder \
Zone 1 I Zone 2 \ Zono 3 \ Zone 4 I Zgne S
I I I I
Output: 1.BCO Ib/hr
Melt Temp: 300"F
Temp: 325*F
Press: 1,240 psi
Temp: 30CTF
Press: 0 psl
Temp:
Press: 380 ps
Temp: SOOT
Press: 2,000 psi
Temp: soo-p
Press: o psl
Figure 6-11. Schematic of PE encapsulation process showing two feed hoppers.
71
-------
Figure 6-12. Photograph of PE waste form.
water immersion and temperature fluctuations. In tests
conducted before and after a 90-day water immersion,
however, PE waste forms showed no significant
changes in compressive strength (see Figure 6-13). In
addition, temperature cycles between -40ฐC and 60ฐC
over a course of 150 hours did not significantly alter
the compressive strength of PE waste forms.
6.6.4.2 Radiation Stability
Exposure to ionizing radiation breaks down the
hydrocarbon chains in many thermoplastic materials,
weakening polymer structures and liberating hydrogen
gas. This is an obvious concern for a technology
developed to encapsulate radioactive wastes. In testing
at the BNL, exposure to radiation doses of up to 108 rad
increased cross linking of the hydrocarbon chains in PE
BO 60
Wnl* Loedlng (wt*)
UnlroUd E2I After Immersion
70
* 90-Diy Witor Imnwralon 1kซt;
ASTM D495 CodiprtMlv* Strength
Figure 6-13. Effect of water Immersion on compressive
strength of PE waste forms.
waste forms. The cross linking produced waste forms
that were stronger (see Figure 6-14), more stable under
thermal cycling, and more resistant to solvents, and had
lower teachability.
6.6.4.3 Toxic and Radionuclide Leachability
Leaching is the primary mechanism by which
contaminants are released to the environment from
material encapsulated in a waste form. The American
Nuclear Society's dynamic 90-day test (ANS 16.1) in
distilled water measures the relative radionuchde
teachability of different materials. The ANS 16.1
generates an index of teachability based on the
negative log of the waste form's effective diffusion
coefficient. PE waste forms have teachability indices
ranging from 7.8 to 11 on the ANS 16.1 scale (see
Figure 6-15). These indices are two to five orders of
magnitude higher than the minimum index suggested
by the Nuclear Regulatory Commission. Preliminary
data from EPA's 18-hour TCLP in acetic acid suggest
that PE waste forms have low toxic teachability as well.
(Because the teachability index [LI] is a negative
logarithm, the higher the LI, the better the performance
of the waste form.)
6.6.4.4 Biodegradability
PE is an organic material, so biodegradation under
microbial conditions is a logical concern. Attempts by
engineers to stimulate the biodegradation of PE in
landfills, however, have been largely unsuccessful. In a
3-week test for bacterial and fungal growth under ideal
conditionstemperatures of 35 to 37ฐC, humidity
greater than 85 percent, and an abundance of
nutrientsPE waste forms showed no microbial growth.
Since the conditions of this test were extremely
conservative, researchers expect that PE waste forms
will not biodegrade under ordinary disposal conditions.
72
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Control
Irradiation
Figure 6-14. Effect of exposure to 10s rad on compresslve
strength of PE waste forms.
so so
Waste Loading (wt%)
70
Sodium lซซch.blllty determined tiring
ANS K.I LMCh T*ซt
Figure 6-15. ANS 16.1 teachability indices of PE waste
forms containing sodium nitrate.
6.6.5 Advantages and Limitations
The advantages of using a solidification and
encapsulation process involving a thermoplastic
material rather than a hydraulic cement derive primarily
from the processes by which the two binder materials
solidify. Thermoplastic materials solidify as they cool,
usually in a matter of hours. Furthermore, thermoplastic
materials are inert, so they cannot react with waste of
any kind. By contrast, hydraulic cement takes days to
cure and solidify through a series of hydration and
chemical reactions. These reactions increase the
chance of chemical interaction between the waste and
the cement, which limits the amount and types of waste
that can be solidified and can compromise the integrity
of the final waste form.
Since PE melts at a fairly low temperature (120ฐC),
there is little risk of volatilizing contaminants or
radionuclides during mixing of the waste and binder. PE
has a relatively low density, making PE waste forms
significantly lighter than those made from hydraulic
cement. In addition, PE waste forms achieve waste
loadings as high as 70 percent by weight and 550 Ib per
drum for some waste streams, compared to just 20
percent and 200 Ib for Portland cement forms (see
Figure 6-16). This difference in loading can translate to
substantial cost savings. For example, the Rocky Flats
Plant in Golden, Colorado, which generates up to 1
million kg of sodium nitrate per year, could save
between $1.5 and $2.7 million by using PE
encapsulation instead of conventional technologies.
Figure 6-17 is an economic analysis for treatment of
nitrate salts at the Rocky Flats Plant, comparing the
expected costs of using PE and conventional
encapsulation.
The advantages of sulfur cement encapsulation over
hydraulic cement encapsulation are similar to those of
PE encapsulation. Like PE, sulfur cement does not
require a chemical reaction to set and attains full
strength within hours rather than days. In general, sulfur
cement waste forms have much higher waste loadings
than those of hydraulic cement waste forms, although
these loadings vary with the type of waste being
encapsulated. Sulfur cement waste forms have greater
compressive and tensile strengths and are highly
resistant to corrosion by acids and salt. Figure 6-18
shows Portland cement concrete and modified sulfur
cement concrete specimens after a 2-week exposure to
a solution of 10 percent hydrochloric acid. The Portland
cement sample was severely attacked, exposing the
quartz aggregate, whereas the sulfur cement sample
was unaffected.
An additional advantage of sulfur cement encapsulation
is that waste sulfur is in abundant supply from the
desulfurization of incinerator flue gas and the cleanup
of petroleum products. Currently, most of this supply,
which is expected to increase to 30 million tons per year
by 2000, is disposed of as waste. Therefore, sulfur
cement encapsulation essentially uses one type of
waste to encapsulate another. The price of sulfur is
about 13 cents/lb, but this is expected to drop as supply
increases.
6.7 In Situ Grout Injection
6.7.1 Background
In situ grout injection contains waste material in a solid
monolith by mixing it with cement grout, thereby
increasing the waste's physical stability and
compressive strength, decreasing water intrusion to the
waste, and decreasing the teachability of waste
constituents. This section discusses the applicability of
in situ grout injection for radionuclides, describes the
grout injection process and the mechanisms by which
grouts contain waste, and discusses the advantages
and limitations of the technology.
6.7.2 Treatable Wastes and Media
In general, in situ grout injection can be considered at
any site from which wastes cannot be removed, but
73
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Encapaulallon Matrix
P
-------
Figure 6-19. Grout Injection apparatus.
Figure 6-21. Grout Injection system with In situ mixer.
Figure 6-20. Row of grout from bottom of grout Injection
pipe.
Of the many types of grout available, cement-based
grouts are the most common, for several reasons. First,
materials for cement-based grouts, such as cement, fly
ash, and blast furnace slag, usually are available within
150 miles of any site, making cement-based grouts
relatively inexpensive. Second, cement-based grout is
a proven material. The construction industry has
extensive experience with in situ grouting and has
shown that cement-based grouts can withstand extreme
natural forces.
6.7.3.2 Containment Mechanisms
The mechanisms by which grouts contain hazardous
wastes are not fully understood, because the crystalline
structure of the cement-waste matrix is morphologically
Figure 6-22. Monolith formed by overlapping grout columns.
complex and incorporates a diverse array of elements. As
a result, modern instruments have difficulty locating trace
concentrations of waste constituents within the matrix.
Nevertheless, some mechanisms of containment have
been identified. These include adsorption, particularly of
organics and gamma pellet clays; precipitation,
especially of metals as hydroxide in cements with pHs
between 9.5 and 11; encapsulation, whereby wastes
are physically coated and surrounded by cement; and
ion exchange, passivation, and diadochy. The ability of
these mechanisms to contain a contaminant species
depends on the contaminant's pH, solubility constant,
equilibrium constant, and redox potential in the pore
water. In some cases, contaminants may need to be
reduced to less soluble states prior to grout injection.
Figure 6-23 shows the general chemistry of cement
formation. A series of reactions leads to the formation
and collapse of an ettringite structure, followed by the
formation of a concrete-like calcium silica hydrate
(CSH) structure. The grouted waste is not identical to
concrete, because waste constituents affect the set and
phase structure of the cement. Due to the similarity
75
-------
between concrete and grouted wastes, however, the
flow of grouted waste is very predictable and can be
modeled. Rgure 6-24 shows flow behavior of grout at
two different densities.
6.7.4 Advantages and Limitations
6.7.4.1 Advantages
The ability of the monolith to resist leaching is its most
important feature. The ANS's 16.1 test assigns a
teachability index to a structure based on the negative
Ctnwnt Grains
Figure 6-23.
General chemistry of cement formation,
showing growth and collapse of ettrlnglte
structure, followed by growth of CSH structure.
1.0
s
I 1.0
u
i
0.1
0.05-m-ID PIPE
Density 1
I
I
0 0.2 0.4 0.6 0.8 1.0
Bow Behavior Index, T|'
Figure 6-24. now behavior of grout at two different
densities.
log of its effective diffusion coefficient. Figure 6-25
shows the total releases over time, and Figure 6-26
shows the annual rates of release, from two
hypothetical structures with teachability indices of 11
and 13. These indices are typical for metals; organics
tend to leach at rates four to seven orders of magnitude
higher.
Cost is another advantage of in situ grout injection.
Although the initial capital costs for batch or surface
processes often are less than those for in situ
processes, the total costs for batch and surface
processes, including transportation and disposal, tend
to be greater.
Grouts can be formulated to set very quickly. This is an
advantage at sites, such as solar ponds, that essentially are
open pits. Within a day, previously grouted areas become
a platform for further grout injection operations. The injection
apparatus also is fairly small and portable, so it can be
maneuvered into sites with tight space constraints.
Figure 6-25. Releases over time from structures with ANS
16.1 teachability Indices of 11 and 13.
127 190
Time (Yean)
Figure 6-26. Releases per year from structures with ANS
16.1 teachability Indices of 11 and 13.
76
-------
6.7.4.2 Limitations
Because the technology operates in situ, process
control is relatively poor and it is difficult to verify that
the grout actually contained the waste. Rigorous
verification involves digging up the perimeter of the
grouted area. In addition, in situ grouting does not lend
itself to waste retrieval, so it is not a good choice for
DOE sites from which wastes may have to be retrieved
after 30 or 40 years.
Cement-based grouts have some specific disadvantages.
First, injection of a cement grout creates a volume
increaseonce the grout fills the available voids, it returns
to the surface as berm. Second, since cement is
paniculate, it can flow only to soil pores of sufficient
size. The first two or three injection holes at any site
usually are test holes to determine how much grout the
soil uptakes. Third, cement-based grouts have limited
application. Cement-based grouting is a BOAT for a
variety of metals but not for organic wastes.
6.8 Electrokinetic Soil Processing
6.8.1 Background
Electrokinetic soil processing (variably known as
electrokinetic remediation, electromigration, or
electrochemical decontamination) uses electric current
to decontaminate soils and slurries that contain
radionuclides, heavy metals, certain organic compounds,
or mixed organic and inorganic wastes (Acar, 1992; Acar
and Named, 1991; Acar et al., 1993c; Banarjee et al.,
1990; Bruel et al., 1990; Named et al., 1991; Kelsh,
1992; Lageman, 1989; Pamukcu and Wittle, 1992;
Probstein and Hicks, 1993; Runnels and Wahli, 1993;
Renauld and Probstein, 1987; Runnels and Larsen,
1986; Shapiro and Probstein, 1993; Shapiro et al.,
1989; Wittle and Pamukcu, 1993). The application of
electric current has several effects: (1) it produces an
acid in the anode compartment that sweeps across the
soil and desorbs contaminants from the surface of soil
particles (Acar et al., 1991; Aishawabkeh and Acar,
1992), (2) it initiates electromigration of different species
toward the respective electrodes (Acar and Aishawabkeh,
1993), and (3) it generates an electric potential difference
that can lead to electroosmosis-generated flushing of
different species (Acar et al., 1993b; Acar et al., 1989;
Aishawabkeh and Acar, 1992). This section provides an
overview of electrokinetic phenomena in soils, outlines
the types of waste and media to which electrokinetic soil
processing can be applied, examines some potential
environmental uses of electrokinetic soil processing,
discusses bench- and pilot-scale testing of the
technology, and looks at current research on different
techniques that may improve the technology's
effectiveness.
Electrokinetic soil processing is a controlled application
of electroosmosis and electrical migration together with
electrolysis reactions. Electroosmosis is one of several
transport processes induced in soils by an electric
current. Electroosmosis and electrophoresis are defined
as the mass flux of pore fluid and charged particles,
respectively, under an electric field. Figure 6-27 depicts
electroosmosis. The fluid in the anode compartment
flows across the soil mass to the cathode compartment
under an electric field. This flow ceases when the
counteracting flux under the hydraulic gradient
becomes equal to the electroosmotic fluid flux. Figure
6-28 depicts electrophoresis through transport of
negatively charged particles toward an anode under an
electric field.
Pore fluid between soil grains moves toward the
cathode, because most soils have a negative charge on
their surface. This charge is due mostly to imperfections
in the mineral produced during its formation as elements
of similar size and kind replace the ones in the mineral
lattice. The charge deficiency also may be caused by
broken edges or the existence of natural organic
species in the soil mass. The excess negative charge
exists in all soils, and the total electrical charge per unit
surface area (surface charge density) increases as the
specific surface of the soil mineral increases. The
surface charge density increases in the following order:
sand < silt < kaolinite < monmorillonite.
The interaction of the pore fluid ions with the negatively
charged soil surface results in alignment of the ionic
species as depicted in Figure 6-29. The excess
negative charge on the soil surface attracts and
clusters excess cations close to the surface, while a
neutrality of charge in the pore fluid is maintained by
a corresponding concentration of negative species
away from the soil surface. When an electric field is
established along the capillary, cations close to the
surface move towards the cathode, thereby imparting
a strain on the pore fluid surrounding their shells,
DC Current/Voltage
Figure 6-27. Electroosmotic (low of pore fluid In saturated
soil.
77
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which results in a pore fluid flux towards this electrode.
The thicker the zone with the excess cations, the
greater the electroosmotic flow will be. The thickness of
this zone, however, depends upon the electronegativity
of the soil surface, the concentration of ions in the pore
fluid, the valence of the cation, and the dielectric
properties of the pore fluid. When the ionic
concentration increases, the thickness of this layer
decreases, and the net momentum imparted by the
migrating cations and anions decreases. As a result,
electroosmotic advection substantially decreases or
ceases.
Ionic species in the pore fluid are transported across the
soil mass even when electroosomotic transport ceases
(Acar, 1992; Acar and Alshawabkeh, 1994; Acar et al.,
1993c). This movement of ionic species is at least an
order of magnitude faster than transport of species by
diffusion or electroosmotic advection and is one of the
reasons why electrokinetic soil processing is a
cost-effective means of extracting species from soils.
aocjoft
Figure 6-28. Electrophoresls of negatively charged particles
toward the anode.
Electrokinetic soil processing involves not only ionic
migration and electroosmotic advection but also
electrolysis reactions generated at the electrodes (Acar
et al., 1990; Acar et al., 1991; Alshawabkeh and Acar,
1992). Figure 6-30 shows the transport of the
hydronium (protons) and hydroxyl ions generated at the
electrodes by the electrolysis reactions. In unenhanced
electrokinetic soil processing, the protons migrate
across the soil mass and meet the hydroxyl ions close
to the cathode compartment, generating water within
that zone and decreasing ionic conductivity. The sweep
of this acid front across the soil mass also assists in
desorption of the cationic species concentrated close to
the soil surface. Figure 6-31 depicts the removal of lead
from a soil capillary and its electrodeposition on the
cathode and precipitation close to the cathode at its
hydroxide solubility value. The hydrogen ion generation
and transport can be used as an acid washing process
in electrokinetic soil processing, if desired.
6,8.2 Treatable Wastes and Media
Electrokinetic soil processing can be used to treat soils
contaminated with the following species: lead (Hamed
et al., 1991); cadmium (Acar et al., 1993c);
radionuclides (Acar et al., 1993b), such as uranium,
thorium, and radium; polar organic species, such as
phenol (Acar et al., 1992) and nitrophenol (Wittle and
Pamukcu, 1993); and nonpolar organic species, such
as BTEX compounds below the solubility values (Bruel
et al., 1990). The applicability of the technique to
nonpolar organic species by different surfactant
enhancements is under investigation (Acar et al.,
1993b). This application requires the introduction of a
conditioning fluid at the electrodes and relies upon
conductance of current across the electrodes through
the pore fluid. Electroosmotic flow is shown to saturate
a soil mass in case partially saturated conditions are
encountered.
O O O 0 O O O O O 9 9
0******ฉ10**-**-0*
0
* ซr
- - * ป
**ฉปฉ 0*0
0
Velocity
Profile
0
Figure 6-29. Diagram of advection by electroosmosls,
depicting the excess cations at the clay
surface and the resulting velocity profile
across the soil capillary.
Anode
Cathode
M$*ฉ
Figure 6-30. Migration of ionic species and colloids under
an electric field.
78
-------
Figure 6-31. Schematic of protons displacing lead from the soil surface and the transport of both protons and lead toward the
anode compartment
6.8.3 Operation and Maintenance
A diagram of electrokinetic soil processing is shown in
Figure 6-32. Anode and cathode series are inserted or
laid on the ground, and a current is established across
the electrodes. A conditioning fluid is circulated at the
electrodes, serving both as a conducting medium and
as a means to extract and exchange the species.
Another use of this conditioning fluid is to control and/or
depolarize the cathode reaction so that the base
generated does not lead to premature precipitation of
the incoming species at their hydroxide solubility values.
The movement of the acid and/or the conditioning fluid
across the electrodes assists in desorption of species,
as well as dissolution of carbonates and hydroxides.
Electroosmotic advection together with ionic migration
assists in the transport and removal of contaminant
species. Some species electrodeposit on the
electrodes; others are extracted through the use of
chemical processes or ion exchange systems within the
process control container.
6.8.4 Bench- and Pilot-Scale Applications
6.8.4.1 Bench-Scale Studies
The following is a brief summary of the results of some
of the bench-scale work using electrokinetic soil
processing to treat specimens containing lead,
cadmium, uranium, and phenol.
Figure 6-32.
Schematic of electrokinetic soli processing,
showing the migration of ionic species and the
transport of the acid front and/or pore fluid
across the processed medium.
Lead
Figure 6-33 presents the lead profile in lead-spiked
kaolinite specimens after electrokinetic soil processing.
Lead is redistributed across the specimen in shorter
duration tests mainly due to the desorption in the anode
compartment by the advancing acid front and
reprecipitation close to the cathode. In longer duration
tests, however, the lead is removed from the cell due to
the sweep of the acid across the specimen and the
prevailing electromigration of lead. The energy
79
-------
expended to decontaminate the specimen in these tests
varied from 30 to 60 kilowatt hours per cubic meter
(kWh/m3). This translates to an electrical cost of roughly
$1.50 to $3.00 per m3. Lead is efficiently removed from
spiked kaolinite specimens at concentrations of up to
1,500 ug/g (Hamed et al., 1991). In all the tests, most
of the lead precipitates on the cathode.
Cadmium
Figure 6-34 shows the results of experiments conducted
in investigating cadmium removal at a concentration of
about 100 ug/g from spiked kaolinite specimens. The
cadmium was found to electrodeposit on the cathode or
precipitate on the cathode as cadmium hydroxide (Acar
etal., 1993c).
Symbol Charge Concentration
A-h/mซ H9/9
388
362
B t,34S
O 1,483
O 1,982
143.7
133.8
145.0
122.9
117.5
A
0 0.2 0.4 0.8 0.8 1
Normalized Distance from Anode
Figure 6-33. Lead removal across the specimens. Closed
symbols represent shorter duration tests with
lower charge input to specimens (Hamed et al.,
1991).
Uranium
Uranium removal has been investigated by running
unenhanced remediation tests in uranyl nitrate-spiked
kaolinite specimens. The results are presented in Figure
6-35. The precipitate close to the cathode compartment
is uranium hydroxide. This premature precipitation of
the migrating ions when confronted with the hydroxide
ions generated at the cathode is one reason why a
conditioning fluid is needed (Acar et al., 1993b).
Phenol
Phenol removal also has been investigated after spiking
kaolinite specimens with 500 ng/g of phenol (Acar et al.,
1992). The results are presented in Figure 6-36. The
effluent concentration is presented as a function of pore
volumes of flow. Most of the phenol in the kaolinite
specimens is removed in two pore volumes of flow.
Phenol is one of the easier organics to remove by
electrokinetic soil processing because it is miscible and
it protonates in an acid to produce positively charged
species. Thus, phenol functions just as any other
cationic species, in its removal by electroosmotic
advection, electromigration, and the protonation
generated by the acid front. An energy expenditure of
only 10 to 30 kWh/m3 was sufficient to remove 95
percent of the phenol in the specimen.
6.8.4.2 Pilot-Scale Studies
In collaboration with the U.S. EPA Risk Reduction
Engineering Laboratory (RREL), the Louisiana State
University group is conducting pilot-scale studies of
electrokinetic soil processing both in the laboratory and
at a site in Baton Rouge, Louisiana. Laboratory studies
indicate that lead is removed from specimens of
kaolinite at an energy cost of about $15 per m3 within
a period of 3 months. At the site, lead concentrations at
CD(II) Removal Efficiency
0.2
0.4 0.6
Normalized Dittance from Anode
Figure 6-34.
Cadmium removal In spiked kaolinite
specimens (Acar et al., 1993c).
0.2
0.4 0.6 0.8
Normalized Distance from Anode
Figure 6-35. Uranyl removal in uranyl nitrate-spiked
kaolinite specimens. Open symbols represent
shorter duration tests (Acar et al., 1993b).
80
-------
500 tig/8 Phenol In Kaollnlta
Kaol!n!tecซป1,000|ig/g
1 2
Pore Volumw ot Row
Figure 6-36. Phenol concentration profile In the effluent In
spiked kaollnlte specimens (Acar et al., 1992).
one location are as high as 100,000 u.g/g. These high
concentrations, together with the presence of shells
rendering calcium concentrations of up to 90,000 u.g/g,
are the major obstacles to the efficiency of electrokinetic
processing of the soil at the site. Migration and
precipitation of calcium as bicarbonates and hydroxides
clog the soil pores and prevent the transport of lead.
The presence of calcium increases by 10 times the
amount of acid necessary to remove the lead. At
locations where calcium concentrations are lower (10,000
(ig/g) and shells are not encountered, bench-scale
studies demonstrate that lead can be successfully
removed by unenhanced and enhanced remediation
(Acar et at., 1993a). The pilot-scale studies are run at a
current of up to 800 uA/cm2 across electrodes placed 2-
to 4-m apart.
Pilot-scale field studies also have been reported in the
Netherlands on soils contaminated with lead, arsenic,
nickel, mercury, copper, and zinc (Lageman et al.,
1989). In one study, the process removed 75 percent of
the lead from fine sand with an initial concentration of
9,000 ppm. Another study achieved a 90 percent
removal of arsenic from clay with an initial concentration
of 300 ppm. Both of these studies used energy levels
of 60 to 200 kWh/m3 and involved chemical conditioning
of the anolyte and the catholyte.
6.8.4.3 Studies on Chemical Conditioners
The effects of injecting chemical conditioners at the
anode and the cathode currently are being investigated
(Acar et al., 1993a). These conditioners can modify the
chemical reactions that take place at the electrodes and
enhance the effectiveness of the system. For example,
acetic acid depolarizes the reaction at the cathode and
prevents base formation. When acetic acid is added, the
main reaction becomes the reduction of proton and the
evolution of hydrogen. Acetate anions also migrate into
the system, solubilizing contaminant species. In one
test, acetic acid successfully solubilized uranium at
1,000 ppm. Instead of collecting at the cathode as a
solid precipitate, uranium was solubilized and removed
in the effluent.
Similar studies are being conducted on clays
contaminated with thorium at concentrations of 1,500 to
2,000 u.g/g. Thorium has four charges and adsorbs very
strongly onto clay. Researchers expect that conditioning
the cathode with acetic acid will allow thorium to be
removed at high levels by preventing the formation of
upstream base, which blocks the pores of the clay.
Chelating agents are another type of chemical
conditioner used to solubilize specific contaminants.
Currently, researchers are trying to identify a chelating
agent to solubilize radium, which ordinarily forms a
highly insoluble sulfate that intercalates with the clay
structure. As a result, radium resists electrokinetic
removal in bench-scale studies, even at 1 ppb and as
many as 3 pore volumes of acid flow. To remove radium,
a chelating agent also could be used to process the
media with mixed radionuclides, such as radium,
strontium, and thorium. Alternatively, radium-contaminated
media could be flushed with ammonium ions instead of
with acid.
The impact of micelles on the removal of polar organic
compounds, such as hexachlorobutadiene is being
studied (Acar et al., 1993b). A micelle is a charged
particle that is nonpolar on the inside. These particles
desorb polar organic contaminants, allowing them to be
flushed from the soil. Preliminary results suggest that
injecting positively charged micelles at the cathode
increases electrokinetic removal of such organic wastes.
6.8.5 Advantages and Limitations
The primary advantage of this technology is the
potential for many in situ applications. Electrokinetics
has several potential applications in waste
management. Besides enhancing chemical migration,
the technique can be employed in implementing
electrokinetic flow barriers; diverting plumes; detecting
leaks; and injecting chemicals, grouts, microorganisms,
and nutrients to subsurface deposits.
The fact that the technique requires a conducting pore
fluid in a soil mass could be considered a shortcoming,
particularly at sites where there are concerns about
introducing an external fluid into the soil. In addition, the
technique has been demonstrated to be successful at
electrode spacings of only 6 to 10 m. Large-scale
applications will require that several electrodes be
placed across a site.
81
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6.8.6 References Cited
Acar, Y.B. 1992. Electrokinetic soil processing: A review
of the state of the art. ASCE Grouting Conference,
February 1992. ASCE Special Publication No. 30,
Vol. 2. 1420-1432.
Acar, Y.B. and A. Alshawabkeh. 1994. Modeling
conduction phenomena in soils under an electric
current. Proceedings of the Fifteenth International
Conference on Soil Mechanics and Foundation
Engineering, New Delhi, India. January 1994. In
press.
v
Acar, Y.B. and A. Alshawabkeh. 1993. Principles of
electrokinetic remediation. Environmental Science
and Technology. In press.
Acar, Y.B. and J. Hamed. 1991. Electrokinetic soil
processing in remediation/treatment: Synthesis of
available data. Bulletin of Transportation Research,
Record No. 1312. Geotechnical Engineering 1991.
152-161.
Acar, Y.B. and R.J. Gale. 1992. Electrbktnetic
decontamination of soils and slurries. U.S. Patent No.
5,137,608. Commissioner of Patents and
Trademarks.'Washington, DC. August 11', 1992.
Acar, Y.B., S. Puppala, R. Marks, R.J. Gale, and M. Bricka.
1993a. An investigation of selected enhancement
techniques in electrokinetic remediation. U.S. Army
Corps of Engineers. Waterways Experiment Station.
Electrokinetics, Inc. Baton Rouge, Louisiana. Report
hi preparation.
Acar, Y.B., A. Alshawabkeh, and R.J. Gale, 1993b.
Fundamental aspects of extracting species from soils
by electrokinetics. Waste Management 12(3).
Pergamon Press, New York, 1410-1421.
Acar, Y.B., J. Hamed, A. Alshawabkeh, and R.J. Gale.
1993c> Cadmium removal from soils by
electrokinetics. Geotechnique. London. In press.
Acar, Y.B., R.J. Gale, G. Putnam, and J. Hamed. 1989.
Electrochemical processing of soils: Its potential use in
environmental geotechnology and significance of pH
gradients. Proceedings of the Second International
Symposium on Environmentaf Geotechnology, Voi. 1.
Shanghai, China, May 14-17, 1989. Envo Publishing,
Bethlehem, Pennsylvania. 25-38.
Acar, Y.B., R.J. Gale, and G. Putnam. 1990.
Electrochemical processing of soils: Theory of pH
gradient development by diffusion and linear
convection. Journal of Environmental Science and
Health. Environmental Science and Engineering
25(6): 687-714.
Acar, Y.B., J. Hamed, R.J. Gale, and G. Putnam. 1991.
Acid/base distribution in electroosmosis. Bulletin of
Transportation Research, Record No. 1288. Soils
Geology and Foundations. Geotechnical Engineering
1990. 23-34.
Acar, Y.B., H. Li, and RJ. Gale. 1992. Phenol removal
from kaolinite by electrokinetics. Journal of
Geotechnical Engineering 188(11): 1837-1852.
Alshawabkeh, A. and Y.B. Acar. 1992. Removal of
contaminants from soils by electrokinetics: A
theoretical treatise. Journal of Environmental Science
and Health 27(7): 1835-1861.
Banerjee, S., J. Homg, J.F. Ferguson, and P.O. Nelson.
1990. Field scale feasibility of electrokinetic
remediation. Report presented to U.S. EPA Risk
Reduction Engineering Laboratory Land Pollution
Control Division.
Bruel, C.J., BA Segall, and H.T. Walsh. 1990.
Electroosmotic removal of gasoline hydrocarbons
and TCE from clay. Journal of Environmental
Engineering 188(1): 84-100.
Bjerrum, L., J. Mourn, and O. Eide. 1967. Application
of electroosmosis on a foundation problem in a
Norwegian quick day. Geotechnique 17(3): 214-235.
Casagrande, L. 1983. Stabilization of soils by means of
electroosmosis: State of the art. Journal of the Boston
Society of Civil Engineers (93): 209-236.
Esrig, M.I. 1968. Pore pressures, consolidation, and
electrokinetics. Journal of Soil Mechanics and
Foundation Division, Vol. 94, No. SM4, 899-921.
Gray, D.H. and J.K. Mitchell. 1967. Fundamental
aspects of electroosmosis in soils. Journal of Soil
Mechanics and Foundation Division, Vol. 93, No.
SM6, 209-236.
Hamed, J., Y.B. Acar, and RJ. Gale. 1991. Pb(ll)
removal from kaolinite using electrokinetics. Journal
of Geotechnical Engineering (112): 241-271.
Kelsh, D., Ed. Proceedings of the Electrokinetics
Workshop. Atlanta, Georgia. January 22-23, 1992.
Office of Research and Development. U.S.
Department of Energy.
Lageman, R., P. Wieberen, and G. Seffinga. 1989.
Electro-reclamation: Theory and practice. Chemistry
and Industry (9): S85-590.
Mitchell, J.K. and T.C. Yeung. 1991. Electrokinetic flow
barriers in compacted clay. Bulletin of Transportation
Research, Record No. 1288. Soils Geology and
Foundations. Geotechntcal Engineering 1990,1-10.
Pamukcu, S. and J.K. Wittle. 1992. Electrokinetic
removal of selected heavy metals from soil.
Environmental Progress 11(3): 241-250.
82
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Probstein, R.F. and R.E. Hicks. 1993. Removal of
contaminants by electric fields. Science 260:
498-504.
Runnels, D.D. and C. Wahli. 1993. In situ
electromigration as a method for removing sulfate,
metals, and other contaminants from ground water.
Ground Water Monitoring Review, 11(3): 121.
Renauld, P.O. and R.F. Probstein. 1987. Electroosmotic
control of hazardous waste. Physicochemical
Hydrodynamics 9(1/2): 345-360.
Runnels, D.D. and J.L. Larsen. 1986. A laboratory study
of electromigration as a possible field technique for
the removal of contaminants from ground water.
Ground Water Monitoring Review, 81-91.
Shapiro, A.P. and R.F. Probstein. 1993. Removal of
contaminants from saturated clay by electroosmosis.
Environmental Science and Technology 27(2):
283-291.
Shapiro, A. P., P. Renault, and R.F. Probstein. 1989.
Preliminary studies on the removal of chemical
species from saturated porous media by
electroosmosis. Physicochemical Hydrodynamics
11(5/6): 785-802.
Shmakin, B.M. 1985. The method of partial extraction
of metals in a constant current electrical field for
geochemical exploration. Journal of Geochemical
Exploration 23(1): 35-60.
Wittle, J.K. and S. Pamukcu. 1993. Electrokinetic
treatment of contaminated soils, sludges, and
lagoons. Final Report to Argonne National
Laboratory. Electro-Petroleum, Inc. Wayne,
Pennsylvania.
83
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Appendix A
A-1
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SEARCH FOR A WHITE PHOSPHORUS MUNITIONS DISPOSAL SITE IN CHESAPEAKE BAY1
Gary Buchanan, International Technology Corporation, Edison, New Jersey
Harry Compton, Environmental Response Team, U.S. EPA, Edison, New Jersey
John Wrobel, U.S. Army Environmental Center, Aberdeen Proving Ground, Maryland
EXECUTIVE SUMMARY
The White Phosphorus Munitions Burial Area (WPMBA) is located in the Chesapeake Bay within the confines
of the restricted waters of the U.S. Army Base at Aberdeen Proving Ground (APG). This investigation was
designed to determine the exact location of the WPMBA and determine the impacts upon the surrounding
ecosystem. The lack of any records from the period of disposal (1922-1925) has exacerbated the problem of
locating the site. The present assumed location of the site is based on information obtained from former
employees, and the designation of this area as the "Phosphorus Area Unit" by President Roosevelt in 1940 as part
of the Migratory Bird Treaty Act. The exact number of munitions, the volume of white phosphorus, and the exact
location of the original disposal site are all unknown.
Several techniques have been used during this investigation to determine the location of the WPMBA. A search
was conducted to locate related information concerning the disposal, storage, and handling of white phosphorus.
Aberdeen Proving Ground records, historical maps and aerial photos were reviewed. Manufacturers, former
employees, and historians (National Archives, Library of Congress, U.S. Army Archives) were also contacted for
relevant information. A geophysical investigation at the site was also conducted.
An initial geophysical survey was conducted during October of 1988 within the WPMBA. A coarse grid was
developed to screen the area with an underwater proton magnetometer. Discrete areas exhibiting numerous or
extremely large gamma changes were investigated in a second survey. Based on a review of the data, the area
adjacent to Black Point was selected for a more intensive study during June of 1989.
Based on the geophysical data four areas were selected for sediment core analysis to determine if a burial site
existed. A fifth area, the channel adjacent to the WPMBA, was selected for coring due to maintenance dredging
concerns. A reference area was also selected north of the site in Spesutie Narrows. The coring was conducted
during August of 1989 in each of the five areas. Due to the safety concerns in dealing with the burial area and
the known presence of unexploded ordnance on APG, a remote coring operation was necessary. An EPA work
barge was retrofit to perform the remote coring.
A total of 60 cores were obtained, ranging in depth from 1 to approximately 9 feet. Cores were screened on-site
for high explosives using a Scan X Jr. portable gas chromatograph and composite samples were collected for
analysis. All samples were analyzed for elemental phosphorus, high explosives, and RCRA analyses. Select
samples were analyzed for total organic carbon, grain size, and toxicity testing.
Water samples were also collected at each of the areas cored and analyzed for elemental phosphorus and high
explosives. Water quality measurements were recorded in each area and included temperature, pH, conductivity,
salinity, oxidation-reduction potential, and dissolved oxygen.
Gull Island which is located along the eastern border of the WPMBA was examined as a potential disposal site.
A proton magnetometer and metal detectors were used to survey the island for ferrous metals. Several test pits
were excavated to examine the stratigraphy and soils of the island. Soil cores were collected from two locations
on the island and analyzed for elemental phosphorus, high explosives, and grain size.
The results of the investigation indicate that white phosphorus was detected in 11 of the 60 core samples at
concentrations less than 5 ug/kg. No white phosphorus was detected in the water column. No high explosive
'Reprinted from the Proceedings of the U.S. EPA Forum on Remediation of Superfund Sites Where Explosives
Are Present, December 1989, San Antonio, Texas.
A-2
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QUADRANGLE LOCATION
1000 2000 3000 4000 MOO 6000 7000 '1C
A-3
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compounds were detected in the water or sediment samples. RCRA analyses indicate that the sediment cores
would not be considered a hazardous waste. Definitive boundaries for the WPMBA could not be determined due
to the diffuse and isolated nature of the contamination. No impacts upon the aquatic ecosystem are expected.
Release of White Phosphorus are not expected unless the sediments are disturbed.
1.0 INTRODUCTION
This investigation concentrated on determining the presence, location and characteristics of the White
Phosphorus Munitions Burial Area (WPMBA). The WPMBA is located in the Chesapeake Bay (Figure 1)
within the confines of the restricted waters of the U.S. Army Base at Aberdeen Proving Ground (APG),
Maryland.
This investigation was conducted as part of a Resource Conservation and Recovery Act (RCRA) Corrective
Action Permit Condition. This Permit Condition required that the Permittee (APG) conduct a RCRA
Facility Assessment (RFA). The primary purpose of the RFA is to insure the burial area is studied and any
released wastes are identified and evaluated.
The Aberdeen area of this base was established in 1917 as the Ordnance Proving Ground. It became a
permanent military post in 1919 and was designated Aberdeen Proving Ground. Testing of ammunition was
begun in January of 1918 (Weston, 1978). Two other major additions to the base occurred. Spesutie Island
was acquired in 1945 and the Edgewood portion of the facility merged with APG in 1971.
The open water areas of APG total approximately 37,000 acres (15,000 hectares). Large segments have been
used as ordnance impact areas since 1917. There are an estimated four million unexploded and sixteen
million inert projectiles of all calibers in these restricted waters (USATHAMA, 1980).
The WPMBA is located on the western side of the Upper Chesapeake Bay. The area is situated in the
shallow waters off the mouth of Mosquito Creek, between Black Point and Gull Island. Spesutie Narrows
and Spesutie Island lie to the north and northeast, respectively. The WPMBA is adjacent to and offshore
of the Main Front Land Range Area which has been active since 1917. An estimated one million rounds of
all calibers up to 16 inches have been fired at this range. The types of rounds fired included high explosives,
anti-personnel, armor defeating, incendiary, smoke, and illuminating (USATHAMA, 1980). Although the
WPMBA is adjacent to this range, discussions with APG personnel have indicated that there are no records
of the open water areas of the WPMBA having been used as an impact area. The closest active range is the
Ballistics Workshop located just north of the WPMBA. The WPMBA lies partially within the 1800 ft (550
m) safety clearance of this range. The Fuze Range, another active range, is located to the east of the
WPMBA.
Based on interviews of former employees who worked on the base following World War I (WWI) the
existence of the WPMBA was discovered in the late 1970's. Reportedly, an unknown amount of WWI white
phosphorus (WP) munitions were buried in Chesapeake Bay in the area of Black Point during the period
1922-1925. The ordnance supposedly consisted of U.S., British, and French land mines, grenades, and
artillery shells. Bulk phosphorus may also have been disposed of here. It is possible that this disposal event
involved a single barge load of munitions; however it may have involved considerably more.
The site is located within Chesapeake Bay, a major estuarine ecosystem. Numerous species of fish utilize
the bay during various stages of their life cycle. Up to 65 species of fish have been identified in the waters
at APG and the adjacent Upper Chesapeake Bay waters (Miller, Wihry, & Lee, Inc., 1980). Several
commercially and recreationaUy important species utilize the area, including striped bass (Morone saxatilis)
and the blue crab (Callinectes sapidus) (USATHAMA, 1980). Aberdeen Proving Ground also lies in the
pathway of the Atlantic Flyway, resulting in an abundance of migratory waterfowl. Due to the toxicity of
white phosphorus, releases from the WPMBA could impact these resources within Chesapeake Bay. Fish
are especially sensitive to concentrations of WP in the water column. It is important, therefore, to determine
whether aquatic organisms and other wildlife are being exposed to WP.
A-4
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BLACK
POINT
WHTTE PHOSPHORUS MUNITIONS
BURIAL AREA
FIGURE 1 /.
WHITE PHOSPHORUS MUNITIONS /
BURIAL AREA / /
ABERDEEN PROVING GROUND. MD
i
CHESAPEAKE BAY
C'5' /.;
MVMX. SCALE
v - asr
X X
X X
LEGEND
CHANNEL
DISPOSAL SITE
SAFETY CLEARANCE
N *6' CHANNEL BUDYS
A-5
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2.0 MATERIALS AND METHODS
Due to the complex nature of this project, several methods were employed to investigate the WPMBA. A
historical and information search was conducted to obtain more data concerning the site. Geophysical surveys
were completed to define the boundaries of the WPMBA. Finally, physical, chemical and biological analyses
were performed on the sediments and waters to determine the characteristics of the WPMBA. The results
of initial surveys were used to modify the investigation in an ongoing fashion.
2.1 Historical/Information Search
Aberdeen Proving Ground records, historical maps, and aerial photographs were reviewed and analyzed.
The Library of Congress, National Archives, the Ordnance Museum at APG, and several white
phosphorus manufacturing companies were contacted for relevant information.
Previous environmental impact assessment documents produced for the installation were also reviewed.
Attempts were made by APG to locate and interview former employees. Two former employees were
contacted and questioned by APG.
Historical aerial photographs and bathynaetric maps were reviewed to determine if indications of the
disposal site were evident. In addition, a USGS Aeromagnetic map of the area was reviewed for
indications of magnetic field anomalies.
2.2 Geophysical Surveys
On October 14-15, 1988, an in-depth geophysical investigation was conducted in the WPMBA.
Transects were completed in two phases due to safety considerations and constraints of the nearby firing
range. A Fisher Proton 2 Marine Magnetometer was used to screen the entire WPMBA. A proton
magnetometer was deemed the most effective survey instrument based on field tests comparing various
remote sensing instrumentation. A proton magnetometer is an electronic instrument which measures
the strength of the earth's magnetic field in gammas. Ferromagnetic materials (containing iron) will
alter the magnetic field and result in changes in the gamma readings. This instrument has a sensitivity
of 1 gamma and can detect a large ferromagnetic object (several tons) from approximately 200 feet.
An area larger (approximately 285 acres) than that reported for the WPMBA was screened to get
maximum coverage. Transects were approximately 200 ft apart. The distance between transects was
selected based on the reported size of the actual burial area (6 hectares, or 15 acres). A Lowrance X-16
fathometer and a Sitex EZ-97 LORAN C (Long Range Navigation) receiver were used throughout the
sampling periods for bathymetric and navigational purposes, respectively.
Transects were run in an approximately north-west direction and then repeated in a south-east direction.
The magnetometer was towed at an average speed of 2-3 knots (1.0-1.5 m/sec) approximately 50 feet
(15 m) behind the boat at a depth of approximately 2-2.5 feet (0.6-0.8 m). Ten transects were run in
duplicate for a total of 20 passes over the near-shore area. Seven additional transects were run in
duplicate in the off-shore area. A graphical representation of the transects is shown in Figures 2 and
3. The path of the transects shown deviates from a straight line; this is a function of the LORAN
coordinates and the plotting techniques utilized.
Buoys were set and surveyed at those sites where large fluctuations were recorded, indicating a target
or anomaly, and which were deemed significant. During this investigation, the magnetometer was
"walked" over Gull Island to determine its potential as a dump site.
A-6
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T-C
LACK
POINT
T-6
M
FIGURE 2
PROTON MAGNETOMETER NEAR-SHORE TRANSECTS
WHITE PHOSPHORUS MUNITIONS BURIAL AREA
ABERDEEN PROVING GROUND. MD
OCTOBER 14-15, 1988
.At
AS*
/
/
/.
/ C-5'
APPROX. SCALE
1" - 2W
A
A HITS k LORAN READINGS
NORTH TO SOUTH
SOUTH TO NORTH
CHANNEL
N."6" CHANNEL BUOYS
A? ANOMALY BUOYS *
SURVEY POINTS
T-C TRANSECTS
A-7
-------
FIGURE 3
PROTON MAGNETOMETER OFF-SHORE TRANSECTS
TTHITE PHOSPHORUS MUNITIONS BURIAL AREA
ABERDEEN PROVING GROUND, MD
OCTOBER 14-15, 1988
A HITS ft LORAN READINGS
T-11 TRANSECTS
NORTH TO SOUTH
SOUTH TO NORTH
CHANNEL
CHANNa BUOYS
ANOMALY BUOYS *
SURVEY P094TS
N-6%
A7ซ
APPROX SCALE
I' - 250'
A-8
-------
Based on a review of the data in conjunction with the U.S EPA Environmental Monitoring Services Lab
(EMSL-Las Vegas), the area adjacent to Black Point was selected for a more intensive survey in June
of 1989. Transects lines were set up every 20 feet (6 m) to more accurately define the magnetic field
and the associated anomalies. The even numbered transects (i.e., T-2, T4) are depicted in Figure 4,
while the odd numbered are shown in Figure 5. Additional transects were run perpendicular to the
north and south transects in an east-to-west or a west-to-east direction at select points. These were
titled 'tie lines' and functioned to tie in the data from adjacent transects for data interpretation. All
data from the magnetometer was passed through a digital-to-analog converter and then to a portable
strip chart recorder. Concurrently, LORAN coordinates were recorded through an interface onto the
fathometer chart paper at select time intervals and at buoy markers.
23 Remote Sediment Coring
Coring activities occurred August 7-17,1989 and involved the remote collection of 60 sediment cores
within the WPMBA. Due to the inability to confidently define the boundaries of the WPMBA, a
systematic search sampling method was employed in five areas. A square grid size of 273 feet (83 m)
was utilized assuming a circular target size of ISO ft (46 m) with a 0.9 probability (90% chance) of
finding the target. Based on this method, a total of 50 cores would be required to cover those areas
with numerous or large magnetic field anomalies.
Cores were collected off Black Point, in the channel, north of Gull Island (Area I), east of the channel
(Area II), and west of the channel (Area III). In addition, ten cores were collected in the adjacent
APG channel to assist in future dredging decisions. Sediment coring was utilized to secure samples for
white phosphorus and high explosives analysis.
Core liners ( 6 ft butyrate plastic tubes) were utilized throughout the WPMBA investigation to collect,
transport, store and maintain the integrity of the cores. Four reference samples from two cores were
collected in Spesutie Narrows.
All core samples were screened at the staging area for high explosives using a Scan X Jr. Portable Gas
Chromatograph, inspected for white phosphorus, and examined for stratigraphy. The Scan X Jr., a
portable GC with an Electron Capture Detector (ECD), was configured to detect the presence of
Nitrogrycerine (NG) and trinitrotoluene (TNT).
If the stratigraphy of the core was relatively homogeneous, a composite sample of the core was
collected. The core composite was collected by using a clean scoop to obtain equal amounts of
sediment at six inch intervals throughout the length of the core. If a discrete strata was observed, a
separate sample of that strata was collected. All sampling equipment was decontaminated between
samples following ERT/REAC procedures, and all notes were logged on field data sheets or log
notebooks. Each sample was assigned a unique sample number which corresponded to a field data
sheet.
To determine whether Gull Island was the location of the WPMBA, core samples were collected in
September of 1989. Soil cores were collected from the south end and the north end of the island.
Samples were collected at one foot intervals from a depth of 5-8 ft and composited for WP and high
explosive analyses. A listing of the physical/chemical analyses performed on the sediment samples is
depicted in Table 1.
A-9
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PROTON MAGNETOMETER TRANSECTS.
. ..AT BLACK POINT (EVEN NUMBERS> ...
WHITE PHOSPHORUS MUNITIONS BURIAL AREA
. .ABERDEEN PROVING GROUND, MD V
''- V ...". JUNE 6-9. 1989 A' V \ .-
'.'' '' .'"' .''' ' .' '. .'*.
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, . EVENLY NUMBERED
T z TRANSECTS
58199.0 LORAN COORDINATE
24* numceTxnn
A7 ANOMALY WOtS *
A-10
-------
v '. .-' . -: fiGURE 5'- :; '.- ' -"
-' PROTON MAGNETOMETER TRANSECTS.-"
' AT BLACK POINT (ODD NUMBERS) '
WHITE PHOSPHORUS MUNITIONS BURIAL AREA
- .-ABERDEEN PROVING GROUND, MD v .
V '- -'. JUNE 6-9. 1989 :' '-,.' . .-
'32.-
A/'-
'. .' --I I". ' . .-. / .' X) .". '.' ' ' '. SOURCE: OEMERAl SITEMAP
'. }' '.. '. .T-15* '-. '. .' .' .-ABERDEEN PROVIN8 OROUNOS,
.'..-' ."' ' -'I ' MMYUND 19BC
''APPROX. SCALE .' I '.
' ' \ 1".".13B< '.-' '.I .'
. [ . . '
LSGEND
T . ODDLY NUMBERED
TRANSECTS
59195.0 LORAN COORDINATE
249 TRANSECT BUOYS
A7 ANOMALY BUOYS *
SURVEY POINTS
A-ll
-------
TABLE 1. LIST OF ANALYSES PERFORMED
WHITE PHOSPHORUS MUNITIONS BURIAL AREA
ABERDEEN PROVING GROUND, MD
ANALYSIS MATRIX
White Phosphorus S,W
High Explosives S,W
RCRA S
EP Toricity for Metals S
EP Toricity for Herbicides/
Pesticides S
Reactive Cyanide S
Reactive Sulfide S
IgnitabUity (Flash Point) S
Corrosivity S
Total Organic Carbon S
Grain Size S
Metals W
Base/Neutral/Acid Extractables W
Pesticides/PCBs W
S - SEDIMENT
W - WATER
The following water quality parameters were collected in-situ: pH, temp., dissolved oxygen, conductivity,
salinity, oxidation-reduction potential.
2.4 Water Analysis
During the remote coring operation, water samples were collected for white phosphorus and high
explosives analysis. Water samples were collected at the surface and 0.5 m off the bottom of each
coring area. This included the reference area by Brier Point, the channel north of Gull Island, Black
Point, and Areas I, II, and III. Water samples were collected with a Kemmerer bottle for bottom
depths, and for surface samples by immersing the sample containers under the water surface.
In-situ water quality data was collected at each site using a Hydrolab Surveyor II. Parameters measured
were dissolved oxygen, temperature, pH, conductivity, oxidation-reduction potential and salinity.
Readings were taken at 0.5 m above the bottom and 0.5 m below the surface at all sites.
2.5 Analytical Methods
Elemental phosphorus was extracted and analyzed using the methods and techniques outlined in the
method "Direct Determination of Elemental Phosphorus by Gas-Liquid Chromatography" by R.F.
Addison and R.G. Ackman (1970). Sediment and water samples were extracted with toluene and
analyzed by gas chromatography/mass spectrometry. The mass spectrometer was selected as the
detector because it can be programed to scan specifically for the P4 molecule of elemental phosphorus.
This eliminates the misidentification of phosphorus due to coeluting peaks or any interferences in the
matrix.
A-12
-------
Matrix spike and matrix spike duplicate samples were analyzed for each batch of ten samples for each
matrix. Blanks were analyzed on each analysis day. The method detection limit using GQMS was 1.0
ug/L for water samples, and 5.0 ug/kg for sediment samples.
The high explosives (Table 2) hi water and soil were extracted and analyzed using Method No. UW01,
Explosives in Water, and Method No. LW02, Explosives in Soil (Roy F. Weston, Lionville Lab).
Water samples were not extracted and were analyzed by injecting 10 ml of sample onto a sample loop
and then analyzing by High Pressure Liquid Chromatography (HPLQ. Soil samples were analyzed by
extracting the sediment with acetonitrile, filtering the extract, and analyzing by HPLC The HPLC was
equipped with a diode array detector so wavelengths could be set for specific peaks to enhance
sensitivity. Traditionally the wavelength is set at 250 nm.
Matrix spike and matrix spike duplicate samples were analyzed for each batch of 10 samples for each
matrix. Blanks were analyzed on each analysis day. The method detection limit for nitroexplosives was
5.0 ug/L for water samples, and 1.0 mg/kg for sediment samples.
TABLE 2. LIST OF EXPLOSIVES ANALYZED
WHITE PHOSPHORUS MUNITIONS BURIAL AREA
ABERDEEN PROVING GROUND, MD
HMX - Cyclotetramethylenetetranitramine
RDX - Cyclotrimethylenetrinitramine
1,3,5 TNB - 1,3,5 Trinitrobenzene
13 DNB -1,3 Dinitrobenzene
Tetryl - Trimtrophenolmethylnitramine
2,4,6 TNT - 2,4,6 Trinitrotoluene
2,6 DNT - 2,6 Dinitrotoluene
2,4 DNT - 2,4 Dinitrotoluene
TABLE 3. LIST OF EP TOXICITY HERBICIDES/PESTICIDES ANALYZED
IN SEDIMENTS WHITE PHOSPHORUS MUNITIONS BURIAL AREA
ABERDEEN PROVING GROUND, MD
2,4 - Dichlorophenoxyacetic Acid (2,4 - D)
2,4,5-Trichlorophenoxypropionic Acid (2,4,5 - TP)
gamma-Benzenehexachloride (gamma-BHQ
Endrin
Methoxychlor
Toxaphene
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2.6 Health and Safety
The risk of encountering UXO's in the area, in conjunction with the U.S. Army's safety procedures,
required that coring activities be conducted remotely. The sampling procedure established a series of
step-by-step standing orders for positioning the barge, readying it for sampling, evacuating the barge,
remotely coring and retrieving, screening of the cores, transporting the cores, and sampling the core
material. A 200-foot safety zone was established during all coring and retrieval activities. The remote
operation of the vibracore was conducted from the tow vessel, and sampling personnel evacuated the
barge using a motorized Zodiac inflatable boat.
Reactive Materials Management, Inc., was secured to provide assistance with standard UXO safety
procedures. Their primary role was to survey and inspect the core for metal objects after retrieval and
prior to handling, and assist sampling personnel in the event that munitions were found.
The maximum credible event (MCE) was discussed as well as procedures for such an event. The MCE
for this investigation involved determining what was the most dangerous ordnance that would be
encountered or entrained within the core tube. The MCE for this investigation was determined to be
a 40 mm grenade; it was improbable that larger munitions would be entrained by the core.
The other major risk to personnel involved the potential contact with white phosphorus and WP
munitions. The hazards posed to sampling personnel from WP included the potential for fire and
explosion, and the inhalation of toxic fumes produced during its burning.
Several contingencies were put in place in order to minimize the WP hazard. A 55-gallon drum, filled
with water and placed in close proximity to all core handling operations (i.e., on the barge, near the
sample prep table), was to be used to submerge a core with an isolated flare-up. A pressurized hose
was also available on the barge (via pump) and at the sample prep area to douse any core which could
not be isolated and submerged. In the event of an incipient fire, personnel were instructed to don
emergency respiratory equipment (self contained breathing apparatus) and evacuate the area
immediately. As a back-up to the water systems available, a ten gallon pail filled with wet mud was
placed on the barge and in the sample prep area.
In order to control incidental skin contact with WP or other contaminants which may have been
contained hi sediments, personnel involved with sample handling wore butyl aprons, rubber boots,
nomex coveralls, and long sleeve butyl gloves. Hard hats equipped with face shields prevented
sediments or contaminants from splashing into eyes. The use of protective clothing increases the
potential for heat stress related injuries. Frequent breaks between sampling events, construction of
shaded areas, and resuppty of fluids eliminated the hazards associated with the sun and hot weather
conditions.
3.0 RESULTS
3.1 Historical/Information Search
The results of the historical and information search led only to clues as to the location and contents of
the WPMBA. The review of the Aberdeen Proving Ground records did not reveal the exact location
or the contents of the WPMBA. A review of previous environmental impact assessment documents
revealed that no documentation of the actual dumping location was found. It was stated in one of these
reports that generally, records on the manufacturing and disposal operations prior to World War II did
not exist or were largely incomplete (USATHAMA, 1980). Reportedly, the existence of the disposal
site was based on interviews of former installation employees. One reference stated ..."the phosphorus
disposal area, was established nearly 55 years ago to dispose of deteriorated World War I white
phosphorus projectiles of various calibers. After disposal in 5 feet of water, this area was backfilled
with earth. An additional two feet of fill was then placed over the area" (USATHAMA, 1980).
Another references stated the following: "Area 12, just off Spesutie Island, was the site of a 1922 to
1925 dumping operation for World War I munitions containing WP. The site is about 6 ha (hectare)
A-14
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in area. The WP is buried under about 0.6 m of fill, covered with 0.9 m of water. The amount of WP
buried at this site is unknown" (ESE, 1981). Another excerpt stated: The burial reportedly occurred
in the waterfront region near Black's Point [sic], encompassing an area of 6 hectares (15 acres). When
disposed, the munitions were placed in the tidal flats and covered with 0.6 m of sediment".
No evidence of a disposal site was observed in any of the historical aerial photographs reviewed. The
most pertinent observation was the presence of what appears to be dredge spoils on Gull Island in the
1944 photo. The size of the island was greatly increased compared to earlier photos. Evidence of
shoaling and exposed dredge spoils is also evident inshore, northwest of the island. The dredge spoils
are not visible in the 1951 and 1956 photos, indicating the rapid dispersal of these sediments by winds,
tides, and storms. The most obvious shoreline change is evident at Black Point. The photos indicate
the shoreline is growing due to an accretion of sand in a northern direction towards the mouth of
Mosquito Creek. The most recent aerial photo, from 1981, shows that this accretion has extended
approximately half way to the mouth. Based on field observations, this process seems to have
accelerated in recent years. At present, this peninsula has formed a protected cove across the mouth
of Mosquito Creek and only an entrance way of approximately 10 meters is present.
A review of the NOAA historical bathymetric maps indicated: there was no indication of Gull Island
on any of the maps dated prior to the dumping, Black Point was rounded with no visible peninsula, and
the bathymetry of the area was similar.
The 1971 aeromagnetic map (USGS) that was examined did not indicate the location of the WPMBA.
The map indicated that the intensity contours were bent towards Black Point and Mosquito Creek to
the northwest, however, no maximum or minimum intensities were recorded in the WPMBA.
No direct information concerning the disposal site was available from the Library of Congress, the
National Archives, or several white phosphorus manufacturers, including E.I. Dupont a manufacturer
of WP during WWI.
Through the examination of U.S. Army bulletins and other federal regulations it was determined that
bulk white phosphorus was transported in iron or steel containers. The significance of this is that if
bulk white phosphorus was disposed at this site, it should have been contained in ferrous metal
containers. Therefore, if still present, these containers would be detected by a proton magnetometer.
One major piece of information comes from Proclamation 2383, signed by President Franklin D.
Roosevelt on January 24,1940. Previously, two areas were designated as Migratory Waterfowl Closed
Areas under a regulation adopted by the Acting Secretary of the Interior on December 12,1939, under
the authority of the Migratory Bird Act of July 3,1918 (40 Stat. 755,16 U.S.C. 704). One of the areas
approved by the proclamation was entitled the "Phosphorus Area Unit".
Reportedly a large migratory waterfowl kill had occurred during the 1930's due to a release of white
phosphorus from this area. Speculation is that this proclamation was a result of this kill.
This proclamation was the only written document found that specifically mentions phosphorus and
delineates the boundary of the area. The size of this area encompasses approximately 130 acres (53
hectares). It was assumed that the area described incorporated the WPMBA.
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One former employee of the base was contacted by APG (J. Wrobel, APG, Personal communication).
He reported that a hurricane in the 1930's uncovered the WPMBA which led to a large waterfowl kill.
He stated that "the ducks turned pink and died". The Army then placed a flood light on the area to
discourage waterfowl use. No other persons with knowledge of the site were identified.
Several storms occurred during the 1930's which could have been responsible for eroding the sediment
cap on the WPMBA, with the August 23, 1933 hurricane the most likely of these. This storm was
actually termed a gale in the vicinity of APG with winds reaching 42 miles per hour (mph). The storm
reportedly caused the greatest statewide damage of all time. Waves and tides caused the majority of
damage and considerable erosion of the western shore of Chesapeake Bay was reported (Truitt,
undated; USDA, 1933). Winds in the vicinity of APG were reported to be out of the northeast shifting
to the southeast during the storm. Waves impacting the Black Point area from the southeast could have
caused considerable erosion and led to the uncovering of the WP munitions. Two other hurricanes
occurred, in 1936 and 1938, and both passed by the coast of Maryland and caused high winds inland.
Aberdeen Proving Ground supplied information concerning World War I munitions. In addition,
several reference books were reviewed to determine the types of munitions that may have been disposed
at the site. Three types of rounds which contained WP were listed by one reference (Prentifs, 1937).
All rounds were constructed of steel. One, a Livens Projectile, contained up to 30 pounds (Ibs) of fill
(WP). Two sizes were in use, a 2 foot 9 inch, and a 4 foot projectile. The second type of round listed
was a four inch Stokes mortar shell. The fill in this shell was 63 to 95 Ibs of WP. The third type
mentioned in this reference was a 4.2 inch mortar shell which contained approximately 8 Ibs of WP.
Another undated reference, entitled "Chemical Techniques and Practices of Artillery", contained
information on two other types of ordnance. The first was a 75-mm gun that used a shell containing
1.81 Ibs of WP. The bursting charge contained 1.6 Ibs of TNT. The second ordnance was a 155-mm
howitzer that used shells containing 15.4 Ibs of WP.
The APG records also included a more recent investigation involving samples collected from the
channel east of the WPMBA (USACOE, 1982). Approximately eight sediment samples were collected
in the channel between the Mulberry Point dock and buoy number 2. Additional samples were
collected from Spesutie Narrows and disposal areas (presumable dredge spoils) northeast and southwest
of the WPMBA. These samples were analyzed for metals, volatile solids, hexane extractables, chemical
oxygen demand, total kjeldahl nitrogen, total phosphate, phosphorus, and grain size. No phosphorus
was detected in any of the samples at a detection limit of <30 ppb.
32 Geophysical Surveys
The geophysical surveys were initially set up to screen the entire WPMBA with subsequent surveys
focusing in on particular areas. A preliminary review of the first survey results indicated that no large
(i.e. several acres) homogeneous burial area was evident. What was evident was the fact that numerous
isolated magnetic field anomalies were present within the entire WPMBA. Some of these anomalies
were outside of the WPMBA boundaries. A total of approximately 110 major anomalies were detected
during these surveys (Figures 2 and 3). Transects T-6, T-7, T-10, T-ll, T-14, T-15, and T-16 contained
the majority of the anomalies and some of the largest in magnitude. These magnetic field anomalies
indicate the presence of ferrous objects. This could include munitions from the WPMBA, UXO's from
the firing ranges, construction debris, or any other object containing iron which may have been dumped
in the area.
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During the October, 1988 survey the proton magnetometer was utilized to screen Gull Island. This
survey did not detect any major anomalies on the island.
The Black Point survey also detected numerous magnetic anomalies. Anomalies greater than 400
gammas were observed throughout the transects. Many of these anomalies were probably caused by
single containers (camion shells). However, no homogeneous areas were detected which would indicate
the exact boundaries of the WPMBA. What was detected was a heterogeneous zone with the majority
of anomalies concentrated in the near-shore transects (T-0 T-9). Three areas were identified as
containing clusters and the largest anomalies. One area was located directly off Black Point along
transects 3 and 5; one was located approximately 600 feet north of Black Point along transects 5 and
7; and one was located approximately 400 feet south of Black Point along transects 5 through 9. In
these areas, a significant number of anomalies occurred on at least four to six adjacent survey lines
(approximately 80 to 120 feet across).
33 Remote Sediment Coring
The screening results indicated that none of the cores analyzed with the Scan X Jr. had nitroglycerine
present at a detection limit ranging from 1 to 10 ppm NG.
The results of the elemental phosphorus (WP) analysis of the sediment cores are listed in Table 4. A
total of 11 samples out of 71 contained elemental phosphorus. The concentrations ranged from 0.62 -
4.64 ug/kg dry weight, and 0.28 -1.90 ug/kg wet weight. All concentrations are reported as below the
quantitation limit and are approximate. Seventeen of the 60 cores collected were located directly in
the assumed boundaries of the WPMBA (Figure 6). Four of these cores contained WP. Thirty-three
cores were adjacent to or outside of the WPMBA. Six of these cores contained WP. Ten cores were
located in the boat channel and one contained WP. The locations of the cores were distributed
throughout the study area. One core contained elemental phosphorus in Areas I, II and the channel;
three cores contained phosphorus hi Area III; and five cores contained elemental phosphorus in the
Black Point area. The core lengths ranged from less than one foot to nine feet Three of the samples
(17,18, and 20) at Black Point were adjacent to one another. The three cores in Area III were also
in close proximity, as were cores 3 and 31 of Area I and the channel, respectively. The remaining three
cores were solitary. No elemental phosphorus was detected in the samples collected on Gull Island.
An examination of the core locations in conjunction with the target locations at Black Point reported
by EMSL indicated that seven cores (9, 13,14, 18,19, 37, and 38) were within this target area. Only
core 18 had detectable concentrations of WP. It appears that cores 14 and 37 were collected almost
directly on top of two of the areas with major anomalies, neither detected WP. Cores 17, 20, and 25
with concentrations of WP were adjacent to this target zone. Nine other cores were adjacent to the
areas outlined by EMSL, none detected WP. Core 11, which also contained WP, was outside of the
EMSL survey area.
No high explosives were detected in any of the core samples.
Four of the eight metals tested for in the RCRA EP toxicity analysis were detected in the sediments
in very low quantities. Arsenic (As) was detected in fifty-four samples tested. Arsenic levels ranged
from 0.002 mg/1, core 36, in the Black Point Area to 0.18 mg/1, cores 11 and 56, in the Black Point Area
and Area III, respectively. Barium (Ba) was detected in fourteen locations in each of four areas: Black
Point - cores 15 and 36; Area II - core 49; Area III - cores 51 and 52; Channel - cores 26-31 and 33-35.
Detected barium levels ranged from 0.08 mg/1, core 33, to 0.29 mg/1, core 30.
A-17
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37
.36
38
.80
FIGURE 6
REMOTE CORING LOCATIONS / /
WHITE PHOSPHORUS MUNITIONS BURIAL AREA
ABERDEEN PROVING GROUND, MD
AUGUST 8-16, 1989 .ป
Ji
,54
53
52
,55
56
,58
57
/
;*:* ฐ41
42
47
.ซ .*
26
.44
.49
ttnuu. SCMC
r-saor
CHANNa
CORE LOCATIONS
O WRVCYPOWn
OHAMHBL
A-18
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TABLE 4. RESULTS OF ELEMENTAL PHOSPHORUS ANALYSIS IN SEDIMENTS
ABERDEEN PROVING GROUND, MD
AUGUST 1989
Location
Core
Sample #
Phosphorus (ug/kg)
Dry Weight
Phosphorus (ug/kg)
Wet Weight
Core Length (ft)
Area I
Black Point
Black Point
Black Point
Black Point
Black Point
Channel
Area II
Area III
Areain
Area III
J = Anah/te
3
11
17
18
20
25
31
40
54
55
58
detected
4356
4427
4433
4434
4436
4441
4448
4457
4475
4476
4480
but below quantitation limit
0.78J
222J
0.72J
0.62J
222}
1.16J
0.74J
2.41J
4.64J
338J
3.84J
0.42J
1.00J
030J
0.28J
0.71J
0.94J
034J
1.04J
1.90J
1.55J
1.80J
4.5
4
45
43
53
<1
6
S3
6
6
9
Cadmium (Cd) was detected only in the Channel Area, core 30, at 0.0087 mg/1. Mercury (Hg) also was
detected only in the Channel Area, core 32, at 0.0014 mg/1. Silver (Ag), chromium (Cr), lead (Pb), and
selenium (Se) were not detected in any of the EP Toxicity samples. All detected metal levels fell below
cited maximum contaminant concentrations for EP toxicity (40 CFR Ch. 1 Sec. 261.24).
Herbicides and pesticides in the EP toxicity tests were undetected in all samples. Additional RCRA
inorganic analysis included ignitability, corrosivity and reactivity for cyanide and sulfide. Cyanide
reactivity was below the detection limit for all samples analyzed. Reactive sulfide was detected in 24
samples and ranged from 13.6 to 157.0 mg/kg. The flash point for all samples was greater than the limit
of 200ฐF indicating the lack of highly combustible material. The corrosivity was also below the
detection limit of 635 millimeters per year (nun/year) for all samples tested.
Sediment grain size analyses were performed to examine the composition and characteristics of the
cores. Based on these analysis results and field observations the majority of cores exhibited a similar
grain size composition. Most cores were predominantly silt with lesser amounts of clay and sand. This
pattern was evident for Areas I, II, III, and the channel Black Point sediments were similar offshore
and north of the point, dose to Black Point the sediments were predominantly sand with increasing
amounts of fines with depth. Peat and organic matter were common in the cores closer to shore and
at a shallower core depth. Cores 44 and 45 in Area III contained peat at depths of 65 to 9 ft
Total organic carbon concentrations in the sediments ranged from 34,000 - 340,000 mg/kg (3.4 -34 %).
The majority of the cores contained less than 10 % organic carbon.
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3.4 Water Analysis
Fourteen water sampks were secured in representative areas during the coring operation in August,
1989. Samples were analyzed for elemental phosphorus and high explosives. There was no elemental
phosphorus detected in any of the water sampks at a minimum detection limit of 1.0 ug/L. The analysis
for high explosives failed to reveal the presence of any of the nine explosive compounds tested for at
the 5.0 ug/L minimum detection limit.
In-situ water quality parameters were consistent with seasonal variations common for this estuarine
water body.
4.0 DISCUSSION
The purpose of this investigation was to answer questions related to a RCRA Facility Assessment. The
primary purpose was to insure that the burial area was studied and any released wastes were identified and
evaluated in subsequent study phases. The only waste for which there is evidence of a release is white
phosphorus. The presence of WP in low concentrations in 11 cores indicates sediment contamination. The
source may or may not be the WPMBA.
Other purposes of this investigation were to identify the boundaries of the WPMBA. Based on the results
of this investigation it appears that boundaries for this burial area no longer exist. Due to the extended
burial period and the dynamic nature of the bay, it appears that the material buried has been dispersed over
a large area. It is also possible that isolated dumping episodes occurred over the general area, or that the
WP detected is from more recent testing of munitions (UXO's). Another purpose of the RFA was to
determine if releases of hazardous waste are occurring or have occurred. RCRA analyses indicated that the
core samples would not be characterized as a hazardous waste. The historical information would lend
credence to the reported uncovering of the WPMBA in the 1930's and subsequent release. The presence
of trace concentrations of WP in the sediment indicate that releases have most likely occurred. However,
the magnitude of past releases, and the present mass of WP remaining are unknown.
The results of the historical and information search revealed that no records were found which would identify
the exact location and content of the WPMBA. The general area was determined based on references which
were based on interviews of former base employees and the delineation of the area by the Migratory Bird
Treaty Act Relevant information indicated that white phosphorus was stored in ferrous metal containers
and therefore should be detectable by proton magnetometers. An initial assumption that the shells were
intact to a sufficient degree was found to be accurate since many targets were detected. In addition, the
presence of WP in the areas where magnetic anomalies were found indicated that this was a correct
assumption. A second important piece of information was the 1933 hurricane which was reported to have
uncovered the WPMBA. Records indicating extensive erosion of the western side of Chesapeake Bay during
this storm were located. This is further substantiating evidence that a release of WP occurred during the
1930's.
The fate of WP in the environment is an important issue at this site. "White phosphorus enters the aquatic
environment as phossy water which is generated wherever WP is manufactured, stored under water, or
spilled. Phossy water contains dissolved and colloidal WP as well as larger suspended particles. Data from
manufacturing and munitions loading plants indicate that much of the WP in phossy water is dispersed or
colloidal rather than dissolved. The mixture, whether dissolved, dispersed, or colloidal, reacts with dissolved
oxygen and hydroxide ion to form various oxides, acids, and phosphine. In high concentrations as a
suspension, it results in low to zero dissolved oxygen in the surrounding water; unreacted particles settle out
and can be incorporated into aquatic sediments. These particles, when buried in anoxic sediments, are stable
for long periods of time." (Environment Canada, 1984).
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The lack of detectable quantities of WP in the water column indicates the stability of the WP in the
sediments. However, it is possible that WP could be released to the water column during disruption of the
substrate. Based on the low concentrations of WP that cause toxicity and the detection limit of 1 ug/1 used
in this study, it is important to look at concentrations that are potentially present. The current US EPA
criteria (1986) for marine or estuarine waters is 0.10 ug/L of elemental phosphorus. An examination of the
water chemistry of WP will lend some additional insight, however, data on reaction kinetics and
decomposition products of WP in water are poorly defined (Environment Canada, 1984). Oxidation rates
vary widely and appear to depend on pH, dissolved oxygen, temperature, metal ions, and the degree of
dispersion of colloidal or suspended material. Half-lives of WP in seawater and freshwater were 240 and 150
hours, respectively, for an initial concentration of 1-50 ppm at 0ฐC (Environment Canada, 1984).
A major factor controlling the rate of disappearance of white phosphorus apparently is whether it is
suspended or dissolved. At concentrations below the solubility limit, and where a majority of the material
is dissolved, it initially oxidizes in aerated water via a first order reaction to concentrations below 0.01 ppm.
The material continues to slowly oxidize to equilibrium levels of 0.04 to 0.10 ppb. Other preliminary results,
however, suggest that white phosphorus at low concentrations rapidly oxidizes to below 0.01 ppb. The
disappearance rate from more concentrated suspensions apparently is controlled by diffusion and the
protection of the phosphorus from the dissolved oxygen. It has been shown that saline water may influence
the reaction rate. The authors suggested that perhaps salts coagulate the colloidal particles and make them
less accessible to oxygen. It is suggested that WP may oxidize in a single step or react stepwise to form
several oxides that are ultimately converted to phosphate as phosphoric acid. (Environment Canada, 1984)
It is possible that the WP sediment concentrations observed in the various areas are remnants of the disposal
site. The dispersed nature of the WP may indicate that the exposure of the site in the 1930's spread WP over
a wide area. Due to the assumed heavy sediment load in the water column during the 1933 storm, the WP
may have been dispersed and then quickly covered by sediment. The anaerobic conditions observed in most
of the cores would indicate that the WP would be stable for a long period of time.
Another explanation could be that the WP detected in each area was the result of isolated shells from prior
testing which have deteriorated and released WP. If WP was tested at the adjacent ranges, the munitions
could also have ended up in Mosquito Creek. Subsequently, contaminated sediment could have been
transported downstream to the mouth of Mosquito Creek and the Black Point area. The lack of information
on the life of WP in sediments, whether aerobic or anaerobic, makes it difficult to determine the source of
thisWP.
Low concentrations of elemental phosphorus in the water column have been documented as causing acute
effects on aquatic organisms. Existing toxicity test data of WP on aquatic organisms was summarized by
Sullivan et al. (1979). They report that freshwater and marine invertebrates are less sensitive to WP than
fish. Various species of invertebrates were tested, with results for Chironomus tentans reported as a 48-hour
EQo ov 140 ug/1 WP. EQo is defined as the concentration of a contaminant that affects 50 % of the test
population in a sublethal manner, such as immobilization. The lowest 48-hour EQo was 30 ug/1 for the
freshwater cladoceran, Daphnia magna. Limited data was reported for marine invertebrates and included
a 24-hour EQo of 6500 ug/1 for Gammarus oceanicus and a 168-hour EQ, of between 20 and 40 ug/1 of WP
for the lobster (Homarus americanus).
Fish are much more sensitive to the effects of WP. Of the freshwater fish studied, the bluegill (Lepomis
macrochirus) was the most sensitive to WP with a static 96-hour LQ<, of 2 ug/L (Sullivan et al., 1979).
Marine and euryhaline fish are also very sensitive to WP. Atlantic salmon (Salmo salar) had a reported 96-
hour LQo of 23 ug/L whereas the strictly marine fish Atlantic cod (Gadus morhua't had a reported value of
25 ug/L WP (Sullivan et al., 1979).
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Rapid bioaccumulation of WP has been documented and is related to the lipid content of the organism.
Bioconcentration factors of between 20 and 100 have been reported for aquatic organism tissues, and in an
extreme case up to several thousand in the Atlantic cod liver. Rapid removal from the tissues has also been
reported if the organism is transferred to clean water (Sullivan et al., 1979).
The mechanism of toxkity of white phosphorus is reported to be related to its potent reducing powers. WP
enters via the gills or intestinal tract, circulates in the blood and damages all tissues that it contacts. Damage
appears to be related to exposure time and concentration (Sullivan et al., 1979). Gross effects of WP toxkity
on fish include hemorysis with symptomatic reddening of the skin, jaundiced liver, and/or green intestines.
In mammals, shock and cardiovascular system damage result in rapid death due to acute poisoning (Craig
et al., 1978). Lower dosed deaths have been attributed to renal or liver failure and digestive tract damage.
The reported threshold dietary level for retarding growth in rats is in the range of 0.003-0.07 mg P4/kg/d>
while the lethal dose is 7 mg/kg. Humans are about five times more sensitive than rats to the lethal effects
of WP (NRCC, 1981; Sullivan et al., 1979).
Another concern is the impacts of contamination through the food chain. White phosphorus contamination
in various fish tissues has been shown to be toxic or lethal if ingested by other fish or mammals including
humans (NRCC, 1981; Sullivan, 1979). However, due to the reactivity of WP, the transfer of this element
through the food chain would not be expected to last In terms of long term food chain contamination, the
potential from WP is considered nil (Environment Canada, 1984).
Based on previous investigations, the "no effect level" for WP in sediment probably lies below 2 ug/kg (wet
weight). This value was the minimum sediment concentration found at which adverse impacts occurred to
the benthic community in a freshwater system (Sullivan, 1979; Environment Canada, 1984). All WP wet
weight concentrations were below 2 ug/kg for the WPMBA investigation. This would indicate "no effect"
" concentrations. The fact that "these samples were composite samples may indicate that higher concentrations
were present hi distinct layers. However, the relative position hi the core is important If WP is close to the
surface it will probably impact the benthic organisms; if WP is buried several feet under the surface it will
not impact the benthic biota, unless uncovered.
Examining the data for marine environments indicates that sediment concentrations of WP above 70 ug/kg
and water concentrations of 3 ug/L have been associated with impacts on the invertebrate community in the
form of selected mortalities (Environment Canada, 1984). Furthermore, it is stated that concentrations of
WP greater than 1 ug/L do not persist for appreciable periods of time, although resuspension of sediments
may maintain a concentration of 0.5-1.0 ug/L in overlying water. Marine sediment concentrations of WP are
also reported as stable (Environment Canada, 1984).
The threat of exposure of migratory waterfowl to WP is considered minimal. Eleven species of waterfowl
associated with the Atlantic Fryway have been identified within the confines of APG. Dabbling ducks
[mallard, black duck (Anas rubripes). wood duck (Ajx soonsa)], diving ducks [canvasback, goldeneye
(Bucephala clangula)], Canada geese, whistling swan, loon (Gavia inner), merganser (Mergus merganser').
gallinule (Gallinula chloropus). and the American Coot (Eulica americanal have all been observed (Miller,
etal. 1980). APG waters and wetlands are primarily utilized as winter habitat for all species cited. Wood
duck have been observed during the summer breeding season. The diving ducks, loons, and mergansers are
the species most apt to be of concern in relation to WP. Since these are all subsurface foragers, particularly
feeding in the sediment, WP exposure is possible. Vegetative root stock, benthic invertebrates, mussels, and
soft shell crabs are preferred sources for the associated species. Dabbling ducks feeding in shallow surface
water on preferred aquatic vegetation may also be exposed to bottom sediments. Ingestion of WP could
result during acquisition of the food source or directly from the food source itself. The observed waterfowl
kill from 1933 is suspected to have occurred through actual consumption of available WP in the food and
sediment. No additional waterfowl kills in the WPMBA have been cited since that time. '
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The absence or low levels of WP detected in the sediments of the WPMBA suggests a low probability of WP
toxkity to lower food chain organisms. However, bioaccumulation to an upper level consumer, such as
waterfowl, should be considered. Bioaccumulation of WP is manifested through its lipophilic tendency
(Environment Canada, 1984). Waterfowl do exhibit high lipid levels due to their insulation requirements,
therefore WP accumulation may be more pronounced. Avian toxkity data is minimal but the lethal dose has
been cited as 3 mg/kg (NRCC, 1981). Several factors, however, suggest that bioaccumulation may be
negligible. Waterfowl are utilizing the WPMBA waters during a few months in the winter season. Therefore,
exposure to the small quantities of WP detected should be minimal. Additionally, waterfowl lipid content
during the winter is elevated. This may serve to isolate any WP ingested and prevent manifestation of acute
WP symptoms until metabolism can occur. Furthermore, large birds rather than more sensitive precocial
young would be utilizing the food resource. For these reasons, sub-lethal effects on waterfowl should be
isolated or of a low probability.
Previously cited references stated that the WPMBA was located in 0.9 m (3 ft) of water. Assuming this was
low water, an examination of the bathymetry of the WPMBA (Figure 7) and the core locations indicate that
5 of the cores where WP was detected were in waters deeper than 4 feet (at low water). The remaining six
cores were located in water depths of between 2 ft and 4 ft. The tidal range for this area of the Chesapeake
Bay is approximately 0.8 to 2.4 feet depending on the tidal period. Even taking the tidal range into account,
the former five cores are located in deeper water. These were the cores located in Areas II and III, and the
channel. Changes in bathymetry have also most likely occurred due to storms, tides, and the closing of the
Spesutie Narrows causeway in the 1960*5. A comparison with historical bathymetric maps indicate that depth
contours have changed in the WPMBA due to the accretion of sand in the Black Point area, the addition of
Gull Island, and the dredging of the channel to Mulberry Point dock. The majority of the WPMDA's
bathymetry is similar to historical maps, including Areas II and III.
The physical processes which occur within the WPMBA also need examination. Shorelines can be altered
due to erosion and accretion. Erosion occurs due to the refraction of waves, with the wave energy
concentrated on lands that extend into open water (Thurman, 1975). Storm waves can cause more erosion
in one day than by average waves in one year. The rate of erosion is affected by the exposure of the
shoreline, by the tidal range, and by the composition of the shoreline. A smaller tidal range results in greater
erosion since there is less area to spread the wave energy (Thurman, 1975). A longshore current is
established when waves strike the coast at an angle. This current of water carries sediment and is called
longshore drift. The deposition of this sediment is a form of accretion. An example of this is Black Point,
which can be termed a spit - a linear ridge of sediment attached at one end to land with the other end
pointing in the direction of longshore drift (Thurman, 1975). Sand eroding from the coast south of the
WPMBA is being transported along the coast and deposited on the spit at Black Point. This will occur when
the wind and waves are out of the south, southwest, or south/southeast. Waves from the east/northeast to
the east/southeast will reverse the longshore drift to the south/southwest. Winds out of the west, north, or
northeast would probably not cause a drift due to the sheltered position of the area and the small fetch.
Periodic storms and shifts hi winds and waves are the cause for changes in the geomorphometric processes
at Black Point and the WPMBA. Accretion will occur when the longshore current and drift are in a northern
direction. Erosion of the spit may occur when the direction is reversed to the south. An examination of the
wind rose at APG (APG, 1988) indicates that winds which may cause accretion occur approximately 26 %
of the time. Winds which may cause erosion occur approximately 16 % of the time, and the WPMBA is
sheltered from winds approximately 58 % of the time. Wave of sufficient height and energy are needed to
cause significant geomorphometric charges and only occur with high winds. Waves of sufficient height and
energy are required to cause significant geomorphometric changes and only occur with high winds (i.e. 1933
hurricane). Winds greater than 17 knots in the erosional or accreting directions only occurred about 1 %
of the time. This would indicate that significant erosion or accretion would only occur during high winds and
the occasional severe storms.
A-23
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FIGURE 7
BATHYMETRIC MAP OF /
WHITE PHOSPHORUS MUNITIONS '
BURIAL AREA / /
ABERDEEN PROVING GROUND. MD
/
7/
I
CHESAPEAKE BAY
APPROX SCALE
v tar
LEGEND
CHANNEL
1 rijui CONTOURS
WPPROX3MATD
N."6> CHAMCL lUDW
A-24
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5.0 CONCLUSIONS
The lack of detectable quantities of WP in the water column, combined with the relatively low concentrations
of WP in the sediments and the depth which they were found, indicates that WP is probably not being
released into the water column. Based on the presence of WP in the sediments after such a long burial, it
seems unlikely that large quantities are being released to the water. WP could be released when the
sediments are disturbed due to severe storms or if dredging is conducted in the WPMBA. Without knowing
the amount of WP originally buried it is impossible to determine how much WP has been released to the
environment It is possible that these detectable quantities of WP are the last remnants of the WPMBA, and
the vast majority of the WP has already been released. Conversely, pockets of high concentrations of WP
could be present in areas between core locations. Another possibility is that the observed WP concentrations
reflect isolated shells fired from nearby ranges.
The following conclusions are listed to summarize the findings of this investigation:
1) Numerous metallic objects were detected surrounding and within the boundaries of the WPMBA.
These objects may be ordnance from the WPMBA or from nearby firing ranges, or from other disposal
activities.
2) No definitive boundaries for the WPMBA could be determined, although the largest concentration of
magnetic anomalies (ferrous objects) was detected in the Black Point region.
3) No high explosives were detected in the sediments or waters of the WPMBA. Therefore no impacts
upon the ecosystem are expected from high explosive contamination.
4) RCRA analyses indicated that the sediment cores would not be considered a hazardous waste.
5) No white phosphorus was detected in the water column of the WPMBA, therefore no impacts are
expected upon the aquatic ecosystem. Releases of WP are not expected unless the WPMBA is
disturbed.
6) White phosphorus was detected in trace concentrations (<5 ug/kg) in 11 of the 60 sediment cores.
Concentrations which would indicate a large scale release or contamination problem were not detected.
7) White phosphorus was detected in all five areas sampled. These areas were widely spaced in the
general WPMBA and no disceraable contaminant pattern or trend was evident
A-25
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BIBLIOGRAPHY
Addison, R.F. and R.G. Ackman, 1990. Direct Determination of Elemental Phosphorus by Gas-Liquid
Chromatography. J. Chromatog. 47 (1970) 421-426.
Breinter, S., 1973. Applications Manual for Portable Magnetometers. Geometries. Sunnyvale, CA.
Chemical Techniques and Practices of Artillery. "Source Unknown".
Craig, P.N.; K. Wasti; KJ.R. Abaidoo; and J.E. VUlaume, 1978. Occupational health and safety aspects of
phosphorus smoke compounds. U.S. Army Medical Research and Development Command Contract No. DAMO-
17-77-C-7020. Final Report. Franklin Institute Research Laboratories, Philadelphia, PA.
Environment Canada, 1984. "Environmental and Technical Information for Problem Spills - Phosphorus.
Beauregard Press Limited. 122pp.
ESE, 1981: "Environmental Science and Engineering, Inc., Aberdeen Area, Report No. 301." prepared for US.
Army Toxic and Hazardous Materials Agency, Aberdeen Proving Ground, Maryland, February 1981.
Fontana, Mars G. 1978. Corrosion Engineering. McGraw-Hill, Inc. N.Y., N.Y.
Lippson, Alice Jane, Ed. 1973. The Chesapeake Bay in Maryland - An Atlas of Natural Resources. Johns Hopkins
University Press. Baltimore, Maryland.
Meidl, James H. and 1978. Flammable Hazardous Materials - 2nd Ed. Glencoe Publishing Co. Encino, CA.
Meidl, James H. and 1970. Explosive and Toxic Hazardous Materials. MacMillan Publishing Co. New York.
Meyer, Rudolf, 1987. Explosives. 3rd Edition. Weinhem, New York.
Miller, Wihry & Lee, Inc. 1980. Natural Resources Management Plan, Part IV, Fish and Wildlife Management,
Aberdeen Proving Ground, Maryland. Urban Wildlife Research Center, Maryland.
National Association of Corrosion Engineers, 1984. Corrosion Basics - An Introduction. Houston, TX.
National Research Council of Canada, 1981. Effects of Yellow Phosphorus hi the Canadian Environment. NRCC
No. 17587. Ottawa, Canada.
Patterson, James, Norman I. Shapira, John Brown, William Duckert and Jack Poison, 1976. State-of-the-Art:
Military Explosives and Propellants Production Industry. Vol. I and III. EPA-600/2-76-213a and 213c. U.S.
Environmental Protection Agency, Cincinnati, OH.
Perry, Robert H. and Cecil H. Chilton, Ed. 1973. Chemical Engineer's Handbook 5th Ed. McGraw-Hill, Inc. N.Y.,
N.Y.
Prentifs, Augustin. 1937. Chemicals in War. McGraw-Hill, Inc., N.Y., N.Y.
Shapira, Norman I, James Patterson, John Brown and Kenneth Noll, 1978. State-of-the-Art Study:
Demilitarization of Conventional Munitions. EPA-600/2-78-012,U.S. Environmental Protection Agency, Cincinnati,
OH.
A-26
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Sullivan, J.H., Jr., H.D. Putnam, MA., Keim, B.C. Pruitt, Jr., J.C., Nichols, and J.T. McClave, 1979. "A Summary
and Evaluation of Aquatic Environmental Data in Relation to Establishing Water Quality Criteria for Munitions-
Unique Compounds. Part 3. White Phosphorus, Final Report, Water and Air Research, Inc., Gainesville, FL.
Thunnan, Harold V. 1975. Introductory Oceanography. Charles E. Merrill Publishing. Columbus, OH.
Truitt, Reginald V. undated. High Winds-High Tides - A Chronicle of Maryland's Coastal Hurricanes. Natural
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United States Army Corp of Engineers, 1982. Report on Aberdeen Proving Ground Waters-Sediment Sampling.
Aberdeen Proving Ground, Maryland.
U.S. Army Toxic and Hazardous Materials Agency, 1980. Installation Assessment of Aberdeen Proving Ground,
Vol. I, Report No. 101. Aberdeen Proving Ground, Maryland.
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A-27
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Appendix B
B-1
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Case Study: Remedial Action Implementation, Elizabeth, New Jersey
Following a fire at the Chemical Control Corporation
Superfund site, Elizabeth, New Jersey, In August 1980,
EPA and the U.S. Army Corps of Engineers cleaned up
and removed waste gas cylinders from the site. Initially,
the cylinders had been blanketed in sand and encased
In overpacking. Most of the cylinders contained an
explosive mixture. This explosive gas was treated and
rendered inert before the cylinders were removed from
the overpacks.
Remedial engineers sampled the 188 unmarked
cylinders using a cylinder recovery vessel (CRV), which
is a. pressure vessel that remotely samples and
evacuates cylinders with inoperable valves. The
cylinders were stored in a vapor containment area
(VGA) during this operation, and sampled and analyzed
remotely from a laboratory 200 ft away. Analysis was
performed using mass spectroscopy and Fourier
transform infrared spectroscopy. The atmosphere in the
VCAwas monitored continuously and precautions were
taken to protect against detonation.
Video Monitoring
Camera*
Cylinder Rack
Vapor Containment
Structure
Following analysis, the cylinder contents were treated
using four principal methods:
Flare stack, which allowed combustibles to be vented
and ignited.
Activated carbon adsorption.
Liquid impinger scrubber, which reacted various
gases with appropriate reagents in a packed column.
Molecular sieve, which used ion exchange to bind
chemicals for disposal.
Cylinder contents that could not be treated by one of
the above methods were re-encapsulated for offsite
treatment The entire cylinder cleanup operation took
approximately 8 weeks.
Figure B-1 is a schematic of a later generation system
for waste gas cylinder management. This equipment
was used to decommission approximately 2,000
cylinders from the Grace Laboratories Superfund site in
Remote Valve Sampling
Vacuum Pump
Venturl Vacuum Pumps
Liquid
Reactors
Sample
Panel
Emergency
Treatment
Unit
Cooling
System
Video
Monitors
Reclrculatlon
Pumps
Control
Panel
Air Tight
Sealed Hatch
Bulk Head
Figure B-1. Schematic of waste cylinder management system.
B-2
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Greer, South Carolina. The system, which to endoeed A unit designed to thermally destroy flammable
in a mobile trailer, provided several separate treatment gases.
Equipment for removal of oxidation products from the
Three liquid reactors that treat reactive gases, thermal oxidation system.
"** which
U.S. GOVERNMENT PRINTING OFFICE: 1995-650-006/22047
D*3
-------
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Environmental Protection Agency
Center for Environmental Research Information)
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