Dioxin Treatment Technologies

November 1991

OTA-BP-O-93

NTIS order #PB92-152511
Recommended Citation:

U.S. Congress, Office of Technology Assessment, Dioxin Treatment Technologies+

Background Paper, OTA-BP-O-93 (Washington, DC: U.S. Government printing Office,

November 1991).

For sale by the U.S. Government Printing Office

Superintendent of Documents, Mail Stop: SSOP, Washington, DC 20402-9328

ISBN 0-16 -036007-2
Foreword

Nearly 100 hazardous waste sites around the United States have serious problems with

dioxin contamination. Very little actual cleanup has been done at these sites. Plans to

incinerate dioxin-contaminated materials at some sites have caused concern in the local

communities that has led to public debate about the effectiveness of incineration and the

availability of other remediation alternatives.

Because of these public concerns, Congressman Richard A. Gephardt asked OTA for

some technical assistance on dioxin remediation technologies. OTA’s previous assessments

of hazardous waste treatment technologies, done for various committees, provided an

appropriate base of expertise from which to undertake this more focused follow-on work. This

resulting background paper evaluates alternative destruction technologies suitable for

dioxin-contaminated soils and debris, and assesses the potential benefits and risks of their use

on a large-scale dioxin cleanup.

This paper presents the status of national efforts to cleanup dioxin-contaminated sites and

the technologies that have been used, proposed, and researched. It covers thermal and

nonthermal treatment techniques as well as approaches such as stabilization and storage. It

discusses the development of these technologies as well as advantages and disadvantages of

their use.

Because dioxin destruction is both difficult and costly, to date only a few technologies

have advanced beyond the research stage, and only incineration has been fully tested and

approved for use at specific sites by the regulators. OTA concluded that, while these other

technologies have promise, they will require more development effort and funding to prove

suitable for specific applications.

OTA appreciates the assistance and support this effort received from workshop

participants, reviewers, and other contributors. They provided OTA with valuable information

critical to the completion of this study and enabled OTA to incorporate much more complete

and accurate analyses. OTA, however, remains solely responsible for the contents of this

report.

u JOHN H.-GIBBONS

Director
Dioxin

Workshop Participants

Charlotte Baker

Environmental, Health, and Safety Office

University of California, Irvine

Stephen A. Boyd

Department of Crop and Soil Sciences

Michigan State University

Robert E. Ginsburg

Environmental Health Consultant

Linda E. James

Dioxin Management Unit

Treatment Technologies

Other Reviewers

Jimmy W. Boyd

J.M. Huber Corp.

Kevin R. Bruce

Acurex Corp.

A.M. Chakrabarty

University of Illinois College of Medicine

Ritu Chaudhari

Metcalf & Eddie

Robert Feild

U.S. Environmental Protection Agency

Missouri Department of Natural Resources - -

A

Ralph A. Koenig

Merlin Co.

Stephen Lester

Citizens Clearinghouse on Hazardous Waste

Peter Montague

Environmental Research Fund

Dennis J. Paustenbach

McLaren Hart Co.

Patrick A. Phillips

Vesta Technologies, Ltd.

Paul W. Rodgers

Limno-Tech, Inc.

Charles J. Rogers

Risk Reduction Engineering Laboratory

U.S. Environmental Protection Agency

Paul E. des Rosiers

Dioxin Disposal Advisory Group

U.S. Environmental Protection Agency

Ray Forester

McLaren Hart Co.

Robert D. Fox

International Technology Corp.

Florence Kinoshita

Hercules, Inc.

Donald A. Oberacker

Risk Reduction Engineering Laboratory

U.S. Environmental Protection Agency

Abu Talib

MITRE Corp.

Evelyn Tapani

Massachusetts Department of Environmental

Protection

Armon F. Yanders

Environmental Trace Substances Research Center

University of Missouri

NOTE: OTA appreciates and is grateful for the valuable assistance and thoughtful critiques provided by the workshop participants.

The workshop participants do not, however, necessarily approve, disapprove, or endorse this report. OTA assumes full

responsibility for the report and the accuracy of its contents.

iv
OTA Project Staff:

Dioxin Treatment Technologies

John Andelin, Assistant Director, OTA

Science, Information, and Natural Resources Division

Robert W. Niblock, Oceans and Environment Program Manager

Peter A. Johnson, Project Director

German Reyes, Principal Analyst

OTA Contributors

Emilia L. Govan

Joan Ham

Tara O’Toole

James Curlin

Michael Gough

Administrative Staff

Kathleen Beil, Office Administrator

Sally Van Aller, Administrative Secretary

Contractor

Florence Poillon, Editor

v
Contents

Page

Chapter 1. Introduction and Summary ..o. ..*. ..o*. ... o.. .*ooo. **co .so. *.. ... Q*....**** 1

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Federal Efforts To Address the Dioxin Problem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

How Regulations Affect Technology Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Summary of Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Chapter 2. Thermal Treatment Technologies ... ... ..** ... e *********m******.*********** 11

ROTARY KILN INCINERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Stationary or Land-Based Rotary Kiln Incinerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Mobile Rotary Kiln Incinerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

LIQUID INJECTION INCINERATION TECHNOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Cost Estimates for Liquid Injection Incineration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

FLUIDIZED-BED INCINERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Waste-Tech Services System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Ogden’s Circulating-Bed Combustor (CBC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Cost Estimates for Fluidized-Bed Incineration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

HIGH-TEMPERATURE FLUID WALL DESTRUCTION-ADVANCED

ELECTRIC REACTOR (AER) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Cost Estimates for AER Incineration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

INFRARED INCINERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Testing and Availability of Infrared Incineration Technology . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Cost Estimates for Infrared Incineration Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

PLASMA ARC PYROLYSIS INCINERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Testing and Availability of PAP Incineration Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

SUPERCRITICAL WATER OXIDATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Testing and Availability of SCWO Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Cost Estimates for SCWO Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

IN SITU VITRIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Testing and Availability of ISV Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Cost Estimates for ISV Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Chapter 3. Nonthermal Treatment Technologies ... ... ... ... ... *.. ..** **** e *0********** 35

DECHLORINATION TECHNOLOGIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Early Dechlorination Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Recent Dechlorination Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

BIOREMEDIATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Testing and Availability of Bioremediation Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Cost Estimates for Bioremediation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Chapter 4. Other Remediation Technologies ● *.** **m. .. *****e******.******************* 51

ONSITE SOIL WASHING TECHNOLOGIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Testing and Availability of Soil Washing Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Westinghouse Electric Soil Washing Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

BioTrol Soil Washing Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

SOLIDIFICATION AND STABILIZATION TECHNOLOGIES . . . . . . . . . . . . . . . . . . . . .....52

Testing and Availability of S/S Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

EPA QUICKLIME TREAMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

INTERNATIONAL WASTE TECHNOLOGIES TREAMENT . . . . . . . . . . . . . . . . . . . . . . . . . . 55

UNDERGROUND MINE STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

ABOVEGROUND, ELEVATED STORAGE BUILDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Chapter 5. Technology and Cost Summary ... ***. .*** **9 ***************e********.***** 59

THERMAL TREATMENT TECHNOLOGIES ... ... *.** .*. *.. ... ... .*** *OF...*.....***. 59

NONTHERMAL TREATMENT TECHNOLOGIES . . . . . . . . . . . * . . * . * * . . * * . * . . . ...*...** 61

COST ESTIMATES OF DIOXIN TREATMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Appendix A. Summary of the Cleanup at Times Beach ● **** *0**   ** *. ... *.. ******00* 67

Figures

Figure Page

2-1. Rotary Kiln . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2-2. Rollins Environmental Services Rotary Kiln Incineration System . . . . . . . . . . . . . . . . . . . . . 14

2-3. Vertically Oriented Liquid Injection Incinerator ● . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2-4. Schematic Diagram of the Waste-Tech Incineration Process . . . . . . . . . . . . . . . . . . . . . . . . . 20

2-5. Circulating-Bed Combustion System Offered by Ogden Environmental Services,

San Diego, CA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

2-6. Major Components of the AER Treatment Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2-7. Infrared Incineration Process Offered by Westinghouse Environmental Services,

Pittsburgh, PA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

2-8. Westinghouse Environmental Services’ Pyroplasma Waste Destruction Unit . . . . . . . . . . 28

2-9. Supercritical Water Oxidation Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2-10. Bench-Scale ISV Unit Tested With Dioxin-Contaminated Soil From the

. . . . . . . . . . .

Jacksonville, AR Superfund Site in February 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

3-1. Galson Remediation Corp.’s APEG-PLUS chemical Treatment System . . . . . . . . . . . . . . 38

3-2. Reactor Used for Thermochemical Treatment in Eco Logic Process . . . . . . . . . . . . . . . . . . 43

3-3. Schematic Flow Diagram of the Thermal Gas-Phase Reductive Dechlorination

Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3-4. Low-Temperature Thermal Resorption Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4-1. Westinghouse Soil Washing Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4-2. Soil Washing System Offered by BioTrol, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

4-3. Example of Proposed Design for Above-ground Storage Facility . . . . . . . . . . . . . . . . . . . . . . 58

Tables

Table Page

1-1. Dioxin-Contaminated Sites on the National Priorities List as of Mar. 14, 1991 . . . . . . . . . . 3

1-2. Major Regulatory Initiatives To Address Dioxin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1-3. Sites With Highest Dioxin Contamination Levels in Soil Identified in EPA’s 1987

National Dioxin Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1-4. Dioxin Treatment Standard Expressed as Concentration in Waste Extract Under

the Resource Conservation and Recovery Act (RCRA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1-5. Development Status of Dioxin Treatment Technologies Reviewed in This

Background Paper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2-1. Estimated Average Cost Per Pound To Incinerate PCB Waste . . . . . . . . . . . . . . . . . . . . . . . . . 15

vii
Chapter 1

Introduction and Summary

INTRODUCTION

About 100 waste sites across the United States

contain serious dioxin contamination; 18 of these, in

10 States, are Superfund sites.l Treating dioxin

contamination at these sites is both costly and

difficult. Current cleanup standards require that

treatment reduce dioxin residuals to very low

levels. 2 The allowable level of residuals is so strict

because of past studies and the Environmental

Protection Agency’s (EPA) assessment that dioxin

poses a serious cancer hazard. Recently, EPA has

decided to reevaluate dioxin’s toxicity and its

regulatory requirements,3 however, currently approved cleanup projects and most of those planned

must meet the current standard.

The term dioxin encompasses all aromatic organic chemicals known as dibenzo-p-dioxins. The

dibenzo-p-dioxins of greatest concern to public and

environmental health belong to a group of chemicals

called halogenated dioxins. Because they are most

common, the 75 chlorinated dioxins that contain one

or more chlorine atoms in their molecular structure

are the form given most attention.4 Dioxins are

extremely insoluble in water and slightly soluble in

organic solvents. They have a strong affinity for

absorption on organic matter and are very biologically and environmentally stable.5 Therefore, as

environmental contaminants, they persist for long

periods of time.

Dioxins are undesirable byproducts formed during the manufacture of some useful chemicals such

as chlorophenols, chlorobenzenes, and chlorophenoxyl pesticides. Almost all dioxin-containing products are no longer manufactured.G For example, Dow

Chemical and Vertac ceased production of phenoxy

herbicides in 1979 and 1983, respectively. However, past use has resulted in contamination of a

variety of sites. Dioxin contamination is now found

primarily in soil and in processing waste containers

stored at inactive production sites. Of the 500,000

metric tons of dioxin-contaminated materials reported by EPA in 1986,8 more than 98 percent

consisted of dioxin-contaminated soil; most of the

remaining consisted of stored, processed material.

While not a subject covered in this background

paper, there also is public concern about other

current sources of dioxin that may result in releases

to the environment. For example, dioxin may be

formed and subsequently released into the atmosphere during the incineration of trash, garbage, and

discards (municipal solid waste) containing chlorinated materials.9 Plans for studying and controlling

U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, National Dioxin study-Report to Congress,

EPA/530/SW-87/025 (Washington, DC: August 1987), p. II-3; “Current National Priorities List” (dioxin sites only); information provided by G. Willey,

U.S. EPA, Hazardous Waste Evaluation Division, Site Assessment Branch, June 17, 1991.

2The current action level is 1 part per billion ppb) (of 2,3,7,8-tetrachlorodibenzo-p-dixoin (TCCD) equivalents) when the site is in a residential area.

When the site is in a nonresidential, nonindustrial area the action level is 20 ppb. The 1 ppb level was established as a response to a Centers for Disease

Control risk assessment that established this as a “level of concern.” See: R.D. Kimbrough H. Falk, P. Stehr, and G. Fries, “Health Implications of

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) of Residual Soil,” J. Toxicol. Environ. Health, vol. 14, 1984, pp. 49-93.

3EPA is currently reviewing the potnency of dioxin. A reevaluation report Written by the Office of Research and Development With the help of outside

scientists will be completed next year. See: David J. Hanson “Dioxin Toxicity: New Studies Prompt Debate, Regulatory Action,” Chemical &

Engineering News, Aug. 12, 1991, pp. 7-14.

4The most tofic of tie c~o~ted dio~ is 2,3,7,8-T~D. ~ addition to 2,3,7,8 -TCDD, o~er products of con~m include ChhrhMkd

dibenzofurans (CDFS), chlorophenols, chlorobenzenes, and chlorophenoxy compounds.

5u.so Env~nmen~ ~otection Agency, ~dous wa5te ~~~~ R~~ch ~boratory, T~ea~~n~ Technologies for Dioxz”n-contai?ling

Wastes, EPA/600/2-86/096 (Cincinnati, OH: October 1986), pp. 1.3-1.4, 3.4-3.7; D. Oakland, “Dioxins: Sources, Combustion Theories & Effects,”

Imndon Scientilc Services, 54th Annual NSCA Conf. Proc., Brightoq U.K., 1987.

%e one exception in the United States is pentachlorophenol (PCP). EPA estimates that current PCP production at Vulcan Chemicals in Wichi@

KS, may be responsible for the generation of up to 5,000 pounds of dioxins and other related chemicals annually; however, these chemicals are generally

contained within the treated wood produced at the plant.

72,4,5 -~cMorophmol.

8u.s. Environmental Protection Agency, op. Cit., foo~ote 5.

*or a complete discussion on the potential routes or pathways by which humans may be exposed to dioxin emissions from incinerators, see: G.F.

Fries and D.J. Paustenbach “Evaluation of Potential Transmission of 2,3,7,8-tetrachlorodibenzo-p-dioxin-con taminated Incinerator Emission to

Humans Via Foods,” J. Toxicol. Environ. Health, vol. 29, 1990, pp. 1-43.

–l–
2 ● Dioxin Treatment Technologies

dioxin emissions from municipal waste incinerators

were recently published by EPA.10 Another dioxin

source is the manufacturing and chlorine bleaching

of pulp and paper products. Some dioxin containing

effluents are discharged from pulp and paper plants

into surface waters. Dioxin contamination is also

found at abandoned paper production plants and at

paper waste disposal sites.ll

In the past, a variety of incidents have led to

dioxin contamination of the environment. A few

examples of such incidents include: the accidental

discharge of dioxin from a trichlorophenol/hexachlorophene production plant in Seveso, Italy;

dioxin contamination of large quantities of soil at a

Gulfport, Mississippi, Naval Ship Yard Repair Base

from the leakage of stored drums of Agent Orange;

and the use of dioxin-containing still-bottom waste

oils12 as a road dust suppressant in towns such as

Times Beach, Missouri. Contamination of soil has

also occurred in areas where dioxin-contaminated

herbicides were used for vegetation control or where

material from these contaminated areas was used for

construction purposes.13

Human health effects from exposure to dioxin

have been studied by scientists for about two

decades. Animal studies showed dioxin to be the

most potent carcinogen ever tested. However, studies of humans exposed to low doses of dioxin have

not demonstrated excess cancers among these

groups. l4 A recent epidemiologic study of chemical

workers at 12 plants in the United States exposed to

dioxin, however, does provide evidence of carcinogenic effects following chronic exposure to relatively high doses.15 Scientists are now debating a

relatively new theory about the action of dioxin on

a molecular level, and some believe that the outcome

of this debate could change the way EPA estimates

the levels of dioxin exposure that are dangerous to

human health. At present, Environmental Protection

Agency standards for dioxin exposure are generally

considered conservative and are much lower than

those recommended by the World Health Organization and most other countries’ regulatory agencies.l6

Whether or when exposure limits in the United

States will change, however, is not known and has

not been analyzed by OTA for the purposes of this

background paper.

Nevertheless, exposure of humans to dioxin

continues to be of great public concern. For many

reasons, sites with dioxin-contaminated soil have

been studied for a long time, but no actual cleanup

work has begun. Because communities surrounding

these sites have been told of the dangers of dioxin

and have been convinced that something needs to be

done, they have been disappointed that so few

remedial actions have occurred. Further, since they

have read that no technology can totally destroy

dioxin or that some technologies can pose other

health hazards, the public is understandably skeptical of technological solutions now being proposed.

Because of the public’s concern, OTA was asked

to prepare an analysis of alternative technologies for

10U.S. Environmen~ Protection Agency, OffIce of Research and Development Office of Environmental En@IUXT@ ad ~hnoIotIY

Demonstratio~ Municipal Solid Waste Research Agenah (Washington DC: April 1991), p. 32.

llForacomprehensive analysis of theenvironmental effect associatedwith the pulp andpapermaking industry and technologies avddleforr~ucing

dioxin releases, see: Oftice of lkchnology Assessment, Technologies for Reducing Dioxin in the Manufacture of Bleached Wood Pulp-Background

Paper, OTA-BP-O-54 (Washington DC: U.S. Government Printing Mice, May 1989).

lzIn some cues, s~l-~ttom residues were mixed with waste oil from a variety of sources, probably largely used crankcase Om md ~ at le~t oQe

other case, it is suspected, undiluted still-bottoms themselves were applied directly to roads and horse mnas.

13M.A. ~~d P.W. Rodgers (~.), Diom”n~ in the Environment (New Yor~ NY: Hemisphere Publishing Inc., 1985); S. Cerlesi A. Di Domenico

and S. Ratti, “2,3,7,8-tetrach.lorodibenzo-p-dioxin (TCDD) Persistence in the Seveso (Milan, Italy) Soil,” Ecotox. Environ. Safety, vol. 18, 1989, pp.

149-164; A. Di Domenico, G. Viviono, and G. Zappo@ “Environmental Persistence of 2,3,7,8-TCDD at Seveso,” in O. Hutzinger, RW. Frei, E.

Merioq and F, Pocchiari (eds.), Chlorinated Dioxins and Related Compounds: Zmpact on the Environment (New Yo~ NY: Pergamon Press, 1982),

pp. 105-144; D.A. Oberacker, J.J. Cudahy, and M.K. Richards, “Remediation (Clean Up) of Contamma “ ted Uncontrolled Superfund Dumpsites by

Incineration and Other Popular lkchnologies,” 1991 (paper submitted for publication).

14M,ic~el GOU~ “HumaII Health Effects: What the Data Indicate,” The Science of the Total Environment, vol. 104, undated, pp. 129-158, 1991;

G.F. Fries and D.J. Paustenbac@ “Evaluation of Potential Transmission of 2,3,7,8-tetrachlomdibenzo-p4ioxin-Con taminated ~cinerator Emissions to

Humans Via Foods,” J. ToxicoL Environ. Health, vol. 29, 1990, pp. 1-43; D.J. Paustenbach et al., “Recent Developments on the Hazards Posed by

2,3,7,8-tetrachlomdibenzo-p-dioxin in Soil: Implications for Setting Risk-Based Cleaning Levels at Residential and Industrial Sites,” this paper was

submitted for publication to the J. Toxicol. Environ. Health, June 1991.

15M.A. Ffigmhu4 W-A. ~W~ D.A. wlow, et d., “c~cer Mortality in Workers Exposed to 2,3,7,8-te~cMomtibemo-p-dioti’ ‘New England

Journal of Medicine, vol. 324, No. 4, Jan. 24, 1991, pp. 212-218.

16The world H~th ~g~ation is the coor~fig ~ency of the unit~ Nations responsible for in@’xMtio~ health work. SOIQe Of be @tiVitieS

carried out by WHO include: providing advice and practical assistance to mtional governments to strengthen their national health services; providing

means to control or eradicate major disease; and improving sanitation.
Chapter 1-Introduction and Summary ● 3

Table l-l—Dioxin-Contaminated Sites on the National Priorities List

as of Mar. 14, 1991 (effective date of Revised Hazard Ranking System)

Observed release

Ground- Surface

Site nameaLocation water water Air

Standard Steel & Metal Salvage Yard . . . . . . . . .

Arkwood, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Jacksonville Municipal Landfill . . . . . . . . . . . . . . . .

Rogers Road Municipal Landfill . . . . . . . . . . . . . .

Vertac, inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wedzeb Enterprises, inc. . . . . . . . . . . . . . . . . . . . . .

Parsons Chemical Works, inc. . . . . . . . . . . . . . . .

Minker/Stout/Romaine Creek . . . . . . . . . . . . . . . .

Shenandoah Stables . . . . . . . . . . . . . . . . . . . . . . . . .

Syntex Agribusiness, Inc. . . . . . . . . . . . . . . . . . . . .

Times Beach site . . . . . . . . . . . . . . . . . . . . . . . . . . .

Brook industrial Park . . . . . . . . . . . . . . . . . . . . . . . . .

Diamond Aikali Co. . . . . . . . . . . . . . . . . . . . . . . . . . .

Hooker (Hyde Park) . . . . . . . . . . . . . . . . . . . . . . . . .

Love Canal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mallory Capacitor Co. . . . . . . . . . . . . . . . . . . . . . . . .

Saunders Supply Co.. . . . . . . . . . . . . . . . . . . . . . . .

Centralia Municipal Landfill . . . . . . . . . . . . . . . . . . .

Anchorage, AK

Omaha, AR

Jacksonville, AR

Jaoksonville, AR

Jacksonville, AR

Lebanon, IN

Grand Ledge, Ml

Imperial, MO

Moscow Mills, MO

Verona, MO

Times Beach, MO

Bound Brook, NJ

Newark, NJ

Niagara Falls, NY

Niagara Falls, NY

Waynesboro, TN

Chuckatuck, VA

Centralia, WA

No

No

No

No

No

No

No

No

No

Yes

No

Yes

No

No

No

No

No

No

No

No

No

No

Yes

No

Yes

Yes

No

Yes

No

No

No

Yes

Yes

No

No

No

No

No

No

No

Yes

No

No

Yes

Yes

No

No

No

Yes

Yes

No

No

No

No

aseveral other Supedund sites known to contain dioxin contamination (e.g., Baitd & McGuire in Holbrook,

Massachusetts) were excluded because dioxin was not the only reason for their inclusion by EPA on the Nationai

Priorities List.

SOURCE: “Current National Priorities List” (dioxin sites only), and supplementary information communicated by G.

Willey, U.S. Environmental Protection Agency, Hazardous Site Evaluation Division, Site Assessment

Branch, June 17 and Sept. 12, 1991.

treating soil and other materials contaminated by

dioxin. This analysis is thus focused on the efficacy,

availability, and merits of various technologies that

could be used to treat dioxin contamination. This

report evaluates the various technologies that are

proven and readily available to be applied as well as

those still in the research stage. It compares the

advantages and limitations of these technologies,

and explores the factors that will determine whether

they may actually be applied to a dioxin cleanup

operation.

This OTA background paper, however, is not

meant to represent a complete summary of all

potentially applicable technologies that have been

developed to date but is a review of those treatment

processes with most promise to treat dioxincontaminated soils.

Table 1-1 lists the contaminated sites known to

contain dioxin that EPA has placed on the National

Priorities List (NPL) for cleanup (also known as

Superfund sites). These sites represent the major

dioxin cleanup challenges that the technologies

covered in this paper would address.

Federal Efforts To Address

the Dioxin Problem

The potential hazard posed by dioxin has been

addressed by Federal and State agencies in a number

of ways for about 25 years. It has been identified as

a toxic substance, advanced notification and treatment requirements for dioxin disposal have been

written, a national dioxin strategy has been established, and incineration has been selected as the

preferred technology for dioxin destruction. Table

1-2 contains a chronological description of major

regulatory activities carried out in the United States

since 1966 to address the dioxin problem.

In November 1983, EPA issued its national

strategy to investigate, identify, and remediate
4 ● Dioxin Treatment Technologies

Table 1-2—Major Regulatory Initiatives To Address Dioxin

1966:

1974:

1976:

1979:

1980:

1982:

1983:

1985:

U.S. Department of Agriculture (USDA) and the Food and

Drug Administration (FDA) establish residue tolerance for the herbicide 2,4,5-T in food products.

Centers for Disease Control (CDC) identifies dioxin as

the toxic substance in Missouri waste oil.

Resource Conservation and Recovery Act (RCRA), the

first Federal law governing waste cleanup or proper

disposal is passed.

The Environmental Protection Agency (EPA) issues an

emergency suspension order banning use of the

phenoxy herbicide 2,4,5-T.

EPA requires advanced notification of disposal of dioxincontaminated waste. Drums of waste contaminated

with dioxin are found on the Denney Farm in Missouri.

The first clear evidence that the half-life of dioxin in

Missouri soil was much longer than 1 year, based on

the laboratory findings obtained at the University of

Missouri’s Environmental Trace Substances Research

Center.a

EPA discovers dioxin levels up to 1,200 parts per billion

(ppb) in Times Beach, MO, and contamination in 14

other Missouri sites. Meremec River overflows in

December, and officials worry about contamination

spreading to other sites (it did not).

EPA and Missouri Department of Natural Resources offer

to buy Times Beach because of the unavailability of

demonstrated treatment technologies and the uncertainty about when cleanup would be completed.

EPA issues a proposed rule allowing disposal of dioxincontaminated waste only in approved landfills and a

“national dioxin strategy” for investigating, identifying, and cleaning up sites contaminated with dioxin

(99 sites across the United States were identified with

potentially serious dioxin contamination).

RCRA dioxin-listing rule now defines waste streams

designated as acutely hazardous. Moreover, this rule

replaces the regulation concerning the disposal of

waste contaminated with 2,3,7,8-TCDD under the

Toxic Substance Control Act (TSCA).

1986: Because dioxin wastes are banned from land disposal

under the Hazardous and Solid Waste Amendments

(HSWA) of 1984, EPA issues interim rule that these

wastes must be treated to a detectable level of 1 ppb

in the waste extract for TCDD and five other compounds.They must also be treated to a nondetectable

level for 2,4,5-T and three other compounds.

EPA efforts to prevent potential dioxin exposure

include regulation of dioxin-containing discharges

under the Clean Water Act.

1987: The Risk Assessment Forum of the Environmental

Protection Agency develops and publishes 2,3,7,8-

tetrachlorodibenzo-p-dioxin (TCDD) Toxicity Equivalent Factors (TEFs).

1988: EPA issues its Record of Decision to employ incineration

as a remedial technology at Times Beach, based on

results from a research incineration project at Denney

Farm, MO. EPA Dioxin Disposal Advisory Group

(DDAG) recommends a general approach for the

disposition of pentachlorophenol (PCP) and PCBs

waste and contaminated soil. The recommended

levels of this approach were 1 ppb TCDD equivalents

for residential areas and 20 ppb TCDD equivalents for

industrial or nonresidential sites.

1990: State of Connecticut issues dioxin ambient air quality

standard of 1 picogram per cubic meter (1 picogram

= one-trillionth of a gram) to protect the public from

combined effects of dioxin from all media, sources,

and exposure routes.

1991 : EPA orders reevaluation of the risk assessment model for

dioxin in light of the increasing scientific data available. This effort will focus primarily on reassessing

health effects due to dioxin, gathering new laboratory

data, and investigating ecological effects.

%ialf-lbms for dioxin ranging from 25 to 100 years (subsurface soils) and from 9 to 35 years (surface soils) have been suggested since then. Recent efforts

to control dioxin emissions, such as Connecticut’s dioxin ambient air quality standard, have assumed half-live values for dioxin of nearly 6 years (2,120 days).

Formoredetails see: Dennis J. Paustenbach, “Recent Developments on the Hazards Posed by 2,3,7,8-tetrachlorodibenzo-pdioxin in Soil: Implications for

Setting Risk-Based Cleanup kvels at Residential and Industrial Sites,” paper submitted for publication to J. Toxicd. & i%vinm. Health, June 1991; H.V. Rao

and D.R. Brown, “Connecticut’s Dioxin Ambient Air Quality Standard,” Flisk Analysis, vol. 1, No. 2, 1990, pp. 597-603.

SOURCES: J.R. Long and D.J. Hanson, “Dioxin Issue Focuses on Three Major Controversies in U.S.,”Chemical & Engineering News, vol. 61, June 6,1983,

p. 25; P.E. des Rosiers, “National Dioxin Study,” J.H. Exner (cd.), So/ving Hazardous 14’aste Prob/ems:Leaming From Dioxins, ch. 3, pp. 34-53,

ACS Symposium Series 338, Washington, DC, 1987; R.D. Kimbrough et al., “Health Implications of 2,3,7,6-tetrachlorodibenzo-pdioxin (TCDD)

Contamination of Residential Soil, J. Toxicd. & Environ. F/ea/th, vol. 14, 1984, p. 47; H.V. Rao and D.R. Brown, “Connecticut’s Dioxin Ambient

Air Quality Standard,” Risk Ana/ysls, vol. 1, No. 2, 1990, pp. 597-603; U.S. Environmental Protection Agency, Office of Solid Waste and

Emergency Response, National Dioxin Study-Report to Congress, EPIV530/SW-87/025 (Washington, DC: August 1987), pp. VI-V5; J.S. Benin

and D.G. Barnes, Risk Assessment Forum, “Interim Procedures for Estimating Risks Associated With Exposures to Mixtures of Chlorinated

Dibenzo-pdioxins and Dibenzofurans (CDDS and CDFS),” EPA/625/3-87/O12, March 1987; A.F. Yonders, C.E. Orazio, R.K. Puri, and S. Kapila,

“On Translocation of 2,3,7,8-tetrachlorodibenzo-pdioxin: Time-Dependent Analysis at the Times Beach Experimental Site,” Chemosphere, vol.

19, 1989, p. 41a.

dioxin-contamin ated areas.17 Accompanying the As part of its strategy, EPA identified suspected

congressionally mandated strategy was a plan to areas of dioxin contamination by the source of

conduct research to determine existing contamina- dioxins. By the end of its study, EPA had identified

tion levels and available treatment and disposal 99 sites across the United States with potentially

methods. Evaluation of environmental and human serious dioxin contamination. As expected, the

health risks posed by dioxin contamination of majority were sites where chlorinated organics had

various media was also part of the study. been produced or used in the formulation of pesti17u.s. Env~omen~ ~otection Agency, ()&~C~ of Water ~d Office of Solid Waste and Emergency Response in Conjmction With Dioxin

Management Task Force, Dioxin Strategy (Washington, DC: Nov. 28, 1983).
Chapter 1-Introduction and Summary ● 5

cides and herbicides, or disposed of on land.18 As

indicated in table 1-3, 9 of the 14 sites with the

highest measured levels of dioxin contamination

were located in Missouri.

In addition to its high dioxin contamination, the

Denney Farm, Missouri, site attracted national

attention because it was there that EPA tested and

perfected the mobile rotary kiln incineration technology now recommended for dioxin cleanup. The

field testing of mobile incineration at Denney Farm

started in February 1986 and concluded in June

1989.19 Since then, this system has been upgraded by

commercial firms and employed with success at

several small contaminated sites. So far, incineration

is the only remediation technology that has been

shown effective at destroying dioxin in soil.

Mobile incineration has yet to be applied at larger

dioxin-centaminated sites such as those on the NPL

and listed in table 1-1. At three of these Superfund

sites, EPA has selected incineration as the remedial

technology. These are: the Arkwood site and Vertac

Chemical Corp. site in Arkansas and the Times

Beach, Missouri site. At the Vertac site, current

plans are to incinerate 28,500 drums containing

dioxin-contamin ated phenoxy herbicides from still

bottoms. 20 Prior to implementing this plan, however,

the contractors will have to submit adequate trialburn data to demonstrate that mobile incineration

will meet the required performance criteria and the

local air pollution standards. These trials began

during 1991 and are continuing. If they are successful and prove to meet the standards, operations may

proceed soon after. Continuous public opposition

and some recent operating equipment problems at

Vertac have contributed to delays in the project.21

Developments at the Vertac site are being monitored

closely by some environmental groups, and the level

of success achieved there could substantially influence public acceptability of future incineration

projects.

EPA’s Record of Decision of September 29,1988

for the Times Beach Superfund site calls for the

incineration of more than 92,000 cubic yards of

dioxin-contamin ated soil. Companies with incineration technology capability are currently being

invited to submit contract proposals for treating this

soil. (App. A Summarizes the activities proposed for

remediation at Times Beach.) The plans and progress at this site are also being carefully watched by

the environmental community.

How Regulations Affect Technology

Development 22

The Superfund law or CERCLA (Comprehensive

Environmental Response, Compensation, and Liability Act) requires that the application of remedial

technologies at Superfund sites protect human

health and the environment according to established

Federal, State, and local regulations. In implementing this mandate, EPA has developed a process to

identify the extent of contamination at sites considered national priorities for cleanup, to select and

evaluate cleanup technologies, and to apply the

appropriate remedy. During an early step in the

process known as the Feasibility Study, efforts are

made to develop, screen, and evaluate existing

proven and alternative remedial technologies that

may be applied to the site. Thus far, technology

selection for dioxin sites such as Vertac and Times

Beach has been based on general categories (e.g.,

thermal treatment) rather than on specific treatment

processes (e.g., rotary kiln, circulating-bed combus18Paul E. des Rosiers, “Evaluation of ‘IkcAnology for Wastes and Soils Contaminated With Dioxins, Furaus, and Related Substances,” .lournal of

Hazardous Materials, vol. 14, 1987, p. 120.

lw.s. EIWiZOnmenM Protection Agency, OffIce of Research and Developmen~ Hazardous Waste Engineering Research Laboratory, Destruction of

Dioxin-Contanu”nated Soils and Liquids by Mobi/e Incineration, EPA/6oo/S2-87/033 (CinCinIMti, (IH: June 1987); U.S. Environmental Protection

Agency, Office of Research and Development Risk Reduction Engineering Laboratory, EPA Mobile Incineration System Modifications, Testing and

Operations, Februaq 1986 to June 1989, EPA/600/52-87/033.

20AMy, EpA selat~ ~c~erationfortie on-site cle~up under its removal authority and the State of Arknsw selected incineration for tr~tm~t

of the drummed, still bottoms waste.

zl’’snafw Plague Vertac Barrel Burn ‘lksts,” Supeq%nd, July 12, 1991, p. 4.

22U.S. Env~omen~ ~otection Agency, ~lce of Rme~ch ~d Developm@ Risk Reduction --g hbomto~, SZTE program

Demonstration Test Soliditech, k., Solidification/Stabilization Process, vol. 1, EPN540/5-89/005a (Cincinnati, OH: February 1990); U.S.

Environmental Protection Agency, Offke of Research and Development Risk Reduction Engineering Laboratory, SITE Superfund Innovative

Technology Evaluation: Technology Projiles, EPW540/5-90/006 (Cincinnati, OH: November 1990); Arthur D. Little, Inc., Evaluation of Available

Cleanup Technologies for Uncontrolled Waste Sites-Final Report, prepared for The Office of ‘I&3mology Assessmen4 Nov. 15, 1984; U.S.

Environmental Protection Agency, Office of Solid waste and Emergency Response, and OffIce of Radiation Programs, Assesswnt of Technologiesfor

the Remediation of Radioactively Contaminated Super@d Sites, EPA/540f2-90/001 (Washington DC: January 1990), p. 1.
6 ● Dioxin Treatment Technologies

Table 1-3-Sites With Highest Dioxin Contamination

Levels in Soil Identified in EPA’s 1987 National

Dioxin Strategy

Concentration

Site Location (ppb)

Diamond Alkali

Hooker Chemical

Brady Metals

Denney Farm

Piazza Road

Shenandoah Stables

Quail Run Mobile Home Park

Dow Chemical Co.

Times Beach

Vertac

Syntex Agribusiness

Sullins Residence

Sontag Road

Bliss Tank Property

Newark, NJ

Niagara Falls, NY

Newark, NJ

Aurora, MO

Rosati, MO

Moscow Mills,MO

Gray Summit, MO

Midland, Ml

Times Beach, MO

Jacksonville, AR

Verona, MO

Fenton, MO

Ballwin, MO

Frontenac, MO

51,000

18,600

3,500

2,000

1,800

1,750

1,650

1,500

1,200

1,200

979

820

588

430

SOURCE: U.S. Environmental Protection Ageney, Office of solid Waste

and Emergency Response, fVationa/ Dioxin Stu@—RePort to

Congress, EPA/530/SW-87/025 (Washington, DC: August 1987),

pp. 11.22-11.33.

tion, infrared thermal combustion, dehalogenation,

etc). A specific technology is selected after contract

proposals submitted by remediation companies are

evaluated and the technology is tested.

In addition to the procedures established under

CERCLA for the testing and selection of technologies at Superfund sites, EPA has also established the

Superfund Innovative Technology Evaluation or

SITE program under its Offices of Research and

Development (ORD) and Solid Waste and Emergency Response (OSWER). According to EPA, the

SITE program was created to “accelerate the

development, demonstration, and use of new or

innovative technologies that offer permanent, longterm cleanup solutions at Superfund sites.’ ’23 Since

its inception, the goals of the SITE program have

been to facilitate and encourage the development

and commercialization of alternative technologies;

conduct field demonstrations of promising technologies to gather and make available data regarding

their performance and application cost; and develop

procedures and policies that favor the selection of

alternative technologies at contaminated sites.

Several potential technologies for dioxin treatment, such as dechlorination, nondestructive treatment or stabilization, and in situ vitrification,x have

been field-tested by EPA under the SITE program

with varying degree of success. Because this opportunity, which often arises during the early stages of

development, is offered only once developers may

face difficulties in implementing and ensuring that

their technologies are at least as effective as incineration. 25 Hence, few of these innovative technologies

are likely to be applied soon to dioxin-contaminated

soil.

Unlike CERCLA, which addresses abandoned

waste sites, the Resource Conservation and Recovery Act (RCRA) addresses the application of treatment technologies at active hazardous waste management facilities. Under RCRA authority, EPA has

established specific treatment and disposal standards for dioxin waste (see table 1-4). EPA has also

used its RCRA authority to address past contamination at active facilities and to establish corrective

action procedures to identify and select treatment

technologies. However, unlike the Superfund law, in

which identifying, evaluating, and selecting a remedial technology is scheduled to take up to 18 months,

RCRA allows a maximurn of only 9 months. Even

though these schedules are not necessarily met in

practice, the time requirement often results in

limited test and evaluation of new technologies.

To SUmmarize , under CERCLA and RCRA, it is

required that selected technologies demonstrate the

ability to significantly reduce the volume, toxicity,

and mobility of dioxins in a cost-effective manner.

In practice, the time allowed to develop alternative

technologies is limited, and the range of applications

tested is narrow.

The favoring of demonstrated technologies for

dioxin treatment, although protective of human

~U.S. Enviro~en@ protection Agency, OflIce of Research and Development Risk Reduction --g bbmtory, s~E program

Demonstration Test Soliditech, k., Solidijicution/Stabilization Process, vol. 1, EPA/540/5-89/005a (CinCiXWMti, OH: February 1990); U.S.

Environmental Protection Agency, Gfflce of Research and Development Risk Reduction Engineering Laboratory, SZTE Superfund Znnowztive

Technology Evaluation: Technology Profiles, EPA/540/5-90/006 (Cincinnati, OH: November 1990).

2@e0,@e cow., the fmrespomible for-g in situ vitri.tlcation available for commercial applications, ksus~nded ~ ~ge-sc~e reme~tion

workpendinganinvestigation (and probably System motilcations) of a recent unexplained explosion or expulsion of the molten glass material due either

to a steam pocket and/or anuncontrolledreaction fiomburied waste drums during a large-scale test. (Source: letter from James E. Hanse@ Geosafe Corp.,

to Norm Neidergang, Associated Division Director, Hazardous Waste Management Division, Oftice of Superfun4 U.S. EPA Region V, June 21, 1991.)

~Formorefio-tion on~etec~olo= ~plaen~tionproblew at tie SI~ progr~ ~dpro~bleways to solve thCIII, S(X2: U.S. (!OngrWS, offlCe

of lkchnology Assessemen4 Coming CIean: Super@uiProblem Can Resolved. . ., OTA-ITE-433 (Washingtor4 DC: U.S. Government Printing Office,

October 1989), pp. 50-51, 181-187.
Chapter 1-Introduction and Summary ● 7

Table 1-4-Dioxin Treatment Standard Expressed as

Concentration in Waste Extract Under the Resource

Conservation and Recovery Act (RCRA)

Dioxin present in waste Concentration a

HxCDD-all hexaohlorodibenzo-pdioxins.......

HxCDF-all hexachorodibenzofurans . . . . . . . . . . .

PeCDD-all pentachlorodibenzo-g+dioxins......

PeCDF—all pentachlorodibenzofurans . . . . . . . . .

TCDD-all tetrachlorodibenzo-p-d ioxins . . . . . . . .

TCDF-all tetrachlorodibenzofurans . . . . . . . . . . . .

2,4,5-Trichlorophenol . . . . . . . . . . . . . . . . . . . . . . . . .

2,4,6-Trichlorophenol . . . . . . . . . . . . . . . . . . . . . . . . .

2,3,4,6-Tetrachlorophenol . . . . . . . . . . . . . . . . . . . . .

Pentachlorophenol . . . . . . . . . . . . . . . . . . . . . . . . . . .

<1 ppb

<1 ppb

<1 ppb

<1 ppb

<1 ppb

<1 ppb

<50 ppb

<50 ppb

<100 ppb

<10 ppb

a

ppb= parts per billion

SOURCE: “Dioxin Treatment Standard Expressed as Concentration in

Waste Extract,” 40 CFR 288.41 (1989).

health and the environment as required by law, also

tends to preclude serious consideration of many

promising emerging technologies that need further

testing. This is particularly true for dioxin treatment

because most promising technologies are at an early

stage of development and they lack sufficient

quantitative performance data. In addition, most

emerging technologies require substantial development costs. The high liability costs associated with

dioxin treatment are also considered an impediment

to technology development. For these reasons, and

because overall innovation is difficult in any case, it

is unlikely that development of new technologies for

dioxin treatment can be accelerated without increases in Federal support for demonstration efforts.

The uncertainty surrounding current thinking about

dioxin toxicity may also slow technology development efforts because industry may wait until a

decision is made to change or not to change

treatment standards.

Summary of Findings

A wide range of existing and proposed hazardous

waste treatment technologies that may be considered

for treating dioxin in soil are analyzed in this

background paper (see table 1-5). At present, incineration is the only available technology that U.S.

regulatory agencies deem acceptable for treatment

of dioxin-contaminated materials. Other technologies are promising, but none has been sufficiently

developed or shown in tests to be adequate for

routine, current cleanup work. Although it may be

possible for cleanup work to be delayed at some sites

until alternative technologies are proven effective or

until the dioxin toxicity question is answered, it is

unlikely that private industry will invest in the

necessary R&D or testing to make this happen soon;

on the other hand, they might if the technology has

broader applications.

Dioxins present a unique problem for those

seeking to develop appropriate treatment technologies because they are difficult to remove from soil

for treatment, and are present in a variety of

contamination settings (i.e., different types of soils

and environmental conditions). To meet cleanup

standards for dioxin, it is also necessary to design

special treatment systems capable of removing the

dioxin from its matrix. The treatment systems must

also meet stringent operating requirements. Many

researchers have consequently focused more attention on contaminants such as polychlorinated biphenyls (PCBs), for which the problem is somewhat

simpler, the quantities of materials to be treated are

much larger and more uniform, and the standards are

less stringent. Moreover, when a permit under the

Toxic Substances Control Act (TSCA) is obtained

for PCBs, it is issued as a national permit, whereas

a RCRA permit for dioxin is only site-specific—

which means that anew permit must be obtained for

each site.

Thermal technologies for dioxin treatment offer

the most straightforward approach because, given

the appropriate temperature and other conditions

needed, one can be assured that the dioxins will be

broken down. Thermal technologies have therefore

been given the most attention, and certain incineration designs have been built, tested, and successfully applied (on a small scale) to dioxin treatment.

Effective incineration requires control and monitoring of emissions and residues. The incinerator

must also handle a wide variety and large quantity of

material (e.g., soil and rubble) present at most

dioxin-contaminated sites. Unique site conditions

combined with the current regulatory process make

it necessary to qualify each proposed technology for

its specific application.% In addition, the public is

skeptical about the actual performance of incinerators operating in their communities and concerned

about whether design conditions will always be

maintained. Safe operating conditions appear attainable with carefully designed and applied incineration technology.

%s takes the form of a “test bum” for each incinerator.
8 ● Dioxin Treatment Technologies

Table 1-5-Development Status of Dioxin Treatment Technologies Reviewed

in This Background Paper

Status of development

For dioxin For other waste

Chapter Category Technology treatment treatment

Two

Two

Two

Two

Two

Two

Two

Two

Three

Three

Three

Three

Three

Thermal

Thermal

Thermal

Thermal

Thermal

Thermal

Thermal

Thermal

Nonthermal

Nonthermal

Nonthermal

Nonthermal

Nonthermal

Rotary kiln incineration

Liquid injection incineration

Fluidized bed incineration

Advanced electric reactor

Infrared incineration

Plasma arc pyrolysis

Supercritical water oxidation

In situ vitrification

Chemical dechlorination

(KPEG, APEG-PLUS)

Base-catalyzed decomposition

Thermal-gas phase reduction

dechlorination

Thermal resorption

(UV destruction)

Bioremediation

A

B

1

B

c

C

2

D

D

D

c

D

E

c

D

A

A

A

c

c

c

c

c

A

D

c

c

c

Key to status of development

A. An operating system has been built, tested, permitted and used on a site cleanup.

B. A system has been built and tested but not permitted or used on a site cleanup.

C. A pilot plant has been built and tested with waste material.

D. Laboratory or bench-scale tests have been completed.

E. Technology is in the research or study phase.

NOTES:

1A sea-based system.

2More experience in Europe.

SOURCE: Office of Technology Assessment, 1991.

All of the above factors, as well as the low level

of allowable residuals, contribute to the relatively

high costs of treatment of dioxin contamination with

incineration technology, and have sparked interest in

alternative technologies such as chemical dechlorination and bioremediation.

Although some alternatives look promising and

have been shown effective in laboratory settings (or

in application to other pollutants), none have received enough development and testing to make

them viable for large-scale treatment of dioxin

centamination today.

Chemical dechlorination techniques (discussed in

ch. 3) have certain advantages that make them good

candidates for development. For example, chemical

dechlorination may be used to treat dioxincontaminated soil and sludge within enclosed reactor systems under mild temperature and pressure

conditions. Such reactors could be relatively simple

to build and operate with minimum production of

off-gases. Chemical dechlorination techniques can

also result in cost savings since reagents can be

recycled. But, chemical dechlorination has not been

sufficiently field tested with dioxins at this time.

Two other highly promising dechlorination technologies, now undergoing field testing, are base

catalyzed decomposition and thermal gas-phase

reductive dechlorination. Other technologies such as

bioremediation are currently in the research stage,

but if research and development proves successful,

they could be useful for in situ treatment, which
Chapter 1-Introduction and Summary ● 9

would eliminate many problems associated with

excavating, transporting, and handling of dioxincontaminated soil. The key factor for bioremediation

technologies continues to be getting the dioxin

molecules off the soil and in contact with a

microorganism. Demonstration of the effectiveness

of most bioremediation approaches is still some

years away but laboratory tests continue to be

promising.

Finally, some combinations of technologies (e.g.,

use of both thermal and dechlorination techniques)

could also prove very effective at certain locations

because the best features of each may be enhanced

through careful design. Much more engineering and

testing would be necessary, however, before a

specific application could go forward.

Some researchers have attempted to develop

innovative, in situ treatment technologies for dioxin

but have encountered difficulties in measuring the

extent of dioxin destruction for these processes.

These researchers claim that there is limited longterm support for alternative technology research and

development.

It does not appear that private industry has

sufficient incentive to invest in developing alternative technologies for dioxin. Spinoffs from developments in the treatment of other contaminants (e.g.,

PCBs) could prove useful but, even here, investment

would be required for tests with dioxins. A more

aggressive government program to develop and

prove alternative dioxin treatment technologies

would assist in evaluating their real potential. At

present, however, the development of these alternatives is moving very slowly, and any new solutions

to treating dioxin contamination appear to be along

way off.

Some large corporations have promoted incineration for dioxin treatment through substantial financial investments. Some other companies have designed alternative technologies that they claim could

treat and destroy dioxins. In general, firms have had

difficulty financing the needed development, testing, and marketing for alternative systems, as well as

the legal costs and the cost of attempting to obtain an

EPA operating permit. For example, even after a

technology has been tested, the period required by

EPA to approve a permit application often exceeds

1 year. In light of the relatively small number of

contaminated sites, there appears to be little incentive for the private sector to develop new technologies for destroying dioxin in soil.

In sum, reasonably good performance data in real

applications are available for thermal treatment

technologies for dioxin contamination. Specific

incineration technologies are commercially available that will operate effectively and safely if

properly managed. Promising alternatives to incineration will require further attention and resources if

we wish to determine whether they can be equally

effective. If they are developed, and if specific

designs can be prepared and tested and proven

useful, costs and other factors could be compared.

Such comparisons are not possible with currently

available information.

297-943 0 - 91 - 2 QL 3
Chapter 2

Thermal Treatment Technologies

Thermal technologies involve the use of heat as

the primary treatment agent. During thermal destruction or incineration, organic materials in the

waste are reduced to carbon dioxide (C02) and water

vapor (both of which exit through a stack). Other

chemicals such as chlorine and phosphorus are

captured by the pollution control equipment, whereas

noncombustible materials are captured in the ash.

The Environmental Protection Agency (EPA)

began to consider incineration the preferred technology for treating dioxin-containing materials after

laboratory studies showed that dioxins broke down

easily when exposed to temperatures in excess of

1,200 OC.l To test this process on a much larger

scale, EPA built a mobile research incinerator

specifically designed to treat recalcitrant organic

chemicals. The success of this research, in which the

destruction and removal efficiency (DRE)2 of

dioxin in treated waste exceeded 99.9999 percent,

led EPA to adopt thermal treatment as the appropriate method for destroying dioxin-containing waste.

Extensive research has resulted in the development of several incineration technologies. The most

noteworthy in relation to dioxin treatment are rotary

kilns, liquid injection, fluidized bed/circulating fluidized bed, high-temperature fluid wall destruction

(advanced electric reactor), infrared thermal destruction, plasma arc pyrolysis, supercritical water oxidation, and in situ vitrification.

ROTARY KILN INCINERATION

The variety of containerized and noncontainerized solid and liquid wastes that can be treated

individually or simultaneously in kiln incinerators

has made this thermal technology the most versatile

and popular in the United States. Rotary kilns in use

today are classified into two major categories:

stationary (land based) and mobile (transportable).

The key component of the system, the rotary kiln,

is a refractory-lined cylinder that rotates at a

horizontal angle of 5 degrees or less and at a speed

of 1 to 5 feet per minute. Other features of kiln

incinerators include a shredder, a waste feed system,

a secondary combustion chamber or afterburner, air

pollution control equipment, and a stack. Operators

may also make use of auxiliary heat systems to heat

the kiln to the desired operating temperature.3

As shown in figure 2-1, the solid and liquid wastes

fed into the rotating kiln are partially burned into

inorganic ash and gases. The ash is discarded in an

ash bin, and the gaseous products in which uncombusted organic materials still reside are sent to the

secondary combustion chamber for complete destruction. 4

Rotary kilns in which combustion gases flow

opposite to waste flow through the incinerator

(called countercurrent rotary kilns) are preferred to

those in which gases flow in the same direction

(concurrent). Countercurrent rotary kilns have a lower

Iu.s. ~v~mcn~ ~ot=tion Agency, -dous Wwte fi@~r@ R~~ch ~boratory, ~rearmnt Technologies for DiOXZ”n-cOtltUbli~g

Wastes, EPA/600/2-86/096 (Cincinnati, OH: October 1986), p. 4.1.

?DRE is a major performance standard that, when applied to thermal treatment of dioxin-containing materials, corresponds to a destruction and

removal efficiency of dioxin at a 99.9!399 percent level (or “six nines”). DRE is a function relating the concentrations of a contaminant t prior to and

after treatment. Because treatment residues must not contain dioxins or furans exceeding the EPA standard for land disposal (1 part per billion (ppb);

see note below), it is imperative to Imow in advance if residues from exhaust gases, scrubber water, filter residues, and ash generated by the treatment

chosen will be in complkuw.

NOTE: If the dioxin waste is characterized as an acutely hazardous Resource Conservation and Recovery Act (RCFL4) listed F-waste, see ch. 1, table

1-4 for treatment standards; if such material is not an F-waste, then the required level of treatment is to a dioxin concentration of less than 1 ppb

2,3,7,8-tetrachlorodibenzo-@ioxin equivalents (TCDDe). For instance, when incinerating RCIL4 non-F waste (e.g., PCBs, pentachlorophenol), the

facility operator is required to calculate DREs ftom measurements of chlorodibenzo-p-dioxins and chlorodibenzofurans (CDDs/CDFs) made in the field,

followed by their conversion into TCDDe, because these contaminantts are known to contain a variety of CDDS snd CDFS.

3C~v~ R. B-er, z~inerafion Sysfe~e/ection a~Design @Jew York NY: ~Nostr~d Retiold, 1984), p. 239; ad U.S. Environmental

Protection Agency, op. cit., footnote 1, p. 4.4,

4u.s. Environmen~ Protection Agency, op. cit., footnote 1, p. 4.4.

-11–
12 ● Dioxin Treatment Technologies

1.

2.

3.

4,

5.

6.

7,

Figure 2-l—Rotary Kiln

Material handling system

Auto-cycle feeding system:

feed hopper, door, ram feeder

Waste to incinerator

Combustion air

Refractory-lined, rotating cylinder

Tumble-burning action

Incombustible ash

8. Ash bin 14.

9. Auto-control burner package: 15.

programmed pilot burner 16.

10. Afterburner chamber 17.

11. Heat recuperation

12. Precooler 18.

13. Scrubber package: 19.

stainless steel, corrosion-free scrubber

I

I

I

I

I1,

t

I

I

I

I

I

1

I

I

I

I

I

I

I

I

I

I

I

I

I

I

1

II19

Recycle water, fly ash

Neutralization column

Exhaust fan and stack

sludge

Self-compensating instrumentation

and controls

Support frame

Support piers

SOURCE: Calvin R. Brunner, Incinerator Systems-Selection and Design (New York, NY: Van Nostrand Reinhold, 1984), p. 239.

potential for overheating because the auxiliary heat

burners are located opposite the incinerator.5

The use of rotary kiln incineration for dioxincontaining waste is more common in Europe than in

the United States. An example of this is the

treatment of 2,500 kilograms of toluene still bottoms

waste6 in the CIBA-Geigy incinerator in Basel,

Switzerland. This waste was from the Icmesa reactor

in Seveso, Italy, and it contained approximately 600

grams of 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD).

The treatment achieved residual levels below limits

of detection (0.05 to 0.2 part per billion (ppb)).

Another example is the treatment of dioxin- and

furan-contamin ated oils generated during the conversion of lindane waste through 2,4,5 -TCP7 to

2,4,5-T8, which leaked out of a landfill in Hamburg,

Germany. The dioxins and furans were reported to

be present in the waste at levels exceeding 42,000

p p b

9

Stationary or Land-Based Rotary

Kiln Incinerators

As the name indicates, stationary or land-based

facilities are built to remain at one site. At present,

several stationary rotary kiln facilities have permits

to burn waste containing toxic constituents such as

%id.

%s waste resulted from a process designed to produce 2,4,5 -trichlorophenol from alkaline hydrolysis of 2,3,4,6-tetrachlorophenol.

Y2,4,5-~cMorophenol.

82,4,5-~chlorophaoVacetic acid.

%Iarmut S. Fuhr and J. Paul E. des Rosiers, “Methods of Degra&tioq Destruction Detoxillcalioq and Disposal of Dioxins and Related

Compounds, ” Pilot Study on International Information Exchange and Related Compounds (North Atlantic Treaty Organization Committee on the

Challenges of Modem Society, Report No. 174, August 1988), pp. 23,24-25.
Chapter2-Thermal Treatment Technologies ● 13

those permitted under the authority of the Toxic

Substances Control Act (TSCA) for polychlorinated

biphenyls (PCBs); these include the Rollins Incinerator in Deer Park, Texas; the Waste Chem incinerator in Chicago, Illinois; the ENSCO incinerator in

El Dorado, Arkansas; and the Aptus incinerator in

Coffeyville, Kansas. To date, none of these facilities

has been used to burn dioxins because of the

likelihood of strong public opposition and the lack

of appropriate operating permits under the Resource

Conservation and Recovery Act (RCRA).10 Only

one application-submitted by Rollins in October

1988 and still awaiting EPA approval—has been

filed with EPA to obtain a RCRA permit for burning

dioxin-containing waste. 11 Other stationary incinerators, however, may be able to be upgraded to treat

dioxins if they can satisfy permit requirements.

Other firms also have plans to build and operate

such incinerators. For example, Ogden Environmental Services-in combination with American

Envirotech, Inc.-plans to construct a RCRA incinerator to destroy hazardous waste at a location in

Texas. Construction costs are estimated to be about

$60 million, and operation is expected to begin by

1993 pending permit approval. A draft Part B RCRA

permit has already been issued by the Texas Water

Commission. 12 If built, this facility could eventually

be used for dioxin incineration if its design meets

permit requirements.

Rollins’ Rotary Kiln Incinerator

An example of current stationary incinerator

technology is the stationary rotary kiln incinerator

facility owned by Rollins, Inc., located in Deer Park,

Texas. As shown in figure 2-2, solids are conveyed

or fed into a rotary kiln in 55-gallon metal or fiber

drums, whereas liquid waste is atomized directly

into the secondary combustion chamber or afterburner. The latter unit normally operates between

1,300 and 1,500 ‘C. After being burned, combustion

gases are passed to a combination venturi scrubber/

absorption tower for particle removal. Fans are

employed to drive scrubber gases through the stack

and into the atmosphere.13 Maximum feed rates for

the Rollins incinerator are l,440 pounds per hour for

solids and 6,600 pounds per hour for liquids.14

Rollins Environmental Services already has a

RCRA permit to store and dispose of hazardous

waste; therefore, it intends to add only the inciner-

. 15 Granting of a new ator unit to its current permit.

permit is expected within a year. According to a

company official, however, the real challenge is to

gain the approval of the general public and public

officials to begin operations.l6 If this system is

permitted, it may also be able to meet requirements

for dioxin treatment.

Cost Estimates for Land-Based

Rotary Kiln Incineration

No cost figures on the treatment of dioxincontaining waste are available because to date no

stationary kiln has been permitted to incinerate

dioxins. However, because of the similarities between PCBs and dioxins, one could expect the costs

to be relatively similar to those listed in table 2-1 for

the Rollins incinerator.

Mobile Rotary Kiln Incinerators

The primary purposes of designing and building

a mobile (transportable) incinerator are: 1) to

facilitate temporary field use for treating waste

resulting from cleanup operations at uncontrolled

hazardous waste sites; 2) to promote the application

of cost-effective and advanced technologies; and 3)

to reduce the potential risks associated with transporting waste over long distances.17

IOJew N~.1, Ro~ins J2nviromen~ sewiuS, ~=s, ~aso~ Communication J~. 9, IW1 ~d J~y ltj, 1991; Dtie Schille, APTUS, ~,

personal communicatiorq July 11, 1991; Keith Paulson, Westinghouse Environmental Systems and Services Divisio~ pittsbur~ personal

communication Feb. 11, 1991; U.S. Environmental Protection Agency, op. cit., footnote 1, p. 4.9.

llpJeill, op. cit., foomote 10.

lzpress releme issued by Ogden Projects, hlC., OCt. 22, 1990.

l%id., p. 4.5.

141bid., p. 4.15.

lsBWaWe of dfilc~ties fi Ob-g ~fits,~o~t ~mp~= now apply for regio~ or r@o@ rather~s~tewide, p~ts under TSCA for

burning PCBs and PCB-contaminated waste. Unlike TSCA, RCRA authorizes EPA to grant only site-speciilc permits for treating dioxin-containing

waste.

IGNeill, op. cit., footnote 10.

17uoso Env~o~en~ fiotwtion Agency, ~~k Reduction ~inee~ ~bo~tory, “EPA’s Mobile ~Cinc~tiOn systm for Cleanup Of ~dom

Wastes-Fact Sheet,” January 1989.
14 ● Dioxin Treatment Technologies

G mL

5 u

c.— u

E al

c)

+ 1

c

0 \

141

L

a)

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u.—3

.—u—

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.—L
Chapter 2—Thermal Treatment Technologies ● 15

Table 2-l—Estimated Average Cost Per Pound

To Incinerate PCB Waste

Concentration (ppm)a

Liquids Solids

0-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $0.25 $0.40

50-1,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $0.30 $0.45

1,000-10,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . $0.35 $0.50

10,000-100,000 . . . . . . . . . . . . . . . . . . . . . . . . . . $0.40 $0.60

100,000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $0.45 $0.70

a

ppm = parts per million.

SOURCE: U.S. Environmental Protection Agency, Hazardous Waste Engineering Research Laboratory, Treatment Technologies for

Dioxin-Containing Wastes, EPA/600/2-86/096 (Cincinnati, OH:

October 1986), p. 4.14.

History of EPA’s Mobile Incinerator

In 1985, EPA sponsored research on dioxin

incineration technology by using a stationary facility

in Jefferson, Arkansas to conduct pilot-scale studies.18 Two burns of waste containing dioxincontaminated toluene still bottoms from the Vertac

Chemical facility in Jacksonville, Arkansas were

performed in late 1985 in a rotary kiln research unit.

Although monitoring and sampling detection limits

were too high at both waste burns,19 EPA concluded

that rotary kiln incineration technology could be

utilized in the destruction of dioxin if emission

controls were improved. Results of the tests included

the following:

●

●

●

concentration levels of the most toxic dioxin

species (2,3,7,8 -TCDD) were found to be

negligible in scrubber blowdown water (1 part

per trillion (ppt)) and kiln ash;

most dioxin forms were undetected at the

detection limits used; and

no tetra-, penta-, hexa-, or heptachlorodibenzop-dioxins- or chlorodibenzofurans were detected in kiln ash samples at detection limits of

1.3 to 37 ppt.20

In light of these results, EPA concluded that residues

from incineration treatment of dioxin- and furancontaminated materials with this type of system

could be considered nonhazardous.21 22

After these early tests in Arkansas, EPA developed a mobile incinerator system with equivalent

technology specifically to treat dioxin-contaminated

material.

After successful trial burns of the mobile incinerator in Edison, New Jersey and laboratory studies to

establish optimum conditions for soil incineration,

the EPA mobile incinerator was transferred in 1985

to the Denney Farm site in Missouri for a series of

tests using 2,3,7,8 -TCDD. At the conclusion of the

experiment, EPA had achieved DREs of 99.9999

percent, with process wastewater and treated soil

containing dioxins at insignificant levels. To date,

the EPA mobile incinerator unit, the best known

transportable rotary kiln in the United States, has

successfully incinerated more than 12 million

pounds of dioxin-contaminated soil and 230,000

pounds of dioxin-contaminated liquid waste.23 The

presence of state-of-the-art pollution control systems, claim cleanup experts, makes mobile (transportable) incinerators less controversial and safer

than other systems that have not had the same design

and development attention.24

Although EPA has invested more than $10

million in this unit, other mobile incinerator systems

have been constructed at much lower costs through

the experience and data gained from it. Research

with the mobile unit was instrumental in the design

and modification of several incineration components, including enlargement of the feeding system,

reduction in gas velocity, addition of cyclones

between kiln and afterburner so that less material

accumulates in the latter, and addition of a venturi

18R.w. ROSS II et al., ACUKX COqL, fiergy and Environmental Divisioq “Combustion Research Facility: Pilot-Scale kcheration Wt Bum of

TCDD-Con taminated Toluene Stillbottoms From Trichlorophenol Production From the Vertac Chemical Co,” paper prepared for the U.S.

Environmental Protection Agency, Office of Research and Developmen~ Hazardous Waste Engineering Research Laboratory, under EPA contract No.

68-03-3267, Work Assignment O-2, Acurex ‘I&hnical Report TR-86-100/EE, January 1986; Richard A. Carries and F.C. Whitmore, “Characterization

of the Rotary Kiln Incinerator System of the U.S. EPA Combustion Research Facility (CRF),” Hazardous Wrote, vol. 1, No. 2, 1984, pp. 225-236.

lgothm prob~ems enmuntered were clogging of the waste feed system ~d malfimction of the emission monitoring system.

20U.S. Environmental Protection Agency, op. cit., footnote 1, pp. 4.12413.

zlFor additio~ ~omtion on EpA~s rmWch ~cfitor f~ili~, s= ~so: Cmes ~d whi~ore, op. cit., foo~ote 18, ~d R.W. ROSS, H, F.C.

Whitmore, and R.A. Carries, “Evaluation of the U.S. EPA CFR Incinerator as Determined by Hexachlorobenzene Incineration’ Hazardous Waste, vol.

1, No. 4, 1984, pp. 581-597.

22At the tie of ~s pilot s~dy, however, WA ~re-levels ~d not ~~ prom~gat~; hey ~d o~y ken proposed in the FederalRegister. ~Or

details, see “Hazardous Waste Management Systenq Land Disposal Restrictions; Proposed Rule,” 51 Fed. Reg. 1602 (1986)]

‘G.D. Gupta, “Mobile Incinerator for ‘Ibxic Wastes,” Environmental Science& Technology, vol. 24, No. 12, 1990, p. 1776.

24pa~ck ~ips, fiecutive vi~-~siden~ Vesti lkchnologies, Ltd., personal COmmtiCatiOQ ~. 25$1991.
16 ● Dioxin Treatment Technologies

and wet electrostatic precipitators to reduce air

emissions. 25

The EPA system is designed to achieve full

combustion of organic, inorganic, and debris materials, including halogenated compounds such as PCBs

and dioxins.26 Several existing commercial mobile

incinerator facilities are based on the EPA system.

Components of EPA’s Mobile Incinerator

The EPA mobile incinerator system consists of

specialized incineration equipment mounted on four

heavy-duty semitrailers and auxiliary pads. The first

trailer contains: 1) a waste feed system for solids,

consisting of a shredder, a conveyor, and a hopper

(liquids are injected directly into the afterburner); 2)

burners; and 3) the rotary kiln.27 Organics are burned

in this portion of the system at about 1,600 ‘C.

Once the waste has been incinerated, incombustible ash is discharged directly from the kiln, and the

gaseous portion of the waste-now fully vaporized

and completely or partially oxidized-flows into the

secondary combustion chamber or second trailer in

which it is completely oxidized at 2,200 ‘F (1,200

‘C) and a residence time of 2 seconds. Flue gas is

then cooled by water sprays to 190 ‘F, and excess

water is collected in a sump.

Immediately after being cooled, the gas passes to

the third trailer on which the pollution control and

monitoring equipment is located. At this junction,

gases pass through a wet electrostatic precipitator

(WEP) for removal of submicron-sized particles and

an alkaline mass-transfer scrubber for neutralization

of acid gases formed during combustion. Cleaned

gases are drawn out of the system through a

40-foot-high stack by an induced-draft fan whose

other function is to keep the system under negative

pressure to prevent the escape of toxic particles.

Efficient and safe system performance is maintained

through the use of continuous monitoring instrumentation, which includes computerized equipment

and multiple automatic shutdown devices.28

The EPA mobile incinerator unit consumes 15

million British thermal units (Btu) per hour and

handles up to 150 pounds of dry solids, 3 gallons of

contaminated water, and nearly 2 gallons of contaminated fuel oil per minute. 29 It is concurrently located at

EPA’s Edison Laboratory in Edison, NJ. EPA no

longer plans to employ it for combustion of waste.30

Commercially Available Mobile Rotary

Kiln Incinerators

Only a few private companies have actually built

and operated mobile incinerators for dioxin treatment using EPA research as a base. The ENSCO

Corp., Little Rock, Arkansas, has designed and built

three modified versions of the EPA model, which

include improvements in waste handling and particle removal. One unit was used for cleaning up waste

contaminated with chlorinated organics near Tampa,

Florida; a second unit is located at El Dorado,

Arkansas (also the location of ENSCO’s stationary

kiln incinerator). The third is not currently in use.

Available ENSCO units are capable of treating

150 gallons of liquid waste and 2 to 6.3 tons of

dioxin-contaminated solid waste per hour. Results of

tests conducted on an ENSCO unit by the U.S. Air

Force at the Naval Construction Battalion Center,

Gulfport, Mississippi, indicate that this transportable incinerator could remove and destroy dioxins

from contaminated soils at DREs greater than

99.9999 percent.31

Another private company that has built mobile

incinerators is Vesta, Inc., of Ft. Lauderdale, Florida.

This firm has three transportable incineration units

capable of treating dioxin-contaminated soil at a

maximum estimated rate of 5 tons per hour.32

Treatment of soil, liquid, or sludge is accomplished

in a two-stage incineration process (countercurrent

rotary kiln; cocurrent secondary combustion cham-

‘Paul E. des Rosiers, “Advances in Dioxin Risk Management and Control lkchnologies,” Chemosphere, vol. 18, Nos. 1-6, 1989, pp. 45-46.

%u.s. Environmen~ Protection Agency, op. cit., footnote 17.

ZTU.S. Environment Protection Agency, op. cit., footnote 1, p. 4.16.

~~id., pp. 4.16-4.18; U.S. Environmental Protection Agency, op. cit., footnote 17.

Z9U.S. Environmen~ Protection Agency, op. cit., footnote 1, p. 4.16.

~paul E. des Rosiers, ChiMJWA Dioxin Disposal Advisory Group, U.S. EPA, personal communication June 10, 1991,

slF~ and des Rosiers, op. cit., footnote 9, pp. 29-30; U.S. Environment prot~tion Agency, op. cit., footnote 1, p. 4.16; and des Rosiers, Op. Cit.,

footnote 25.

32p~fips, op. Cit., footnote
Chapter 2-Thermal Treatment Technologies ● 17

ber) followed by ahigh-efficiency multistage scrubbing process. Vesta systems can be deployed in

about 24 hours; longer setup times are needed when

incinerator and prepared stockpiles require covering

with inflatable tent-like structures to avoid delays

due to inclement weather. Decontamination and

demobilization of the entire process maybe accomplished in less than 72 hours. Operations may be

conducted by using liquid propane gas, liquid

oxygen, fuel oil, or any waste or waste blend

considered suitable. Examples of dioxin-contaminated sites at which Vesta’s transportable incinerators have been used successfully include American

Cross Arms Site (Chehalis, Washington), Fort A.P.

Hill (Bowling Green, Virginia),34 Rocky Boy Post&

Pole Site (Rocky Boy, Montana), and Black Feet

Post & Pole Site (Browning, Montana).34

Cost Estimates for Mobile Rotary Kiln

Incineration

Among the factors that must be taken into

consideration in developing cost figures for mobile

(transportable) incineration are:

●

●

●

●

the throughput capacity of the system;

the caloric content (Btu) and moisture content

of the waste because they determine the feed

rates that can be maintained;

the maintenance and consistency of uninterrupted operations; and

the duration of operation (the longer it is, the

higher are the costs).

Setup costs incurred by design requirements and

permitting processes also play very important roles;

however, they vary from one site to another.35 One

firm reports that mobile incineration operating and

maintenance costs can range from $400 to $600 per

ton of waste treated.36

LIQUID INJECTION

INCINERATION TECHNOLOGY

Liquid injection (LI) is not currently available for

dioxin treatment, but it has been used aboard ships

for ocean-based incineration of Agent Orange. It is

also employed in many industrial and manufacturing

sectors for treatment of hazardous organic and

inorganic wastes. As shown in figure 2-3, the typical

LI incinerator consists of a burner, two combustion

chambers (primary and secondary), a quench chamber, a scrubber, and a stack. Vertical LI incinerators

are preferred for treating liquid waste rich in

organics and salts (and therefore ash) because the

incinerator unit can be used as its own stack to

facilitate the handling of generated ash. Portions of

the vertical LI unit can also be used as a secondary

combustion chamber. The horizontally shaped LI

units are connected to a tall stack and are preferred

for treating liquid waste that generates less ash. In

both systems, the use of external waste storage and

blending tanks helps maintain the waste in a

homogeneous form and at a steady flow.37

Some of the limitations that must be considered

before applying LI incineration to dioxin destruction

include the following:

●

●

●

LI systems are applicable only to combustible

low-viscosity liquids and slurries that can be

pumped;

waste must be atomized prior to injection into

the combustor; and

particle size is critical because burners are

susceptible to clogging at the nozzles.38

ssAt thk U.S. Army inswktioQ Vesta successfully treated 189 cubic yards (more than 190 tons) of soil tit Md ~en ~n~“ ted by corroding

storage drums containing the dioxin-bearing herbicides Silvex; 2,4dichlorophenoxyacetic acid (2,4-D); and2,4,5-trichlorophenoxyacetic acid (2,4,5-T).

Ritu Chaudhari, A.W. hlllIIIOQ snd J. TOW@C~, “Dioxin Destruction on a Small Scale-A Success Story,” paper presented at the Sixth Annual

DOE MODEL Conference, Oak Ridge, TN, Oct. 29 to Nov. 2, 1990; htter from Dennis J. Wynne, Department of the Army, U.S. Army Toxics and

Hazardous Materials Agency, Aberdeen Proving Ground, MD, to Paul E. des Rosiers, U.S. EPA, Office of Research and Development, with enclosure

on the U.S. Department of the Army’s “Remediation of Contamma “ tion at Fort A.P. Him” dated May 22, 1989. For additional information see Metcalf

& Eddy, Inc., Report on the Remedial Action Fort A.P. Hill Sit+#ina2 Report (Contract No. DAAA15-86-D 0015; Task Order-7), Mar. 16, 1990;

prepared for Comman der, U.S. Army Toxic and Hazardous Materials Agency, Aberdeen Proving Ground (Edgewood Area), MD; U.S. Army Training

and Doctrine Comman d, Office of the Comman d H.istoriaq The Dioxin Incident at FortA.P. Hill, 1984-1985 (Fort Monroe, VA: U.S. Army Training

and Doctrine Coremand, Jtdy 1987).

~Vesti Technologies, Ltd., “VESTA 80-’Ikchnology Specifications,” August 1989; “VESTA 100-lkchnology Specifications,” August 1989;

“Vesta Project Profiies,” undated, pp. 1, 2-3; “Performance History,” undated; “Burning Facts,” undated.

35u.s. Environmen~ Protection Agency, op. cit., fOOtIMe 1, p. 4.30.

36~fips, op. cit., fOOtnOte 240

WU.S. Environmental ~otection Agency, op. cit., footnote 1, p. 4-32.

3sIbid., pp. 4.32-4.34; see also Timothy E. OPpe14 “Incineration ofHazardous Waste: A Critical Review,” Journal of the Air Pollution Control

Association (JAPCA), vol. 37, No. 5, pp. 558-586.
18 ● Dioxin Treatment Technologies

Figure 2-3-Vertically Oriented Liquid Injection Incinerator

Effluent directly to atmosphere

or to scrubbers and stack

hamber

tream

Air-waste entrainment

compartment

e sensitizer

ulence compartment

Waste line Iiary fuel line

Iar support columns

01234 5

u u u

\

Electrical power line

feet

Approximate scale

SOURCE: U.S. Environmental Protection Agency, Hazardous Waste Engineering Research Laboratory, Treatment

Technologies for Dioxin-Containing Wastes, EPA/600/2-86/096 (Cincinnati, OH: October 1986).

The only documented use of liquid injection Although land-based LI facilities must install

technology in the United States for dioxin destruc- scrubbers to remove acid gases (particularly hydrotion comes from the burns that took place aboard the gen chloride), the M/T Vulcanus was not required to

ocean incinerator M/T Vulcanus in the summer of on the assumption that acidic gases resulting from

1977. This facility consisted of: combustion would be absorbed and neutralized by

●

●

●

a modified LI system;

two LI incinerators at the stern;

a combustion chamber and a stack for each

incinerator;

electrical pumps for sending the waste to the

combustion chamber; and

a blending device for mixing and reducing

solids to a pumpable slurry.39

the ocean. Some operating parameters included: 1)

a flame temperature of 1,375 to 1,610 ‘C, 2) a

furnace wall temperature of 1,100 to 1,200 ‘C, and

3) a residence time of 1 to 2 seconds. Results of the

EPA-sponsored trial burns indicated that the ocean

incinerator’s destruction of dioxin averaged more

than 99.93 percent DRE. A subsequent EPAsponsored trial burn of PCBs in August 1982

39u.s. Enviro~en~ prot~tion Agency, op. cit., footnote 1, pp. 4.32-4.34. See also T.A. Wastler, C.K. Offutt, C.K. Fit=tiom, and P.E. des

Rosiers, Disposal of Organochlorine Wastes at Sea, EPA-43019-75-014, July 197S; D.D. Ackerman et al., At-Sea Incineration of Herbicide Orange

Onboard the MIT Vulcanus, EPA-60012-78-086, April 1978.
Chapter 2—Thermal Treatment Technologies ● 19

revealed no TCDDs in the stack gas (based on a 2- to

22-ppb detection limit).40 41

No data exist on the burning of dioxins at

land-based liquid injection incinerators. Existing LI

units that may be able to burn dioxins most

effectively (i.e., with a 99.9999 percent DRE)

include General Electric’s thermal oxidizer (in

Pittsfield, Massachusetts) and LI incinerator (in

Waterford, New York) permitted to burn PCBs, and

Occidental Chemical’s LI unit currently employed

for burning hazardous leachate from the Hyde Park

Superfund site in New York.42

Cost Estimates for Liquid Injection

Incineration

As for most incineration methods, the cost of

liquid injection depends on the type of waste to be

treated. Aqueous, low-Btu waste costs more to

incinerate because of increased heat energy or fuel

requirements; highly halogenated waste also costs

more to incinerate because a scrubber is required to

remove acid gases formed during combustion. In

1986, EPA reported that the typical cost for the

treatment of halogenated solvents containing more

than 50 percent waste was $200 per metric ton. In the

same report, EPA indicated that LI treatment of

PCB-cent aminated oil would cost more than $500

per metric ton because of the “six-nines” DRE

requirement and suggested that, because of similar

performance requirements, treatment costs of incinerating liquid dioxin waste would be approximately

the same.43 More recent estimates indicate that the

cost of LI treatment for dioxin-contaminated liquid

waste could be much higher than for PCB -

containing waste.44

FLUIDIZED-BED INCINERATION

Traditionally, fluidized-bed combustion systems

(FBCs) were employed for the treatment of sludge

produced by municipal waste treatment plants and

waste generated from oil refineries, pulp and paper

mills, and the pharmaceutical industry. Today, about

25 FBCs are operating in the United States and

Europe; only a few of them are used commercially

to treat hazardous waste. None are available for

dioxin treatment, but with certain design improvements, some experts believe they have the potential

for this application.

The FBC system consists of a vertical refractorylined vessel holding a perforated metal plate on

which abed of granular material (preferably sand) is

located. Bed particles are fluidized by forcing hot air

up through the medium to create a highly turbulent

zone that ensures the mixing of waste materials with

bed particles and combustion air. Startup temperatures are reached by use of a burner located above the

bed; once heated, the bed material causes the waste

to combust. Solid noncombustible materials in the

waste become suspended and exit into a cyclone for

particle removal; exhaust gases flow into the afterburner for additional combustion.45 Particular attention must be paid to the type and size of materials to

be incinerated because variations in gravity and

density could be deleterious to the process.%

The fluidized-bed incinerator system has been

modified on several occasions; the two systems with

the highest potential for dioxin treatment (one —

designed

General

below.

by Waste-Tech Services and the other by

Atomics Technologies47) are discussed

Waste-Tech Services System

In August 1985, Waste-Tech Services, Inc.,48 of

Golden, Colorado, designed and built its modified

fluidized-bed incineration unit, which uses a granular bed composed of a mixture of combustion

40U.S. Environment protection Agency, op. cit., footnote 1, pp. 432,4.34-4.37.

41 For ~ditio~ ~o-tion on he fo-tion ~d de~~ction of ~o~ at ~/T V~JCanU~, s~: N.C.AC w~rm~ghe, JCL. M-M~. Gross, @

R.L. Harless, “The Analysis of lktrachIorodibenzo-p-dioxins and ‘lHrachlorodibenzofumns in Chemical Waste and in the Emissions From Its

Combustion.” L.H. Kei@ C. Rappe, and G. Choudhary, ChlonnatedDionns & Dibenzojitrans in the Total Environment (Stone- MA: Butterworth

Publishers, 1983), pp. 425-437.

AZU.S. Env~onmenM Protection Agency, op. cit., footnote 1, pp. 4.38440.

ASLJ.S. ~v~omen~protection Agency, op. cit., footnote 1., p. 4.38.

*ales RoSi~s, op. cit., footnote 30.

45u.s. hvironmen~ Protection Agency, op. cit., footnote 1, p. 4.41.

46p~fips, op. cit., fOOmOte 24.

ATThis system is ~keted by Ogden Environmental Services, San Diego, CA.

‘$sW~te-T~h Services, Inc., is an affiliate of the Amoco Oil Hokhg CO.
20 ● Dioxin Treatment Technologies

Figure 2-4-Schematic Diagram of the Waste-Tech Incineration Process

Solid waste

n

/

I I

Sludge waste

Liquid waste

‘m

l - l

I I Bed region

Fuel oil *

*

T T T T T

Cyclone

I

Ash to

client

I

- Quench water

from client

IIII

rAd-=Ll II

+JQ.-.+ J%zJ-jz2-@-~

>

‘jjn~h Venturi

HCI Ionizing wet Induced Stack

Scrubber scrubber draft fan

I

Combustion

vessel

Forced draft fan

SOURCE: Charles D. Bartholomew and R.W. Benedict, Waste-Tech Services, Inc., “Performance of a Fluidized Bed Hazardous Waste Thermal Oxidation

System,” paper presented at the 81st Annual Meeting of the Air Pollution Control Association, Dallas, TX, June 19-24, 1988,

catalyst and limestone rather than sand. This unit is

presently located at a plant that manufactures

chlorinated chemicals in Lake Charles, Louisiana.49

With a thermal rating of 22 million Btu per hour,5o

the Waste-Tech unit is composed of multiple feed

systems, a fluidized bed,51 secondary combustion

chambers, air pollution control equipment, and

ancillary support equipment for removing cyclone

ash, fugitive emissions in storage tank area, and

scrubber blow-down water.52 Figure 2-4 is a schematic of the Waste-Tech incineration process.

A feature that makes this treatment technology

highly attractive is its ability to sustain continuous

addition of limestone and extraction of bed material

during operations; this, in turn, allows the system to

operate at lower temperature, thus reducing fuel

consumption. 53

During a RCRA Part B trial burn conducted in

October 1987, to demonstrate its operability, the

Waste-Tech unit was tested under varying operating

conditions (e.g., temperature, feed rate, chlorine

49c~le~ D. B~~lom~w ad Row. &~~&~ waste~h se~icq ~q “Performance of a Fluidized Bed Hazardous Waste Thermal Oxidation

System” paper presented at the 81st Annual Meeting of the Air Pollution Control Association, Dallas, TX, June 19-24, 1988.

%elterfiom Francis M. Ferraro, Manager lkchnologyApplications, Waste-lkch Services, Inc., to German Reyes, Olliee of ‘Ibchnology Asaessmen4

Feb. 11, 1991.

S1’’f’he bed is approximately 3 feet deep, with fluidizing velocities XZUW@ between 6 to 8 ft%t Pa s~nd.

szBartholomew and Benedict, op. cit., footnote 49, P. 2.

%J.S. Environmental Protection Agency, op. cit., ftitnote 1., P. 4.41.
Chapter 2—Thermal Treatment Technologies ● 21

loading, and particulate loading) with chlorinated

waste containing carbon tetrachloride, tetrachloroethane, and p-dichlorobenzene. Dioxins and furans

were also tested. With one exception, all bed ash

tests showed no measurable amount of any of the

chlorinated pollutants treated. No 2,3,7,8 -TCDD

was detected in any of the four samples tested.54

On the basis of the results obtained during the trial

burn, company officials feel that the “fluidized bed

combustion system is a viable technology for the

destruction of hazardous wastes.’ ’55 Currently, WasteTech is concentrating its efforts on obtaining a

TSCA operating permit for treating PCBs and

PCB-contaminated material.56

Ogden’s Circulating-Bed Combustor (CBC) 57

The second modification of the fluidized-bed

system with good potential for dioxin destruction is

the circulating-bed combustor (CBC), designed and

built by General Atomics Technologies, Inc. (G.A.

Technologies, Inc.) and now the property of Ogden

Environmental Services, Inc., San Diego, California. Some unique characteristics of this system

(shown in figure 2-5) include its high-velocity

combustion medium and, more significantly, the

utilization of contaminated soil as bed material. In

1986, EPA referred to the Ogden system as “[appearing] to have significant potential for future use

in the destruction of hazardous wastes"58 today,

Ogden holds an operating permit from EPA (under

TSCA) 59

The high-velocity air flow of the system (three to

five times higher than conventional fluidized-bed

systems) suspends the bed solids, creating a highturbulence zone (800 to 1,100 ‘C) into which solid

or liquid waste is poured for treatment. Rapid

movement of the bed particles and waste materials

in turn promotes more efficient combustion at lower

temperature, without the need for an afterburner.

Residence times are generally 2 seconds for gases

and 30 minutes for solids.60

The major components of Ogden’s CBC incineration system axe:

a startup combustor burner, which uses natural

gas and is off after waste ignition;

a combustor consisting of a refractory-lined

carbon steel tube;

a cyclone, which is a carbon steel and refractorylined device responsible for both filtering and

recirculating uncombusted bed materials in the

suspended gases;

a flue gas cooler for cooling the off-gases; and

a baghouse filter that collects the suspended

particulate matter of incomplete combustion.61

All parts making up the Ogden CBC system can

be transported in 17 flatbed trucks; requiring only

2,500 square feet of space to operate and approximately 3 weeks to set up. Ogden Environmental

Services currently offers CBC treatment units in a

variety of sizes, the smallest being its 16-inchdiameter combustor with a thermal rating of 2

million Btu per hour. Construction of a 36-inchdiameter combustor is now being planned.62

Advantages of the Ogden units include the

following:

. the absence of moving parts in the combustor to

ensure greater reliability;

● simpler operation demanding smaller crews;

● no requirement for scrubbers;

. low-temperature operation that reduces fuel

consumption and eliminates the need for an

afterburner; and

~B@olomew and Benedic~ op. cit., footnote 49, p. 5-6.

551bid., p. 9.

SGFr~cis M. Ferraro, Waste’lkch Services, kc., Lakewood, CO, personal communicatio~ Feb. 24, 1991.

57S= ~o: HMO Yip ~d H*R. Dio$ ~$c~~a~ Bed ~ineratioq>s ~dom ~te~ x~ent confer~m, ~ronto, Ontdo, Septmbr

1987; H.R. Diet and H.H. Yip, “Transportable Circulating Bed Combustor for Thermal Treatment of Hazardous Liquids, Sludges, and Soils,” Ogden

Environmental Services, Inc., September 1987; U.S. Environmental Protection Agency, Offke of Research and Development The Supe@dZnnovative

Technology Evaluation Program: Technology Profiles, EPA 540/5-90/006 (Washington DC: EPA, November 1990), pp. 64-65.

58u.s. Environmen~ Protection Agency, op. cit., footnote 1., P. 449.

Sgogden Environmental fkrviCes, hlC., “Circulating Bed Combustion+’ un&ted.

@ales Rosims, op. cit., footnote 25, P. 47.

GIu.s. ExlvironmenM Protection Agency, op. cit., footnote 1, pp. 4.43,4.49.

G~~W~er, “Ogden’ sSuccessti ‘New Image’ Combustor,’ WasteAlternatives, December 1989; and, OgdenEnvironmental Services, Inc., “Site

Remediation. . . PCB Contaminated soil,” undated.
22 ● Dioxin Treatment Technologies

Figure 2-5—Circulating-Bed Combustion System Offered by Ogden Environmental Services, San Diego, CA

Solid

feed

I

Limestone

feed

i

a. , “,.:”

. . . .

., .. .;::.. . .:. :... . . . ,, ., . . .:.:? : ~. .. . . . . .. . . . . .

Combustion

chamber . . . . . . . . . . . ~ ,,, . ,- . .

. . . ,

/

. .

.,, “,, , ‘.” , ->

. . :.

I lb

:j””~

i

;~coo’er

,. ..-

. ~, l\\w// Cyc’one l“.?’”

Flue gas

~duus;)

. . — .,.<

.’

. . . .

. . .

. .,

. . . ,

.

!,

. .

. ‘. .

,.

. .

Q

i

c

I

Fan

Stack

Fan

t

I Ash conveyor

Cooling system

water

SOURCE: Ogden Environmental Services, Inc., “Circulating Bed Combustion,” undated.

. the ability to treat dioxin-containing liquid, temperature throughout, thus eliminating the need

soil, or sludge waste.63 for an afterburner (see figure 2-5).64

The Ogden CBC system uses high-velocity air to Bottom ash is removed from the system on a

fluidize the bed particles and create a highly continuous basis, cooled in a water-cooled screw

turbulent combustion loop. Solids are introduced at conveyor, and solidified or packed in drums for final a point between the cyclone and the combustion disposition.65 Hot exhaust gases from the cyclone are chamber and are immediately swept to the bottom of

the combustion chamber. Liquids are injected di- passed through the flue gas cooler; once cooled, they

rectly into the combustion zone. The increasing are filtered in the baghouse before exiting through

circulating flow of hot air and hot suspended the stack. DREs of 99.9999 percent have been

particles around the loop formed by the combustion achieved with soil containing about 12,000 parts per

chamber, cyclone, and return leg maintains a high million (ppm) PCBS.

66

630gden Envim~en~ services, kc., Op. Cit., fOOhlOk 59.

64FW and des Rosiers, op. Cit., footnote 9, p. 35.

65uoso fiv~omen~ ~otection Agency, op. ~ite, foomote 1, Pp, 4.,43, 4.49; des RoSierS, op. cit., foo~ote 25, p. 47; and ogden EnvkOIIIIIeI.Wd

Services, Inc., op. cit., footnote 59.

tides RoSierS, op. cit., foomote 25, p. 47; us. Enviro~en~ ~otection Agency, op. cit., fOOtiOte 57, p. 64.
Chapter 2—Thermal Treatment Technologies ● 23

Testing and Availability of Ogden’s

CBC Technology

Prior to its incorporation into Ogden Environmental Services, G.A. Technologies conducted three

trial bums on its stationary pilot-scale unit using soil

contaminated with PCBs at levels ranging from

9,800 to 12,000 ppm. Test results demonstrated the

ability of the system to meet the destruction and

removal standard of 99.9999 percent for incinerating

chlorinated waste.67

Under Ogden’s ownership, CBC technology was

tested in 1988 at the Swanson River oil field, Kanai

Peninsula, Alaska. The successful achievement of

DREs greater than “six nines” was primarily

responsible for issuance of a national permit by EPA

under TSCA in June 1989.68

Ogden has five separate National, State, and local

permits; the national permit is one of seven granted

by EPA to incinerator facilities in the United States

for PCB burning. 69 A summary of existing and

planned portable CBC units offered by Ogden is

presented below:

One unit, located in Stockton, California, is part

of a soil remediation project involving the

cleanup of soil contaminated with fuel oil. A

total of 80 to 100 tons of soil is treated and

disposed of daily.

Another unit is operating at Alaska’s Swanson

River oil field (Kanai Peninsula) to remove and

treat about 75,000 tons of PCB-contaminated

soil. Completion of the Swanson River project

is scheduled for the end of 1991.

Two additional transportable units are now

being built (one of which will be dealing with

a coal tar remediation project in California).

Ogden is also planning to build smaller systems

for permanent onsite application, particularly

the treatment of waste streams at chemical and

petroleum plants.70

Cost Estimates for Fluidized-Bed Incineration

Although costs for conventional fluidized-bed

systems depend largely on factors such as fuel

requirements, scale of equipment, and site conditions, they are for the most part comparable to those

of rotary kiln incineration.

The cost of circulating-bed combustion treatment,

on the other hand, is considered by EPA to depend

more on the size of the incinerating unit and the

waste types requiring treatment.71 For example,

installing a 25-million-Btu-per-hour unit costs $1.8

to $2.0 million, with an annual operating cost of

$0.25 million for chlorinated organic sludge, $0.35

million for wet sludge, and $0.35 million for

contaminated soil. Circulating bed incineration treatment costs per ton of material treated are therefore

$60, $32, and $27 respectively.72 Costs for PCBcontaminated soil, such as that being treated at

Swanson River, Alaska, are estimated to range

between $100 and $300 per ton.73 The costs of

dioxin treatment are not available. According to a

company official, the cost of processing more than

20,000 tons of soil in 1991 is approximately $250

per ton; this price includes site preparation.74

HIGH-TEMPERATURE FLUID WALL

DESTRUCTION—ADVANCED

ELECTRIC REACTOR (AER)

Advanced electric reactor (AER) technology is

not available commercially, but R&D shows that it

may have potential for dioxin treatment. A typical

system consists of a porous tube (primarily graphite)

or reactor enclosed in a hollow cylinder. To radiate

heat to the waste, the reactor uses radiant energy

provided by heated carbon electrodes. Waste is

prevented from coming in contact with the reactor

core by a blanket of nitrogen flowing countercur670gdm fivil-onmen~ services, kc., op. Cit., fOO~Ote 59. 680gden ~v~~en~ SeNice, ~co, op. cit., foo~ote 59; ~d Harold R. Dio~ Ogden Environmental Semices, “Circ*~g ~uidi~d B~

Incinerators for Site Remediation: An Update on Ogden’s Successes,” March 1990.

@Warner, op. cit., footnote 62; U.S. Environmental Protection Agency, op. cit., footnote 59, pp. 64-65.

Towmer, op. cit., footnote 62.

TIu.s. Environment Protection Agency, op. cit., footnote 1, p. 4.49.

T%id., p. 4.51.

TqBmndaM+ Anderson ~d Rob@ G. Wilbo- ogden Environment@ Services, “COnWlllM“ ted Soil Remediation by CircuMing Bed Combustion:

Demonstration ‘Ikst Results,’ November 1989, p. 7.

%ls-Sextou (Jgdm ~v~~en~ SmiceS, ~c., Sm Diego, Qperso~ cmmmnicatio~ J~. 25, 1991.
24 ● Dioxon Treatment Technologies

rently upward through the porous core walls.75

Although originally designed by Thagard Research

(Costa Mesa, California), this technology is known

as the Huber process because of proprietary modifications incorporated into the original design by J.M.

Huber Corp. (Huber, Texas). Figure 2-6 shows the

major components of AER technology.

During processing, liquid or solid waste is poured

through an airtight feed bin or nozzle located at the

top of the reactor. After passage through the heated

reactor (about 4,500 ‘F), pyrolyzed waste products

and gases are sent to two post-treatment chambers.

Whereas the first chamber is designed to provide

additional combustion heat (about 2,000 ‘F), the

second cools the off-gases.

Once cooled, gases are passed through a pollution

control system composed of four major devices: a

cyclone for collecting particles that did not fall into

the solids bin, a bag filter for removing fine

particles, an aqueous caustic scrubber for removing acid gases and free chlorine, and an activated

carbon bed. In AER technology, activated carbon

beds are used primarily to remove trace residues of

chlorine and organic compounds.76

Some of the advantages of AER considered

relevant to dioxin treatment include the following:

1) waste is destroyed by pyrolysis rather than by

oxidation as in rotary kiln incinerators; and 2) the

extremely lower gas flow rates77 and the absence of

oxygen allow longer residence times, which in turn

reduces the production of toxic gases. This results in

the emission of much cleaner off-gases through the

stack. 78

Several limitations have also been identified in

AER thermal technology. The following limitations

are most relevant to the treatment of dioxincontaminated material:

● the system is unable to treat solids and liquids

simultaneously;

Figure 2-6--Major Components of the AER

Treatment Process

Expansion bellows —

Power feedthrough

cooling manifold ?

Power

feedthrough

assembly /

End plate

Electrode

Radiation

heat shield

Heat shield

insulator /

.

Cooling jacket

,.

2

-J

1

IL Power clamp

J’”-l,Porous core

b-- Radiometer port

I 1 ‘Blanket gas inlet

1 I

SOURCE: U.S. Environmental Protection Agency, Hazardous Waste Engineering Research Laboratory, Treatment T&nologies for

Dioxin-Containing Wastes, EPA160012-861086 (Cincinnati, OH:

October 1986).

. the system treats only free-flowing nonagglomerating solids no larger than 0.0059 inch in size,

hence shredding and drying are required prior

to treatment; and

75H.M. Free~ Us. Environmental Protection Agency, Hazardous Waste Engineering Research Laboratory, “U@~ on New ~te~tiv?

Hazardous Waste Treatment Processes,” pp. 8-9. Paper prepared for presentation at conference on Performsnce and Costs of Alternatives to Land

Disposal of Hazardous Wssteof the Air Pollution Control Association New Orleans, LA, Dec. 8-12, 1986; H.M. Freeman and R.A. Olexsey, “AReview

of Treatment Alternatives for Dioxin Wastes,” Jourm.d of the Air Pollution Control Association, vol. 36, No. 1, Jauusry 1986, p. 70.

W.S. 13nvironmen@ protection Agency, op. cit., footnote 1, PP. 4.52A$.55.

77GU flow rates ~ ~R tW~oloH differ ~m hose of rotary kiln incinerators by an order of magnitude (350 cubic feet Per minu~ comP~ to

10,000 cubic feet per minute).

7SJ~Boyd, J.M HuberCo~., perso~ comm~catioq July 16, 1991; H.M. Free- op. cit., fOOtnOte 75, pp. 8-10; Free- “~ovative ~-

Processes for the Destruction of Hazardous Wastes,” Pollution Equipment News, April 1988, pp. 108-109; U.S. Environmental Protection Agency, op.

cit., footnote 1, p. 4.55.
Chapter 2-Thermal Treatment Technologies ● 25

● the system lacks supplementary fuel sources

making it less competitive with conventional

incineration techniques (e.g., rotary kilns) for

treating waste with high-Btu content.79

Cost Estimates for AER Incineration

Treatment costs for AER incineration depend on

several factors, including quantity and characteristics of the materials to be incinerated.80 Although

never proven, typical costs for a 100,000-ton cleanup

have been said to range from $365 to $565 per ton.

J.M. Huber has not used this technology since 1987,

opting to invest in other treatment processes with

greater market potential. One company official

points out that a national research and development

program with a focus on dioxin treatment would

help to further test and develop this promising

technology.81

INFRARED INCINERATION

Another technology with dioxin treatment potential but with no current commercial use in the United

States is infrared incineration. An infrared incineration mobile pilot unit was developed in 1985 by

Shirco Infrared Systems, Inc., Dallas, Texas. It

consists of a waste feed system, two combustion

chambers (primary and secondary) made of carbon

steel, a venturi scrubber system, a blower and heat

control system, and a monitoring and pollution

control system. The entire unit could be transported

in a 45-foot trailer and set up in a few hours for the

treatment of PCBs, pesticides, dioxins, and furans.82

The primary chamber contains electrically heated

silicon carbide elements for radiating incoming

waste. 83 Depending on chemicals present in the

waste, the elements can be heated to 1,850 0C for 10

minutes to 3 hours. After infrared radiation treatment in the primary combustion chamber has been

completed, the partially combusted particulate and

exhaust gases are passed into the secondary chamber

for complete combustion.84 The combusted material

or ash is then conveyed to the end of the furnace

where, after passage through a chute, it is deposited

in an enclosed hopper.85

Combustion in the secondary chamber is accomplished by using electrical elements in combination

with a propane burner; air from the blower system

helps maintain the turbulence necessary for complete combustion. Exhaust gases from the secondary

chamber are released into the atmosphere after being

passed through the wet scrubber for particle removal

and cooling.86

Testing and Availability of Infrared

Incineration Technology

2,3,7,8-TCDD-contaminated (156 to 227 ppb)

soil from Times Beach, Missouri was collected and

treated by the Shirco pilot-scale technology during

a 2-day experimental test in June 1985. Results

showed that the Shirco system was successful in

treating dioxin, with DRE values exceeding 99.999996

percent. Relatively insignificant levels of dioxin

were found in the off-gas. The DRE for gases was

calculated and found to exceed 99.999989 percent.87

Larger Shirco units have been tested by EPA at

several contaminated sites with varying degree of

success. Tests of a full-scale unit at the Peak Oil site,

Florida and a pilot-scale unit at Township-Demode

Road, Michigan, for example, yielded positive

results. However, the full-scale unit tested under

EPA’s Superfund Innovative Technology Evaluation (SITE) Program, has not produced comparable

results.

Although infrared incineration has also been

employed in remediation of the Florida Steel Corp.

Superfund site, Florida and the LaSalle Electric

Superfund site, Illinois, much of the success associ79u.s. Enviro~en~ Protection Agency, op. cit., footnote 1, P. 4.55.

%ical energy requirement for treating normal soil is 800 to 1,000 kilowatt-hours per ton.

81J~ Boyd, J.M. Hu&r Corp., ~2us, perSOIIid COmm@CatiOQ J~. 2% 1~1”

82F~ ~d des Ro5ieN, op. ci~, fm~ote 9, p. 32; U*SO ~vironm~~ ~ot~tion Agency, op. cit., footnote 1, p. 4-61; Free- Op. cit., fOOtnOte 75,

pp. 6-7.

83~e exte~ ~emiom of theP-~~~r~2.5 f-t wide, 9 feet Ml, ~d 7 feet deep; with a weight of approximately 3,000 pollrlds.

~~e much li~tm secon~ chamber (1,500 pounds) is 3 feet wide, 9 feet Ml, ~d 3 feet deep.

85u.s. ~vhomen~ ~tation Agency, op. cit., foomote 1, p. 4.61; Us. Enviro~en~ protection Agency, op. Cit., fOOtrlOtO 57, p. 84.

8Gu.s. Enviromnen~ Protection Agency, op. cit., fOOtnote 1, pp. 4.614.62.

87des Rosiers, op. cit., fw~ote 25, Pe 46; Ues. ~v~omen~ ~ot~tion Agency, op. cit., foornote 1, pp. 4.62-4.64; ~d Freeman and Olexsey, op.

cit., footnote 75, pp. 70-71.
26 ● Dioxin Treatment Technologies

Figure 2-7—Infrared Incineration Process Offered by Westinghouse Environmental

Services, Pittsburgh, PA

Infrared conveyor furnace system

Exhaust

stack

b

I

L

I

o

Ph control

a

Emergency

chemicals stack

I

Scrubber

A n

Gas l & l

burners

“- r

-

/\/\/\/\/\/ J

Waste feed Combustion

T’

air Secondary chamber

Fuel o f f

oil gas

Infrared heaters Combustion

TL~● 000000000000*000 *

Conveyor L] () c> c1

belt o 0 u

Primary chamber

SOURCE: Westinghouse Environmental Services, ‘Thermal Destruction—Infrared Conveyor Furnace System,”

undated.

ated with infrared technology has been achieved in Cost Estimates for Infrared

Europe. 88 In Hamburg, for example, DEKONTA, a Incineration Technology

C.H. Boehringer-Ingelheim subsidiary, has com-

-.

pletely redesigned the basic unit to the point where Information on treatment costs for infrared incinit no longer employs the Shirco process.89 eration is limited. However, preliminary estimates

by EPA indicate that operation and maintenance of

the Shirco technology could cost at least $200 per

To date, Shirco Infrared Systems, now known as ton of treated waste.92

ECOVA, 90 has built three small pilot units capable

of treating 20 to 100 pounds of waste per hour. Each

unit can be housed in a 42-foot-long trailer truck for

shipment to treatment sites. The Westinghouse

PLASMA ARC PYROLYSIS

INCINERATION

Environmental Services Division in Pittsburgh cur- Plasma arc pyrolysis (PAP) is a technology

rently offers a full-scale system (shown in figure currently in the R&D stage, with features that could

2-7) that uses the Shirco process. Westinghouse make it a candidate for dioxin treatment in the future.

claims that this unit is able to treat 100 to 175 tons In PAP, the chemical substances that make up the

per day.91 waste are dissociated into their atomic elements by

88u.s. Env~omen~ ~otection Ag~~cy, ~p. cit., foomote 57, p. 85; F~ and des Rosiers, op. cit., footnote 9, p. 32; Paul E. des Roskrs, am

Dioxin Disposal Advisory Group, U.S. EPA, personal comrnunieatiom Dec. 6, 1990.

Sgdes Rosiers, op. cit., footnote 30.

90EC0VA of RicNmd, WA p~c.ed s~co ~w~ system in the late 1980s. An ECOVA subsi&q in Dallas, m is currently responsible fOr

commercializing the Shimo system.

91c. Keith pa~sow Technolo~, Re@ations andcompliance, westinghouseEnvironmen~ systems and services Divisio~ Pittsburgh, PA, p~SOXld

cmmmmicatioq Feb. 11, 1991.

~1’bid. U.S. EnvfionrnenM Protection Agency, op. cit., fOOtnOte 1, p. 4.64.
Chapter 2—Thermal Treatment Technologies ● 27

passage through a thermal plasma field. The thermal

plasma field is created by directing an electric

current through a low-pressure air stream; plasma

fields can reach 5 to 15,000 ‘C. This system can

process nearly 10 pounds per minute of solid or

55 gallons per hour of liquid waste.93

The central component of the PAP system is a

cylindrical pyrolysis reactor or chamber, which

consists of a plasma device, a wet scrubber, a flare

stack, a process monitoring system, and a laboratory.

These components, plus transformers and switching

equipment, can be mounted on a 45-foot-long

tractor-trailer bed.

Immediately after waste has been injected or

atomized into the plasma device of the pyrolysis

chamber, the resulting elements are passed to the

second portion of the chamber and allowed to

recombine to form hydrogen, carbon monoxide, and

hydrochloric acid. The typical residence time in the

second portion of the pyrolysis chamber (’ ‘recombinant zone’ is about 1 second, and temperatures are

between 900 and 1,200 ‘C.

Recombined gases are then passed through a wet

caustic scrubber for removal of particulate matter

and hydrochloric acid. The remaining gases, ‘a high

percent of which are combustible, are drawn by an

induction fan to the flare stack where they are

electrically ignited. ’94 Although no supporting data

were submitted to OTA, Westinghouse claims that

because hydrogen, carbon monoxide, and nitrogen

are produced, the gas ‘burns with a clean flame after

being ignited,” which indicates that most toxic

constituents have been destroyed.95

Some of the theoretical advantages of PAP

technology relevant to dioxin treatment include:

the ease of transport from one site to another;

the ability to incinerate chlorinated liquid

wastes, such as those found at the Love Canal

and Hyde Park Superfund sites;96 and

the ability to use organic effluents as fuel to run

a generator.97

The most significant limitation of PAP treatment

is that only liquids can be treated. Contaminated soil

and viscous sludge thicker than 30- to 40-weight

motor oil cannot be processed by the system.98

Testing and Availability of PAP

Incineration Technology

Westinghouse is currently developing PAP incineration technology (see figure 2-8) but has not

specifically tested the system with dioxins. Nonetheless, tests in which PCBs containing dioxins,

furans, and other chlorinated pollutants were treated

in a bench-scale PAP unit showed dioxin levels in

scrubber water and stack gases in the part-pertrillion range. DREs in the test ranged from six to

eight nines .99

SUPERCRITICAL WATER

OXIDATION

A technology receiving recent R&D effort, with

some promise for dioxin treatment, is supercritical

water oxidation (SCWO). A system developed by

MODAR, lnc., Natick, Massachusetts, is based on

the oxidizing effect of water on organic and inorganic substances at 350 to 450 ‘C and more than 218

atmospheres (pressure)-or a supercritical state.

Under supercritical conditions, the behavior of water

changes, and organic compounds become extremely

soluble whereas inorganic salts become “sparingly’ soluble and tend to precipitate.lOO

gswe~figh~u~eE~viro~en~se~ice~, $$The@ De~~ction-~oplWW,$ ~ July 1988, PO 20

~u.s. Environmental Protection Agency, op. cit., footnote 1, p. 4-67.

gs~id.; Westinghouse Environmental Services, op. Cit., footnote 93.

%Ibid.

~u.s. Environment Protection Agency, op. cit., footnote 1, pp. 4.68,4.72.

gslbid., p. 4.67.

W-J.S. Environmental Protection Agency, op. cit., footnote 1, pp. 4.68-4.71; des Rosiers, op. cit., footnote 25, p. 48; Fuhr and des Rosiers, op. cit.,

footnote 9, p. 37; Nicholas P. Kolak et al,, “Trial Burns-Plasma Am ‘lkchnology,” paper presented at the U.S. EPA Twelfth Annual Research

Symposium on Land Disposal, Remedial Actio~ Incineration and Treatment of Hazardous Waste, Cincinnati, OH, Apr. 21-23, 1986; Freeman and

Olexsey, op. cit., footnote 75, pp. 4-5.

lmu.s. Environment Protection Agency, op. cit., footnote 1, pp. 4.80-4.82; lkrry B. Thouon et ~., “The MODAR Supercritical Water Oxidation

Process,” paper submitted for publication to Innovative Hazardous Waste Treatment Technology series, Nov. 3, 1988, p. 3. T& paper was found in

MODAR, Inc., MODAR Information, an undated company report; K.C. Swallow et al., “Behavior of Metal Compounds in the SuperCritical Water

Oxidation Process,” paper presented at the 20th Intersociety Conference on Environmental Systems of the Engineering Society for Advancing Mobility,

Land, Sea, Air, and Space; Williamsburg, VA, July 9-12, 1990; Freeman and Olexsey, op. cit., footnote 75, pp. 7-8.
28 ● Dioxin Treatment Technologies

Figure 2-8—Westinghouse Environmental Services’ Pyroplasma Waste Destruction Unit

nd control

\\

~ Scrubber water” Gas analYsis /-

>

,,, . tank

/- \

,,

6%

\

\

Product gas

,.=-

 -

@

Feed pumps

@

d Scrubber

Water tank

water effluent

\

Recombination chamber L w Feed hose

SOURCE: Westinghouse Environmental Services, ‘Thermal DestructionPyroplasma,” July 1988.

The process is designed to convert the intricate

arrangements of carbon and hydrogen that make up

organic compounds into their most basic forms,

carbon dioxide and water. Treatment of contaminated liquid waste results in two effluents-a solid

composed primarily of precipitated salts containing

metals and elements such as chlorine, and a liquid

consisting of purified water.lO1 The typical low

temperature found during SCWO treatment helps

prevent the formation of the primary pollutants

sulfur dioxide and nitrogen oxides.102 Figure 2-9

represents a flow diagram of this technology.

Although SCWO can treat contaminated materials with up to 100 percent organic content, most

R&D has focused on aqueous waste containing

20 percent organics or less. In this range, SCWO

technology is said to be highly competitive and

cost-effective with other available alternative treatment technologies. 103 SCWO can be used to treat

organic solids; slurries and sludge may also be

treated with the addition of high-pressure pumping

systems. The evaluation of SCWO on dioxincontaminated soil, although successful, has been

limited to bench-scale tests.l04

MODAR’s SCWO process involves pumping

contaminated materials into a highly pressurized

reactor vessel; liquid oxygen and air are also

pumped alternatively into the reactor vessel. The

optimum heat content of the mixture (1,800 Btu per

pound) is maintained either by adding water to

reduce the heat content or by adding organic

materials or fuels, such as natural gas or fuel oil, to

increase it. Caustic may also be added to the

supercritical reactor to neutralize the acid produced

when organic and inorganic contaminants in the soil

or waste are oxidized. Normally, part of the effluent

is recycled by mixture with the waste stream being

fed into the reactor to maintain proper operating

temperatures, as well as rapid and effective destrucIOIU.S. Enviro~en@ Protection Agency, op. cit., footnote 1, p. 4-82.

loz~ornason et al., op. cit., footnote 100, p. 4.

lo%id., p. 5.

l~~id., pp. 4,5; mph Morg~’, MoJJ~ ~co, perso~ co~~cation, Mar. 28, 1991.
Chapter 2—Thermal Treatment Technologies ● 2 9 — — .-— —.—. —. -. ..—. ——.——

Figure 2-9—Supercritical Water Oxidation Treatment

j ;

,--- \

~ ~---- ~

., L ‘6000C

System System , ~ water wate r

heate4r

L —.-—- -–1 L..— .— . . .

}

$

,“ \

“\ A

f=-- -’%

Aqueous

1

feed \‘~. 1

L–.-– -- “. ,

=.. ‘i, I I

7

, \, ~!- - ~

Reactor

.

Organic solid s

feed - *’” “ ~ separato r

; ~ I

.— J I

v Gaseous I

I -- — .-,

effluent

i 4:*

Heat 4

,,

exchanger

I

I 2 1

Gas/liquid ,

separator s

~ G

k 1

‘“.. /“

I

I

+

I

I

‘\ /

- . .

Feeds are pumped to

23 MPa* operating

pressure. System

water is heated to

6 0 0

0C. Compressed

air is sent to the

reactor with materials

to be treated.

*M Pa ● megapasca I

Organics are oxidized

to carbon dioxide (CO) 2

)

and water. Inorganic

solids and salts from

neutralized acids are

precipated in the reactor

Remaining liquids exit

through the top of the

reactor into the heat

exchanger u n i t

Fluid from reactor

is cooled to ambient

temperature, and

forms a two-phase

system

I Two phases are separated

I

in gas/liquid separator.

I Gaseous effluents are

combined for sampling. 1

I Liquid effluents are

sampled and C OIIected.

SOURCE: K.C. Swallow et al., “Behavior of Metal Compounds in the Supercritical Water Oxidation Process “ paper presented at the 2t3th tntwsoeiety

conference on Environmental Systems of the Engineering Society for Advancing Mobility, Land, Sea. Air, and Space; Williamsburg, VA,Ju}y9-12,

1990.

tion of pollutants; heat from the effluent can also be toring and COntrol, automated start-up/shutdow n

used to generate power for running pumps, com- procedures, and emergency shutoff and response

pressing oxygen, and other uses,l05 According to systems.

claims in an undated MODAR report,106 the SCWO During SCWO treatment, organic compounds are

technology has ‘‘sufficient instrumentation for oper- oxidized rapidly into their most basic chemical

ation and automatic control by a distributed com- components; inorganic chemicals (salts, halogens,

puter control system” that includes process moni- metals) become insoluble in the supercritical envi-

—..— .- .- —————— ——— —.

l~smomason et ~., q, cit., footiote 100, pp. 6-7; Carl N. S(a-wfik w al., MO~AR, Inc., ‘ ‘The Pilot-Scale Demostmion d the MODAR Oxidation

Process for the Destruction of Hazardous organic Waste Materials, ’ Environmental Progress, vol. 6, No. 1, February 1987,.p. 40; and Michael Lawson

and Kenneth Brooks, “New lkchnology Tackles 13ilutc Waste:, ’ C’hemrcal Week. Oct 1 1986, p. 40.

106” ‘The MODAR Oxidation Process. I%OCCSS Ftow Diagram Representative Mass and Energy Balance System Economics,’ MO13AR,lnc., NW. 15,

1!%$. This paper wa,, found in MOD. AR, Tnc., MOi)AR fnformution, an undated ,-ompam report,
30 ● Dioxin Treatment Technologies

ronment and descend to the bottom of the reactor

where they are removed as salt or cool brine; and hot

aqueous and gaseous reaction products are recycled

or released to the atmosphere after cooling.107 Although brine may be disposed of in a deep well,

salts-especially if they contain heavy metals—

must be disposed of in a secure landfill after proper

solidification.108 The discharged effluents consist of

clean water and off-gases (carbon dioxide, oxygen,

nitrogen). 109

The advantages of SCWO technology (if developed as proposed) most relevant to dioxin treatment

include the following:

●

●

●

●

the reduction of contaminants to their most

basic chemical form and the harmless effluents

produced eliminate the need to dispose of

treated effluents;

compounds that are difficult to dispose of are

reduced to their most basic, nonhazardous

forms in a process that can be adapted to a wide

range of waste streams or scale of operations; l10

all chemical reactions occur in a totally enclosed and self-scrubbing system, thus allowing complete physical control of the waste and

facilitating the monitoring of reactions throughout the process; and

MODAR’s SCWO technique can also be applied to condensates produced from the use of

soil washing technologies.

The firm marketing this technology claims that it can

be cost-effective when compared to incineration,

particularly in treating waste with an organic content

of less than 20 percent.lll

SCWO systems are limited by their ability to treat

dioxin-contamin ated waste in liquid form. Often,

organic waste must be diluted with benzene112 prior

to treatment (to at least 20 percent by weight). Use

of the MODAR system for treating waste with

higher heat content is not cost-effective.113 Because

SCWO’s particle size limitation is 200 microns, it

has been suggested that one way to remediate

contaminated sites such as Times Beach may be by

grinding and pulverizing the soil to make a slurry

that can then be oxidized.114 This practice, however,

is yet to be demonstrated and, if proved feasible, may

be prohibitively high in cost.

Testing and Availability of SCWO Technology

Since 1984 when SCWO was permitted by EPA

as a research treatment facility, the MODAR process

has been tested at various locations and on different

scales to destroy waste contaminated with substances, such as chlorinated organics and dioxins.115

Laboratory analysis of the effluents after testing

showed no detectable dioxin in the residues.llG

Laboratory-scale tests using waste feed containing

a mixture of synthetic dioxin and trichlorobenzene

(about 100-ppm concentration) demonstrate a DRE

for dioxin in liquid organic waste exceeding the EPA

standard of 99.9999 percent. On this occasion, lab

tests showed that 110 ppb of 2,3,7,8 -TCDD present

in waste was reduced to less than 0.23 ppb.117

Bench-scale tests have been conducted on different organic chemicals, including chlorinated solvents, PCBs, and pesticides. Efforts to detect dioxins

in treated effluents have been unsuccessful. Similar

results were obtained in field demonstrations

conducted by MODAR in New York and Pennsylvania. In one test, for example, SCWO treatment of

dioxin-contaminated methyl ethyl ketone achieved

loT~owon et aI., op. cit., footnote 100, Pp. 6-7.

108 MoDAR, rnc., op. cit., footnote 106.

log~omason et al., op. cit., footnote 100, Pp. 6-7, 10.

ll~id., pp. 8-10; ‘lkrry B. Thomason and Michael Moclell, “Supercritical Water Destruction of Aqueous Wastes,” Hazardous Waste, vol. 1, No. 4,

1984, p. 465.

lllB~ (jO l?v~, Development M~ag~, ABB Lummus crest, ~c., perso~ communication, Apr. z, 1!)91.

112A bow cancer-causing solvent.

113u.s. Environment@ Protection Agency, op. cit., fOO@Ote 1, pp. ‘$.80-4.82.

l1413v~, op. cit., footnote 111.

115A’BB Lummus Crest, ‘‘The MODAR lkcbnology: Supercritical Water Oxidation Process, ” a technical proffle, un&ted; ‘f’homason et al., op. cit.,

footnote 100, pp. 14-15.

l16u.s. )7nviro~en~ ~otation Agency, op. cit., foo~ote 1, p. 4.83.

llTFti and des Rosiers, op. cit., footnote 9, p. 34.
Chapter 2—Thermal Treatment Technologies . 31

DREs ranging from 99.99994 to 99.999991 perCent.118 MODAR has tested its SCWO process on

more than 50 different types of organic waste. 119

Bench-scale studies of the MODAR technology

have also shown that when treated, organic pollutants (e.g., PCBs and dioxins) are oxidized completely to carbon dioxide, water, nitrogen, and

inorganic salts with DREs of 99.9999 percent or

higher. After oxidation under supercritical conditions, the chlorine present in PCB and dioxin.

molecules is converted to inorganic chloride.120

Plans for commercialization of this technology

began in 1989 as a joint venture between MODAR,

Inc. (Natick, Massachusetts), and ABB Lummus

Crest, Inc. (Houston, Texas). To date, ABB Lummus

Crest, the only worldwide SCWO licenser, offers

two engineering packages for small (5,000 gallons

per day) and medium-sized (20,000 gallons per day)

plants. R&D work is underway with the U.S.

Department of Energy at the Savannah River site to

treat radioactive organic waste.121 The National

Aeronautics and Space Administration has also

shown considerable interest in SCWO because of its

ability to treat human waste and recycle water

simultaneously. 122

Cost Estimates for SCWO Treatment

No experience with full-scale operation of this

technology is available, and the only cost estimates

have been made by private firms marketing these

systems. According to ABB Lummus Crest, Inc.,

costs for dioxin treatment are expected to be higher

than liquid incineration but significantly lower than

those for rotary kiln incineration--this, however,

has yet to be demonstrated. Expenses incurred from

permitting and other factors would increase these

costs. 123

1 Ismornason ct al., op. cit., footnote 100, pp. 13-14, 15.

I l~u~ and des Rosiers, op. cit., footnote 9. p. 34.

IN SITU VITRIFICATION

In situ vitrification (ISV) is a technology developed to thermally treat waste in place and to solidify

all material not volatilized or destroyed. It may have

application to special types of dioxin contamination

if current developments can be successfully tested.

ISV was developed in 1980 by Pacific Northwest

Laboratories (PNL), a division of Battelle Memorial

Institute, under the primary sponsorship of the U.S.

Department of Energy (DOE). PNL has also received financial support for vitrification research

from the U.S. Environmental Protection Agency and

the Electric Power Research Institute. Battelle holds

exclusive rights for the application of this technology at DOE sites, whereas the Geosafe Corp.,

sublicensed by Battelle, is responsible for carrying

out the development and application of ISV in the

private sector.124

Vitrification involves placing four electrodes at

specified depths and distances on the surface of the

contaminated soil to be treated. Space between the

electrodes is covered with a layer of graphite and

glass frit to make up for the typically low conductivity of soil. Soil treatment areas may range from 100

to 900 square feet, with a maximum depth of 30 feet

per setting. At this depth, its developers expect ISV

to be able to treat 800 to 1,000 tons of contaminated

soil at rate of 4 to 6 tons per hour. The electrodes and

the layer of conductive materials are covered by an

octagon-shaped hood to collect off-gases rising from

the melting zone and surrounding soil.125

As electricity is applied to the electrodes, current

flows through the graphite/glass layer, heating it to

1,000 to 2,000OC. Once the top soil layer has been

melted, it becomes electrically conducting and

facilitates the transfer of heat and current to deeper

——

l’2os~as& et al., op. cit., footnote 10s, p. 42; Terry B. Tlomason et al., op. ci(., footnote 100, p. 20.

l’21Ev~~, op. cit., footnote 111.

122G1enn’E Hong et al., MODAR, Inc., ‘‘ Supercritical WaterOxidation: Treatment of Human Waste and System Configuration Tradeoff Study, ’ paper

presented at the Space 88 Conference sponsored by the American Society of Civil Engmccrs, , Albuquerque, NM, Aug. 29-31, 1988.

123Evm, op. cit., footnote 111.

*24Geosafe Corp., “Application and Evaluation Considerations for In Situ Vitrification Technology: A Treatment Process for Destruction and/or

Permanent Immobilization of Hazardous Materials, ’ April 1989, pp. 1-2; Geosafe Corp., “Geosafe Corporation Comments on Claims by Larry

Penberthy, President of PEI, Inc., Against In Situ Vitrification Technology, Nov. 22, 1990; and James E. Hansenet al., “Status of In Situ Vitrification

Technology: A Treatment Process for Destruction ,and/or Permammt Immobilization, ’ paper presented at the 8th Annual Hazardous Materials

Conference, Atlantic City, NJ, June 5-7, 1990.

125 Geosafe Corp., “Application and Evaluation Considerations for In SI(U Vitrification Technology: A Treatment Process for Destruction and/or

Permanent Immobilization of Hazardous Materials, ’ op. cit., footnote 124, pp 4,5,6.8
32 ● Dioxin Treatment Technologies

portions of the soil block. The transferred heat and

electricity in turn mix or blend different materials

and contaminants found in the melting zone.

During melting, solids and contaminants in the

soil undergo physical and chemical changes, including:

●

●

●

The

thermal decomposition of chlorinated organic

pollutants into simpler compounds of carbon,

hydrogen, and chlorine;

breakdown of nitrates into nitrogen and oxygen; and

thermal decomposition of inorganic soil components into oxides such as silica and alumina.

latter products are responsible for the crystalline, glasslike appearance that characterizes vitrified

soil. 126

On completion of treatment, electrodes are left in

place until the soil cools; once cooled, the electrodes

are removed, reused, or recycled. Off-gases escaping

the melting zone are trapped within the hood and

sent to the gas treatment system, which consists of

a quencher, scrubber, dewatering or mist-elimination system, heating system (for temperature and

dew point control), and filtration and activated

carbon adsorption systems. According to Geosafe

officials, only 1 percent of the off-gases treated by

the pollution control system originates at the melt

itself.127

Testing and Availability of ISV Technology

ISV has been tested in the United States and

Canada on several different soil types containing

heavy metals (lead, cadmium, mercury), liquid

organics (dioxin, PCBs, toluene), solid organics

(wood, polyvinyl chloride, DDT), and radioactive

materials (plutonium, radium, uranium). Although

considerable differences were said to exist among

tested soils (e.g., permeability, density, water content), the developers claim that they had no adverse

128 The developers, however, effects on the process.

caution that when fully saturated soils are being

treated, water reduction or extraction should be

employed in advance to minimize overall treatment

costs, because the removal of 1 pound of water

consumes as much energy as the removal of 1 pound

of soil.

ISV treatment of soil contaminated with pentachlorophenol (PCP) and PCBs has been subject to

concern because of the potential to produce dioxins

as well. Dioxins were detected in the off-gas during

testing of ISV at the U.S. Navy’s PCB-contaminated

Superfund site on Guam in 1990. However, no

dioxins were detected in most other cases involving

pilot testing of ISV on PCB-contaminated soil.129 In

early 1987, a bench-scale ISV test on soil from the

Jacksonville, Arkansas Superfund site containing

nearly 10 ppb of dioxins, resulted in DRE values of

99.9999 percent; treatment of off-gases would,

according to a company report, have resulted in even

higher DREs.130 Figure 2-10 is a flow diagram of the

bench-scale unit tested at the Jacksonville, Arkansas

site.

Support by DOE and its contractors have been

essential for the development and application of

ISV, particularly at the nuclear weapons complex. *31

Following the work by DOE, ISV was selected

under EPA’s Superfund Innovative Technology

Evaluation (SITE) program. EPA has since sup126Geosafc Corp., ‘‘Theoretical Basis of process Operation for Volatile Components-Appendix B,” Pilot Test Report for Application of In Situ

Vitrification Technology to Soils and Ash Contaminated With Dioxznt PCBS, and Heavy Metals at the Franklin Burns Site #1, vol. 2. GSC 1005, Geosafe

Corp., KM&red, WA, June 27, 1990, p. 8. Geosafe Corp. ‘‘Apphctttlon and Evaluation Consideration for In Situ Vitrification lkchnology: A Treatment

Process for Destruction and/or Pernmmmt Immobilization of Hazardous Materials, ” op. cit., footnote 124, p. 12; and Fuhr and des Rosiers, op. cit.,

footnote 9, p. 17.

127 Geosafe Corp., “Application and Evaluation Comidcrations for In Situ Vitrification Technology: A Treatment Process for Destruction and/or

Perman ent Immobilization of Hazardous Materuds, op. cit., footnote 124, pp 2-3, 5.

1281bid., pp. 13-15.

129Geosafe Corp., ‘‘Geosafe Corporation Comments on Claims by Larry Penberthy, President of PEI, Inc., Against In Situ Vitrification ‘Rdmology,”

Nov. 22, 1990; James E. Hansen et al., op. cit., footnote 124; Naval Civil Engineerln~ Laboratory, Engineering Evaluatio~Cost Analysis (EE/CA) for

the Removal and Treatment of PCB-Contaminated Soils at Building 3009 Site, Naval Civil Engineering Laboratory, Port Hueneme, CA, July 3, 1990,

p. 9.

130s.J, Mitchell, Battel]e Pacific Nofi~est ~~ratorles, Richjmd, WA, ‘ ‘II) Situ Virnfication for Dioxin-Contaminated SOdS, ’ repOrt prepm(!d for

American Fuel & Power Corp., Panama City, FL, April 1987, pp 2, 18

]3]For ~o=tlon reg~~g the ~~~s of ISV at DOE weapons Sites, sw of fIce of WchUo@y Assessmen~ ~ng.Lived Legacy: Ma~ging HighLevel and Transuranic Waste at the DOE Nuclear Weapons Complex---Background Paper, OTA-BP-O-83 (Washington, DC: U.S. Government Printing

Office, May 1991).
Chapter 2—Thermal Treatment Technologies . 3 3

Figure 2-10—Bench-Scale ISV Unit Tested With Dioxin-Contaminated Soil From

the Jacksonville, AR Superfund Site in February 1987

Off-gas

bypass

m I

Glass fiber

filter

Insulat i

Molybdenum

electrodes

Pyrex

beake

Dioxin

ampul

.+’”’

>

Electrical M

supply 1

-

Pyrex plate k 1

1 l - ]

{

L

4

I

d

\

111~ I 1

::wicat’on “1-_N__-i l._L:-

5+gallon conta~ne;

ICCJ bath

yly .,.,. .,”

::,..

 .“. :. .’..

.:. . . . . .

. . . . .

: ,

.) ;

,.

y

/

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SOURCE: S.J. Mitchell, Battelle Pacific Northwest Laboratories, Rlchlancl, WA, “lr Situ Vitrification for i3ioxln-Cmttamlnated Soils, ’’wncwt prc+pamd; for

American Fuel & Power Corp., Panama City, FL, Apri! 1987

ported the testing of this technology at highly

centaminated sites.

Thus far, in-situ vitrification has been developed

on four different scales: bench (5 to 10 pounds),

engineering (50 to 150 pounds), pilot (1O to 50 tons),

and large (500 to 1,000 tons). Current plans call for

additional tests to gather- the data needed to understand the behavior of large-scale systems in deeper

soil, particularly because ISV has not been very

successful at depths of more than 16 feet.

According to reports of most bench-scale tests

performed, ISV technology has exceeded EPA’s

efficiency requirement for the destruction and removal of dioxins from soil (9.9999 percent).132

Additional research, however, is still needed particpilot- and large-scale levels, to demoneffectiveness of ISV.

Cost Estimate for ISV- Technology

Cost data for ISV treatment of soil contaminated

with dioxins do not exist at this time. Like most

innovative technologies discussed in this paper, ISV

costs would depend heavily on site-specific factors

such as the amount of site preparation required; the

properties of the soil to be treated, including volume

and the amount of glass-forming material present;

treatment depth (the deeper, the less costly because

more soil can be treated); moisture content; unit

price of electricity: and season of year.133

132Geosafe Corp., “Application and EvaluaUon Corrsidemtirms for Ir; Situ Vitrifwaticm ‘IWmoloW ,4 Treatment Process for Desmrction and/or

Permanent Immobilization of Hazardous Materials, ’ Op cit.. foo!note 124, pp ~ “’, ~?

133fiid,, pp. 13, 28-29.
Chapter 3

Nonthermal Treatment Technologies

DECHLORINATION

TECHNOLOGIES

The ultimate objective of all dechlorination methods is to destroy or detoxify hazardous chlorinated

molecules through gradual, but progressive replacement of chlorine by other atoms (particularly hydrogen). The study and application of dechlorination

dates back more than 70 years when it was first used

in the commercial production of phenols. For the

most part, chemical companies focused their efforts

on searching for new reagents as well as for ways to

reduce their dependence on dechlorination processes

requiring high temperature and pressure. Only in the

past decade did researchers begin to look at the

potential applications of dechlorination technology

to dioxin treatment.l One of the first U.S. Environmental Protection Agency (EPA) reports on the

potential application of reagents for the destruction

of polychlorinated biphenyls (PCBs) in soils was

presented in 1983.2

Dechlorination processes are now designed to use

glycols, alcohols, or water as their primary reagents.

The degree of success of glycol- or alcohol-based

methods in removing chlorinated compounds (e.g.,

PCBs, dioxins, and furans) from contaminated

material at any given site varies among methods and

among sites. The conditions that most commonly

determine the efficacy of dechlorination methods

employing glycols or alcohols (e.g., on contaminated soil) include:

the organic carbon content of the soil,

the size distribution of soil particles,

the chemical forms (or isomers) of chlorinated

compounds present in the soil,

the soil moisture content,

. the temperature of the chemical reaction,

● the type of reagent formulation used, and

. the length of time during which contaminated

soil is exposed to the reagents.

These factors, as well as the cleanup level required,

also greatly affect total remediation costs.3

Unlike glycol- or alcohol-based methods, the

water-based dechlorination treatment researched by

EPA, called base-catalyzed decomposition (BCD),

is not affected by the same factors. As an example,

water is used in the BCD process to distribute

reagents throughout the soil. This unique feature

allows as little as 1 to 5 percent (wet weight) of

reagent to be used to treat soil and eliminates the

need to recover reagents for reuse.4

Early Dechlorination Methods

Early dechlorination techniques were used primarily for the destruction of PCBs and PCBcontaminated materials such as certain oily wastes.

As a consequence, relatively little information exists

on their potential to detoxify dioxins. The most

relevant dechlorination processes in this group are

those of the Goodyear Tire & Rubber Co., Acurex

Corp., and Sun Ohio.

The Goodyear technique was designed primarily to dissociate PCB molecules from transformer

fluids by using sodium naphthalene and sodium

tetrahydrofuran. Although PCB concentrations up to

500 parts per million (ppm) could be reduced to 10

ppm in 1 hour of treatment, this practice was

abandoned because of the presence of the primary

pollutant naphthalene in treated residues. The effectiveness of the Goodyear system on dioxins is

unknown. 5

1~balyA.Roy, 6WhtmChmistryk R@” 00 A Fine-’lhnedDechlorinationProcess Destroys Dioxins, PCBS,” Hazmut World, September 1990,

p. 36; Robert L. Peterson and Stephen L. New, Galson Remediation Corp., ‘‘APEG-PLUS: Dechlorination of Dioxins, PCBS, and Pentachlorophenol

in Soils and Sludges, ” undated paper, p. 1.

Z.J. Rogers, “Chemical Treatment of PCBS in the Environment” paper presented at the Eighth Annual Research Symposium, Cincinnati, OH,

September 1983 (EPA-600/9-83-003), pp. 197-201.

3Paul E. des Rosiers, “Chemical Detoxification of Dioxin-Contaminated Wastes Using Potassium Polyethylene Glycolate,” Chemosphere, vol. 18,

No. 1-6, 1989, p. 351; and U.S. Environmental Protection Agency, Hazardous Waste Engineering Laboratory, Treatment Technologies for

Dioxin-Containing Wastes, EPA/600L-86/096 (Cincinnati, OH: October 1986), p. 5.12.

Wharles J. Rogers, Risk Reduction Engineering Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH, personal communication June

13, 1991.

5u.s. Envfionmen~ protection Agency, op. cit., footnote 3, pp. 5.2-5.3, 5.5.

–35–
36 e Dioxin Treatment Technologies

.-— ——.——

The Acurex (Chemical Waste Management)

technique involves mixing filtered PCB-contaminated oil with a sodium-based reagent in an inert

nitrogen atmosphere to produce: 1 ) oil with no

detectable PCBs, and 2) sodium hydroxide (NaOH)

solution. This system, which is commercially available, is known to reduce dioxin levels in PCB 1 liquids

ranging from 1,000 to 10,000 ppm to !ess than 1

ppm.6

Known as the PCBX process, the Sun Ohio (now

ENSR, Canton, Ohio) process is a mobile, closedloop system in which dewatered PCB-contaminated

mineral/bulk oils are mixed with a reagent. After

filtration, the end products include clean oil, PCBS,

and salt residues that are solidified in a Toxic

Substances Control Act (TSCA) PCB-permitted

landfill. This process has been effective in reducing

PCBs only in oils. Two to three passes through the

closed-loop system are sufficient to reduce PCB

concentrations from 3,500 to approximately 2 ppm.

Treatment costs for the Sun Ohio PCBX process are

estimated to be in the range of $3 per gallon of bulk

oil

7

Today, the methods developed by Acurex,

Goodyear, and Sun Ohio are commercially available, but the reactivity of these primarily sodiumformulated reagents with water hampers their use on

dioxin-contaminated soil, sediment, sludge, and

dredging. g Although these dechlorination methods

are marketed for a variety of uses, treatment of

dioxin-contaminated soil is not one of them.

Recent Dechlorination Methods

Alkaline Polyethylene GIycolate (APEG or KPEG)9

In 1978, Franklin Research Institute began an

attempt to identify a chemical reagent that would

break down carbon-halogen bonds in the PCB molecule. Of the dehalogenation formulations tested, the

most successful was composed of 60 grams of

molten sodium and 1 liter of polyethylene glycol

(PEG) with a molecular weight of about400.’1011 The

effect of the PEG-based formulation on dioxincontaminated soil was also studied by the EPA Risk

Reduction Engineering Laboratory (RREL), Cincinnati, Ohio, and Wright State University, “Dayton,

Ohio, in 1982.

Testing and Availability of APEG Treatment—

In 1985, under the auspices of EPA, the Galson

Remediation Corp. (East Syracuse, New York)

tested and compared two dechlorination reagent12

on soil and slurry containing a dioxin isomer13 at

concentrations as high as 2,000 parts per billion

(ppb). At the conclusion of the study, the PEG-based

formulation (known as APEG) was found to reduce

the dioxin level to less than 1 ppb in about 12 hours.

Later that same year, EPA tested the APEG process

on dioxin-contaminated soil at the Shenandoah

Stables, Moscow Mills, Missouri, and learned that

the moisture content of the soil tested (18 to 21

percent water) significantly reduced APEG’s effectiveness. l4 In light of these results, in 1986 EPA

concluded that although APEG was highly efficient

under laboratory conditions, more work was required in the field.15

. —— . ———.———

61bid., p, 5.5.

7~id., pp. s.3, 5.5, 5.12.

6~fred Komel, Charles J. Rogers, and Hmold L. sp~ks, “KPEG Application From the Laboratory to Guam, ‘‘ in U.S. I%vircmrnentfd Protection

Agency, Risk Reduction Engineering Laboratory, Third Inwrnatlonal (“’onferencc on NrM’ Frontiers of Hazardous Waste Management,

EPA/600/9.89/072 (Cincinrum, OH: August 1989), p. 461.

%rou.ghout this section, APEG and KPEG are uwd interchangeable> because both processes employ a polyethylene glycol/potassium hydroxide

solution to remove chlorine atoms from the dioxin molecule APEG is offered by Galson Remediation Corp., Syracuse, NY (patent covers dimethyl

suLfoxide cosoIvent/catalyst) and KPEG by remediation companies such as Canonie Environmental, Inc., in Colorado.

10A ~u~lar process us~g heavier ~4C7s (mol=ulm ~,eigh~ ~~een ~ ,5W ad 6,000) in comhinatirm wi~ a weak bme (potassium CtWbO!’Ult13) Or Un

inorganic peroxide (sodium peroxide) ‘‘to form a clear soh~tion has been tested at bench scale in Europe for the destruction of dioxins such as those

found at Seveso, Italy. However, this process, although investigated has never been used

1 IU.S. Environmental Protection Agency, Op Cil., footnOte ~, p 5.4

12~e reagents tested ~ae po~ssiu~ hydroxide/po]ycthy lenc glyco~ 400/~irncthyl” sulfoxide (KOH/PE(3/DMSO),

(2-methoxyethoxy)ethanol/dimethyl sulfoxide

1~1 ,2,3,4-tetrachlorodibenzo-p-dioxin

IQu.S, Environrnen@] Protection .Agcncy, Op cil., fOOtnOte g, p s 9

‘

s

Ibid., p. 5.12.

and potassium hydroxide/2-
Chapter 3-Nonthermal Treatment Technologies ● 37

APEG and KPEG processes are extremely hygroscopic, and exposure to water readily deactivates the

PEG-based reagent formulation.l6 EPA, in response

to poor results obtained from tests on in situ

treatment of soil in U.S. EPA Region II (Glenn Falls,

New York; South Buffalo, New York) and Region

VII (Moscow Mills, Missouri), has concluded that in

situ chemical treatment of soil with APEG is not a

viable option.17

Costs Estimates for APEG or KPEG Treatment—

According to hypothetical scenarios developed by

Galson Remediation Corp. and EPA’s RREL, the

costs incurred from APEG treatment are as follows:

For in situ treatment, the cost is nearly $300 per ton

of soil treated, with about two-thirds of this resulting

from the purchase of reagents; setup and operational

activities would be responsible for only about 22

percent of the total.

For slurry or batch treatment, theoretical calculations showed that costs could be about $91 per ton

of soil treated. Of this total, 22 percent is for reagent

purchase and 59 percent for setup and operation.

Compared to in situ treatment, the slurry process was

three times less costly due to the ability of the system

to recycle the reagents used in treatment.18

More recently, actual costs of using dechlorination (KPEG process) have been reported by Canonie

Environmental. According to a company official, the

cost for treating 1 ton of PCB-contaminated soil at

the Wide Beach, New York, site, is about $265. For

dioxin-containing soil, costs are expected to range

between $250 and $350 per ton.19

APEG-PLUS Treatment Process

From 1981 to 1986, Galson Remediation Corp.

(GRC) conducted laboratory- and pilot-scale studies

on its APEG process. These efforts were later

implemented by the construction of a mobile treatment unit by Niagara-Mohawk Power Co. (then

under contract with GRC) to provide the first

full-scale application of GRC treatment. Until that

time, application of the APEG process had been

limited primarily to oil contaminated with chlorinated hydrocarbons; the new treatment facility made

soil treatment possible.20 This GRC dechlorination

process for treating soil (shown in figure 3-1) is now

patented in the United States, Canada, and Europe

and is known as APEG-PLUS.21

APEG-PLUS detoxifies materials contaminated

with dioxins, PCBs, pesticides, and other chlorinated hydrocarbons. The patented APEG-PLUS

process consists of potassium hydroxide (KOH) in a

mixture of polyethylene glycol and dimethyl sulfoxide (DMSO). According to company officials, the

PEG-DMSO mixture is not toxic.22

Once the unit has been assembled, excavated soil

or sludge is conveyed to a mixer, where it is

combined with reagents to form a slurry. When

proper mixing has been achieved and chlorinated

organic compounds (PCBs, dioxins, furans) are

extracted from the soil particles and incorporated

into the mixture, the slurry is pumped into the reactor

vessel and heated to 150 ‘C. During the reaction,

chlorine atoms attached to the dioxin molecule are

replaced by PEG to form a water-soluble substance

(glycol ether) that can be degraded easily into

nontoxic materials or washed from the soil.23 24

After chemical analysis performed in the mobile

laboratory unit indicates that the required treatment

level has been reached, the slurry is sent to a

centrifuge. The spinning motion of the centrifuge

separates the reagent from treated soil. The soil is

water-washed for decontamination and removed for

redisposal on land. The wash water is passed through

l%id., p. 5.9.

17~gers, op. cit., fOOtUO~ 4“

ISU.S. Exlvironmenti protection Agency, op. cit., footnote 3, Pp. 5.12-5.13.

19Alis~r Montgornq, Canon.ie Environmental, h.tc., pwSOd comm~atio~ *. 20* 1$$1”

%bert L. Peterson and Stephen L. New, op. cit., footnote 1, p. 2; Roy, op. cit,, foomote 1, p. 38; and Brief review of APEG-PLUS by McLaren

Associates for Syntex Corp., submitted to Missouri Department of Natural Resources, Oct. 10, 1990, p. 5.

21ROY, op. Cit., foo~ote 1$ pp” 3637”

22G~son Remediation Corp., “GRC’S APEG-PLUS: Dechlorination for the ‘90s,” fact sheet, January 1991; Peterson and New, op. cit., footnote 1,

p. 5.

~~e ~~wat= solubiliV of~ ~ga, ~ble #ycoI e~r molecule facilitates its flushing from soil after treatmtxtt with PEG-PLUS. ($$OUKG Brief

review of APEG-PLUS, op. cit., footnote 20.)

UWM L. Peterson and Stephen L. New, “Dioxin Destruction with APEG-PLUS Chemical Dechlorination” Galson Remediation Corp., paper

undated; Peterson and New, op. cit., foomote 1, pp. 3-4.
38 ● Dioxin Treatment Technologies

Figure 3-1—Galson Remediation Corp.’s APEG-PLUS Chemical Treatment System

SOURCE:

Soil and

Soil conveyed

into reactor tank

“x

T

Soil and reagents are

separated and washed

reagents are

slurried and

heated to

1500 c.

I I

w4

+--- Makeup water

Centrifuge

D

Clean soil

conveyed

1

out

Water/

reagent

\~

- - 1

-PReagent recovery

system

I

I I

Makeup Reagent and water from the centrifuge and

reagent water from the condensate system are sent

through the reagent recovery system and

separated and recycled into the chemical

treatment process

Galson Remediation Corp., “Galson’s APEG-PLUS Treatment System-Equipment and Job Description,” 1990.

a bed of activated carbon to remove dechlorinated

products; the contaminated carbon is then treated.

The collected reagent and wash water are sent to the

reagent recovery system for recycling (soils with

high clay content are known to consume reagents in

significant quantities). This process may take 30 to

120 minutes.25

Dechlorination of oversized materials is generally

accomplished by washing the soil particles and

treating the washed soil. However, if the materials

have concrete surfaces, they must be crushed and

treated with the soil because concrete is known to

absorb solvents that contain dioxins. The type and

size of equipment needed to wash and crush such

materials generally depend on specific site conditions.26

Testing and Availability of APEG-PLUS Process—

The most complete demonstration of APEG-PLUS

(on a pilot scale) was sponsored by EPA as part of

the cleanup activities conducted at the PCBcontaminated site in Wide Beach, New York. Test

results indicated that cleanup levels could be met;

the pilot-scale test also showed that reagents could

be recycled up to seven times without noticeable

reduction in the ability of the treatment to meet the

required cleanup level. Results of this and other tests

have shown that dioxins are most susceptible to

APEG-PLUS, followed by PCBs and pentachlorophenol (PCP).

Concerned about the toxicity of dechlorination

byproducts from treated dioxin-contaminated soil,

the EPA Risk Reduction Engineering Laboratory

(Cincinnati, Ohio), asked scientists at the Health

Effects Research Laboratory (HERL) in North

Carolina to evaluate whether its residues or byproducts were toxic or mutagenic .27 At the end of the test,

HERL concluded that:

● the alkaline polyethylene glycol mixture was

neither toxic nor mutagenic to Salmonella

strains studied,

. dechlorination byproducts resulting from the

treatment of 2,3,7,8-tetrachlorodibenzo-p2spetemon ~d New, op. cit., footnote 1, p. 8.; Kimberly A. ROY, op. cit., foo~ote 1.

zGGalson Remediation Corp., “Galson’s APEG-PLUS Treatment System: Equipment and Job Deseriptio~” un&ted, p. 2.

zTDavid M. DeM~ ad Jane E. Simmons, “Toxicological Evaluation of By-Products From Chemically Dechlorinated 2,3,7,8 -TCDD,”

Chenwsphere, vol. 18, No. 11-12, 1989, pp. 2293-2294.
Chapter 3-Nonthermal Treatment Technologies ● 39

dioxin (TCDD) were toxic but not mutagenic to

guinea pigs, and

● no deaths occurred from exposure of guinea

pigs to dechlorination residues.

Studies on fish (carp) led to similar conclusions. No

effects on liver tissue and thymus gland were

detected. 28 HERL stated at the end of the report that "

. . . the present study provides evidence for the

efficacy and relative safety of KPEG for dechlorinating TCDD and helps to put KPEG in context with

other clean-up technologies. ”29 Other tests conducted by EPA at Research Triangle Park, North

Carolina and Duluth, Minnesota on samples containing dechlorinated waste from the Butte, Missouri

and Western Processing, Washington sites showed

no toxic effects (including bioaccumulation, cell

mutation, acute toxicity) from exposure to byproducts.30

APEG-PLUS technology has been applied at

several contaminated sites in the United States.

Some of these are:

● Montana Pole, Butte, Montana—This 20-

acre site, formerly a wood-treating facility, is

located in an abandoned mining site in which

soil and groundwater were contaminated with

dioxins and furans. In January 1986, research

was conducted to determine if APEG-PLUS

dechlorination could be used to treat nearly

9,000 gallons of dioxin- and furan-containing

petroleum oil collected from groundwater over

a 2-year period. The oil was estimated to

contain 3.5 percent PCPs; dioxin and furan

concentrations ranged from 422 to 83,923 ppb.

Because of the success achieved, particularly

with respect to the presence of dioxins and

furans in the waste, EPA selected APEG-PLUS

technology for treatment of the remaining

9,000 gallons of contaminated oil at the site.

●

●

●

Complete decontamination was achieved in

July 1986. Neither dioxin nor furan derivatives

were detected in treated oils at limits of

detection (part-per-trillion level) .31

Western Processing Site, Kent, Washington—

The Western Processing site was remediated

almost completely in 1984; the only remaining

task involved treating more than 7,500 gallons

of spent solvents contained in a storage tank.

These materials were known to be contaminated with dioxins32 at levels of about 120 ppb.

Treatment with dechlorination was accomplished in September 1986, by using the reactor

employed earlier at the Montana Pole, Montana

site. No dioxin was found in the treated solvents

at the detection limit of 0.3 ppb.33

Signo Trading Site, New York—Remediation

at the Signo Trading site involved dechlorination of about 7 gallons of dioxin-contaminated

liquid waste retrieved from the Signo warehouse in Mount Vernon, New York. The liquid

was treated in a 40-gallon drum for 50 minutes.

No dioxin was found in the treated oil at a

detection limit of 0.3 ppb; as a consequence,

EPA’s Dioxin Disposal Advisory Group declared the treated waste dioxin-flee and no

longer subject to the Resource Conservation

and Recovery Act (RCRA) dioxin-listing rule.34

Wide Beach, New York—The Wide Beach

site is a 55-acre residential community located

in the Town of Brant, about 30 miles south of

Buffalo, on the shores of Lake Erie. In 1980,

State officials estimated that this site contained

30,000 to 40,000 cubic yards of PCBcontaminated soil resulting from the application of dust suppressants between 1968 and

1978. PCB levels, primarily Aroclor 1254,

ranged from 10 to 1,000 ppm. In 1985, despite

the fact that a large-scale dechlorination system

was not commercially available, EPA selected

~~ido, pp. ZZ9G.ZZ9’7; Thomas O. Tie- “Treatment of Chemical and con~“ ted Soils Containing Halogenated Compounds and Mrious

Metrds With Potassium-Polyethylene Glycol Reagen~” Proceedings of the Oak Ridge Model Conference, Oct. 13-16, 1987, Oak Ridge, TN, p. 126;

David DeMarini, U.S. EPA, Health Effects Research Laboratory, personal Communication Jan. 9, 1991.

z~em~d Simmons, op. cit., footnote 27, p. 2299.

%Iarmut S. Fuhr and J. Paul E. des Rosiers, “Methods of Degradation Destruction, Detoxifkatiou and DisposaJ of Dioxins and Related

Compounds,” Pilot Study on International Information Exchange and Related Compounds (North Atlantic Treaty Organization Committee on the

Challenges of Modem Society, Report No. 174, August 1988), pp. 5-6.

slKomel, Rogas, sp~~, op. cit., foo~Ote 8, p. 4.62; Tie% op. cit., footnote 28, p, 114.

32 “PIUlldy 2,3,7,8-TCDD.

Ssdes Rosims, op. cit., footnote 3, pp. 343-345.

~Memor~d~frompa~ des Rosiers, Chairmam Dioxin Disposal Advisory Group, to Charles E. Fitzsimmons, On-Scene Coordinator, EPA Region

II, Edisom NJ.
40 ● Dioxin Treatment Technologies

●

dechlorination (KPEG) as the specified technology for treating soil containing PCBs at

concentrations higher than 10 ppm. From

October 1990 to October 1991, the 200-ton-perday unit located at the Wide Beach Superfund

site successfully treated more than 42,000 tons

of contaminated soil; equipment removal is

now taking place.35

U.S. Navy Base, Guam—The Guam site

corresponds to a l/4-mile-long storm drainage

ditch contaminated with PCBs from transformer repair operations and past hazardous

waste disposal practices at the U.S. Naval

Public Works Center. Remediation of the site is

required by both CERCLA (Comprehensive

Environmental Response, Compensation, and

Liability Act) and RCRA.36 Results of characterization studies estimate that PCBs (primarily

Aroclor 1260) are present at levels ranging

from O to 6,500 ppm; the total volume of soil

contaminated with 25 ppm or more of PCBs is

estimated to be 4,000 cubic yards (5,500

tons) .37 APEG38 treatment of soil during two

separate pilot-scale studies in 1988 showed

PCB destruction efficiencies greater than 99.9

percent. Larger field-scale testing is under way

at the site.39

In the past, critics have claimed that the APEGPLUS process was too time-consuming and costly to

treat certain soils. Reaction time does not seem to be

a problem now, but APEG-PLUS’s limited record

on dioxin-contaminated soil, coupled with the risk

that its liquid byproducts may require incineration—

thus making it less cost-effective—may still be

significant factors to consider.

In addition to the full-scale mobile treatment unit

currently available, which is capable of treating 40

tons of contaminated soil daily, GRC officials

expect to offer a 100-gallon reactor pilot unit soon.

The construction of several truck-mounted units and

of a ‘‘treatment train” that would include bioremediation, solidification, and metal extraction procedures is also planned.40

According to company officials, given 24-hour-aday operation, 7 days a week, for 260 days a year, the

cleanup of nearly 100,000 cubic yards of dioxincontaminated soil (at a site such as Times Beach)

could be accomplished in about 2-1/2 years by using

GRC's 200-ton-per-day facility.

Although APEG-PLUS has been tested at a

number of sites, some public officials continue to

view it as a highly experimental technology .41

Cost Estimates for APEG-PLUS Process—For

PCB-contaminated soil, APEG-PLUS processing

costs have ranged between $100 and $800 per ton,

depending on factors such as the nature and volume

of soil treated, characteristics of the site, and cleanup

levels required. At the U.S. Naval Public Works

Center in Guam, for example, the cost of dechlorinating PCB-contaminated soil with APEG-PLUS

was anticipated to be about $270 per ton.42

The above figures, however, do not include the

costs incurred by: 1) performance of treatability

studies prior to actual treatment (about $25,000 to

$30,000 for an average site), 2) excavation and

handling of soil, and 3) final disposal of waste

(RCRA incinerator or onsite if delisted).43 Remediation costs can be further affected by the price of

electricity, the cost of fuels and chemicals, the

S%-ief review of APEG-PLW prepared by McLaren Associates for Syntex Corp., and submitted to Missouri Department of Nti~ Resources on

Oct. 10, 1990, p. 5; Michael Andurer and Chofran Tsang, “Bench and Pilot ‘lksting of the KPEG Process on PCB-Contamma“ ted Soils,” EBASCO

Services, Inc., Oct. 10, 1990, pp. 1,2, 5; and Alister Montgomery, Canonie Environmental, personal communicatio~ Mar. 20 and Oct. 31, 1991.

qGNav~ Civil Engineering ~borato~, Engineering Evaluatio~Cost Analysis @E/CA) for the Removal and Treatment of pCB-Con~“ ted Soils

at Building 3009 Site, Naval Civil Engineering Laborato~, Port Hueneme, CA, July 3, 1990, pp. 1-2.

371bid., p. 3.

3WMS reagent develop~ in EPA’s RREL, is composed only of polyethylene glycol and potassium hydroxide.

%Kornel, Rogers, and Sparks, op. cit., footUote 8, PP. 462-464.

@G~son Remediation Corp., op. cit., footnote 22.

AIM~or~dw~mDavid A. Shon, D~ctor, Division of Environmen~ Q~ty, to G. Tr~y Me@ ~, Dh~tor, Missouri Department of Natural

Resources, July 3, 1990, p. 3; Paul E. des Rosiers, chairm~ Dioxin Disposal Advisory Group, U.S. Environmental Protection Agency, personal

communicatio~ June 10, 1991.

‘$zNav~ Civil Engin~ring Laboratory, op. cit., footnote 36.

AqBrief review of APEG-PLUS, op. cit., fOOb30te 20.
Chapter 3-Nonthermal Treatment Technologies ● 41

efficiency of the centrifuge stage, and off-site

transportation if required.44

For dioxin-contaminated sites, the costs incurred

by APEG-PLUS treatment are expected to be higher

than those for PCBs due to the more stringent

cleanup level required. According to a public

official, the cost of using APEG-PLUS at Times

Beach, Missouri “will be about the same as thermal

destruction.’ ’45

Base-Catalyzed Decomposition Process

(Free-Radical Dehalogenation)

The base-catalyzed decomposition (BCD) process46 developed by RREL in Cincinnati, Ohio, was

initiated in 1989 after pilot-scale testing of APEG

had been completed on Guam.47 The BCD process

was developed to eliminate processing problems

experienced during the Guam field test of APEG.

Unlike APEG, the BCD process:

reduces the processing requirements of soil

(size reduction to 0.5 inch or less);

employs lower-cost bases such as sodium

bicarbonate or sodium hydroxide instead of the

more costly potassium hydroxide;

eliminates the need to use costly polyethylene

glycol as a reagent component;

treats soil or other matrices in minutes rather

than hours;

employs reagents in concentrations as low as

1 to 5 percent by weight of the matrix to be

treated;

eliminates the need to recover and recycle

reagents;

achieves complete dechlorination of pollutants

in contaminated matrices; and

reduces the volume of waste for disposal.

BCD processes employ hydrogen from hydrogen

donor compounds48 to effect the removal of halogens or chlorine from halogenated compounds. This

is accomplished by treating the contaminated matrices in the presence of a hydrogen donor and base at

higher temperature (250 to 350 ‘C) than in the

APEG-PLUS method (150 to 180 ‘C).

Once heated to temperature in the presence of a

base, the organically bound hydrogen is released as

a nucleophile, to combine with and remove chlorine

from chlorinated compounds (hydrogenation).

Testing and Availability of BCD Process—In

treatability tests, the BCD process has been demonstrated on a laboratory scale to destroy PCBs (3,000

ppm) in soil to less than 0.4 ppm within 2 hours.

Also, in recent treatability tests on the phenoxy

herbicides 2,4-D-49, 2,4,5-T-50, Silvex-, and dioxincontaminated soil from the Jacksonville and Rogers

Landfills in Jacksonville, Arkansas, BCD destroyed

the herbicides and reduced dioxins to the part-pertrillion (ppt) level.51

Currently, the EPA Region VII has approximately

25,000 gallons of herbicides (42 percent), 2,4,D-,

and 2,4,5-T contaminated with up to 4,000 ppb of

TCDD for disposal. In treatability tests, BCD has

achieved complete destruction of the 42-percent

herbicide and reduction of TCDD to an average of

100 ppt. Although the BCD process was developed

to reduce chlorinated organics in contaminated

matrices to ppm concentrations, it has also been

demonstrated to destroy chlorinated organics at a

concentration of 42 percent. Tests are going on to

examine the use of BCD to treat 70,000 gallons of

PCBs in transformer oil (60 percent) on a U.S.

Department of Energy (DOE) site, as well as the

25,000 gallons of herbicide and 1.3 million pounds

of 2,4-D/2,4,5-T vermiculite formulation contaminated with TCDD in EPA Region VII. Test results

confirmed that BCD is a candidate technology for

the cleanup of halo-carbon-contaminated liquids

44M~or~dum horn Shorr, op. cit., footnote 41, pp. 1-2; Galson Remediation Corp., op. cit., footnote 26, P. 3; RoY, oP. cit., foo~o~ 1, P. 38; ~d

des Rosiers, op. cit., footnote 3, p. 343.

ASM~or~dum from Shorr, op. Cit., footnote 41, p. 2.

fic~o Rog~s,~dKomel, mdwld sp~~,~er~~~f~r~e~~~c~~~ ofHalogenaredCompounds in Contamz”natedMedium, patentNo. 5,019,175;

May 1991.

ATNav~ Civil ~gfiee~La~ratory, “p. cit., fm~o~ 36, p. 9; ~d c~l~ Rogers, U.S. EPA, Risk R~uction E@@I@ hboriito~, ~OIld

communication Dee. 17, 1990, Apr. 1, 1991, and Oct. 28, 1991.

4sc~l= J. Rogers et ~., “Base Catalyzed Decomposition of Toxic and Hazardous Chemicals,” paper presented at the HazPac ’91 Conference,

cairns, AustralitL Apr. 17, 1991; U.S. BPA pending patent No. 07/515,892, April 1990.

@2,4-dichlorophenoxyWetic acid.

%2,4,5-trichlorophenoxyacetic acid.

SIRogers et ~., op. Cit., fOOtllOk 48.
42 ● Dioxin Treatment Technologies

and soils in an environmentally acceptable manner

(closed system).

BCD treatment has been selected over both

incineration and APEG-PLUS as the preferred

technology for cleanup of the U.S. Navy’s PCBcontaminated sites. The first BCD process (1 ton per

hour) has been constructed and is being used to treat

approximately 90 tons of PCB-contaminated soil on

a U.S. Navy site in Stockton, CA. The process will

then be transported to Guam to treat an additional

5,550 tons of PCB-contaminated soil, starting in

December 1991.52

Cost Estimates for BCD Process—The limited

field application of this promising technology is the

primary reason for the current lack of cost estimates

for BCD treatment of dioxin-contaminated soil.

However, the BCD process theoretically could

achieve significant cost reductions over APEGPLUS because of the much lower cost of the reagents

required. Regarding the application of the BCD

process to dioxin-contaminated soil, theoretical

calculations by EPA suggest that the estimated

projected cost would be about $245 per ton.53

Thermal Gas-Phase Reductive Dechlorination54

Thermal technologies make use of heat as the

major agent in the destruction of waste. Typical

glycol- and alcohol-based dechlorination processes

detoxify hazardous waste through a progressive

replacement of chlorine atoms by other atoms,

notably hydrogen. One new process has incorporated the best of both of these existing methodologies to develop a patented thermochemical reduction

technology. This new process could be suitable for

a variety of matrices, particularly waste that is

primarily aqueous in nature, such as harbor sediment, landfill leachate, lagoon sludge, and potentially soil.

For the past several years, ELI-Eco Logic International, Inc. (Rockport, Ontario and Ann Arbor,

Michigan) has been conducting research on a bench

scale, a laboratory scale, and a mobile pilot-scale

field unit for the destruction of toxic waste. Several

criteria have been used in developing the process

technology, including maximization of destruction

efficiency, absence of dioxin or furan formation,

continuous process monitoring, process control

suitability, suitability for aqueous waste, mobility as

opposed to transportability, and reasonable waste

processing costs.

Thermal gas-phase reductive dechlorination is

based on the gas-phase thermochemical reaction of

hydrogen with organic matter and chlorinated organic compounds at elevated temperature. At or

above 850 ‘C, hydrogen reacts with organic compounds reductively to produce smaller, lighter hydrocarbons. For chlorinated organic compounds

such as dioxins and PCBs, the reaction products

include hydrogen chloride, methane, and ethylene.

The reaction is enhanced by the presence of water,

which also acts as a reducing agent. Bench-scale and

laboratory-scale testing with compounds such as

trichlorobenzene and chlorinated phenols have yielded

destruction efficiencies in a range of 99.999 to

100.000 percent.

The Eco Logic process is not an incineration

technology. Combustion and incineration processes

destroy chlorinated organic waste by breaking down

contaminant molecules at high temperature and then

combining them with oxygen, usually from the

atmosphere. The Eco Logic process uses hydrogen

to produce a reducing atmosphere devoid of free

oxygen and thus eliminates the possibility of dioxin

or dibenzofuran formation.

Other nonchlorinated hazardous organic contaminants (e.g., polycyclic aromatic hydrocarbons (PAHs)),

are also reduced to smaller, lighter hydrocarbons,

primarily methane and ethylene. Because of the

tendency of the reaction to produce lighter, more

volatile gases, the process lends itself to continuous

monitoring of the destruction efficiency. Incorporated into the Eco Logic technology is an online

chemical ionization mass spectrometer, capable of

measuring up to 36 toxic organic compounds every

szC~lesRogms,U.S. EPA, op. cit., footnote 47; Department of the Navy, Naval Civil Engineering Laboratory, ChemicalDeha20genation Treatment.’

Based-Catalyzed Decomposition Process (BCDP), Technical Data Sheet (Port Hueneme, CA: Department of the Navy, August 1991).

53Rogers, op. cit., footnote 47; and Departznent of the Nwy, op. cit., footnote 52.

54D+J. ~et~ KOR. Cwphfl, ~d W-R. Sw@ ‘~~em~ G~.p~se R~uction of org~c ~dous w~tes iII AqUeOUS Matrices,” EPA Abstract

Proceedings: SecondFonm on Innovative Hazardous Waste Treatment Technologies: Domestic andInternational, Philadelphia, PA, May 15-17,1990,

EPA/500/2-09/009 (U.S. Environmental Protection Agency, 1990); D.J. Hallett and K.R. Campbell, ‘‘Demonstration TXi.ng of a Thermal Gas Phase

Reduction Process,’ Proceedings of the ThirdFomm on Innovative Hazardous Waste Treatment Technologies: Domestic andInternational, June 11-13,

1991, Dallas, TX (U.S. Environmental Protection Agency, in press); Wayland R. Sw@ Vice President, Eco Imgic International, Inc., personal

communication July 3, 1991 and C)ct. 20, 1991; Paul W. Rodgers, Vice President, Limno Tech Inc., personal communicatio~ May 29, 1991.
Chapter 3-Nonthermal Treatment Technologies ● 43

0.1 second. Data from the mass spectrometer can be

directed to the process controller so that any increase

in undesirable organic compounds either alters the

rate of waste or reaction gas input or, in the extreme

case, halts the input of waste and alerts the operator

that the system has been shut down.

Figure 3-2 is a schematic of the reactor vessel

designed to accommodate thermochemical reduction. A mixture of preheated waste and hydrogen is

injected through nozzles mounted tangentially near

the top of the reactor. The mixture swirls around a

central ceramic tube past glo-bar heaters, which heat

the waste to 850 ‘C by the time it exits the ports at

the bottom of the ceramic tube. Particulate matter up

to 5 mm in diameter not entrained in the gas stream

impacts the hot refractory walls of the vessel,

thereby volatilizing any organic matter associated

with the particulate. Larger particulate exit from the

reactor bottom into a quench tank. Finer particulate

entrained in the gas stream flow up the ceramic tube

and through the retention zone. The reduction

reaction takes place within the ceramic tube and

requires less than 1 second to come to completion.

Figure 3-3 presents a complete process schematic

of the field demonstration unit. In this unit, waste

liquid and suspended solids are pumped from a small

storage tank to a heat exchanger vessel for preheating to 1500C by a small boiler. The hot liquid and

steam from the watery waste are metered continuously by use of special metering valves and are

injected into the reactor by use of atomizing nozzles.

A mixture of hydrogen and recirculation gas also

enters the reactor near the top after passage through

a gas-fired heat exchanger. Heavy particulate exit

as grit from the bottom to a quench tank. Fine

particulate matter passes up the ceramic tube (shown

in figure 3-2) where gas-phase reduction takes place.

Additional residence time is provided by the retention zone elbow and extension pipe. On exiting the

reaction zone, gases enter the scrubber where they

are quenched by direct injection of scrubber water

spray. Hydrogen chloride and fine particulate matter

are removed by contact with scrubber water as the

gases pass through carbon steel scrubber media on

the down leg and polypropylene on the scrubber up

leg. Scrubber water is collected in a tank by means

of a large water-sealed vent, which also acts as an

emergency pressure relief duct. Scrubber water is

cooled to 35 0C by using a heat exchanger fed by

cooling water from an evaporative cooler. Sludge

and decant water represent the two effluent streams

Figure 3-2—Reactor Used for Thermochemical

Treatment in Eco Logic Process

a

<

SOURCE: ELI-Eco Logic International, Inc., Ann Arbor, Ml, 1991.

from the scrubber. Both of these effluents are held in

tanks for batch analysis prior to disposal.

Gases that exit the scrubber consist of excess

hydrogen, reduction products (e.g., methane and

ethylene), and a small amount of water vapor.

Approximately 95 percent of this gas is recirculated

to the reactor after being reheated to 500 ‘C. The

remaining 5 percent of the hydrocarbon-rich gas is

used as supplementary fuel for the boiler. The boiler

uses propane gas as its main fuel to produce steam

for use in the heat exchanger. The only air emissions

are from the boiler in the form of stack gas. Because

the fuel going into the boiler is very clean (i.e., no

chlorine content), emissions from the boiler to the air

are insignificant.

In the event of a process upset in which total

destruction of hazardous organic compounds is

incomplete, the online mass spectrometer automatically diverts all gases into the recirculation mode.

No sidestream gas is sent to the boiler, and the waste
44 ● Dioxin Treatment Technologies

Figure 3-3-Schematic Flow Diagram of the Thermal Gas-Phase Reductive Dechlorination Process

Gas-fired

heat

exchanger

,

recirculation

gas

Hydrogen

Hydrogen

and + *

t-’-’-- Storage tank

I

i-h’ H 11 !/Grit

Scrubber

I ~r

I Scrubber gas boiler

* Hydrogen

and

Reactor Scrubber water collection tank recirculation

gas

Evaporative cooler

Side stream gas

~ Decant water

Astackgas

@+ ( b“ v , , Boiler Propane gas

\ 1 /

Metering valves

+ 2

-

Heat exchange vessel

. I

SOURCE: ELI-Eco Logic International, Inc., Ann Arbor, Ml, 1991.

feed is stopped. Recirculation continues until analysis indicates that the reaction is again occurring

optimally. Because 95 percent of the gas stream is

recirculated under normal conditions, this procedure

does not represent a drastic action.

The entire Eco Logic technology is contained on

two 45-foot drop-deck flatbed trailers and thus is

mobile. An additional trailer, housing the online

mass spectrometer, the process control unit, and

other analytical equipment, completes the array of

equipment necessary for waste destruction. Onsite,

the space required for processing waste is little more

than the size of the three trailers. Setup time for this

system is a matter of a few days, and the minimum

run with this device may be less than a single unit’s

daily capacity. On the other end of the spectrum, the

continuous throughput process is well suited to

high-volume, long-run waste destruction. Throughput capacity can be varied at will by attaching

additional reactor units to a single ancillary support

and control system, thereby allowing flexibility of

operation and redundancy of design.

Some of the largest and most serious contaminant

remediation requirements involve soil and sediment

having high water content. Incineration technologies

consume very large amounts of energy to heat up the

water component to combustion temperature. Additionally, because these technologies utilize air (79

percent nitrogen) for combustion and must combust

all the organic matter, they often require 10 times the

volume of the Eco Logic process for the same

residence time of reaction. Other dechlorination

technologies (e.g., APEG, KPEG, APEG-PLUS) are

much less efficient in treating water-bearing waste

because of consumption of the reagent by water, and

a potential for explosive reaction exists. By contrast,

in dealing with soil and sediment having a high

water content, the Eco Logic process employs

typical sediment/water mixtures in a range of 30 to

50 percent as optimal for this unit. Treatment

material containing less than 30 percent solids is

possible, but the economy of the destruction process

begins to diminish below this level.
Chapter 3-Nonthermal Treatment Technologies ● 45

Testing and Availability of Thermal Gas-Phase

Reductive Dechlorination Process—At the time of

preparation of this paper, the Eco Logic technology

has been successfully tested by the Canadian Federal

Government and the government of the Province of

Ontario in a site demonstration in Hamilton, Ontario, Canada. The site demonstration began on

April 8, 1991 and took about 4 months to complete.

The demonstration consisted of the destruction of

contaminated sediments (not dioxin) from Hamilton

Harbor in Lake Ontario under the auspices and

supervision of Environment Canada’s Contaminated Sediments Treatment Program and the Province of Ontario’s Technologies Program. Preliminary results show thermal gas-phase reductive

dechlorination to be highly effective in the treatment

and volume reduction of contaminated harbor sediments.

A single full-scale reactor vessel has been designed to process 12 kilograms (26 pounds) of waste

per minute under normal operating conditions. This

throughput is, of course, dependent on the nature of

the contaminant of concern, its degree of chlorination, and its water content. The range of throughput

values lies between 15 and 20 tons per day. Present

design planning calls for the construction of a

50-ton-per-day unit in early 1992. Because it is

possible to use multiples of the reactor vessels with

a single process control entity, treatment capacity

can be increased easily. With the present configuration, as many as three reactors may be grouped per

control unit, enabling 45 to 60 tons of waste to be

treated daily. A new design would handle up to 150

tons per day.

Cost Estimates for Thermal Gas-Phase Reductive Dechlorination Process—The combination of

equipment requirements and process characteristics

suggests a relatively lower capital cost for the Eco

Logic system compared to incineration. Operating

economies to treat water-bearing waste are expected

to be three to five times lower than incineration

technologies of comparable capacities. Cost estimates for the destruction of waste are a function of

both the chlorine content of the contaminant of

concern and its concentration in the environmental

matrix. For sedimentary materials containing resistant chlorine compounds (e.g., PCBs, polychlorinated dibenzofurans (PCDFs), and polychlorinated

dibenzo-p-dioxins (PCDDs)) in a concentration up

to 1,000 milligrams per kilogram, costs can be

expected to fall in a price category of $350 to $500

per ton of waste processed. According to company

officials, this range represents the total cost of

processing the waste, because no residually contaminated materials remain to be transported or treated

elsewhere.

Thermal Desorption/UV Destruction (Photolysis)

Thermal desorption/ultra violet (UV) radiation

destruction technology consists of three main operations: 1) resorption, which involves heating the soil

matrix to volatize the dioxin present; 2) scrubbing or

collection of dioxin into a solvent suitable for

subsequent treatment; and 3) UV treatment or

exposure of the dioxin-solvent mixture to UV

radiation to decompose the dioxin molecules

through photochemical reactions (photolysis).55

Within a reactor system, dioxin-contaminated

soils are continuously passed through a heating unit

(rotary drum or desorber) and heated to temperatures

up to 560‘C to volatize the dioxin molecules present

in soil particles. Once removed, the dioxin vapors,

along with soil moisture, small soil particles, and air,

are scrubbed with a solvent, and subsequently

cooled. Prior to its release into the atmosphere, the

scrubbed off-gas is passed through pollution control

equipment (e.g., carbon adsorption; scrubber) to

remove solvent vapors and any dioxin that may have

been left untreated.56 Following separation or filtration, the scrubber solvent is cooled and recirculated

to the scrubber. The water remaining is treated (e.g.,

filtration, carbon adsorption) and discharged. The

faltered soil particles are either recycled to the rotary

drum or desorber for additional treatment or packaged for disposal (see figure 3-4).57

The developers of this technology (International

Technologies Corp., Knoxville, Tennessee) claim

that it reduces the volume of soils requiring treat55R+ H~l~l et & “lkchnology Demonstration of a Thermal Resorption-W Photolysis Process for Decontamma “ ting Soils Containing Herbicide

Orange,” J.H. Exner, Solving Hazardous Waste Problems: Learning From Dioxins, American Chemical Society Symposium Series 338 (Washingto&

DC: American Chemical Society, 1987), pp. 319-322.

~rbid.; R.D. FOZ ~te~tio~ lkchnoIogy Cow., “Experience With Treatment AheIWit.iveS fOr tigano~ogen con~“ tiorL” paper presented

at Dioxin ’90 Conference, Bayreu@ Germany, Sept. 14, 1990.

SvHelsel et al., op. cit., footno~ 55, pp. 319-322.
46 ● Dioxin Treatment Technologies

Figure 3-4—Low-Temperature Thermal Resorption Process

Vent

t

.-1---- ....,

\ Emission ~

controls :

Organic and A

Make-up solve lt

water vapors

1

Contaminated Thermal Cooling * Solvent

and soil ~ desorber Recycle treatment

scrubbing 4 “ (photolysis)

1

v

Clean soil Aqueous

condensate v

Heat source y- ------- Solvent ‘residues

Water ~

[ treatment \

‘--1 --------

+

Discharge

SOURCE: International Technology Corp.

ment, producing a concentrate that is easier and

more cost-effective to treat. They also claim that this

process will achieve cleanup goals similar to those

of thermal treatment but without a high-temperature

incinerator.

Testing and Availability of Thermal Resorption/

UV Destruction

Although thermal resorption/UV destruction process has been tested on soils containing highly

volatile solvents, testing on soils contaminated with

low volatile chemicals, such as dioxins, is limited.

Of the tests performed by International Technology Corp., only those conducted at the Department

of Defense’s Naval Construction Batallion Center

(Gulfport, Mississippi) in 1985 and at Johnston

Island in 1986 are relevant to dioxin-contaminated

soils .58 59 These pilot-scale tests resulted in reducing

dioxin concentrations in soil from over 200 ppb to

below detection limits (0.1 ppb).60

The researchers who participated in the two tests

concluded that “. . . additional technical information [was] needed for a complete evaluation of the

process and to provide the basis for design of a

full-scale system for on-site remedial action.”6l

Since 1986, however, little additional work related

to dioxin-treatment has been done on this process.

The developers claim that lack of funds and markets

are the major factors inhibiting further development.62

This system, however, is being applied to remediate a PCB-contaminated site in Massachusetts.63

Also, EPA has proposed this technology as a

remedial option for cleaning up nearly 40,000 cubic

ss~e ~on-at of concern at ~ese sites was Herbicide Orange kQown to contain 2.4-D* 2>4>5-Z and diofi”

S%elsel et rd., op. cit., footnote 55, p. 320.

%id., pp. 322-330; Paul E. des Rosiem, ‘‘Advances in Dioxin Risk Management and Control Technologies,” Chemosphere, VO1. 18, NOS. 1-6.1989,

p, 41; Fuhr and des Rosiers, op. cit., footnote 30, p. 33.

slHelsel et al., op. cit., footnote 55, p. 336.

62Ro~fi D. Fox, D~e~tor, ~~olo~ D~velopm@ ~tematio~ M~oIogy COT., persod coLIUllUIlkatiO~ Sept. 1’7, 1991.

63Ro~fi D, Fox, ~te~tio~ T&~ology co~., pe~o~ commticatio~ Sept. 3, 1991.
Chapter 3-Nonthermal Treatment Technologies ● 47

yards of PCB-contaminated soil and debris at the

Carter Industrial Superfund site in Detroit, Michigan.64 One site With dioxin contamination at which

thermal resorption/UV destruction is being considered for application is Baird & McGuire

(Holbrook, Massachusetts).65 Cost estimates for its

application at any of these sites, however, are not

available.

BIOREMEDIATIO N

The use of microorganisms to break down and

metabolize organic pollutants has been studied for

many years, particularly for treating industrial wastewater and domestic sewage. Since the early 1970s,

several organisms have been identified as having the

ability to break down chlorinated substances (including dioxin species such as 2,3,7,8-TCDD in soil

and in water);66 however, neither the level of

decomposition nor the products that result are

known precisely. Of the different strains studied to

date, the white rot fungus (Phanerochaete chrysosporium) is the most promising because of its ability

to degrade halocarbons such as lindane, DDT,

4,5,6-trichlorophenol, 2,4,6-trichlorophenol, and dichlorophenol.67 68 Encouraging results have also

been reported in Germany on the biodegradation

potential of the bacteria Pseudomonas sp.69

In general, bioremediation refers to the transformation of contaminants into less complex and

probably less toxic molecules by naturally occurring

microbes, by enzyme systems, or by genetically

engineered microorganisms. This process can be

carried out in situ or in a reaction vessel, under

anaerobic or aerobic conditions, and alone or in

combination with other treatment methods; several

months or years may be required to achieve complete contaminant removal. Understanding the microbial population to be used, as well as the

characteristics that ensure their survival, is key to

any bioremediation project; these include, among

other factors, moisture and oxygen levels, organic

content, temperature, pH, food source availability,

and possible degradation pathways. Although considerable laboratory and field work has been reported in each of these major areas,70 few studies

exist in which contaminants have been destroyed or

removed at levels higher than 90 percent.71

Dioxins are known to degrade naturally in the

presence of sunlight (ultraviolet radiation) or with

the help of microorganisms. The time that dioxins

“’Thermal DeSorption Fix Offered in Detroi6° Superfund, May 3, 1991, p. 5.

fiu.s. Environmental Protection Agency, Region I, Superfund fiogram, “Fact Sheets-Treatment Ikchnologies,” July 1991.

‘M. Philippi et al., “A Microbial Metabolize of TCDD,” Experiential, vol. 38, 1982, p. 659; S. Banerjee, S. Duttagupta, and A.M. Chrdcrabarti,

“l%oductionof Emulsifying Agent During Growth of Pseudomonas cepacia With 2,4,5-Tnchlorophenoxyacetic Acid,” Arch. Microbiology, 1983 vol.

135, p. 110; J.J. Kilbane, D.K. chatterjee, and A.M. Chakrabarty, “Detoxitlcation of 2,4,5-Trichlorophenoxyacetic Acid From Contaminated Soil by

Pseudomonas cepacia, “ Applied& Environmenta2h4icrobiology, vol. 45, No. 5, March 1983, p. 169; D. Ghosal, L.S. You, D.K. Chatterjee, and A.M.

Chakrabarty, ‘Microbial Degradation of Halogemted Compounds,’ Science, vol. 228, No. 4696, Apr. 12,1985, p. 135; Mary L. Krumme and Stephen

A. Boyd, “Reductive Dechlorination of Chlorinated Phenols in Anaerobic Upflow Bioreactors,” Water Resources, vol. 22, No. 2, 1988, p. 171; and

Gary M. Klecka and D.T. Gibso~ “Metabolism of Dibenzo-p-dioxin and Chlorinated Dibenz.o-p-dioxins by a Be~enrinckia Species, ” Applied &

Environmental Microbiology, vol. 39, No. 2, February 1980, p. 288.

G7u.s. Env~onmen@ protection Agency, op. cit., footnote 3, p. 5.38; des Rosiers, op. cit., footnote 60, p. 53.

‘Rudy Baum, “Degradation Path for Dichlorophenol Found,” Chemical & Engineering News, vol. 69, No. 1, Jan. 7,1991, pp. 22-23; Harry M.

Freeman and R.A. Olexey, ‘‘A Review of Treatment Alternatives for Dioxin Wastes,” Jnl. Air Pollution Control Assoc., vol. 36, No. 1, Jan. 1986, p.

74.

G~&e -etrd., “Transformation of Dibenzo-p-Dioxin by Pseudomonas sp. Strain HH69,” Applied & Environmental Microbiology, VO1. 56,

No. 4, 1990, pp. 1157-1159.

TOSmjoy K. Bhattachayia, we University, “Innovative Biological Processes for Treatment of Hazardous Wastes;” William R. Mahaffey and G.

Compeau, ECOVA Corp., “Biodegradation of Aromatic Compounds;” Michael J.K. Nelso~ J.A. Ciofil, and H.S. Borow, “In Situ Bioremediation of

TCE and Other Solvents;” Proceedings of the HMCRI’S 1 lth Annual National Conference and Exhibition SUPERFUND ’90 (Silver Spring, MD:

Hazardous Materials Control Research Institute, 1990), pp. 776-787; 800-806; 847-852. Harlan S. Borow and J.V. Kinsella, ECOVA Corp.,

“Bioremediation of Pesticides and Chlorinated Phenolic Herbicide+Above Ground and In Situ: Case Studies;” Richard A. Brown and J.R. Crosbie,

“Oxygen Sources for In Situ Bioremediatio~” Proceedings of the HMCRI’S IOth Annurd National Conference and Exhibition SUPERFUND ’89 (Silver

Spring, MD: Hazardous Materials Control ResearchInstitute, 1989), pp. 325-331; 338-344; C. Cernil~ ‘‘Microbial Metabolism of Polycyclic Aromatic

Hydrocarbons,” Adv. Appl. Microbic/., VOI, 30, 1984, pp. 30-70; J.W. Falco, Pacific Northwest Laboratory, “Technologies to Remediate Hazardous

Waste Sites” (PNL-SA-18030; DE90-011946), paper presented at the Mixed Waste Regulation Conference, Washington, DC, Apr. 17-18, 1990; D.’E

Gibson and V. Subrarnani arL “Microbial Degradation of Hydrocarbons” D.T. Gibson (cd.), Microbial Degra&tion of Organic Compounds (New York

NY: Marcel Dekke~, 1984); Harmut S. Fuhr and J. Paul E. des Rositis, op. cit., footnote 30, p. 32; Ronald Sims, “Soil Remediation ‘lkchniqlles at

Uncontrolled Hazardous Waste Sites-A Critical Review,” Jnl. Air Waste Manag. Assoc., 1990, pp. 720-722; Eugene L. hfadse~ “Detenninin gIn Situ

Biodegration: Facts and Challenges, Environ. Sci. TechnoL, vol. 25, No. 10, 1991, pp. 1663-1673.

ylNav~ Civil Er@~ring Laboratov, op. cit., footnote 36, p. 10; U.S. Environmental Protection Agency, Op. cit., footnote 3, Pp. 5.3*5.35.
48 ● Dioxin Treatment Technologies

remain in soil, however, has been particularly

difficult to assess because they are present in low

concentrations (the lower the concentration, the

more difficult it is for microorganisms to find and

break down dioxins) and tightly bound to soil

particles and organic matter. One laboratory study

shows that even after a year of treatment, more than

50 percent of the dioxin remained in test soil.72

Equally significant is the fact that researchers

identified half-lives of more than 10 years for

dioxins at the site in Seveso, Italy and at certain U.S.

Air Force bases in which defoliant use has been

reported. 73

Although information from field work is limited,

some potential advantages of future bioremediation

methods at dioxin-contaminated sites include the

following:

1.

2.

3.

byproducts of biodegradation may be nontoxic;

bioremediation could be used in combination

with other remedial methods (e.g., treatment

trains); and

treatment of dioxins in subsurface soil and

groundwater might not require extensive removal of overlying soil. 74

One bioremediation technique being evaluated by

EPA is in-situ microbial filters. This technology

involves the injection of naturally occurring (indigenous) microbes, cultured bacteria, nutrients, and

oxygen into the soil column or groundwater to form

zones of microbial activity. These zones are established in close proximity to contaminant plumes to

facilitate the availability of the latter to injected

microbes. The bioremediation of chlorinated and

nonchlorinated pollutants has as end products:

carbon dioxide, water, and bacterial biomass. 75

At present, in situ microbial technology has been

tested only in the laboratory; consequently, its

effectiveness in subsurface soil degradation is unknown (microbes may opt to metabolize injected

nutrients instead of contaminants). Cost data are also

nonexistent. A field demonstration planned at the

Goose Farm Superfund site, Plumstead Township,

New Jersey, was canceled in April 1990; efforts to

select a new demonstration site are under way.76

Prior to its utilization on dioxin-contaminated sites,

researchers will be required to determine factors

such

1.

2.

3.

as:

the level of chemical reaction that can be

achieved,

the role of injected nutrients, and

the growth rate of microbes in the subsurface.

Testing and Availability of

Bioremediation Technology

Although bioremediation is theoretically attractive for cleaning up dioxin-contaminated sites, its

real applicability and effectiveness continue to be

highly questionable. Comparisons of dioxin research efforts with 2,4,5-trichlorophenol and Agent

Orange reveal that only a fraction of the vast amount

of laboratory work has been targeted toward dioxin

and demonstrated in the field.77 Furthermore, the

current bioremediation literature lacks any reports

documenting the success of this technology in

treating dioxin-contaminated soil, sludge, or sewage.78

Major obstacles in researching dioxin include:

1. its high acute toxicity and low volubility, such

that it cannot be found in the aqueous environments in which most microorganisms live;

2. the high cost of treatment; and

72p~@ C. Kearney et ~., “Persistence and Metabolism of Chlorodioxins in Soils,” Environ. Sci. Technol., vol. 6, No. 12, November 1972, p. 1017.

73u.s. fiv@~enM Protection Agency, op. cit., footnote 3, p. 5.35; A. DiDominico et ~., “AccidentalReleases of 2,3,7,8-lMrachlorodibenm-p-diOxin

(TCDD) at Seveso, Italy,” Ecotoxicology & Environmental Sufety, vol. 4, No. 3,1980, pp. 282-356; PaulE. des Rosier% “RemedialMeasuresf orW~tes

Containing Polychlorinated Dibenzo-p-dioxins (PCDDS) and Dibenzofurans (PCDFS): Destructio~ Containment or Process Modificatiom$’ Ann.

Occup. Hyg, vol. 27, No. 1, 1983, pp. 59-6Q Ronald Sims, op. cit., footnote 70; Dermis J. Paustenbacb “Recent Developments on the Hazards Posed

by 2,3,7,8-tetrachlorodibenzo-p-dioxin in Soil: Implications for Setting Risk-Based Cleanup Uvels at Residential and Industrial Sites,” paper submitted

for publication to J. ToM”c02. Environ. Health, June 1991.

74u.s. l?nviro~en~ prote&onAgen~y, op. cit., foo~ote 3, p. S-A*; U.S. Environment prot~tion Agency, office of Research ~d Development

Risk Reduction Engineering Laboratory, Technology Projiles, EPA/540/5-90/006 (Cincinnati, OH: November 1990), p. 40.

7S~id.

7’%id., p. 41.

Tlu.s. ~v~omm~ ~otation Agency, opo cit., foo~ote 3, p. 5.4.4; A.M. -am, Dep@ent of Microbiology and hIUIIurlOIOgy, uDhWSity

of Illinois, Chicago, personal communication Jan. 9, 1991, and Aug. 23, 1991.

78FUIU and des Rosiers, op. cit., footnote 30, p. 2.
Chapter 3-Nonthermal Treatment Technologies ● 49

3. its presence at concentrations so low that

microorganisms in the natural environment do

not consider it food (i.e., an important source

of carbon).

The complex nature of the soil environment found at

contaminated hazardous waste sites is also a major

obstacle because it prevents researchers from developing models useful for predicting bioremediation

results accurately.

Experts also criticize the fact that basic environmental research is not well funded. This is due

primarily to the fact that the health effects of

exposure often are not visible for a long time and

companies do not consider environmental bioremediation research to have a market value. Another

reason for the lack of research on dioxin at the

academic level is that 4 years of biodegradation

research produces very little information that could

be used by a graduate student to fulfill dissertation

requirements. According to A.M. Chakrabarty of the

Department of Microbiology and Immunology, University of Illinois, Chicago, ‘‘There is no credible

report on bacterial removal of dioxin at the present

time. ’ ’79

Judging from the review performed at the U.S.

Navy site in Guam for the selection of a remedial

technology, bioremediation techniques must be

studied further before they can be applied. 80 T h e

long time required by bioremediation processes,

coupled with their undocumented ability to reduce

risks to human health and the environment, were

considered by technology reviewers as sufficient

reasons for not recommending soil bioremediation

at that site.

In the view of most experts, bioremediation

processes for dioxin are not ready for field demonstration at this time. However, they may become

cleanup options in the future, aided by scientific

achievements in the fields of biochemistry and

genetic engineering of microorganisms, and of the

chemistry of TCDD surrogates (e.g., chlorophenols,

chlorobenzenes, and the herbicides 2,4,D- and

2,4,5-T).

Cost Estimates for Bioremediation

Cost figures for bioremediation of dioxins do not

exist at present. One reason is that treatment of

chlorinated dibenzo-p-dioxin and chlorinated dibenzofurans has not been proved beyond the analysis

performed on a bench scale in 1985; no field testing

has been conducted to date. According to projections

based on laboratory work, in situ bioremediation

might be the most economical treatment because it

does not require excavation of soil. Nevertheless, in

the long term, the costs of in situ bioremediation

could increase considerably because tilling, fertilizing, and irrigation practices may be required.81

Current figures, however, do not illustrate the costs

involved in actual bioremediation treatment.

79-ab~, op. cit., fOOtnOte 77.

%aval Civil Engineering Laboratory, op. cit., footnote 36, p. 10.

81u.s. ~viro~en~ Protection Agency, op. cit., foo~ote 3, p. 5.46.
Chapter 4

Other Remediation Technologies

To complete the discussion of remediation alternatives for dioxin-contamin ated sites, this chapter

presents techniques that, rather than treating or

destroying dioxins, are used to concentrate, stabilize, or store the contaminated material. Suc h

approaches may be used either in conjunction with

treatment or as a simpler alternative.

ONSITE SOIL WASHING

TECHNOLOGIES

Soil can be washed with solvents or ‘‘soaps’

(surfactants) to extract contaminants into the liquid

stream, thus reducing the volume to be treated. Soil

washing, though relatively new in the remediation

field (as in aquifer restoration), is commonly used in

mining operations. At present, however, there are no

full-scale soil washing systems for treating dioxincontaminated soil commercially available in the

United States.1

Testing and Availability of Soil

Washing Technology

One soil washing technique currently available,

which may be applicable to dioxin-contaminated

soil, is offered by Westinghouse Electric Corp.

(WEC). According to WEC, this method has been

proved effective in the treatment of soil contaminated with organic chemicals, heavy metals, and

even radionuclides. Another technique is expected

to be offered soon by BioTrol, Inc. (Chaska,

Minnesota), for the treatment of soil contaminated

with organic pollutants, including polychlorinated

biphenyls (PCBs) and pesticides.

No information from full-scale studies on the

efficacy of soil washing for dioxins in full-scale

studies exists at the present time. A 1990 review of

available technologies best equipped for cleaning up

the U.S. Navy site in Guam found soil washing

incapable of treating the highly PCB-contaminated

soil present at the site.2 That review, however, did

not consider the WEC and BioTrol soil washing

methods.

Westinghouse Electric Soil

Washing Technology

The WEC process shown in figure 4-1 consists of

several interconnected treatment units, including a

particle separator (by size and density) and chemical

extractors containing soaps to cleanup the soil. One

advantage of this process is that because contaminated soil is treated in a slurry, air emissions and

water discharges are eliminated. After being

washed, soil is returned to the site and the concentrated residuals are processed through incineration,

recycling, or stabilization techniques.

Figure 4-l—Westinghouse Soil Washing Process

Soil/debris feed

I

t

1 !

Clean soil Initial screening

return

I Solid breakup 1~

Initial wash

Particle size separation

Density separation

~

w I ,

Measurement

I I Clean soil

ret urn I

Concentrates treatment 1+

“ ordisposa’ ‘+ Concentrates to sale

I

Recycle Ieachate

SOURCE: Westinghouse Electric Corp., “Soil Washing Applicability and

Treatability Studies,” undated.

IJohn Sheldoq BioTrol, Inc., personal communication, Apr. 1, 1991.

?Naval Civil Engineering Laboratory, “Engineering Evaluation/Cost Analysis (EE/CA) for the Removal and Treatment of PCB-Contaminated Soils

at Building 3009 Site, ’ Naval Civil Engineering Laboratory, Port Hueneme, CA, July 3, 1990, p. 7.

–51–
52 ● Dioxin Treatment Technologies

The chemical composition of the soaps (leach

solutions) can be modified to address specific site

needs. Processes used by Westinghouse have been

employed in Europe. They were used in Germany to

remove 98 percent of the polynuclear aromatics

from soil (at HWZ Bodenmsanering), and more than

90 percent of the heavy metals and organics (at a site

in Hamburg).

The process can be varied to address specific site

conditions because studies have indicated that:

1.

2.

3.

4.

organics concentrate in clay, silt, and humic

materials;

PCBs and other organic components can be

leached out with caustic agents (sodium hydroxide, sodium carbonate) and surfactants;

the abrasive nature of soil particles can be used

to improve the efficiency of the technology;

and

heavy metals and radionuclides are usually

more dense than soil.

The major steps in the WEC soil washing

technique include the excavation of soil and the

removal of large rocks and debris; sorting of soils by

placing them in a rotating drum/vibrating screen

device for size separation; and washing of the large,

and probably uncontaminated, soil particles and

debris (greater than 2 millimeters) with soap solution. This phase is completed by rinsing and

returning large soil particles to the site.

During the second phase, the remaining contaminated soil and debris are passed through a mineral

processing unit where they are exposed to soap

solution and the fries present are separated. Processed soils are then washed, monitored, and finally

returned to the site. The metal frees and soap (mixed

with organic contaminants removed from the soil)

from the mineral processor are passed through a

precipitation tank, where they are exposed to precipitation agents to induce chemical separation. The

clean soap solution is sent to make-up tanks for

recycling; metal frees, if cleaned, are shipped for

recycling, and organic concentrates are sent to

biotreatment or incineration units.3

BioTrol Soil Washing Technology

The BioTrol technology-a patented process

initially designed to treat soils-contaminated with

wood preserving waste-can be used to wash soil

containing hydrocarbons, pentachlorophenol, and

pesticides. The BioTrol system (see figure 4-2) uses

a high-intensity, countercurrent scrubber to separate

freer soil particles containing the pollutants of

concern from coarser soil material; contaminants

that adhere to coarser materials are freed by the

abrasive scouring action of the soil particles. The

efficiency of the soil washing solution may be

improved by: 1) adding detergents, surfactants, or

chelating agents; or 2) adjusting pH and temperature. Effluents from the BioTrol system are clean

soil (which can be redisposed), process water (which

can be recycled or biologically treated), and contaminated soil fines. Depending on the type of pollutants

present, these soil frees may be landfilled, incinerated, stabilized, or treated biologically.4

Preliminary results from a 1989 EPA-sponsored

demonstration at the MacGillis & Gibbs Superfund

site in New Brighton, Minnesota show the ability of

the BioTrol technology to reduce the pentachlorophenol concentration in soil by 91 to 94 percent. The

bench-scale unit tested had a treatment capacity of

12,000 pounds per day.5

SOLIDIFICATION AND

STABILIZATION TECHNOLOGIES

Solidification and stabilization (S/S) technologies

have been employed in the United States for more

than 20 years to treat certain liquid industrial

chemical wastes; more recently, however, their use

has been expanded to treat contaminated soil and

incineration residues.6 S/S techniques focus primarily on limiting the volubility or mobility of contamiSA fifl-sc~e remediation project with WEC process is being carried Out at a uranium mining site in Bnmi, TX. Westinghouse Electric Corp., “Soil

Washing Applicability and Treatability Studies,” undated, D.C. Grant E.J. Laho&, and A.D. Dietrich “Remediation of Uranium and Radium

Contanuna “ ted Soil Using the Westinghouse Soil Washing Process,” paper presented at the Seventh Annual DOE Model Conference, Oak Ridge, TN,

Oct. 14-17, 1991.

4u,so ~v~o~en~ ~ot=tion Agency, offiw of Research ~d Development, Risk Rtiuction Engin~fig Laboratory, Techmdogy f%Ofi/eS,

EPA/540/5-90/006 (Cincinnati, OH: November 1990), pp. 26-27; John K. Sheldo~ BioTrol, ruc., Persoti comm~cation, JUIY 23, 1991.

‘Ibid., p. 27.

6u.so Envil.o~en~ ~t~tion Agency, office of Rese~ch and Development, Risk Reduction Engineering hboratory, lmmobi~izution ~eCh~O/Ogy

Seminar, CERI-89-222 (Cincinnati OH: October 1989), pp. 1-3.
Chapter 4-Other Remediation Technologies ● 53

Figure 4-2—Soil Washing System Offered by BioTrol, Inc.

=EH=FEFE

1

ElDebris &b“_ Contaminated fines

*

treat ment

r%

Dewater

system

+

Recycle

+

I 1 ! 4

Clean Options:

1. Off-site disposal

Make-up water water 2. Incineration

SOURCE: U.S. Environmental Protection Agency, Office of Research and Development, Risk Reduction Engineering Laboratory, 7bchno/ogy Profi/es,

EPA/540/5-90/006 (Cincinnati, OH: November 1990).

-.

nants present in the medium, generally by physical

means rather than by chemical reaction. This goal is

achieved by one or more of the following: improving

the handling and physical characteristics of the

waste; decreasing the surface area of the waste mass;

converting the contaminated medium into a solid

block; limiting the volubility of hazardous constituents; or detoxifying the centaminants present in the

waste to be treated.7

Historically, the physical and chemical bonding

involved in complex stabilization reactions has not

been rigorously researched and understood by most

practitioners. Many view S/S treatments as “low

tech, no-tech, or pseudo-tech.”8 More damaging,

however, is the fact that claims by certain vendors on

the successful application of their particular techniques are largely unsubstantiated.9

The long-term effectiveness of S/S treatment has

always been surrounded by uncertainty. Among the

factors contributing to this are: the difficulty of

determining what actually occurs under field conditions; the difficulty of reproducing in the laboratory

the role played by S/S materials in soil and waste; the

potential for cement bonding to be retarded by

contaminants; and the varying nature and size of soil

particles at contaminated sites. Heat produced by the

reaction between S/S chemicals and the waste may

also induce the volatilization of organic compounds. l0 As a consequence, it is extremely important that bench tests be performed prior to S/S

treatment to determine: 1) proper type and amount of

additive, 2) applicable mixing and curing conditions, and 3) the type of long-term monitoring

needed. 11 Attention to effluent treatment is not

7u.s. J?~v~o~~~~ fiotection Agency, (Jff~C~ of Research ad Development Risk R~uction Enginee@ Laboratory, Znternan”omd ~Usfe

TechnolgieslGeo-Con In Situ StabilizationfSolidijicatioApplications Analysis Report, a Superfund Innovative lkchnology Evaluation (SITE) repofi

EPA/540/A5-89/004 (Cincinnati, OH: August 1990), p. 6.

8J&.ey p. Newtoq The Derivation of Relevant Chemically Reactive Stmcmres for the F~ation of Organic$ and ]norganic$, hlternatiolld Wa8te

‘IMmologies, Wichit% KS, January 1991, p. 2.

gJeffrey P. Newto~ prtiiden~ International Waste Technologies, personal communication Apr. 19, 1991.

10u.S. Environment Protection Agency, op. cit., foo~ote 7, p. 16.

llIbid., pp. 22-23.
54 ● Dioxin Treatment Technologies

necessary because all of the water consumed is used

for processing purposes.12

According to the U.S. Environmental Protection

Agency (EPA), based on the type of additive and

processes used, stabilization methods can be organized into at least six different categories:

1.

2.

3.

4.

5.

6.

cement;

lime plus pozzolans (fly ash, kiln dust, hydrated silicic acid, etc.);

thermoplastic (asphalt, bitumen, polyethylene,

etc.);

thermosetting organic polymers (ureas, phenols, epoxies, etc.);

vitrification; and

miscellaneous.

Of these groups, only cement-based, quicklime, and

vitrification are being researched for their potential

application to dioxin-contaminated soil.

Although traditional S/S treatment has been

conducted simply by mixing two or more products

from the above categories, increasing research has

resulted in a series of new products that use additives

(e.g., proprietary dispersants and organophilic compounds) mixed with setting agents; these mixtures

seem to have a greater potential to bind organics

(PCBs, petroleum hydrocarbons, coal tars, and

probably dioxin) than most commercially available

mixtures. 13 For now, the challenge, some vendors

claim, is being able to determine the extent to which

these techniques are effective and, where appropriate mechanisms of evaluation exist, to determine

whether these techniques can in fact detoxify

dioxins. 14 15

.

EPA has selected S/S as the preferred treatment at

several Superfund sites. Selection has occurred most

commonly at sites with contaminated soil and acidic

sediments known to contain heavy metals, for

example, Sapp Battery (Florida), Marathon Battery

(New York), and Independent Nail (South Carolina).

EPA has also called for the application of S/S

treatment to organic wastes, including PCBs, found

at Pepper Steel & Alloys, Inc. (Florida),16 York Oil

(New York), Fields Brook (Ohio), and Liquid

Disposal Landfill (Michigan) .17 At the majority of

these sites, S/S has been conducted by bulk mixing

in a pit or by treatment of waste in a tank following

excavation. 18

Testing and Availability of S/S Technology

In 1987, a laboratory study was conducted at three

dioxin-contaminated eastern Missouri sites to ident@ and evaluate S/S technologies capable of eliminating the transport of dioxin from soil due to wind

and water erosion. The selected sites were Minker

site (a residential area known to have soil with

2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD)

at 700-ppb (parts per billion) levels, and which could

contaminate a nearby creek); Piazza Road (2,3,7,8-

TCDD was detected at the 640-ppb level); and

Sontag Road (characterized by very fine soil containing 2,3,7,8 -TCDD at 32-ppb levels) .19

As part of the experiment, soil samples from the

sites were mixed with varying amounts of Portland

cement, emulsified asphalt, and/or lime. The cement/

soil mixture was found ineffective because significant amounts of cement became loose after exposure

to laboratory conditions that mimicked weathering.

Emulsified asphalt, on the other hand, was found to

be an effective stabilizer but only after calcitic lime

had been added (about 15 percent) to the mixture.

Mixing asphalt, lime, and native soil was found to be

the most successful S/S technique, allowing dioxin

migration only at concentrations below the detection

limits. 20 (Estimated treatment costs ranged from $5

to $10 per cubic meter [emulsified asphalt] to$11 to

$13 per cubic meter [Portland cement]. An estimated

121bid., pp. 29-30.

131bid., p. 7.

IAAlthough tie ~Wond factor ~ho~d not ~ com~ed ~ a pm purpose of S/S tec~ologies, some treatment compties cltithilt in addition tO

the cementing action, their processes also affect organic contaminantts tbrough chemical interaction.

ISU.S. Enviro~en~ protection Agency, op. cit., footnote 7, p. 6; Newtom 0p. cit., footnote 8, p. 1.

16Clemup at this site consisted of diggingup con~“ ted soil, separating it fromdebris, mixing it with Portland cement andretuming it to its original

site.

ITu.s. Envkonmen~ Protection Agency, op. Cit., footnote v, p. v.

%id.

lgPaul E. des Rosiers, “Evaluation of lkchnology for Wastes and Soils Contamina ted With Dioxins, Furans, and Related Substances,’ Journal of

Hazardous Materials, vol. 14, No. 1, 1987, pp. 121-122.

‘Ibid., p. 123.
Chapter 4-Other Remediation Technologies ● 55

$4 to $8 per cubic meter should be added to these

amounts when health and safety costs are considered.) Although these results highlight the potential

applicability of asphalt/lime as a temporary remedial

measure, additional in depth studies on the long-term

performance of these or other more advanced S/S

technologies have yet to be conducted.

More recently, the EPA Superfund Innovative

Technology Evaluation (SITE) program has undertaken the evaluation of at least seven S/S techniques.

Among the methods under consideration, in addition

to the quicklime process, are those designed and

developed by International Waste Technologies,

Inc. (Wichita, Kansas); Silicate Technology, Inc.

(Scottsdale, Arizona); Separation & Recovery Systems, Inc. (Irvine, California); Soliditech, Inc. (Houston, Texas); Chemfix Technologies, Inc. (Metairie,

Louisiana); and HAZCON, Inc. (Brookshire, Texas) .21

At present, some S/S techniques have proved

effective for stabilizing residues resulting from

chemical or thermal treatment of dioxin-contaminated material.

Although no S/S treatment offered to date is

considered by EPA to be an “alternative disposal

method to incineration, ’ ’22 the future of this treatment has some promise. The increasing application

of incineration to contaminated materials could also

increase the use of stabilization techniques, particularly in those situations in which incinerated ash is

prohibited from land disposal because of the hazardous constituents remaining.

EPA QUICKLIME TREATMENT

EPA’s interest in evaluating certain mixtures of

lime and other alkaline stabilizers originated after

observing reductions in PCB levels at those sites in

which S/S techniques have been employed. In order

to understand the processes involved, EPA’s Risk

Reduction Engineering Laboratory in Cincinnati,

Ohio, contracted with RMC Environmental of West

Plains, Missouri, to conduct laboratory research.

Although preliminary results show decreases in

PCB levels, EPA scientists who reviewed the report

recommended additional evaluation because the

method of reduction is still unknown.

I nsummary, experiments were conducted on

synthetic soil by using three specific PCB congeners

in an open vessel containing calcium oxide (CaO)

and in a closed vessel containing:

. CaO,

. cement kiln dust, or

. a combination of CaO and kiln dust.

Testing in an open vessel in a glove box indicated

that significant removal of all three congeners

occurred within the first 5 hours at 180 to 200 ‘C.

However, most of the disappearance was attributed

to atmospheric releases through dusting, vaporization, and steam stripping. From these results, researchers expected that field demonstrations would

result in slower rates of removal than experienced in

the laboratory because they would be carried out at

much lower temperature. The closed-vessel experiments, on the other hand, were conducted at lower

temperature and had significantly lower rates of

volatilization and steam stripping. Chemical dechlorination and destruction were found to account for less

than 7 percent of the measured removal.23

EPA plans to support further laboratory investigations to examine the decomposition and volatilization process attributed to quicklime. Field examinations are also planned.24

INTERNATIONAL WASTE

TECHNOLOGIES TREATMENT

The International Waste Technologies (IWT)

process, advanced chemical fixation, is a cementbased process that uses proprietary additives (organophilic clays) to solidify and stabilize waste, and to

promote chemical bonding between the contaminants in the waste and the cement matrix.25 The

ability to alter the molecular structure of organic

pollutants, including PCBs, has encouraged company officials to conclude that the IWT fixation

21u.s. lihvironmerl~ Protection Agency, op. cit., footnote 6, pp. 1-3.

22U.S. Environmen~ Protection Agency, op. cit., footnote 7, p. 20.

~U.S. Enviro~en~ ~otection Agency, Office of Research ad Developrne@ Risk Reduction Eq@eefig b~ratory, Statza Report: ~UiC~i~e

Treatment of PCBs (Cincinnati, OH: May 1991).

~~tterfiom Jo~ConveV, DePu~ Director, U.S. EPA Risk Reduction En@~ring hbomtory to German Reyes, Office of ‘lkchnology Assessmen4

June 11, 1991.

~IJ.S. Enviro~en~ Protection Agency, op. Cit., footnote 7, p. 21.
56 ● Dioxin Treatment Technologies

process “sufficiently bonds and prevents the leaching of the PCB decomposition products, substituted

benzenes and phenol compounds.’ ’26

As opposed to all competing S/S techniques,

which require excavation, treatment, and redisposal

of soil, the IWT process calls for the use of in situ

treatment only, thus eliminating the costs of soil

excavation, sizing, handling, and redisposal.27 This

treatment may be tailored to address the specific

types of chemicals requiring treatment.

Of the evaluations performed on the IWT process,

the most extensive to date has been the bench-scale

demonstration conducted in April 1988, under

EPA’s SITE program at a General Electric site in

Miami, Florida. In addition to evaluating the form of

treatment, which consisted of injecting IWT’s chemical fixation material into PCB-contaminated soil by

use of mixing drills,28 EPA engineers studied all

possible reaction mechanisms and the extent of

chemical fixation.

Some of the results from chemical analyses

performed on samples taken during the first 2 weeks

following the test included: 1) a 5- to 10-percent

increase in volume of treated soil; 2) the potential

long-term durability, low permeability and porosity,

and high integrity of the solidified material; and 3)

the probable immobilization of PCBs and heavy

metals.29 Although the reduction of volatile organic

compounds was shown to occur, data limitations

prohibited EPA from confirming the extent to which

the IWT process immobilized these chemicals in the

solidified soil. As a consequence, EPA considered

the results of the evaluation inconclusive,30 stating

that “since very limited bench-scale studies have

been performed, it is recommended that treatability

studies-site specific leaching, permeability, and

physical tests—be performed on each specific site to

be treated . . . whether low or high in organic

content. ’ ’31 32

More successful data have been gathered in the

Netherlands from bench-scale tests of soil and

sludge containing heavy metals, pesticides, and

other organic compounds, such as pentachlorophenol.33 Results obtained from bench-scale tests demonstrated that the maximum concentration of dioxin34 detectable after treatment with the IWT process

was 10.4 parts per trillion (ppt). Tetrachlorodibenzop-dioxin, the same dioxin species of concern at

Times Beach, was found at only the 3.O-ppt level.35

More recently, several studies of the IWT process

conducted by both IWT and EPA have provided

more optimistic results. IWT researchers, for example, have conducted various studies to prove that

their fixation process bonds or destroys the organic

contaminants present in waste. Results of these

studies, however, have not been incorporated into

the EPA demonstration process.36 Despite the additional research required, EPA estimates that the IWT

process has the potential to “meet many of the

current or potential regulations for both organics and

metals [particularly] where reductions in the contaminant concentration in the wastes are [required to

be] measured.”37

26pJe~on, op. cit., footnote 8> P. 2.

27u.s. E~viro~en@) Protection Agency, Op. Cit., footnote 7, pp. 34-35.

~Newton, op. cit., footnote 8, p. 9.

29u.s. Environmental Protection Agency, op. cit., footnote 7, pp. V, 2, 3, 9.

Wbid., pp. 12-13.

SIU.S. Environmental Protection Agency, op. cit., footnote 7, pp. 2, 10.

32Accord@ to a compmy offlc~, tie EpA conclusion is Comidemd fid~~te because: 1) EpA f~~ to apply tie type of chemical illldySiS ht

would identify the extent and relev~ce of chemical bonding that occurs; 2) the SITE evaluation team lacked experts on organic/inorganic chemistry,

clay chemistry, and physics; and 3) EPA ftiled to test whether freezing temperatures affected the ability of the additive to prevent leaching of chemicals

(OIdy physical structure was tested). SOUrCXX: Jeffrey P. NewtoU President International Waste ‘Ikdmologies, personal communication, Apr. 19, 1991;

~d U.S. Enviromnen~ prot~tion Agency, op. cit., footnote 7, pp. 46-48.

ssNe~on, op. cit., foo~ote 8> P. 16”

~hep@MorodbeH.p4io~

ssJe~y pe Newto~ presiden4 kte~tio~ Waste ‘khOIO@eS, perSOIXd COmmticatioU Apr. 5>19910

3Gu.s. Enviro~en~ Protection Agency, op. cit., footnOte 7, P. 13.

37u.s. Env~omen@ fiotection Agency, Offlce of Rese~h ~d Developmen~ op. cit., footnote 7, p. 13; U.S. Environmental protection Agency,

Oftlce of Research and Development Risk Reduction Engineering Laboratory, Technology Demonstration Summary. International Waste

TechnolgieslGeo-Con In Situ StabilizationJSolidij?cation: Update Report, EP~540/S5-891004a (C~CiI.U@ OH: J~WY 1991).
Chapter 4-Other Remediation Technologies ● 57

UNDERGROUND MINE STORAGE

The use of underground mines as a method for

storing hazardous waste is more common in Europe

than in the United States. In Germany, for example,

the increasing unavailability of storage capacity has

prompted the storage of highly contaminated dioxin

waste in underground mines. With the exception of

packaging and labeling, this waste undergoes no

special pretreatment. According to reports, efforts

by the public and private sectors are focused

primarily on searching for ways in which to store

other dioxin-containing wastes such as fly ash and

dust. 38

Unlike Europe, research and evaluation efforts in

the United States on underground mine storage of

dioxin-contaminated materials are limited. One

research project was conducted in 1985 under the

auspices of the Missouri Department of Natural

Resources, EPA Region VII, and the University of

Missouri School of Mines.

The main purpose of the Missouri study was to

evaluate the feasibility of shallow underground

mines as repository sites for soil originating from

cleanup activities at some of the 44 dioxincontaminated sites in the State. In its scope, the study

covered 29 existing mines on the basis of dryness,

structural stability, potential size, location, accessibility, packaging devices,39 and costs. At its culmination, the project showed that shallow underground

limestone and dolomite mines are most suitable for

storing dioxin-centaining soil, followed by sandstone, lead-zinc, iron, and coal mines.40

Another conclusion of the study was that the costs

of developing a dioxin repository are affected

significantly by the type of container (steel vault,

steel drum, woven polypropylene sacks), as well as

the packaging arrangement selected. With regard to

capital costs, researchers estimated that costs of

handling41 and storing dioxin-contaminated soil at

existing underground mines were lower ($225 to

$275) than those of excavating, bagging, and temporarily storing soil from three Missouri sites in

steel-sided storage structures ($754 to $1,008).42

After the Missouri study, researchers began to

assess the feasibility of digging new underground

depots to store contaminated soil.43 Constructing

new mines instead of using existing ones is being

considered because storage costs may be reduced

through eliminating the expense of rehabilitating

existing, inactive mines. In addition, efforts to

identify and evaluate permitting, packaging, monitoring, and transportation issues are planned.44

ABOVEGROUND, ELEVATED

STORAGE BUILDINGS

Aboveground, elevated storage buildings are

large, permanent buildings constructed of prestressed concrete in which dioxin-contaminated

materials might be stored temporarily in drums or

containers. Although none has been constructed to

date, aboveground storage proponents claim that

once built, these facilities would reduce the cost of

shipping contaminated materials overlong distances

for treatment; reduce potential of groundwater

contamination from landfills due to leaching of

certain toxic components of the materials stored; and

reduce potential air contamination by volatile emissions. According to proponents, another significant

advantage of this approach is that it would facilitate

subfloor, walk-through inspections because the drums

will be stacked about 10 feet above the floor (see

figure 4-3). In addition, this type of storage facility

38Harmut S. Fuhr and J. Paul E. des Rosiers, “Methods of Degradation Destruction, Detoxificatio~ and Disposal of Dioxins and Related

Compounds, ” Pilot Study on International Information Exchange and Related Compounds worth Atlantic Treaty Organizatio~ Committee on the

Challenges of Modem Society, report No. 174, August 1988), p. 21.

Who% tie pac~~g Optiom assess~ Wwe rectan~ar steel vaults, steel drums, and woven polypropylene sac~. me ~t tYPe of conbent?

also called “supersacks,” was the least expensive and had the largest storage capacity.

@ales Rosims, op. cit., footnote 19, pp. 124-125.

dlHandling COStS were found to represent about one-third of the Overd asts.

dzdes Rosiers, op. cit., footnote 19, p. 126.

dqFti and des Rosiers, op. cit., footnote 38, pp. 21-22.

~des Rosiers, op. cit., footnote 19, p. 126.
58 ● Dioxin Treatment Technologies

Figure 4-3—Example of Proposed Design for

Aboveground Storage Facility

.

Double-tee roof

H

7,

\

\

Exteriorwall

panels

Base slab

NOTE: Not to scale

SOURCE: James V. Walters, University of Alabama, “Use of Elevated,

Concrete Buildings for Sanitary Landfills, Hazardous-Waste

Landfill, Monofill, and Cogenerator Facilities,” Journal of Resource Management & T@mology, vol. 17, No. 2, April 1989.

would allow time for the development of better

technologies for treating contaminated soil.45

Although aboveground storage is considered a

viable alternative in hazardous waste management,

particularly for long-term storage of waste or residues of waste treatment, only the New Jersey

Hazardous Waste Facility Siting Commission has

attempted to evaluate this system.

In May 1987, the Commission issued a report of

its investigation on the technical, managerial, and

regulatory experience of nine selected European

nations with aboveground storage. In the report, the

Commi ssion calls for aboveground storage to be

considered as a feasible alternative solution to the

State’s ‘‘residues management” problem because it

may help to:

1.

2.

3.

mitigate the decreasing storage capacity resulting from the promulgation of regulations

b arming hazardous waste disposal on land;

ease the capacity shortage created by the recent

increase in the number of landfill closures; and

allow additional time for replacing current

treatment, storage, and disposal facilities with

newer, environmentally sound ones.46

In November 1989, the Commission issued a report

detailing design and operating criteria for above-

-ground storage buildings.47 At this time, the Commission is considering design and construction plans

for four different facilities in New Jersey .48

45James V. w~te~, universi~ of Alab~ personal communatiorL June 28, 1991; J.V. Walter, ‘‘Use of Elevated, Concrete Buildings for Sanitary

Landfiis, Hazardous-WasteLandfill, Monoffll, and Cogenerator Facilities, ‘‘ Journal ofResourceManagement & Technology, vol. 17, No. 2, April 1989,

pp. 124-130; J.V. Walters et al., “Elevated, Concrete Buildings for Long-lknn Management of Hazardous Wastes,” Environmental Progress, vol. 7,

No. 4, November 1988, pp. 224-229.

ti~si~ CnteM ~k Force, Design c~teria for Above Gr~e ~nd Empzace~nt Faci/ity, repofi prepar~ for me New JmSW ~dous Waste

Facility Siting Commission, November 1989.

47B.W. plm=~ and D-w. Di@ ~eficmH~mdom Con@ol @oup, A~ve Ground ~nd Emplace~nts for pretreated Hazardous Waste: The

European Expen-ence, submitted to the New Jersey Hazardous Waste Facility Siting Commissiou contract No. 491 O-1 OO-237O3O-5O-NM-758; project

activity No. 758, May 1987.

4SSUWI Boyle, Executive Director, New Jersey Hazudoua Waste Facility Sifig COmm.iS siom personal communicatio~ July 3, 1991.
Chapter 5

Technology and Cost Summary

The foregoing analysis by the Office of Technology Assessment (OTA) has covered two fundamental categories of dioxin treatment technologiesthermal and nonthermal. In addition to these, however, OTA has also considered other approaches

such as stabilization or storage (where the technique

is aimed at preventing migration rather than destroying the contaminants) and technologies that combine

two or more techniques. The following summarizes

the overall conclusions concerning each technology,

based on OTA’s technical analyses.

THERMAL TREATMEN T

TECHNOLOGIE S

Several incineration techniques have been developed in the last decade for treating dioxin-contaminated soil and debris. They include rotary kiln

incineration, liquid injection incineration, fluidized

bed/circulating fluidized bed, high-temperature fluid

wall destruction (advanced electric reactor), infrared

destruction, plasma arc pyrolysis, supercritical water

oxidation, and in situ vitrification.1 Of these, only

rotary kiln incineration has been fully demonstrated,

is commercially available, and is permitted for

cleaning up dioxin in soil such as that found at Times

Beach, Missouri. This technology has the ability to

treat containerized and noncontainerized solid and

liquid wastes, individually or simultaneously. It has

been used in at least three successful dioxin cleanup

projects and appears to be able to perform in other

situations (e.g., Times Beach) within current regulatory requirements.

Rotary kiln incinerators are divided into two types

based on their specific design features: 1) land based

(or stationary) and 2) mobile (or transportable). In

addition to the obvious difference between the two

types, mobile incinerators have been specifically

designed with features to meet special requirements

for dioxin treatment, whereas the stationary incinerators have not.

Commercially available mobile incineration facilities have participated in cleanup of various

dioxin-contaminated sites. One firm offers three

mobile incineration units capable of treating dioxincontaminated soil at a maximum estimated rate of

5 tons per hour2 with setup times of 24 hours and

decontamination/demobilization times of about 72

hours. These systems have been successfully employed to treat dioxin contamination at the American

Cross Arms Site (Chehalis, Washington); Fort A.P.

Hill (Bowling Green, Virginia); Rocky Boy Post &

Pole Site (Rocky Boy, Montana); and Black Feet

Post & Pole Site (Browning, Montana). Another

firm also has three mobile incinerators, two of which

are operating on related cleanup work.

Today, there are four land-based rotary kiln

incinerator units operating in the United States with

the potential to treat dioxin-contaminated materials.

Thus far, however, they have been permitted to treat

only polychlorinated biphenyls (PCBs) under the

authority of the Toxic Substances Control Act

(TSCA). None of these facilities has treated dioxins

because of the lack of appropriate operating permits

under the Resource Conservation and Recovery Act

(RCRA).

In addition to the above developed or operating

technologies for thermal treatment of dioxins, several other options are in various stages of development. None of these, however, are available commercially as full-scale, tested systems.

Liquid incineration (LI) technology is employed in many industrial and manufacturing sectors

for treatment of hazardous organic and inorganic

waste. Regardless of their design (vertical LI units

are preferred for treating waste that generates

extensive ash; horizontal LI units are generally used

for low ash-generating waste), LI incinerators are

applicable only to combustible liquid wastes and

thin slurries. To date, the only documented use of LI

technology for dioxin destruction involves Environmental Protection Agency (EPA) -sponsored tests

aboard the ocean incinerator M/T Vulcanus in 1977.

Of the operating LI incinerator facilities in the

United States today, only three have been shown to

meet the criteria required to treat dioxin; however,

IAIt.hou@ in Sim vitrification is traditionally regarded as a solidifkation/stabilization technology, for the purpose of this paper it Wm included waler

thermal treatment technologies because of the high temperature required.

Zpatrick PhiIhpS, fiecutive Vice-president, Vesta Technologies, Ltd., persod commtimtiom ~. 25s 1991.

–59–
60 ● Dioxin Treatment Technologies

their operators have yet to apply for permits that

would allow them to incinerate dioxin-contaminated

liquid waste.

Traditionally, fluidized-bed combustion incineration (FBC) has been used for treatment of waste

and sludge generated by municipal wastewater

treatment plants, oil refineries, pulp and paper mills,

and pharmaceutical plants. Of the approximately 25

FBC facilities built in the traditional design, only a

few are employed today for treating hazardous

waste. None of these facilities is permitted to treat

dioxins.

Process modifications recently developed by two

different firms have given FBC technology the

capability of treating dioxin-contaminated materials. One firm, for example, modified the system to

use a granular bed composed of a mixture of

combustion catalyst and limestone rather than sand.

This system has been tested successfully with

dioxins; developers, however, plan to request a

permit that would allow the application of the FBC

unit now available only to PCB-bearing waste.

A second modification of FBC technology involves the use of a high-velocity air flow to suspend

bed particles and attain more effective thermal

treatment. The particle bed in this system is made up

of the waste to be treated. Pilot-scale testing has

demonstrated the ability of this modified FBC unit,

known as the circulating-bed combustion incinerator, to meet the performance criteria required for

successful dioxin destruction. Developers of the

circulating-bed combustion facility are currently

permitted to burn PCB-bearing waste; and even

though two additional units are under construction,

no plans exist at this time for requesting a permit to

burn dioxins.

High-temperature fluid wall destruction advanced electric reactor (AER) technology consists

of a porous tube or reactor enclosed in a hollow

cylinder through which heat is radiated for waste

treatment. Although originally designed by Thagard

Research (California), the AER technology is known

as the Huber Process because of proprietary modifications incorporated into the original design by J.M.

Huber Corp. (Texas). Two of the most relevant

advantages of AER with respect to dioxin treatment

are: 1) the destruction of dioxins is accomplished by

pyrolysis rather than oxidation as in most thermal

treatment; and 2) the absence of oxygen and low

gasflow rates allow for longer residence times, thus

reducing the production of toxic off-gases.

The only two AER reactors available today, one

stationary and one transportable, have proved successful in treating dioxin-contaminated materials,

including soil at Times Beach. The developer

obtained a permit to use its stationary AER unit for

dioxin treatment in 1986. The firm, however, has not

applied this technology since 1987, opting instead to

invest in other treatment processes with greater

market potential. This decision, a company official

points out, would not have been made if a program

to aid R&D of dioxin treatment technologies had

been available.

Infrared radiation incineration was developed

by Shirco Infrared Systems, Inc. (Dallas, Texas).

The process involves exposing dioxin-contaminated

materials to electrically heated silicon carbide elements, followed by the treatment of off-gases and

the removal of ashes. A transportable pilot-scale unit

was tested at Times Beach for the treatment of

dioxin-contaminated soil in 1985. Test results

showed that the Shirco system was able to treat

dioxin-containing soil to levels exceeding those

established by EPA for thermal treatment. Considerably larger treatment units (100 tons per day) have

also been tested with varying degrees of success at

several contaminated sites.3 Most of the success

associated with infrared incineration comes from

Europe, particularly Germany, and there are no

permitted facilities operating in the United States.

Plasma arc pyrolysis (PAP) incineration works

much the same as incineration at high temperature

by exposing the waste to a thermal plasma field.

Bench-scale units developed thus far can process

nearly 10 pounds per minute of contaminated solids

or 55 gallons per hour of centaminated liquid waste.

PAP technology is applicable only to liquid waste

and contaminated soil or sludge with viscosity,

similar to or lesser than 30- to 40-weight motor oil.

Only one firm offers this technology today. Although the process has not been tested specifically

with dioxins, certain wastes containing PCB dioxins, furans, and other chlorinated contaminants have

been successfully treated to part-per-trillion levels

3Althou@ he testing of a full-scale unit at peak Oil site (Florida) and a pilot-scale unit at Townsl@-DemodeRoad (Mc~g~) Wm suwess~, ms~ts

of an EPA-funded field demonstration test of a full-scale unit were discouraging.
Chapter 5-Technology and Cost Summary ● 61

on bench-scale tests. Although promising for the

treatment of liquid waste contaminated with dioxins,

the real applicability of PAP to dioxin-containing

waste is still questionable because additional research on a much larger scale is required.

Supercritical water oxidation (SCWO) technology is based on the oxidizing effect of water on

organic compounds (which become extremely soluble) and inorganic substances (which become sparingly soluble) at high temperature (350 to 450 ‘C)

and pressure (more than 218 atmospheres). A major

limitation of SCWO is its ability to treat only

dioxin-contamin ated liquid waste or slurries/sludges

with small-sized particles. One possibility suggested

by developers to address dioxins in soil is to grind

and pulverize the soils and make them into a slurry

that can then be treated by the SCWO process. This

practice, however, needs to be successfully demonstrated in larger units. Laboratory- and bench-scale

test results from liquid waste contaminated with

dioxins have met the criteria required for dioxin

treatment. Development plans for commercializing

SCWO technology began in 1989; today, its vendor

offers two engineering packages for small (5,000

gallons per day) and medium-sized plants (20,000

gallons per day).

In situ vitrification (ISV) units now exist on a

variety of scales: bench, engineering, pilot, and

large. ISV has been tested in the United States and

Canada on various soil types, some of which contain

dioxins. In bench-scale tests, ISV has been able to

treat dioxin-contaminated soil to levels exceeding

EPA’s performance requirement (99.9999 destruction and removal efficiency (DRE)). Additional

research is required, particularly on pilot and large

scales, for gathering the data needed to further

understand this technology and fully demonstrate its

effectiveness in treating dioxin-contaminated materials. Support by the U.S. Department of Energy

and the EPA have been essential to the development

of this technology.

NONTHERMAL TREATMENT

TECHNOLOGIES

The study and application of dechlorination

dates back more than 70 years when it was first used

for the commercial production of phenols. Only

recently have scientists begun to look at dechlorination as a viable technology for treating dioxincontaminated materials. Five of the dechlorination

methods developed thus far are highly promising for

dioxin destruction: KPEG4, APEG-PLUS, basecatalyzed decomposition, thermal resorption/UV

destruction, and thermal gas-phase reductive dechlorination, which combine dechlorination and incineration.

Pilot-scale tests with KPEG and APEG-PLUS

have shown, with a certain degree of success, the

ability of these processes to attain the cleanup levels

required for dioxin-contaminated soil. Still, ‘most

pilot-scale applications of the KPEG technique have

involved remediation of PCB-contaminated sites.

The APEG-PLUS system, on the other hand, is

currently available through full-scale mobile units

capable of treating 40 tons of contaminated soil

daily; several additional units are being constructed.

Despite these developments, both KPEG and APEGPLUS dechlorination treatment technologies have

yet to be fully demonstrated for remediating dioxincontaminated sites.

Base-catalyzed decomposition (BCD), is a dechlorination process developed by EPA’s Risk Reduction

Engineering Laboratory as an alternative to KPEG

and APEG-PLUS. The BCD process seems promising, not only in terms of dioxin destruction but also

in terms of cost-effectiveness, because the costs of

the reagents required are minimal compared to those

of most dechlorination techniques. Early results

from laboratory tests on dioxin-containing chlorinated materials indicate that BCD is a promising

technology for the cleanup of dioxin-contaminated

sites. Field demonstration tests are currently underway.

Thermal gas-phase reductive dechlorination

was designed as a thermochemical reduction technology to treat a variety of contaminated matrices

including harbor sediment, landfill leachate, and

lagoon sludge. A full-scale reactor capable of

treating 15 to 20 tons per day is now available, and

a 50-ton-capacity unit is planned for 1992. Thus far,

bench scale and laboratory-scale tests with various

chlorinated compounds have been successful. Preliminary results from field tests in Canada also

demonstrate the effectiveness of this technology in

treating contaminated harbor sediments. Some consider this technology highly promising because of its

4po~sim polyethylene Glicolate.
62 ● Dioxin Treatment Technologies

ability to chemically/thermally treat soil, liquid, and

more importantly, sediment and sludge, which are

considered by many to be the largest sources of

dioxin contamination in the United States. At

present, however, relatively few data to support this

claim exist.

The thermal desorption/UV destruction (photolysis) process involves the use of heat to remove

the dioxin from soil particles into a solvent solution

for treatment. Once in the solvent, dioxin is exposed

to ultra violet radiation and decomposed. In spite of

its wide range of other uses, this technology has only

been tested on a few military sites with dioxincontaminated soils. Additional field testing and

development is required before this technology

could be selected for full-scale cleanup of dioxincontaminated soils.

Bioremediation continues to be a promising

technology over the long term for cleaning up

dioxin-contamin ated sites. However, because of the

limited research to date, most experts think that

considerable work is required before bioremediation

techniques can be applied successfully. A number of

technical obstacles continue to limit the application

of bioremediation: 1) only very specialized biological systems may be effective against the high

toxicity, low volubility, and high absorptivity of

dioxin; 2) a very stringent cleanup standard must be

met; and 3) it may be difficult to find a microorganism that can effectively deactivate dioxins under the

different conditions present at existing dioxincontaminated sites. Experts still believe that these

obstacles will be overcome by future achievements

in biochemistry, the development of genetically

engineered microorganisms, and increased knowledge of the chemistry of dioxin surrogates. Right

now, bioremediation is regarded as an attractive

possibility for cleaning up dioxin-contaminated soil,

but its real applicability and effectiveness is unknown.

Soil washing is also considered an attractive

approach because it can be employed to extract

dioxin from soil and other contaminated materials

for subsequent treatment by other technologies.

Despite its recent introduction to the remediation

field, at least two firms already offer soil washing

techniques for the treatment of soils contaminated

with organics, heavy metals, and even radionuclides.

Soil washing promises to make remediation more

cost-effective because its application would result in

the need to chemically or thermally treat smaller

volumes of contaminated materials. Unfortunately,

data on the efficacy of this technique on dioxincontaminated soil are scarce; and no full-scale soil

washing system is currently available in the United

States on a commercial basis for dioxin treatment.

Solidification and stabilization (S/S) techniques

have been employed in the United States for more

than two decades to treat certain liquid industrial

chemical wastes. Earlier S/S techniques consisted of

mixing two or more products (e.g., cement, lime,

kiln dust, asphalt) to limit the volubility or mobility

of contaminants in the medium, sometimes irrespective of the level of chemical reaction achieved. More

recently, the application of S/S techniques has been

expanded to include treatment of contaminated soil

and incineration residues. Today, researchers are

focusing on developing proprietary additives to

increase the strength of the mixture; enhance the

interaction between cement particles and contaminants; and alter the chemical structure of the

contaminants.

Selection of S/S processes as the remediation

treatment has occurred at several Superfund sites

contaminated with organic waste and heavy metals.

S/S techniques are commonly employed for stabilization of residues that result from the treatment of

dioxin-contamin ated waste. Little information is

available on the actual effectiveness of S/S technology for dioxin-contaminated material. In addition,

none of the processes now available are considered

by EPA to be an “alternative disposal method to

incineration. If current research efforts continue,

however, the future of S/S treatment may be more

promising.

COST ESTIMATES OF DIOXIN

TREATMENT

Developing reliable cost estimates for comparing

technologies to treat dioxin-contaminated materials

is difficult. Cleanup technology experts point out the

following reasons for this: the limited number of

proven technologies now available; the limited

5u.s. ~v~onmen~ ~t~tion Agency, office of Research and Developmen~ Risk Reduction Engineering Laboratory, International Wafe

TechnolgieslGeo-Con In Situ Stabilization/Solidi ficatiodpplications Analysis Report, a Superfund Innovative lkchnology Evaluation (SITE) mpo~

EF14/540/A5-89/1104 (Cincinnati, OH: August 1990), p. 20.
Chapter 5-Technology and Cost Summary ● 63

number of applications to date; the varying nature of

contaminated materials and sites; and the different

types of dioxins/furans found in these materials.

Experts also argue that in addition to operational

factors, cost estimation of thermal and nonthermal

technologies may be further complicated by the

various regulatory (permitting) and technical factors

that must be considered during site remediation. The

most relevant examples of operational conditions

that make cost estimation of thermal technologies

difficult include the following:

1.

2.

3.

4.

5.

6.

7.

throughput of the incineration system;

handling capacity required (the lower the

handling capacity, the lower the labor costs);

term or duration of cleanup (the longer the

term, the higher the cost);

caloric and moisture contents of the material to

be treated, because these characteristics determine how much waste can be treated per day

(the higher the heat and moisture contents, the

higher the costs);

degree of contamination present in the waste,

coupled with level of cleanup required (highly

halogenated wastes are more costly because

they are difficult to treat and require additional

treatment and pollution control equipment);

costs incurred from purchasing electric power,

fuel, oxygen, or reagents that are essential for

operating the chosen technology; and

interruption of operations due to equipment

malfunctioning, inclement weather, or lack of

appropriate personnel.

Another important factor affecting dioxin incineration costs is the amount of reagent required to treat

off-gases and residues resulting from the combustion of dioxin-contaminated materials. Costs incurred from improving incineration processes,6

developing engineering designs for cleanup, transporting and setting up the equipment at a given

location, and obtaining the necessary operating

permits also make cost estimation of thermal technologies difficult.7 Treatment depth (the deeper, the

less costly because more soil can be treated) also

affects the treatment costs for in situ vitrification.8

Although cost estimates are available for some of

the thermal technologies examined in this paper,

limited application of the technologies continues to

hamper the development of more accurate cost

figures. For example, the operating and maintenance

costs of mobile rotary kiln incinerators, on the

average, range from $400 to $600 per ton of

dioxin-contaminated Soil.9 This range, however,

does not include costs incurred in transporting and

setting up equipment, excavating soil, and disposing

of treated material and residue. After these costs

have been factored in, the total cost of mobile

incineration could reach $1,500 per ton or more. No

treatment costs exist for land-based rotary kiln

incinerators because no stationary kiln has yet been

permitted to incinerate dioxins.

The lack of meaningful and reliable cost estimates

for rotary kiln incineration is also typical of most

other thermal treatment technologies. In liquid

injection incineration, for example, EPA reported in

1986 that treatment costs ranged from $200 per ton

for halogenated solvents to $500 per ton for PCBcontaining oils; the cost for dioxin-contaminated

material was expected to be similar to that of

PCBs. 1° More recent estimates, however, seem to

indicate that the cost of treating dioxin-contaminated liquid waste could now exceed $1,500 per

ton.11

The search for reliable, up-to-date dioxin treatment cost estimates for the remaining therma l

technologies addressed in this paper yielded even

more discouraging results. For instance, in the

different applications of fluidized-bed incineration

technology conducted to date, cost figures were

available only for the treatment of chlorinated

sludge and PCB-contamin ated soil ($27 to $60 and

GENSCC), for e~ple, reported tit inqmwing the handling and particle removal capability of its mobile incinerators resulted inhigher tratment

costs.

W.S. Environmental Protection Agency, Hazardous Waste Engineering Research Laboratory, Treatment Technologies for Dioxin-Containing

Wastes, EPA/600/2-86/096 (Cincinnati, OH: USEPA, October 1986), p. 4.1.

8Geosafe Corp., “Application and Evaluation Considerations for In Situ Vitriilcation lkchnology: A Treatment Process for Destruction and/or

Permanent Immobilization of fklZUdOUS Materials,” April 1989, pp. 13,28-29.

*hillips, op. cit., footnote 2.

lw.s. Environmen@.1 Protection Agency, op. cit., footnote 7, p. 4.38.

llPaul E. des Rosiers,~Dioxin Disposal Advisory Group, U.S. Environmental Protection Agency, personal communicatio~ June 10,1991.
64 ● Dioxin Treatment Technologies

$100 to $300 per ton, respectively12). Treatment

costs of $365 to $565 per ton13 were suggested for

advanced electric reactor technology even though

it has not been used since 1987. Preliminar y

estimates of treatment costs using infrared incineration technology are roughly $200 per ton of treated

waste. 14 Relatively lower estimates ($60 to $225 per

ton15) were estimated for supercritical water oxidation soil treatment; however, these calculations

were made on the basis of bench-scale units. Finally,

cost data for in situ vitrification of soil contaminated with dioxins do not exist at this time.l6

The conditions that most commonly determine

soil remediation costs for nonthermal treatment

methods, such as chemical dechlorination, include:

1.

2.

3.

4.

5.

6.

the level of cleanup required;

the organic carbon content, moisture content,

and particle size distribution of the soil;

the chemical forms (isomers) of chlorinated

compounds present in the soil;

the temperature and duration of the chemical

reaction;

the type of reagent formulation used; and

the length of time during which contaminated

soil is exposed to the reagents.

These factors, as well as the recyclability of reagents

and the cleanup level required, greatly affect total

remediation costs.

17

Of the dechlorination methods addressed, only the

KPEG and APEG-PLUS processes seems to offer

cost information, although with the same degree of

uncertainty as thermal technologies.

Based on hypothetical scenarios developed by

Galson Remediation Corp. and EPA, KPEG treatment costs are estimated to range from $91 in batch

systems to about $300 for in situ applications.18

More recently, based on the dechlorination o f

PCB-contaminated soil at the Wide Beach Superfund site, New York, Canonie Environmental officials suggested that treatment costs for dioxincontaminated soil may range from $250 to $350 per

ton .

1 9

According to existing data, the processing costs of

PCB-contamin ated soil using APEG-PLUS have

been estimated to be about $800 per ton. Based on

the similarities between PCB and dioxins, experts

suggest that the costs of APEG-PLUS treatment of

dioxins may be somewhat higher.

Developers of base-catalyzed decomposition

claim that dioxin treatment costs for this technology

will be lower than those of alcohol-based dechlorination processes (KPEG, APEG-PLUS) because

this technology employs cheaper reagents and eliminates the need to use costly polyethylene glycol as

a component. The developer has estimated that the

application of base-catalyzed decomposition to dioxincontaminated soil would cost about $245 per ton. 20

Developers of thermal gas-phase reductive

dechlorination claim that operating costs associated

with this technology will be three to five times

cheaper than incineration. If proven, such processing

costs for dioxin-contaminated soil or sediment could

range between $350 and $500 per ton. No posttreatment and transportation costs need to be added

IZU.S. Environmental protection Agency, op. cit., footnote 7, p. 4.51; Brenda M. Anderson and Robert G. Wilbmnw Ogden Environmenti se~i~s,

“Contaminated Soil Remediation by Circulating Bed Combustion: Demonstration T&t Results,” November 1989, p. 7; Sharin Sextou Ogden

Environmental Services, Inc., San Diego, CA, personal communicatio~ Jan. 25, 1991.

13Jim Boyd, J.M. Huber Corp., Huber, ~, penonrd COmLUti@iO~ Jan. 25, 1991.

IAu.s. Env~onmen~ Protection Agency, op. Cit., footnote 7, P. 4.64.

15Brim G. Evms, P-E., Development -ger, ABB L-US Cresc ~c., perso~ comm~~tio~ Apr. 2, lgf)l; ~rry B. Thomon d d., “The

MODAR SuperCritical Water Oxidation Process,” paper submitted for publication to Innovative Hazardous Waste Treatment Technology Series, Nov.

3, 1988, p. 22. This paper was found in MODAR, Inc., MODAR Zn@rmation, an undated company report.

IGGeosafe Corp., op. cit., footnote 8, pp. 13,28-29.

17pau1E+ des Rosiers, “ChemicalDetoxiilcation of Dioxin-Contaminated Wastes Using Potassium Polyethylene Glycolate,” Chemosphere, vol. 18,

No. 1-6, 1989, p. 351; and U.S. Environmental Protection Agency, op. cit., footnote 1, p, 5.12.

18u.s. Environmen~ protection Agency, op. cit., footnote 7, pp. 5.12-5.13.

19Alister Montgomq, Cmofie Enviro~en@ me., perso~ comm~catio~ ?vIw. ?,(), 1991.

~C~les Rogem, Us. Envhonmen~ fiot=tion Agency, Risk Reduction E@n&ring Laboratory, perso~ coInmUIlication, Dec. 17, 1990.
Chapter 5-Technology and Cost Summary ● 65

because no contaminated residues remain after

processing .

21

In addition to conditions affecting soil remediation costs for the chemical dechlorination methods

described earlier, treatment costs for bioremediation methods are also affected by the nature (high

acute toxicity, low volubility) and distribution (generally very low concentrations) of dioxins in soils.

At present, no cost data are available for bioremediation of dioxin-centaminated soil. One significant

reason for this is that no field testing has been

conducted to date; treatment of chlorinated dibenzop-dioxins was demonstrated only on a bench scale in

‘1985.

At present, no cost data are available for

treatment by soil washing. The relatively

introduction of soil washing techniques

dioxin

recent

to the

hazardous waste remediation field is the primary

reason for the unavailability of cost estimates, as

well as for the lack of information on the performance of this technology on a large scale. Developing

such information may take some time because the

processes now available have yet to be considered

for evaluation at a dioxin-contaminated site.

Developing cost estimates for solidification/

stabilization technologies has thus far been extremely difficult because their application has been

limited to a few laboratory studies or sites. The few

data available on dioxin treatment also make cost

comparisons between batch processes (which require excavation, treatment, and redisposal of soil)

and in situ processes difficult. For instance, a study

conducted in 1987 identified and evaluated” the

potential applicability and costs of several S/S

technologies at three dioxin-contaminated sites in

eastern Missouri;22 however, additional in-depth

studies on their long-term performance were suggested. 23 Although not specifically developed for

treatment of dioxin or its residues, costs for the

application of certain S/S methods are projected to

range somewhere between $110 and $200 per ton of

soil.

21D.J. J3allett and K.R. Campbell, “Thermal Gas-Phase Reduction of Organic Hazardous Wastes in Aqueous Matrices,” U.S. Environmental

ProtectionAgency AbstractPmceedings: SWondForumonIunovative -dousWwteTreatment lkchnologies: Domestic and Intemational-Philadelphi%

PA, May 15-17, 1990, Superfund EPA/500/2-90/009; D.J. Hallett and K.R. Campbell, “Demonstration lksting of a Thermal Gas Phase Reduction

Process,” U.S. Environmental Protection Agency, proceedings of the Tbird Forum on Innovative Hazardous Waste Treatment lkchnologies: Domestic

and International, June 11-13, 1991, Dallas, TX, in press.

22Treatment CONS estimated during this study ranged from $5 to $10 per cubic meter for emukiiied asphalt to $11 to $13 per cubic meter for Po*d

cement.

~paul E. des Rosiers, ‘‘Evaluation of ‘lkchnology for Wastes and Soils Con taminated With Dioxins, Furans, and Related Substances,’ Jourmd of

Hazardous Materials, vol. 14, No. 1, 1987, pp. 121-122.
Appendix A

Summary of the Cleanup at Times Beach

There are 27 contaminated residential and farming

areas in eastern Missouri, of which Times Beach is the

largest. At all sites, including Times Beach, the cleanup

process selected consists of the removal of contaminated

soil to a thermal treatment facility at Times Beach.

Removal of contaminated soil has already been accomplished at sites (excluding Times Beach) posing the

highest health risks. Removal operations consisted of

digging, bagging1, and storing the dioxin-contaminated

soil in nearby steel-sided storage structures. The Missouri

Department of Natural Resources (MDNR) established a

monitoring program to inspect these storage areas periodically.

Contaminated soil still remains in place at Times

Beach. In 1983, the Environmental Protection Agency

(EPA) and MDNR purchased Times Beach and permanently relocated its residents because of: 1) the unavailability of demonstrated technologies to clean up the

contaminated soils when the Centers for Disease Control

recommended the evaluation of residents’ health; and 2)

the uncertainty about how long Times Beach residents

would have to be temporarily relocated. The title to the

land now held by a trustee of the State of Missouri will be

transferred to the State once all land has been purchased.

The decision to employ incineration as a remedial

technology stipulated in EPA’s Record of Decision of

September 1988 is based on the Agency’s Feasibility

Study.2 In response to the limited knowledge available on

incineration (no facilities in the United States were

permitted to incinerate dioxin), EPA carried out a research

project at Denney Farm in southwest Missouri (see ch. 2).

The mobile, rotary kiln incinerator facility used for the

test was successful in destroying the dioxin-contaminated

liquids and soils taken from 8 of the 48 dioxin-contaminated sites identified in the State. EPA now requires that

incineration of dioxin-containing soil at Times Beach be

consistent with the engineering and performance parameters and emission levels obtained at Denney Farm (at least

99.9999 percent 2,3,7,8-tetrachlorodibenzo-p-dioxin destruction and removal efficiency (DRE)).

The MDNR has also been an active participant in the

cleanup process by providing opportunities for the

proponents of alternative dioxin treatment methods to

demonstrate the effectiveness of their techniques. Among

the technologies reviewed were bioremediation, reactive

dechlorination, shipment of soil out of State (this option

was found to cost at least $22 million more than

incineration), and rotary kiln incineration under two

scenarios (treatment at a central area or at five different

locations). Only incineration was found to be suitable.

After evaluating incineration treatment at five different

locations, MDNR concluded that such an option would:

1.

2.

3.

As a

cost nearly $40 million more than incineration at a

central location,

require large open areas for siting the incinerator (a

requirement impossible to satisfy at many small

dioxin-contaminated sites), and

probably expose a larger portion of the population

to dioxin.

result of these findings, MDNR supported the EPA

decision to locate the incinerator at Tim&-Beach, as long

as it was a nonpermanent facility used to treat only

dioxin-contaminated soil from the State of Missouri.

On July 20, 1990, as a result of a lawsuit filed against

it by EPA and the State of Missouri, Syntex Agribusiness

Inc. signed a Consent Order with EPA and two State

agencies, the Attorney General’s Office and the Department of Natural Resources.4 In the agreement approved

by the Court, Syntex Agribusiness Inc. is a responsible

party for the Times Beach cleanup because it owned the

Verona, Missouri, chemical manufacturing plant from

which the dioxin-contaminated oils used at Times Beach

originated. Under the signed agreement, Syntex Agribusiness is responsible for paying and carrying out the cleanup

(soil excavation, incineration) at Times Beach as well for

incineration of the dioxin-contaminated soil from 26 other

Eastern Missouri sites. EPA is responsible for overseeing

and financing the excavation and transport of soil from

these sites, 23 of which are located within a 30-mileradius of Times Beach. Upon satisfactory treatment, the

nonhazardous residues or ash will be buried at the site and

covered with topsoil. Although the incinerator is expected

to be in operation at the site for 3 to 5 years, 7 to 10 years

will be required for the Times Beach site to be considered

adequate for public recreational use. Construction of

lso~ Wme ~m~ kto 1.3 cubic yard double-ply, wove% polypropylene sack (callti “SUP~sac~”) o

r ‘gs”

zU.S. ~vhomen~ ~ot=tion Agency, ()&lce of fiergency ~d R~e~ R~pome, Supefind Record of Decision: Times B~ch, MO,

EPA/ROD/R07-88/015 (W@hin@oU DC: September 1988).

3A s~~d for tie ~e~~~ent of ~ ~g~y toxic compounds re@at~ ~der tie Reso~e Conservation ~d R~ov~ Ad.

dunite~state~ v. Bliss et al., Civil Action No. 84-200 C (i), et al. (ED. Mo.), consent decree a~~J~Y 20, 1990.

-67–
68 ● Dioxin Treatment Technologies

houses, however, is not practical because Times Beach is

located in a floodplain.5

Of the $118 million estimated for the Times Beach

cleanup, Syntex Agribusiness is expected to pay about

$100 million and the State of Missouri nearly $1 million.

The remaining $17 million will be provided by EPA.6

Before incinerating any dioxin-contaminated soil, however, Syntex will have to apply for an operating permit

under the Resource Conservation and Recovery Act to

handle the waste and operate the incinerator. The permit

will be administered by the State and is expected to: 1)

limit operations to 5 years, 2) limit waste to dioxincontaminated soil, and 3) prohibit the incineration of

out-of-State waste. To operate the incinerator, Syntex

Agribusiness is also required to obtain two additional

permits: an Air Pollution Control permit from the St.

Louis County Health Department for the control of

incinerator emissions and a National Pollutant Discharge

Elimination System permit from the Department of

Natural Resources for the control of wastewater discharges.7

At present, Syntex Agribusiness is inviting companies

with incineration technology capability (e.g., rotary kiln,

circulating bed combustion) to submit contract proposals.

Thus far, public opposition to incineration has centered on

plans that call for shipping dioxin-contaminated soil from

26 other contaminated areas to Times Beach for incineration. One of the reasons for opposing incineration

appears to be that once the incinerator facility is installed,

the public fears it will attract further transport of

dioxin-contaminated soils to Times Beach.

5Mi550UIi Department of Natural Resources, “Restoring Times Beach: Questions and Answers About Eastern Missouri Dioxin Cleanup,” undatd

Linda James, Missouri Department of Natural Resources, personal communication% Dec. 5, 1990 and Sept. 12, 1991.

%id.

7MSSOUri Department of Natural Resources, op. cit., footnote 5.