United States
Environmental Protection
Agency
Office of Solid Waste
and Emergency Response
(5102G)
EPA542-B-97-008
September 1997
&EPA
INNOVATIVE SITE
REMEDIATION
TECHNOLOGY
Thermal
Desorpt
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INNOVATIVE SITE
REMEDIATION TECHNOLOGY:
DESIGN AND APPLICATION
THERMAL DiSORPTION
One of a Seven-Volume Series
Prepared by WASTECH®, a multiorganization cooperative project managed
by the American Academy of Environmental Engineers® with grant assistance
from the U.S. Environmental Protection Agency, the U.S. Department of
Defense, and the U.S. Department of Energy.
The following organizations participated in the preparation and review of
this volume:
Air & Waste Management
Association
P.O. Box 2861
Pittsburgh, PA 15230
I American Society of
Mechanical Engineers
345 East 47th Street
New York, NY 10017
American Academy of
Environmental Engineers®
130 Holiday Court, Suite 100
Annapolis, MD 21401
Hazardous Waste Action
Coalition
1015 15th Street, N.W., Suite 802
Washington, DC 20005
American Institute of
Chemical Engineers
345 East 47th Street
New York, NY 10017
Soil Science Society
of America
677 South Segoe Road
Madison, WI 53711
Water Environment
Federation
601 Wythe Street
Alexandria, VA 22314
Monograph Principal Authors:
William L. Troxler, P.E., Chair Joseph H. Button, P.E.
Edward S. Alperin JoAnn S. Lighty, Ph.D.
Paul R. de Percin Carl R. Palmer, P.E.
Series Editor
William C. Anderson, P.E., DEE
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Library of Congress Cataloging in Publication Data
Innovative site remediation technology: design and application.
p. cm.
"Principle authors: Leo Weitzman, Irvin A. Jefcoat, Byung R. Kim"--V.2, p. iii.
"Prepared by WASTECH."
Includes bibliographic references.
Contents: -[2] Chemical treatment
1. Soil remediation-Technological innovations. 2. Hazardous waste site remediation--
Technological innovations. I. Weitzman, Leo. II. Jefcoat, Irvin A. (Irvin Ally) HI. Kim, B.R.
IV. WASTECH (Project)
TD878.I55 1997
628.5'5-dc21 97-14812
CIP
ISBN 1-883767-17-2 (v. 1) ISBN 1-883767-21-0 (v. 5)
ISBN 1-883767-18-0 (v. 2) ISBN 1-883767-22-9 (v. 6)
ISBN 1 -883767-19-9 (v. 3) ISBN 1 -883767-23-7 (v. 7)
ISBN 1-883767-20-2 (v. 4)
Copyright 1997 by American Academy of Environmental Engineers. All Rights Reserved.
Printed in the United States of America. Except as permitted under the United States
Copyright Act of 1976, no part of this publication may be reproduced or distributed in any
form or means, or stored in a database or retrieval system, without the prior written
permission of the American Academy of Environmental Engineers.
The material presented in this publication has been prepared in accordance with
generally recognized engineering principles and practices and is for general informa-
tion only. This information should not be used without first securing competent advice
with respect to its suitability for any general or specific application.
The contents of this publication are not intended to be and should not be construed as a
standard of the American Academy of Environmental Engineers or of any of the associated
organizations mentioned in this publication and are not intended for use as a reference in
purchase specifications, contracts, regulations, statutes, or any other legal document.
No reference made in this publication to any specific method, product, process, or
service constitutes or implies an endorsement, recommendation, or warranty thereof by the
American Academy of Environmental Engineers or any such associated organization.
Neither the American Academy of Environmental Engineers nor any of such associated
organizations or authors makes any representation or warranty of any kind, whether
express or implied, concerning the accuracy, suitability, or utility of any information
published herein and neither the American Academy of Environmental Engineers nor any
such associated organization or author shall be responsible for any errors, omissions, or
damages arising out of use of this information.
Printed in the United States of America.
WASTECH and the American Academy of Environmental Engineers are trademarks of the American
Academy of Environmental Engineers registered with the U.S. Patent and Trademark Office.
Cover design by William C. Anderson. Cover photos depict remediation of the Scovill Brass Factory
Waterbury, Connecticut, recipient of the 1997 Excellence in Environmental Engineering Grand Prize'
award for Operations/Management.
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CONTRIBUTORS
PRINCIPAL AUTHORS
William L. Troxler, P.E., Task Group Chair
Focus Environmental Inc.
Edward S. Alperin Joseph H. Button, P.E.
IT Corporation Smith Environmental Technologies,
Corporation
Paul R. de Percin JoAnn S. Lighty, Ph.D.
USEPA University of Utah
Carl R. Palmer, P.E.
TD*X Associates, LLC
REVIEWERS
The panel that reviewed the monograph under the auspices of the Project
Steering Committee was composed of:
Peter B. Lederman, Ph.D., P.E., Richard S. Magee, Sc.D., P.E.
DEE, P.P., Chair Hazardous Substance Management
New Jersey Institute of Technology Research Center
Michael Cosmos Caroline C. Reynolds
Roy R Weston, Inc. Austin, TX
Peter Kroll Charles O. Velzy, P.E., DEE
ERM, Inc. Lyndonville, VT
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STEERING COMMITTEE
This monograph was prepared under the supervision of the WASTECH® Steering
Committee. The manuscript for the monograph was written by a task group of experts
in chemical treatment and was, in turn, subjected to two peer reviews. One review was
conducted under the auspices of the Steering Committee and the second by professional
and technical organizations having substantial interest in the subject.
Frederick G. Pohland, Ph.D., P.E., DEE Chair
Weidlein Professor of Environmental
Engineering
University of Pittsburgh
Richard A. Conway, P.E., DEE, Vice Chair
Senior Corporate Fellow
Union Carbide Corporation
William C. Anderson, P.E., DEE
Project Manager
Executive Director
American Academy of Environmental
Engineers
Colonel Frederick Boecher
U.S. Army Environmental Center
Representing American Society of Civil
Engineers
Clyde J. Dial, P.E., DEE
Manager, Cincinnati Office
SAIC
Representing American Academy of
Environmental Engineers
Timothy B. Holbrook, P.E.
Engineering Manager
Camp Dresser & McKee, Incorporated
Representing Air & Waste Management
Association
Joseph F. Lagnese, Jr., P.E., DEE
Private Consultant
Representing Water Environment Federation
Peter B. Lederman, Ph.D., P.E., DEE, P.P.
Center for Env. Engineering & Science
New Jersey Institute of Technology
Representing American Institute of Chemical
Engineers
George O'Connor, Ph.D.
University of Florida
Representing Soil Science Society of America
George Pierce, Ph.D.
Manager, Bioremediation Technology Dev.
American Cyanamid Company
Representing the Society of Industrial
Microbiology
Peter W. Tunnicliffe, P.E., DEE
Senior Vice President
Camp Dresser & McKee, Incorporated
Representing Hazardous Waste Action
Coalition
Charles O. Velzy, P.E., DEE
Private Consultant
Representing, American Society of
Mechanical Engineers
Calvin H. Ward, Ph.D.
Foyt Family Chair of Engineering
Rice University
At-large representative
Walter J. Weber, Jr., Ph.D., P.E., DEE
Gordon Fair and Earnest Boyce Distinguished
Professor
University of Michigan
Representing Hazardous Waste Research Centers
FEDERAL REPRESENTATION
Walter W. Kovalick, Jr., Ph.D.
Director, Technology Innovation Office
U.S. Environmental Protection Agency
George Kamp
Cape Martin Energy Systems
U.S. Department of Energy
Jeffrey Marqusee
Office of the Under Secretary of Defense
U.S. Department of Defense
Timothy Oppelt
Director, Risk Reduction Engineering
Laboratory
U.S. Environmental Protection Agency
iv
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REVIEWING ORGANIZATIONS
The following organizations contributed to the monograph's review and acceptance
by the professional community. The review process employed by each organiza-
tion is described in its acceptance statement. Individual reviewers are, or are not,
listed according to the instructions of each organization.
Air & Waste Management
Association
The Air & Waste Management
Association is a nonprofit technical and
educational organization with more than
14,000 members in more than fifty
countries. Founded in 1907, the
Association provides a neutral forum
where all viewpoints of an environmen-
tal management issue (technical,
scientific, economic, social, political,
and public health) receive equal
consideration.
Qualified reviewers were recruited
from the Waste Group of the Technical
Council. It was determined that the
monograph is technically sound and
publication is endorsed.
The reviewers were:
James Donnelly
Davy Environmental
San Ramon, CA
Tim Holbrook, P.E., DEE
Camp Dresser & McKee
Denver, CO
American Institute of
Chemical Engineers
The Environmental Division of the
American Institute of Chemical Engineers
has enlisted its members to review the
monograph. Based on that review the
Environmental Division endorses the
publication of the monograph.
American Society of
Mechanical Engineers
Founded in 1880, the American
Society of Mechanical Engineers
(AS ME) is a nonprofit educational
and technical organization, having at
the date of publication of this docu-
ment approximately 116,400 members,
including 19,200 students. Members
work in industry, government,
academia, and consulting. The Society
has thirty-seven technical divisions,
.four institutes, and three interdiscipli-
nary programs which conduct more than
thirty national and international
conferences each year.
This document was reviewed by
volunteer members of the Research
Committee on Industrial and Municipal
Waste, each with technical expertise
and interest in the field covered by the
document. Although, as indicated on
the reverse of the title page of this
document, neither ASME nor any of its
Divisions or Committees endorses or
recommends, or makes any representa-
tion or warranty with respect to, this
document, those Divisions and Commit-
tees which conducted a review believe,
based upon such review, that this
document and findings expressed are
technically sound.
v
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Hazardous Waste Action
Coalition
The Hazardous Waste Action
Coalition (HWAC) is the premier
business trade group serving and
representing the leading engineering
and science firms in the environmental
management and remediation industry.
HWAC's mission is to serve and
promote the interests of engineering and
science firms practicing in multi-media
environment management and
remediation. Qualified reviewers were
recruited from HWAC's Technical
Practices Committee. HWAC is
pleased to endorse the monograph as
technically sound.
The lead reviewer was:
James D. Knauss, Ph.D.
Shield Environmental Services
Lexington, KY
Soil Science Society of
America
The Soil Science Society of America,
headquartered in Madison, Wisconsin,
is home to more than 5,300 profession-
als dedicated to the advancement of soil
science. Established in 1936, SSSA has
members in more than 100 countries.
The Society is composed of eleven
divisions, covering subjects from the
basic sciences of physics and chemistry
through soils in relation to crop
production, environmental quality,
ecosystem sustainability, waste
management and recycling,
bioremediation, and wise land use.
Members of SSSA have reviewed the
monograph and have determined that it
is acceptable for publication.
The lead reviewer was:
Michael Krstich, Ph.D.
Environmental Management Solutions
Cincinnati, OH
Water Environment
Federation
The Water Environment Federa-
tion is a nonprofit, educational
organization composed of member
and affiliated associations throughout
the world. Since 1928, the Federation
has represented water quality
specialists including engineers,
scientists, government officials,
industrial and municipal treatment
plant operators, chemists, students,
academic and equipment manufac-
turers, and distributors.
Qualified reviewers were
recruited from the Federation's
Hazardous Wastes Committee and
from the general membership. It has
been determined that the document is
technically sound and publication is
endorsed.
VI
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ACKNOWLEDGMENTS
The WASTECH® project was conducted under a cooperative agreement
between the American Academy of Environmental Engineers® and the Office
of Solid Waste and Emergency Response, U.S. Environmental Protection
Agency. The substantial assistance of the staff of the Technology Innovation
Office was invaluable.
Financial support was provided by the U.S. Environmental Protection
Agency, Department of Defense, Department of Energy, and the American
Academy of Environmental Engineers®.
This multiorganization effort involving a large number of diverse profes-
sionals and substantial effort in coordinating meetings, facilitating communica-
tions, and editing and preparing multiple drafts was made possible by a
dedicated staff provided by the American Academy of Environmental Engi-
neers® consisting of:
William C. Anderson, P.E., DEE
Project Manager & Editor
John M. Buterbaugh
Assistant Project Manager & Managing Editor
Karen Tiemens
Editor
Catherine L. Schultz
Yolanda Y. Moulden
Project Staff Production
J. Sammi Olmo
I. Patricia Violette
Project Staff Assistants
vii
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J J
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TABLE OF CONTENTS
Contributors jjj
Acknowledgments vii
List of Tables xiv
List of Figures xviii
1.0 INTRODUCTION 1.1
1.1 Thermal Desorption 1,1
1.2 Development of the Monograph 1.2
1.2.1 Background 1.2
1.2.2 Process 1.3
1.3 Purpose 1.4
1.4 Objectives ,1.5
1.5 Scope 1.5
1.6 Limitations 1.6
1.7 Organization 1.6
2.0 BACKGROUND 2.1
2.1 Scientific Principles 2.3
2.1.1 Scientific Basis 2.3
2.1.2 Engineering Basis - 2.6
2.2 Potential Applications 2.8
2.2.1 General Applicability 2.8
2.2.2 Technology Application Considerations 2.8
2.2.2.1 Contaminant Boiling Point 2.10
2.2.2.2 System Vacuum 2.10
2.2.2.3 Solids Treatment Temperature and Residence Time 2.10
2.2.2.4 Concentration of Organics in Feed Material 2.10
2.2.2.5 Soil Type 2.13
2.2.2.6 Feed Moisture Content 2.13
IX
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Table of Contents
2.2.2.7 Feed Material Size 2.15
2.2.2.8 Type and Quantity of Debris 2.15
2.2.2.9 Quantity of Emission Control Residuals 2.15
2.2.2.10 Metals in Feed Material 2.16
2.2.2.11 Waste Feed Quantity 2.16
2.2.2.12 Thermal Desorber Materials of Construction 2.17
2.2.3 Evaluation Factors 2.17
2.2.3.1 Organic Material Characterization 2.17
2.2.3.2 Particulate Carryover 2.17
2.2.3.3 Fugitive Emissions 2.18
2.2.3.4 Materials Handling 2.19
2.2.3.5 Chlorine and Sulfur Content of Feed Material 2.19
2.2.3.6 Contaminant Treatment Criteria 2.19
2.2.3.7 Emissions Control 2.20
2.3 Treatment Trains 2.20
2.3.1 Feed Handling and Pretreatment 2.20
2.3.2 Solids Posttreatment 2.21
2.3.3 Gas Posttreatment 2.21
2.3.4 Emission Control System Residuals Posttreatment 2.21
2.3.5 Processes Used Prior to Thermal Desorption Treatment 2.21
2.3.6 Processes Used After Thermal Desorption Treatment 2.22
2.3.6.1 Stabilization of Metals 2.22
2.3.6.2 Backfill 2.22
2.3.6.3 Soil Cover 2.22
2.3.6.4 Off-Site Disposal of Emission Control System
Residuals 2.23
3.0 DESIGN DEVELOPMENT 3.1
3.1 Remediation Goals 3.1
3.2 Design Basis - 3.3
3.3 Design and Equipment Selection 3.5
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Table of Contents
3.3.1 Heat and Mass Transfer 3.6
3.3.1,1 Heat Transfer 3.6
3.3.1.2 Mass Transfer 3.9
3.3.2 Reliability and Performance . 3.9
3.3.3 Regulatory Considerations 3.10
3.4 Process Configurations. 3.11
3.5 Pretreatment Processes 3.15
3.5.1 Feed Storage 3.15
3.5.2 Debris Removal 3.18
3.5.3 Size Reduction 3.18
3.5.4 Blending 3.18
3.5.5 Drying/Dewatering 3.19
3.5.6 pH Adjustment 3.19
3.5.7 Conveying 3.19
3.5.8 Weighing 3.20
3.6 Posttreatment Processes 3.20
3.6.1 Solids Posttreatment 3.20
3.6.2 Gas Posttreatment 3.21
3.6.2.1 Organics Control 3.21
3.6.2.2 Acid Gas Removal 3.22
3.6.2.3 Paniculate Removal - 3.23
3.6.3 Emissions Control System Residuals Posttreatment 3.25
3.6.3.1 Aqueous Liquids 3.25
3.6.3.2 Organic Liquids 3.26
3.6.3.3 Particulates 3.26
3.6.3.4 Scrubber Sludge 3.26
3.6.3.5 Activated Carbon 3.26
3.7 Process Instrumentation and Controls 3.27
3.7.1 Measuring Instruments 3.27
3.7.2 Control and Monitoring Instrumentation 3.28
xi
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Table of Contents
3.7.3 Control Logic 3 25
3.8 Safety Requirements 3 29
3.9 Specification Development 335
3.10 Cost Data . 335
3.11 Design Validation 333
3.12 Permitting Requirements 349
3.13 Performance Measures 341
3.13.1 Proof-of-Process Testing 3.42
3.13.2 Sampling and Analysis 3.44
4.0 IMPLEMENTATION AND OPERATION 4.1
4.1 Implementation 4 j
4.1.1 Procurement Methods 41
4.1.1.1 Turnkey Contracts 4,1
4.1.1.2 Thermal Operations Service Contracts 4.2
4.1.2 Contract Terms 42
4.1.2.1 Lump Sum 42
4.1.2.2 Unit Price 43
4.1.2.3 Time and Materials 4.3
4.1.2.4 Cost Plus Fixed Fee 4.3
4.1.3 Project Planning 43
4.2 Start-up Procedures 44
4.2.1 Site Preparation 44
4.2.2 Mobilization/Setup 45
4.2.3 Equipment Startup 45
4.2.4 Performance Verification 45
4.3 Operations Practices 45
4.4 Operations Monitoring 4 7
4.4.1 Process Monitoring 47
4.4.2 Instrument Testing and Calibration 4.8
4.5 Quality Assurance/Quaiiry Control 4 g
Xil
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Table of Contents
5.0 CASE HISTORIES AND PERFORMANCE DATA 5.1
5.1 Overview 51
5.2 Rotary Dryer 55
5.2.1 Old Marsh Aviation Site 5.7
5.2.2 Harbor Point Site 5.5
5.2.3 Re-Solve Superfund Site 5.10
5.2.4 T H Agriculture & Nutrition Site 5.11
5.3 Thermal Screw 5,13
5.3.1 Anderson Development Company Site 5.13
5.4 Paddle Dryer 5 15
5.4.1 Chemical Plant Site 5.15
5.5 Anaerobic Thermal Processor 545
5.5.1 Pristine Superfund Site 5.16
5.6 Conveyor Belt 5 17
5.6.1 Acme Solvents Superfund Site 5.17
5.7 Batch Vacuum System 5.19
5.7.1 PCX Site 5.19
5.8 Mercury Retort 5.20
5.8.1 Fixed Base Commercial System 5.20
5.9 Performance Data — Dioxin 5.21
5.9.1 Soil Residuals 5.21
5.9.2 Stack Emissions 5.21
Appendices
A. Case Histories A. 1
B. Treatment of Nonhazardous Petroleum-Contaminated
Soils by Thermal Desorption Technologies B. 1
C. Acronyms and Abbreviations c.l
D. List of References D.I
xiii
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LIST OF TABLES
Table Tidg Page
2.1 Effectiveness of Thermal Desorption on General
Contaminant Groups 2.9
3.1 Thermal Desorption Work Breakdown Structure
Cost Elements 3.32
4.1 QA/QC Plan Content Requirements 4.9
5.1 Thermal Desorption Applications 5.2
. A.O Case History Summary A.I
A. 1.1 Thermal Desorption System Utility Usage A.6
A. 1.2 Summary of TDS Runs and Parameters During the
Harbor Point Demonstration A. 14
A. 1.3 Schedule of Sampling and Analysis — Experimental and
Formal Phases A. 15
A. 1.4 Percent Removal of Contaminants from Soil A. 17
A. 1.5 Summary of TDS Soil Analytical Results from the
Harbor Point Demonstration A.20
A. 1.6 Summay of TDS Stack Gas Analytical Results from the
Harbor Point Demonstration A.22
A. 1.7 Continuous Emissions Monitoring Averages of
Demonstration Processing Daily Averages A.23
A. 1.8 Description of Cost Categories A .24
A. 1.9 Thermal Desorption Cost Estimate A.25
A.2.1 Mass Balance Results A.34
A.3.1 Matrix Characteristics A.44
A.3.2 Operating Parameters A.47
A.3.3 Timeline A.48
XIV
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List of Tables
Table Title Page
A.3:4 Range of 4,4-Methylene Bis(2-Chloroaniline)(MBOCA)
Concentrations in Treated Soil Piles A.50
A.3.5 Range of VOC Concentrations in Treated Soil Piles A.51
A.3.6 Range of SVOC Concentrations in Treated Soil Piles A.52
A.3.7 Range of Metals Concentrations in Treated Soil Piles A.53
A.3.8 Arithmetic Mean Concentrations of CDDs and CDFs
Measured During SITE Demonstration A.54
A.3.9 ADC Remediation and Support Contractors A.55
A.3.10 Projected Costs for Activities Directly Associated with
Treatment A.56
A.3.11 Projected Costs for Pretreatment Activities A.58
A.3.12 Projected Costs for Posttreatment Activities A.59
A.3.13 MBOCA Concentrations in Pre- and Posttreatment Soil and
Relative Test Run Conditions A.64
A.3.14 Summary of Volatile and Semivolatile Organics in Pre- and
Posttreatment Soil A.65
A.3.1-5 Summary of Volatile and Semivolatile Organics in
Condenser Offgas A.66
A.3.16 Summary of Condensate Analyses A.67
A.4.1 Types of Wastes Stored at Pristine A.71
A.4.2 Feed Soil Concentrations A.74
A.4.3 Matrix Characteristics A.75
A.4.4 Operating Parameters A. 80
A.4.5 Timeline A.81
A.4.6 Cleanup Goals A.82
xv
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List of Tables
Table Title.
A.4.7 Proof-of-Process Tests Stack Gas Emissions Performance
Standards A. 82
A.4.8 Treatment Performance Data A.84
A.4.9 Summary of Analytical Results for the Treated Soil
Piles at the Pristine Superfund Site A.85
A.4.10 Stack Gas Emissions Results from Proof-of-Process Tests A.90
A.5.1 Matrix Characteristics A. 100
A.5.2 Particle-Size Distribution of Stockpiled Soil A. 100
A.5.3 Interlock System Cutoff Conditions A. 103
A.5.4 Operating Parameters A. 106
A.5.5 Timeline A. 107
A.5.6 Treatment Requirements A. 108
A.5.7 Air Emission Standards A.109
A.5.8 Proof-of-Process Performance Test Soil Data A. 112
A.5.9 Proof-of-Process Performance Test Air Emissions Data A. 113
A.5.10 Full-Scale Treatment Activity Soil Performance Data A. 114
A.5.11 Full-Scale Treatment Activity Soil Data A. 116
A.5.12 Treatment Cost Elements A. 119
A.5.13 Pretreatment Cost Elements A.I 19
A.5.14 Treatability Study Results A. 124
B. 1 Comparison of Thermal Desorption System Features and
Operating Parameters B.4
B.2 Common Analytical Test Methods for Hydrocarbon
Contaminated Soils B.23
xvi
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List of Tobies
Title Page
B.3 Thermal Desorption System Soil Treatment Data
Reported by Contractors B.24
B.4 Thermal Desorption System Stack Emissions Data
Reported by Contractors B.30
B.5 Thermal Desorption System Stack Emissions Data
Summary B.33
xvii
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LIST OF FIGURES
Figure Title Page
2.1 Thermal Desorption System Schematic Diagram 2.2
2.2 Vapor Pressure vs. Temperature 2.5
2.3 Transport Phenomena Occurring During Thermal
Treatment of a Solid Bed 2.6
2.4 Contaminant Removal vs. Treatment Time and Temperature 2.7
2.5 Pyrene Removal vs. Treatment Time and Temperature 2.11
2.6 Energy Requirement Diagram 2.14
3.1 Directly-Heated Rotary Dryer Schematic 3.7
3.2 Indirectly-Heated Rotary Dryer Schematic 3.7
3.3 Directly-Heated Rotary Dryer System 3.12
3.4 Directly-Heated Rotary Dryer System Process-Flow
Diagram 3.13
3.5 Directly-Heated Rotary Dryer System Layout 3.14
3.6 Indirectly-Heated Rotary Dryer System 3.15
3.7 Indirectly-Heated Rotary Dryer System Process-Flow
Diagram 3.16
3.8 Indirectly-Heated Rotary Dryer System Layout 3.17
3.9 Example Turnkey Treatment Cost vs. Site Size 3.36
3.10 Example Breakdown of Turnkey Unit Cost 3.37
3.11 Thermal Desorption Historical Unit Cost Data 3.38
5.1 2,3,7,8-TCDD TEQ Values vs. Soil Treatment Temperature 5.22
5.2 2,3,7,8-TCDD TEQ Stack Emission Concentration 5.23
5.3 2,3,7,8-TCDD TEQ Stack Emission Factor 5.24
A. 1.1 Maxymillian Technologies Thermal Desorption System A.4
xviii
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List of Figures
Figure Title Page
A. 1.2 Process-Flow Diagram of Maxymillian Technologies
Thermal Desorption System A.9
A. 1.3 Plan View of Maxymillian Technologies Thermal
Desorption System A. 10
A.2.1 X*TRAX® Process-Flow Diagram A.32
A.2.2 X*TRAX® Availability at Re-Solve Superfund Site A.35
A.2.3 X*TRAX® Treated Tons at Re-Solve Superfund Site A.36
A.3.1 Site Location A.41
A.3.2 Site Layout A.42
A.3.3 Simplified Sectional Diagram Showing the Four Internal
Zones A.45
A.4.1 Site Location A.70
A.4.2 ATP Schematic A.76
A.4.3 Simplified Sectional Diagram Showing the Four Internal.
Zones A.78
A.5.1 Site Location A.97
A.5.2 Williams Environmental Services, Inc. Thermal Desorption
Unit, TPU #1 Used at THAN Facility, Albany, Georgia A. 102
A.5.3 Toxaphene AAC Values vs. Operating Schedule A.I 10
A.5.4 DDT AAC Values vs. Operating Schedule A.I 11
B.I Thermal Desorption System Schematic Diagram B.3
B.2 Counter-Current Rotary Dryer System Process-Flow
Diagram B.6
B.3 Co-Current Rotary Dryer System Process-Flow Diagram B.7
B.4 Thermal Screw Dryer System Process-Flow Diagram B.9
XIX
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List of Figures
Figure Title Page
B.5 Distillation Temperature vs. Thermal Desorber Temperature B. 13
B.6 Vapor Pressure vs. Temperature B.15
B.7 Large Mobile Rotary Dryer Treatment Costs B.34
B.8 Small Mobile Rotary Dryer Treatment Costs B.35
B.9 Stationary Rotary Dryer Treatment Costs B.36
xx
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Chapter 1
INTRODUCTION
This monograph covering the design, applications, and implementation of
Thermal Desorption, is one of a series of seven on innovative site and waste
remediation technologies. This series of seven was preceded by eight volumes
published in 1994 and 1995 covering the description, evaluation, and limitations
of the processes. The entire project is the culmination of a multi-organization
effort involving more than 100 experts. It provides the experienced, practicing
professional with guidance on the innovative processes considered ready for
full-scale application. Other monographs in this design and application series
and the companion series address bioremediation; chemical treatment; liquid
extraction: soil washing, soil flushing, and solvent/chemical extraction; stabili-
zation/solidification; thermal destruction; and vapor extraction and air sparging.
The primary purpose of this monograph is to discuss the use of thermal
desorption systems operating on hazardous substance applications, such as
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) sites, Resource Conservation and Recovery Act (RCRA) Correc-
tive Action sites, State Superfund sites, and Brownfield sites. Thermal des-
orption systems treating petroleum-contaminated materials are subject to
different regulatory requirements, use fewer types of technologies, and typi-
cally result in significantly lower treatment costs than thermal desorption
systems operating on hazardous substance applications. Applications of the
technology on petroleum-contaminated waste matrices are discussed in an
appendix to this document.
7.7 Thermal Desorption
Thermal desorption is a process to separate organic contaminants, mer-
cury, or cyanide from a waste matrix; typically, soils, sludges, sediments, or
filter cakes. Contaminants are volatilized in the thermal desorber and swept
1.1 -
-------
Introduction
into an offgas. The offgas is then treated in an emissions control system
in which the organic contaminants are either (1) collected for subsequent
recovery or off-site treatment/disposal, or (2) destroyed on-site in an
afterburner.
In this monograph, the term, thermal desorber, refers only to the unit opera-
tion that heats the contaminated waste matrix, whereas the term, thermal des-
orption system, refers to the entire process train as described below. Several
subsystems are common to most thermal desorption systems. These sub-
systems consist of feed preparation handling and pretreatment, thermal desorp-
tion, solids posttreatment, gas posttreatment (emissions control), and emission
control system residuals (secondary wastes) posttreatment. The objectives of
the overall treatment system are to produce decontaminated solids,
environmentally-acceptable stack gases and effluent water, and to subsequently
treat, recycle, or dispose of all other emission control system residuals.
7.2 Development of the Monograph
1.2.1 Background
Acting upon its commitment to develop innovative treatment technologies
for the remediation of hazardous waste sites and contaminated soils and
groundwater, the U.S. Environmental Protection Agency (US EPA) estab-
lished the Technology Innovation Office (TIO) in the Office of Solid Waste
and Emergency Response in March, 1990. The mission assigned to the TIO
was to foster greater use of innovative technologies.
In October of that same year, TIO, in conjunction with the National
Advisory Council on Environmental Policy and Technology (NACEPT),
convened a workshop for representatives of consulting engineering
firms, professional societies, research organizations, and state agencies
involved in remediation. The workshop focused on defining the barriers
that were impeding the application of innovative technologies in site
remediation projects. One of the major impediments identified was the
lack of reliable data on the performance, design parameters, and costs of
innovative processes.
1.2
-------
Chapter ]
The need for reliable information led TIO to approach the American
Academy of Environmental Engineers®. The Academy is a long-standing,
multi-disciplinary environmental engineering professional society with
wide-ranging affiliations with the remediation and waste treatment profes-
sional communities. By June 1991, an agreement in principle (later formal-
ized as a Cooperative Agreement) was reached providing for the Academy to
manage a project to develop monographs providing reliable data that would
be broadly recognized and accepted by the professional community, thereby
eliminating or at least minimizing this impediment to the use of innovative
technologies.
The Academy's strategy for achieving the goal was founded on a
multi-organization effort, WASTECH® (pronounced Waste Tech), which
joined in partnership the Air and Waste Management Association, the Ameri-
can Institute of Chemical Engineers, the American Society of Civil Engi-
neers, the American Society of Mechanical Engineers, the Hazardous Waste
Action Coalition, the Society for Industrial Microbiology, the Soil Science
Society of America, and the Water Environment Federation, together with
the Academy, US EPA, DoD, and DOE. A Steering Committee composed of
highly-respected representatives of these organizations having expertise in
remediation technology formulated the specific project objectives and pro-
cess for developing the monographs (see page iv for a listing of Steering
Committee members).
By the end of 1991, the Steering Committee had organized the Project.
Preparation of the initial monographs began in earnest in January, 1992, and
the original eight monographs were published during the period of Novem-
ber, 1993, through April, 1995. In Spring of 1995, based upon the reception
by the industry and others of the original monographs, it was determined that
a companion set, emphasizing the design and application of the technolo-
gies, should be prepared as well. Task Groups were identified during the
latter months of 1995 and work commenced on this second series.
1.2.2 Process
For each of the series, the Steering Committee decided upon the technolo-
gies, or technological areas, to be covered by each monograph, the mono-
graphs' general scope, and the process for their development. The Steering
Committee then appointed a task group composed of five or more experts to
write a manuscript for each monograph. The task groups were appointed
1.3
-------
Introduction
with a view to balancing the interests of the groups principally concerned
with the application of innovative site and waste remediation technologies —
industry, consulting engineers, research, academia, and government.
The Steering Committee called upon the task groups to examine and
analyze all pertinent information available, within the Project's financial
and time constraints. This included, but was not limited to, the compre-
hensive data on remediation technologies compiled by US EPA, the
store of information possessed by the task groups' members, that of
other experts willing to voluntarily contribute their knowledge, and in-
formation supplied by process vendors.
To develop broad, consensus-based monographs, the Steering Com-
mittee prescribed a twofold peer review of the first drafts. One review
was conducted by the Steering Committee itself, employing panels con-
sisting of two members of the Committee supplemented by at least four
other experts (See Reviewers, page iii, for the panel that reviewed this
monograph). Simultaneous with the Steering Committee's review, each
of the professional and technical organizations represented in the Project
reviewed those monographs addressing technologies in which it had
substantial interest and competence.
Comments resulting from both reviews were considered by the Task
Group, appropriate adjustments were made, and a second draft published.
The second draft was accepted by the Steering Committee and participating
organizations. The statements of the organizations that formally reviewed
this monograph are presented under Reviewing Organizations on page v.
1.3 Purpose
The purpose of this monograph is to further the use of thermal des-
orption site remediation and waste processing technologies where their
use can provide better, more cost-effective performance than conven-
tional methods. To this end, the monograph documents the current state
of thermal desorption technology.
1.4
-------
Chapter.]
7.4 Objectives
The monograph's principal objective is to furnish guidance for experi-
enced, practicing professionals who may employ this technology. This
monograph, and its companion monograph, are intended, therefore, not to be
prescriptive, but supportive. It is intended to aid experienced professionals
in applying their judgment in deciding whether and how to apply the tech-
nologies addressed under the particular circumstances confronted.
In addition, the monograph is intended to inform regulatory agency per-
sonnel and the public about the conditions under which the subject processes
are potentially applicable.
7.5 Scope
This monograph addresses thermal desorption technologies that have
been sufficiently developed so that they can be used in full-scale applica-
tions. It addresses all aspects of the technologies for which sufficient data
were available to the Thermal Desorption Task Group to review the tech-
nologies and discuss their design and applications. Actual case studies were
reviewed and included, as appropriate.
The monograph's primary focus is site remediation and waste treatment.
To the extent the information provided can also be applied elsewhere, it will
provide the profession and users this additional benefit.
Application of site remediation and waste treatment technologies is site-
and waste-stream specific and involves consideration of a number of matters
in addition to technology selection. Among them are the following that are
addressed only to the extent that they are essential to understand the applica-
tions and limitations of the technologies described:
• site investigations and assessments;
• site conditions (size, access, adjacent demographics);
• planning, management, specifications, and procurement;
• contingency and emergency response plans;
• regulatory requirements; and
• community acceptance of the technology.
1.5
-------
Introduction
1.6 Limitations
The information presented in this monograph has been prepared in accor-
dance with generally recognized engineering principles and practices and is
for general information only. This information should not be used without
first securing competent advice with respect to its suitability for any general
or specific application.
Readers are cautioned that the information presented is that which was
generally available during the period when the monograph was prepared.
Development of innovative site remediation and waste treatment technolo-
gies is ongoing. Accordingly, post-publication information may amplify,
alter, or render obsolete the information about the processes addressed.
This monograph is not intended to be and should not be construed as a
standard of any of the organizations associated with the WASTECH® Project;
nor does reference in this publication to any specific method, product", pro-
cess, or service constitute or imply an endorsement, recommendation, or
warranty thereof.
7.7 Organization
This monograph and others in the series are organized under a similar
outline intended to facilitate cross reference among them and comparison of
the technologies they address.
Chapter 2, Background, summarizes the process, its scientific basis, the
potential applications, and key requirements for thermal desorption system
components. Design Development, Chapter 3, provides essential informa-
tion for those contemplating use of thermal desorbers. Chapter 4, Implemen-
tation and Operation, focuses on the procedures commonly used to imple-
ment thermal desorption systems and key facets of their operation. Chapter
5, Case Histories and Performance Data, provides a brief description of se-
lected types of desorbers and performance and cost information from ther-
mal desorption applications.
Appendix A contains detailed case history information on five selected
thermal desorption applications. Case histories were selected to represent a
1.6
-------
Chapter
variety of types of technologies, waste types, and site conditions. Appendix
B contains a discussion on the use of thermal desorption systems for treating
petroleum-contaminated materials. As discussed in Section 1.0, the main
body of the text does not address the use of thermal desorption systems for
this application. Appendix C provides a list of relevant acronyms and abbre-
viations. Appendix D contains a list of references.
1.7
-------
I I
-------
Chapter 2
BACKGROUND
Thermal desorption is a process to separate organic contaminants,
mercury, or cyanide from a waste matrix; typically, soils, sludges, sedi-
ments, or filter cakes. Contaminants are volatilized in the thermal
desorber and swept into an offgas. The off gas is then treated in an emis-
sions control system in which the organic contaminants are either (1)
collected for subsequent recovery or off-site treatment/disposal, or (2)
destroyed on-site in an afterburner.
In this monograph, the term, thermal desorber, refers only to the unit
operation that heats the contaminated waste matrix, whereas the term, ther-
mal desorption system, refers to the entire process train as described below.
Several subsystems are common to most thermal desorption systems as
shown in Figure 2.1. These subsystems consist of feed preparation handling
and pretreatment, thermal desorption, solids posttreatment, gas posttreatment
(emissions control), and emission control system residuals (secondary
wastes) posttreatment. The objectives of the overall treatment system are to
produce decontaminated solids, environmentally-acceptable stack gases and
effluent water, and to subsequently treat, recycle, or dispose of all other
emission control system residuals.
Thermal desorption has been accomplished in a variety of types of me-
chanical equipment, including: rotary dryers, thermal screws, paddle dryers,
anaerobic thermal processors, belt conveyor systems, batch vacuum systems,
and mercury retorts. Patents cover many of the thermal desorption systems.
Thermal desorbers can be characterized several ways: (1) method of heating
(directly or indirectly); (2) operating pressure (slight vacuum or high
vacuum); or (3) maximum solids treatment temperature (low: 149 to 315°C
[300 to 600°F], medium: 315 to538°C [600 to 1,000°F]; and high: 538 to
649°C [1,000 to 1,200°F]). Solids temperature ranges and descriptions (low,
medium, or high) are descriptive only of equipment mechanical limitations
and are not intended as descriptions of regulatory limits or requirements,
2.1
-------
Background
Figure 2.1
Thermal Desorption System Schematic Diagram.
a. Rotary Dryer
b. Thermal Screw
c. Paddle Dryer
d. Anaerobic Thermal
Processor
e. Conveyor Belt
f. Batch Vacuum Unit
g. Mercury Retort
a. Organic Collection/
Destruction
b. Particulate Removal
c. Acid Gas Removal
Feed
Handling/Pretreatment
Thermal
Desorption
a. Excavation
b. Storage
c. Size Reduction
d. Debris Removal
e. Blending
f. Neutralization
g. Conveying
h. Weighing
Gas
Posttreatment
Solids
Posttreatment
a. Conveying
b. Cooling/Moisturizing
c. Stockpiling
• Atmosphere
Residuals
Posttreatment
. Off-Site
Disposal
a. Particulate Treatment
b. Scrubber Sludge
Treatment
c. Condensate Treatment
d. Wastewater Treatment
Return
to Site
The emissions control system is characterized as either a recovery-type
or a destructive-type. Recovery-type systems use wet scrubbers, con-
densers, and activated carbon to collect the desorbed organic contami-
nants. Destructive-type systems use a thermal oxidizer to destroy the
desorbed organic contaminants.
Remediation of media contaminated with hazardous substances may be
subject to the requirements of a number of different regulatory programs.
RCRA Part 264, Subpart O or Subpart X requirements typically apply if the
material to be treated is classified as a hazardous waste or if the remediation
2.2
-------
Chapter 2
is carried out under CERCLA. Thermal desorption systems are normally
required to comply with RCRA Subpart O, incineration performance stan-
dards, if the system uses a thermal oxidizer. All other types of thermal des-
orption applications must comply with the requirements of RCRA Subpart
X, including appropriate design and operating parameters, detection and
monitoring requirements, and requirements for responses to releases of haz-
ardous wastes or hazardous constituents from the unit. Systems regulated
under Subpart X are typically required to meet ambient ground-level concen-
trations of contaminants of concern resulting from stack emissions. Accept-
able ambient ground-level concentrations are established by risk assessment
procedures on a site-by-site basis or from state ambient air standards. If the
feed material is derived from materials that contain more than 50 mg/kg
polychlorinated biphenyls (PCBs), Toxic Substances Control Act (TSCA)
regulations may apply. Under TSCA regulations, thermal desorption sys-
tems may be required to demonstrate performance equivalent to a 99.9999%
destruction and removal efficiency (based on the mass of PCBs in the feed
material and stack gas). In many cases, state air emissions and solid waste
regulations may also apply.
For a detailed description of the thermal desorption process, equipment,
and pertinent scientific principles, the reader is referred to the companion
volume, Innovative Site Remediation Technology — Thermal Desorption
(Lighty et al. 1993).
2.1 Scientific Principles
2.1.1 Scientific Basis
Thermal desorption systems are based on the principle that the vapor
pressure of organic contaminants increases as a function of temperature.
As the contaminated matrix is heated, the organic compounds are vapor-
ized and driven from a waste matrix into a purge gas stream for further
treatment. The relationship between temperature and vapor pressure for
many organic compounds can be estimated using the Antoine Equation
which has the general form:
2.3
-------
Background
ln(VP) = ANTa -
a
where: ln(VP) = natural log of the vapor pressure;
ANTa = Antoine Equation coefficient A;
ANTb = Antoine Equation coefficient B;
ANTc = Antoine Equation coefficient C; and
T = temperature.
The values of the coefficients depend upon the units of pressure and
temperature used. A compilation of Antoine Equation coefficients for
hundreds of organic compounds is available in the literature (Reid,
Prausnitz, and Sherwood 1977). Example relationships between tem-
perature and vapor pressure for benzene, ethylbenzene, naphthalene, and
phenanthrene that were developed using the Antoine Equation are pre-
sented in Figure 2.2. These compounds were chosen as examples be-
cause their volatility values span a range from very high (benzene) to
very low (phenanthrene). As shown in this graph, vapor pressures of
organic compounds are very sensitive to temperature.
In any thermal desorption system, heat must be transferred to the solid
particles to vaporize the contaminants, which are then swept from the ther-
mal desorber by a gas stream. The specific modes of heat and mass transfer
vary among the different types of thermal desorbers. The heat and mass
transfer mechanisms to be considered and controlled by the system operators
are shown in Figure 2.3. The performance of a thermal desorber is primarily
a function of the maximum solids temperature achieved during treatment and
solids residence time as shown in Figure 2.4.
As shown schematically in Figure 2.4, the initial 90% of a contaminant
may be easily removed, but the final 10% is removed with greater difficulty
and can take much longer, especially if the cleanup criterion is in the parts
per billion range. This phenomenon is due to the adsorptive properties of
soil, which may strongly adsorb monolayers (single molecules) of the con-
taminant to its surface (Lighty et al. 1990).
2.4
-------
Figure 2.2
Vapor Pressure vs. Temperature
Chapter 2
§
i
1,000,000 e
100,000
10,000
1,000
100
10
o.i
0.01
0.001
I 1
100 200
300 400
Temperature ('C)
500 600 700
2.5
-------
Background
Figure 2.3
Transport Phenomena Occurring During Thermal Treatment of a Solid Bed
Desorption
Radiation (importance depends on the
temperature) and convection from the gas
Radiation (importance depends on the
temperature) from walls or heating elements
GAS
I Mass transfer to
the gas stream
SOLED
Conduction through the bed
/Interparticle mass transfe;
through the bed
Conduction from
the hot wall
Single
Particle
Local desorption kinetics
at the gas/solid interface
Mass transfer out of
particle to the bulk gas
Conduction
through the
particle
•*— Represents heat
< Represents mass
Source: Lighty etal.1993
2.1.2 Engineering Basis
Thermal desorption is an ex-situ physical separation process that transfers
contaminants from one phase to another. The process uses either indirect or
direct energy transfer to heat a bed of material and volatilize and separate the
organic contaminants from the material. Air, combustion gas, nitrogen, or
steam is used as the transfer medium for the volatilized components. System
performance is usually measured by comparing the concentration of organic
contaminants in the untreated waste matrix with those in the processed
2.6
-------
Chapter2
solids. The contaminated medium is typically heated to a temperature be-
tween 149 and 649°C (300 and 1,200°F). The temperature required to
achieve the performance standard depends on the boiling points of the con-
taminants of concern, the cleanup criteria, the residence time of the solids in
the thermal desorber, the degree of vacuum in the desorber, and the degree of
solids mixing. A thermal desorber is not designed to provide a high level of
organic destruction, although the higher temperatures used in some systems
could result in partial oxidalion or pyrolysis.
Air, combustion gas, nitrogen, or steam carry the vaporized contaminants to
the emissions control system. Components of the process gas may include
particulates, metals, organic contaminants of concern, thermal treatment
byproducts, and acid gases. Both recovery-type and destructive-type emissions
control systems include unit operations to remove or destroy organic com-
pounds, remove entrained particulates, and may include unit operations to re-
move acid gases. The selection of the type of emission control system depends
on the concentration of the contaminants in the feed, air emission regulations,
community relations considerations, and economic factors.
Figure 2.4
Contaminant Removal vs. Treatment Time and Temperature
•a
u.
Time
Source: Lkjhtyeta). 1993
2.7
-------
Background
2.2 Potential Applications
2.2.1 General Applicability
Thermal desorption effectively treats contaminated soils, sediments, slud-
ges, and filter cakes. Contaminants for which bench-, pilot-, and full-scale
treatment data exist include volatile organic compounds, semivolatile or-
ganic compounds, polychlorinated biphenyls, chlorinated phenols, pesti-
cides, herbicides, dioxins/furans, mercury, and cyanide. As discussed in
Section 1.0, thermal desorption has also been applied extensively to soils and
sludges contaminated with petroleum products. A discussion of applications
for treating matrices contaminated with petroleum products is presented in
Appendix B.
The effectiveness of thermal desorption on general contaminant
groups for various matrices is shown in Table 2.1. This table is based on
currently available information or professional judgment where no infor-
mation is available. The proven effectiveness of the technology for a
particular site or waste does not ensure that it will be effective at all
sites or that the reported efficiencies will be acceptable at other sites.
For the ratings used for this table, demonstrated effectiveness means
that, at some scale, test data show the technology was effective for that
particular combination of contaminant and medium. The rating of "no
expected effectiveness" is based upon expert judgment and the current
state-of-the-art. If the technology is not applicable or is unlikely to
meet performance standards for a particular combination of contami-
nants or waste matrices, a "no expected effectiveness" rating is given.
2.2.2 Technology Application Considerations
Several factors affect the performance and/or application of a thermal
desorber, including: (1) contaminant boiling point (2) system vacuum, (3)
solids treatment temperature and residence time, (4) concentration of organ-
ics in feed material, (5) soil type, (6) feed moisture content, (7) feed material
size, (8) type and quantity of debris, (9) quantity of emission control residu-
als, (10) metals in feed material, (11) waste feed quantity, and (12) thermal
desorber materials of construction. A brief discussion of key factors is pre-
sented below.
2.8
-------
Chapter 2
Table 2.1
Effectiveness of Thermal Desorption on General Contaminant Groups
Contaminant Groups
Organic
Halogenated Volatiles
Halogenated Semivolatiles
Nonhalogenated Volatiles
Nonhalogenated Semivolatiles
PCBs
Pesticides
Dioxins/Furans
Organic Cyanides
Organic Corrosives
Effectiveness
Soil Sludge Sediments
• • A
• • A
• ' • A
• • A
.
• A A
A A A
.
D D a
Filter Cakes
•
•
•
•
A
A.
A
A
D
Inorganic
Volatile Metals (mercury)
Volatile Metals (excluding mercury)
Nonvolatile Metals
Asbestos
Radioactive Materials
Inorganic Corrosives
Inorganic Cyanides
Reactive
Oxidize rs
Reducers
A
D
D
D
O
O
D
A
O
Q
a
o
a
a
• Demonstrated Effectiveness: Successful treatability test at some scale completed.
* Potential Effectiveness: Expert opinion that technology will work.
D No Expected Effectiveness: Expert opinion that technology will not work.
Adapted from US EPA 1994b
2.9
-------
Background
2.2.2.1 Contaminant Boiling Point
The boiling point of a contaminant is the temperature at which its vapor
pressure is equivalent to the pressure on the system as shown in Figure 2.2.
For example, at a system pressure of 760 mm Hg (atmospheric pressure), the
boiling point of naphthalene is 218°C. A thermal desorption system operat-
ing at near atmospheric pressure should be capable of heating the least vola-
tile contaminant of concern to a temperature within ±56 to 111 °C (100 to
200°F) of its boiling point. The target treatment temperature is also a func-
tion of solids residence time and system vacuum.
2.2.2.2 System Vacuum
A number of thermal desorption systems have been developed that oper-
ate under vacuums of 508 to 635 mm Hg (272 to 339 in. w.c.). Operating
under vacuum conditions lowers the boiling point temperature of contami-
nants compared to the boiling point at near-atmospheric pressure. For ex-
ample, Figure 2.2 shows that the boiling point of naphthalene is 218°C
(424°F) at a pressure of 760 mm Hg (atmospheric pressure); at a pressure of
100 mm Hg, the boiling point is reduced to 144°C (291 °F).
2.2.2.3 Solids Treatment Temperature and Residence Time
Various combinations of solids treatment temperature and solids residence
time can be used to achieve the same treatment objective for a contaminant
of concern. Treatability data for pyrene contaminated soils are presented in
Figure 2.5 which illustrates this principle (Helsel and Groen 1988). The data
in this figure are based on the time the solids were held in the muffle furnace
after reaching the target treatment temperature. As shown in the figure, a
treatment objective of 10 mg/kg of pyrene in treated soils was achieved at
four combinations of time/temperature conditions, but was not achieved at
the lowest temperature tested (250°C [482°F]).
2.2.2.4 Concentration of Organics in Feed Material
The operating conditions required for the treatment system to achieve
performance standards for treated solids, and the associated feed rate and
operating cost, will partially depend on the initial concentration of contaminants
of concern. As the concentration of contaminants of concern in the feed mate-
rial increases, more stringent operating conditions (increased temperature, resi-
dence time, etc.) may be required to achieve performance standards.
2.10
-------
Chapter 2
Figure 2.5
Pyrene Removal vs. Treatment Time and Temperature
10,000
1,000
100
•3
I
10 15 20 25 30
Time at Temperature (min)
Source: Helsel and Groen 1988
For many applications, the contaminants of concern comprise a small
fraction of the total organic material. Examples of sources of other organics
may include humic material in soil, peat, decayed vegetation, coal fines, or
synthetic organic compounds that are not contaminants of concern. The total
2.11
-------
Background
concentration of organics in the feed material affects materials handling
characteristics, the ability to achieve performance standards, waste feed
capacity, safety issues, quantity of emission control system residuals, and
fuel usage in afterburners.
High concentrations of organics increase the potential for materials han-
dling difficulties and internal system fouling for all types of thermal desorp-
tion systems. High concentrations of organics can also generate large quan-
tities of emission control system residuals (such as spent activated carbon
and organic liquids) so that thermal desorption is not economically viable.
Indirectly-heated thermal desorbers that operate in an inert atmosphere
can process very high concentrations of organics in the feed matrix. How-
ever, at feed organic concentrations of greater than 20%, the economics of
thermal desorption may be less favorable than other technologies, such as
incineration, unless the desorbed organics can be recycled. For example,
thermal desorbers are commonly used to process American Petroleum Insti-
tute (API) separator sludges and to recycle the organics to a refining process.
API separator sludges typically have organic contents of 30-40% or higher.
For directly-heated systems, concentrations of volatile organic material
(as measured by a proximate analysis, ASTM Method D-5142) in the waste
feed matrix should be limited to a maximum concentration of less than ap-
proximately 2-3%, unless treatability testing demonstrates that some fraction
of the organic material will not be removed from the waste matrix at the
thermal desorber operating conditions. Safety guidelines limit the concen-
tration of organic vapors in the thermal desorber offgas to a maximum of
25% of the lower explosive limit (LEL) unless a continuous LEL monitor
and controller is provided (National Fire Protection Association [NFPA]
1990). If a system is provided with a continuous LEL monitor and control-
ler, the concentration of organics in the offgas stream should not exceed 50%
of the LEL (NFPA 1990).
The concentration of organics in the feed can have a major effect on the
auxiliary fuel usage for a thermal desorber that uses an afterburner. For
example, a thermal desorber processing 18 tonne/hr (20 ton/hr) of manufac-
tured gas plant waste with a heating value of 222 cal/g (400 Btu/lb) results in
a waste heating value input of 16.86 gigajoules/hr (16 MM Btu/hr). The
organic material in the feed is volatilized and combusted in the afterburner,
'therefore, reducing the amount of auxiliary fuel required. This type of
analysis should be conducted for any potential application to confirm that
2.12
-------
Chapters
the heating value of the waste will not exceed the capacity of the thermal
oxidizer or the volume of gas generated in the system will not exceed the
capacity of other unit operations such as fans and baghouses.
Typical upper limits on feed matrix heating values are in the range of 222 to
556 cal/g (400 to 1,000 Btu/lb) in order to prevent exceeding the design capac-
ity of the afterburner. Afterburners are normally equipped with temperature
control loops which introduce excess air to maintain an exit gas temperature
setpoint. -The lower limit on feed matrix heating value is appropriate for very
volatile organics such as xylene and toluene. The higher limit on feed matrix
heating value is applicable for wastes containing less volatile organic com-
pounds, such as manufactured gas plant wastes, where the full heat content of
the waste may not be released from the soil during thermal treatment.
2.2.2.5 Soil Type
Contaminants desorb relatively easily from granular, free-flowing materi-
als such as sands and gravels. These types of materials have low surface to
volume ratios which enhance heat transfer. Conversely, clay soils that are
tightly aggregated or exhibit plastic characteristics can be difficult to treat
because of the tendency to stick to process equipment and to aggregate into
large clumps that can inhibit heat transfer in the thermal desorber. Materials
with a high clay content and an elevated moisture content may exhibit cohe-
sion characteristics that may prevent adequate desorption of contaminants
bound in consolidated fines.
2.2.2.6 Feed Moisture Content
Moisture has several competing effects on thermal desorption applica-
tions: (1) a significant fraction of the total heat input may be required to
evaporate water; (2) cohesion and material handling properties of soils, espe-
cially clays, change considerably as a function of moisture content; (3) the
capacity of a solid matrix to absorb organic materials is reduced with in-
creasing moisture content; and (4) the removal of organics may be enhanced
by steam stripping as moisture evaporates. Additional details of these
mechanisms are discussed below.
Figure 2.6 shows an example of the relative amount of energy required to
heat the inert, moisture, and organic fractions of waste in a thermal desorber
as a function of waste moisture content. This figure is based on the follow-
ing assumptions: (1) soil discharge temperature of 426°C (800°F), thermal
2.13
-------
Background
desorber gas exit temperature of 538°C ,(1,000°F), soil heat capacity of 0.25
cal/g-°C (0.25 Btu/lb-°F), and soil organic content of 1%. As shown in Fig-
ure 2.6, at a moisture content of greater than 15%, the moisture requires over
half of the total energy to heat the waste. Therefore, waste material feed rate
and process economics are improved significantly as feed moisture content
decreases.
Figure 2.6
Energy Requirement Diagram
400
£=• 300
1
200
100
5 10 15 20 25 30 35 40
Moisture Content (%)
1=3 Moisture
•• Organic
E3 Dry soil
Material pretreatment requirements to obtain a maximum allowable feed
moisture content are system dependent. For example, most rotary dryers and
conveyor belt systems operate best at a moisture content at which the mate-
rial is free-flowing, typically ranging from 5 to 25%. Conversely, systems
such as thermal screws and paddle dryers, which are specifically designed to
dry wet materials, can process materials with up to 60% moisture. Material
handling is generally improved by feeding materials with a relatively low
2.14
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Chapter 2
(<20%) moisture content. However, at a very low (<5%) moisture content,
fugitive dust emissions during feed preparation and handling may be an
operational and health and safety issue.
Steam stripping by evaporating moisture typically improves the kinetics
of contaminant desorption from the solid matrix.
2.2.2.7 Feed Material Size
Decreasing the size of the feed material allows the solids bed to be heated
more quickly because more surface area is exposed to the heat source. Feed
material is generally prepared by screening, crushing, or shredding to a
maximum dimension of 51 to 64 mm (2 to 2.5 in.).
2.2.2.8 Type and Quantity of Debris
Debris is typically a heterogeneous mixture of materials with
non-uniform composition, size, shape, and material handling properties.
Some debris is usually present in feed materials and large debris items
should be separated from the medium to be treated. Debris can jam convey-
ors, air locks, and other mechanical equipment. Inert materials, such as
rocks or masonry, may be crushed and recycled into the waste feed stream.
Organic debris, such as paper and plastic, can become entrained in the ther-
mal desorber offgas and plug or jam downstream emissions control equip-
ment. Large debris (>15 cm [6 in.] diameter) may be separated at the exca-
vation area while smaller debris is typically separated by the materials han-
dling and pretreatment components of the thermal desorption system.
The amount and type of debris affect the types of material pretreatment
processes that are required. If the debris is separated from a RCRA hazard-
ous waste, the RCRA Debris Rule (40 CFR Part 268) must be considered an
Applicable or Relevant and Appropriate Requirement (ARAR). This rule
requires that the debris be treated using technology-specific standards or
waste-specific standards before it can be land disposed.
2.2.2.9 Quantity of Emission Control Residuals
A material balance should be performed for the entire thermal desorption
system, not just the thermal desorber. The ultimate fate of all streams should
be addressed and determined in the treatment decision. The feed material
should be characterized, and a material balance should be performed to
2.15
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Background
estimate the fate of the organic material in the feed (condensed as a liquid,
collected on vapor phase or liquid phase activated carbon, destroyed in a
thermal oxidizer, etc.). In some cases, the fate of inorganic materials (met-
als) must also be addressed to evaluate if individual waste streams will com-
ply with discharge or disposal requirements.
2.2.2.10 Metals in Feed Material
Mercury is the only common toxic metal that is effectively removed
by thermal desorption. Because of the relatively low solids treatment
temperatures used in thermal desorbers, metals other than mercury tend
to stay in the waste matrix rather than preferentially partitioning to the
gas phase. However, factors such as metals partitioning to the gas phase
and leachability from the treated solids should be evaluated on a
case-by-case basis. Stabilization of metals in the treated solids may be
required if Toxicity Characteristic Leaching Procedure (TCLP) limits
are exceeded. The fate of metals entrained in the purge gas should be
considered in the evaluation of the air emission control system.
2.2.2.11 Waste Feed Quantity
Thermal desorption is typically used as a mobile process for hazardous
substance applications, although it is commonly used as a fixed-base process
for treating soils contaminated with petroleum hydrocarbons and/or wastes
from manufactured gas plant sites. For mobile applications, process eco-
nomics are strongly affected by the waste quantity to be treated at a site. For
each mobile system, there is a minimum quantity of feed material for which
treatment will be economically viable because of the cost of mobilizing,
testing, and demobilizing a system. Minimum quantities of materials for
various sizes of systems are typically in the following ranges:
Small systems: 900 to 2,700 tonne (1,000 to 3,000 ton);
Medium systems: 2,700 to 9,000 tonne (3,000 to 10,000 ton); and
Large systems: >9,000 tonne (> 10,000 ton).
For the purpose of this analysis, small, medium, and large systems are
defined with capacities of less than 4.5, 4.5 to 18, and greater than 18 tonne/
hr (less than 5, 5 to 20, and greater than 20 ton/hr), respectively.
2.16
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Chapter 2
2.2.2.12 Thermal Desorber Materials of Construction
The maximum solids temperature that can be attained in a thermal
desorber depends primarily upon the materials of construction of the unit
because of shell strength considerations. Systems made of carbon steel can
typically treat solids to a maximum temperature of 315 to 371 °C (600 to
700°F). These systems are very effective for removing volatile organic com-
pound (VOC) contaminants. Thermal desorbers constructed of various types
of alloys can typically attain solids temperatures in the range of 427 to
649°C (800 to 1,200°F). The higher temperatures are typically required for
less volatile organics, such as pesticides, polycyclic aromatic hydrocarbons
(PAHs), and PCBs.
2.2.3 Evaluation Factors
Thermal desorption has been in commercial use since the late 1980s.
Experience gained in field applications has revealed a number of factors to
be considered in evaluating potential thermal desorption applications. Some
of these factors are described in the following sections.
2.2.3.1 Organic Material Characterization
Sites are typically characterized by collecting extensive data on the con-
taminants of concern. However, the contaminants of concern typically com-
prise only a small fraction of the total organic material. From a process
engineering mass balance basis, technology evaluations must be based on
the total quantity of organic material, not simply the contaminants of con-
cern. Typical indicators of organic concentration in the waste matrix are
heating value in cal/g (Btu/lb), total petroleum hydrocarbons in mg/kg
(TPH), total recoverable petroleum hydrocarbons in mg/kg (TRPH), proxi-
mate analysis (volatile organics, water, ash) in % and ultimate analysis (car-
bon, hydrogen, oxygen, nitrogen) in %. Such analyses should be performed
on. samples from any site being considered for thermal desorption treatment.
2.2.3.2 Particulate Carryover
The degree of paniculate carryover from the thermal desorber into down-
stream emission control devices is a significant design consideration because
of: (1) paniculate mass load on paniculate control devices (cyclone,
baghouses, etc.), (2) potential for accumulation in ducts and process
2.17
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Background
equipment, (3) potential for slagging in afterburners, and (4) management of
potentially-contaminated fines.
The degree of particulate carryover depends on a number of factors, in-
cluding the gas velocity in the thermal desorber; waste feed particle size,
shape, and density; and solids loading in the thermal desorber. Carryover
can range from a low of 1 to 3% of the feed solids for indirectly-heated sys-
tems with gas velocities of 0.3 to 0.6 m/sec (1 to 2 ft/sec) up to 10 to 30% of
feed solids for directly-heated systems with gas velocities in the range of 1.5
to 4.5 m/sec (5 to 15 ft/sec).
Particulates that are carried over from the thermal desorber and collected
hi the emissions control system may not be decontaminated and may require
further treatment. Particulates may be treated by returning them directly to
the thermal desorber, mixing them with hot soil discharged from the thermal
desorber, or segregating them for future recycle to the thermal desorber. If
particulates are returned to the thermal desorber, the net mass throughput
capacity of the unit may be decreased substantially in some cases.
2.2.3.3 Fugitive Emissions
The contaminated waste can generate fugitive dust and VOC emissions
during excavation, screening, crushing, and storage before treatment. Care
must be taken to control emissions and minimize worker and off-site expo-
sures. Control mechanisms include choosing appropriate excavation meth-
ods, covering trucks and stockpiles, and conducting materials pretreatment
operations in enclosed and properly ventilated buildings. Each of these
mechanisms must be designed with consideration for health and safety is-
sues and to control potential environmental releases in compliance with
relevant regulatory criteria.
Fugitive particulate emissions may also result from treated soil handling
operations. The treated solids will typically contain less than 1% moisture.
These emissions are normally controlled by water addition and mixing. In
most cases, treated water from the emissions control system can be used for
this purpose. In some cases, controls must also be provided for steam from
the solids cooling process by collecting it in a hood and ducting it back into
the thermal desorber or the emissions control system.
2.18
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Chapter 2
2.2.3.4 Materials Handling
Tars and other sticky materials can foul the feed system and internal
parts of the desorber. Such materials are commonly found at sites con-
taining residuals from manufactured gas production and some petro-
chemical facilities. In some cases, sticky feed material may have to be
blended with dry soil, treated solids, or other materials to produce a feed
material that will flow readily. However, blending with these types of
materials increases the mass of material to be treated and may increase
the project cost and schedule.
2.2.3.5 Chlorine and Sulfur Content of Feed Material
Chlorinated compounds and a fraction of the sulfur in the feed material
will be volatilized in the thermal desorber. If an afterburner is used as an
emission control device, hydrogen chloride and sulfur dioxide will be gener-
ated. The presence of acid gases at concentrations above regulatory limits
typically requires the use of wet scrubbers as emission control devices. The
presence of acid gases also requires that the temperature of the process gas
must be kept above its dew point or that corrosion resistant materials of con-
struction must be used for process equipment.
2.2.3.6 Contaminant Treatment Criteria
Thermal desorption systems are typically capable of producing treated
solids with concentrations of individual organic contaminants of concern in
the range of 1 to 10 mg/kg. A residual concentration of dioxin expressed as
2,3,7,8 tetrachlorodibenzo-p-dioxin toxicity equivalents (2,3,7,8 TCDD
TEQ) of well below 1.0 |Jg/kg has been demonstrated by some systems.
Treatment criteria established by risk assessment procedures sometimes
result in values below levels that can be achieved in thermal desorption sys-
tems or below analytical detection limits for the treated .waste matrix. At
residual concentrations requirements in the low parts per billion range, waste
feed capacity and process economics can be significantly affected.
Bench-scale treatability tests and analytical testing should be conducted to
confirm that matrix-specific analytical detection limits are below the re-
quired treatment criteria.
2.19
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Background
2.2.3.7 Emissions Control
The emission control system used with the desorber must be properly
selected and operated according to the site characteristics, constituents of
concern, and regulatory criteria. Air emission standards should be clearly
defined and agreed to by all parties, including regulatory agencies, the ther-
mal desorption contractor, and the client before entering into a contractual
relationship. The applicable air emission standards will be site and equip-
ment specific. Emission standards may be considerably different for a
directly-heated desorber with a destructive-type emission control system as
compared to those that apply to an indirectly-heated desorber with a
recovery-type emission control system.
2.3 Treatment Trains
The treatment train is defined in this document as the mechanical pro-
cesses that are typically within the battery limits at a thermal desorption
facility. Other essential operations, such as excavation and backfilling, that
are outside of the battery limits are defined as "processes used prior to ther-
mal desorption treatment" or "processes used after thermal desorption treat-
ment." These operations are discussed in Section 2.3.5 and Section 2.3.6,
respectively. Other processes that are used infrequently, such as stabilization
of treated solids, are also discussed in Section 2.3.6.
Brief discussions of feed handling and pretreatment and posttreatment
requirements are presented below.
2.3.1 Feed Handling and Prefreatment
Feed handling and pretreatment include feed storage and/or stockpiles,
debris removal, size reduction (screening, crushing, shredding, etc.), blend-
ing, neutralization, drying, conveying, and weighing. A detailed discussion
of the unit operations that are typically used to accomplish these functions
and key design criteria are presented in Section 3.5.
2.20
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Chapter 2
2.3.2 Solids Posttreatment
Solids posttreatment operations include cooling, moisturizing, conveying,
storage, and sampling and analysis.
2.3.3 Gas Posttreatment
Gas posttreatment operations include collection or destruction of organic
compounds, paniculate removal, and acid gas removal. A detailed discus-
sion of gas posttreatment equipment and requirements is presented in Sec-
tion 3.6.2.
2.3.4 Emission Control System Residuals Posttreatment
Residuals are secondary wastes that are collected at some point in the
processing of the primary waste stream. The types of residuals posttreat-
ment operations required depend primarily upon the type of emissions con-
trol system that is used. All systems may require treatment of purge water,
particulates, and/or sludges from the emission control system. Systems that
recover the organic contaminants from the offgas may also require treatment
and/or disposal of aqueous condensate, liquid organic condensate, and va-
por- and/or liquid-phase activated carbon. A detailed discussion of emis-
sions control system residuals posttreatment equipment and requirements is
presented in Section 3.6.3.
2.3.5 Processes Used Prior to Thermal Desorption Treatment
The primary operations used prior to thermal desorption treatment are
excavation and transportation of waste. The major issues associated
with both of these processes are fugitive dust and organic vapor emis-
sions control. Methods to control fugitive emissions include limiting the
open areas of excavation faces, using water sprays, applying surfactant
foams, and covering temporary stockpiles and transportation vehicles. A
detailed discussion of methods to estimate and control fugitive emis-
sions from excavation and materials handling processes is presented in a
series of US EPA guidance documents (US EPA 1985; US EPA 1989a).
2.21
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Background
2.3.6 Processes Used After Thermal Desorption Treatment
Processes used after thermal desorption treatment include stabilization of
metals in treated solids, backfilling and compacting treated solids, providing
a topsoil cover, and off-site disposal of emission control system residuals. A
brief discussion of several of these processes is presented below.
2.3.6.1 Stabilization of Metals
Most thermal desorption systems are designed to mix water with the
treated solids to avoid fugitive dust problems as described above. During
this mixing process, a stabilization agent or combination of stabilization
agents such as lime, Portland cement, kiln dust, or other materials can be
added to the solids matrix to prevent metals from leaching at unacceptable
rates. Laboratory treatability studies typically determine stabilization pa-
rameters and additives necessary to meet TCLP criteria. Other tests, such as
compressive strength, may also be required to demonstrate that stabilized
materials meet backfill requirements. These studies must be conducted with
thermally-treated solids samples.
2.3.6.2 Backfill
After adding water to achieve the optimum moisture level, the materials
can be backfilled and compacted to ensure a stable surface. The optimum
moisture content of the material for compaction purposes should be deter-
mined by using a Standard Proctor Test, ASTM D-698, or a Modified Proc-
torTest, ASTM D-1557 (Holtz and Kovacs 1981). Typical compaction
specifications require backfilled material to be compacted to 90 to 95% of
the maximum Proctor density.
2.3.6.3 Soil Cover
Since thermal treatment will alter the organic content of the soil, the
treated soil may not readily support plant growth. In some cases, a top soil
cover is used over the treated, backfilled material in order to establish a
growth of vegetation. In other cases, organic soil amendments are mixed
into the top 30 cm (12 in.) of treated soil to support plant growth.
2.22
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Chapter 2
2.3.6.4 Off-Site Disposal of Emission Control System Residuals
Any organic residuals collected by the thermal desorption system will
require off-site disposal. Examples of residuals include organic liquids col-
lected by condensation systems, sludges from phase separation systems,
scrubber sludges, scrubber purge water, and liquid- and/or vapor-phase acti-
vated carbon.
2.23
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Chapter 3
DESIGN DEVELOPMENT
This section addresses considerations relevant to the design or selection of
a thermal desorption system for a given application. In addition to
site-specific factors such as characteristics of the soil matrix and the con-
taminants, key factors addressed in this section include: remediation goals,
design basis, equipment design and selection, process modifications, pre-
treatment processes, posttreatment processes, process instrumentation and
controls, safety requirements, specification development, cost data, design
validation, permitting requirements, and performance measures.
Thermal desorption treatment is typically provided by contractors who
operate mobile equipment. Therefore, comprehensive guidance on the de-
sign of a thermal desorption system is not provided in this document.
Rather, sufficient information is provided to evaluate a thermal desorption
system for a specific application.
3.7 Remediation Goals
While thermal desorption effectively treats many organic contaminants in
a variety of waste matrices, certain limitations exist. Therefore, the applica-
bility of thermal desorption to a given waste stream must be evaluated rela-
tive to remediation goals for the site or waste stream.
The concentration of contaminants remaining in the treated material
should be reduced sufficiently to allow for the material to be backfilled
on-site. Remediation goals are typically expressed as a maximum allowable
concentration of contaminants in the solids after treatment, but they are
sometimes expressed as a percent reduction in concentration after treatment.
Remediation goals are normally determined by analyzing the risk to human
health and the environment posed by treated material at certain contaminant
3.1
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Design Development
concentrations. Sometimes, remediation goals for a given site or waste
stream are defined by federal or state regulations that delineate treatment
standards for various wastes. For example, the RCRA Universal Treatment
Standards presented in 40 CFR Part 268 specify the maximum concentra-
tions of specific compounds that can be present in hazardous wastes to be
land disposed.
After remediation goals have been identified, it is necessary to confirm if
thermal desorption can achieve the goals. The ability of thermal desorption
to meet remediation goals depends, in general, on the types and concentra-
tions of the contaminants of concern and the character of the waste matrix.
Thermal desorption is a possible treatment option if the target contaminants
can be vaporized at temperatures at or below the maximum solids treatment
temperature of the desorber. Most organic compounds, mercury, and organic
cyanides can be treated by thermal desorption processes (Table 2.1).
The capability of a thermal desorption process to achieve target contaminant
concentrations in treated solids can be evaluated by comparison to bench- or
pilot-scale treatability tests or full-scale data from performance tests or produc-
tion operations, or by engineering analyses. Comparing the character of a waste
and its corresponding remediation goals to data obtained from full-scale sys-
tems operating on similar applications is the best indicator of whether thermal
desorption can achieve given remediation goals. Carefully controlled treatabil-
ity studies on representative samples of waste using equipment that models
full-scale operating conditions also provide suitable scale-up data. If no
full-scale data are available for a specific compound and a treatability study
cannot be performed, an engineering analysis can be used to estimate the prob-
ability of achieving remediation goals. The analysis should consider the key
parameters that affect thermal desorber performance: (1) concentration of con-
taminant in feed material, (2) required concentration in treated material, (3)
boiling point of the contaminant, (4) type of waste matrix, (5) moisture content
of the waste, (6) thermal desorber solids treatment temperature, and (7) thermal
desorber solids residence time. This information can be compared to informa-
tion from case histories (see Appendix A) for contaminants in the same general
class (i.e., volatile organics, semivolatile organics, etc.) in order to make an
engineering judgment The opinions of the pertinent regulatory agencies and
the community must also be examined to gauge whether these entities will
accept thermal desorption as a means to achieve remediation goals. This ex-
amination should consider both the capability of thermal desorption to meet
requirements of applicable or relevant and appropriate state and federal
. 3.2
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Chapter 3
regulations and the general perceptions of the technology by the oversight
agency and the local community.
3.2 Design Basis
Key factors that should be considered in evaluating a thermal desorption
system for a specific application are waste-specific factors, site-specific
factors, and regulatory factors. Waste-specific factors include the mass of
waste to be treated, types and concentrations of organic contaminants, types
and concentrations of metals, total organic content of the waste feed mate-
rial, feed material moisture content, geotechnical characteristics of the soil
(grain-size distribution, plasticity), waste feed pH, and concentration of sul-
fur and total chlorine. Site-specific factors include the amount of space
available for setting up process equipment and staging feed and treated sol-
ids stockpiles, and the availability of adequate utilities such as water, elec-
tricity, sewers, and fuel. Regulatory factors include treated solids standards,
stack gas emission control standards, and wastewater discharge standards.
In many cases, laboratory-scale, bench-scale, or pilot-scale treatability
tests are used to develop or confirm design basis information or assumptions.
Treatability testing is normally conducted using a tiered approach. A de-
tailed discussion of thermal desorption treatability testing procedures is pre-
sented in a US EPA guidance document (US EPA 1992d). RCRA includes
exemptions from hazardous waste regulations for treatability study samples
as described in 40 CFR 261.4(e). These exemptions are applicable provided
that maximum quantity limits of samples are not exceeded; the sample is
properly packaged, labeled, and shipped; and the receiving laboratory is in
compliance with relevant regulations.
A Tier 1 evaluation usually consists of a set of bench-scale static tray tests
in which contaminated samples are heated in a muffle furnace. Sample size
ranges from 100 to 500 g (0.2 to 1.1 Ib) per sample. A matrix of tests is
conducted using a range of temperatures and solids residence times that are
comparable to those used in full-scale equipment. The muffle furnace is
purged with a gas (typically air or nitrogen) that is representative of the
full-scale system being considered. Samples are analyzed before and after
treatment. The results from the tests define the range of temperature and
3.3
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Design Development
solids residence times at which the treatment criteria can be achieved. Tray
tests can also be useful for generating removal data on other components
such as metals, sulfur, volatile organic material, etc. Continuous process
monitoring includes the temperature of the solids and gas in the muffle fur-
nace and purge gas flow rate. Typical costs for Tier 1 treatability tests are in
the range of $8,000 to $30,000 depending on the number of samples and
number of analyses (US EPA 1992d).
Batch or continuous feed laboratory-scale thermal desorption reactors are
often used for Tier 2 testing. Laboratory-scale equipment typically requires
0.5 to 50 kg (1.1 to 110 Ib) of material per test. The thermal desorption
reactor generally mixes the sample to simulate full-scale conditions. The
thermal desorption reactor is purged with a gas (typically air or nitrogen)
that is representative of the full-scale system being considered. Tier 2 test
equipment can include indirectly-heated rotary dryers and thermal screws
and emission control unit operations such as wet scrubbers, condensers,
particulate filters, and activated carbon adsorption systems. Tier 2 test con-
ditions (temperature and solids residence time) are normally based on the
range of conditions that were successful in Tier 1 testing. Typical Tier 2
tests include sampling and analysis of feed and treated solids, condensate
streams, particulates collected from the thermal desorber offgas, and acti-
vated carbon filters, and offgas streams. The temperature of solids, gas and
liquid streams, and the purge gas flow rate can be continuously monitored.
Typical costs for Tier 2 tests range from $10,000 to $100,000 depending
upon the scope of the test program (US EPA 1992d).
Tier 3 tests are conducted with continuous pilot-scale equipment that
closely simulates the unit operations in a specific contractor's full-scale ther-
mal desorption system. Pilot tests typically require 25 to 250 kg/hr (55 to
550 Ib/hr) of feed material. Tier 3 test equipment generally includes emis-
sion control unit operations such as wet scrubbers, condensers, particulate
filters, and activated carbon adsorption systems. Tier 3 tests typically in-
clude sampling and analysis of feed and treated solids, condensate streams,
particulates collected from the thermal desorber offgas and activated carborj
filters, and offgas streams. Continuous process monitoring may include
temperatures of treated solids and gas and liquid streams, pressure in the
thermal desorber, pressure drop across emission control devices, etc. Be-
cause of sample size requirements, Tier 3 tests may be conducted at the con-
taminated site rather than in the laboratory. Therefore, significant costs can
be incurred in moving and setting up equipment. Typical costs for Tier 3
3.4
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Chapter 3
tests range from $50,000 to $200,000 depending upon the scope of the test
program (US EPA 1992d). Because of cost and complexity factors, Tier 3
tests are rarely conducted.
3.3 Design and Equipment Selection
The thermal desorber must be able to provide the necessary solids tem-
perature and residence time to meet the cleanup criteria. Fuel, electricity,
and process water sources must be available. In addition, the process residu-
als must be handled by environmentally-sound treatment or disposal meth-
ods. Selection of the processes necessary for the system to meet the design
goals must be made prior to detailed design of the process equipment. Pro-
cess selection involves both engineering and regulatory considerations. Ba-
sic engineering considerations include heat and mass transfer, equipment
reliability and performance, and estimated operating cost. These consider-
ations are interrelated, and therefore, selections in one area necessarily limit
flexibility in other areas. Once the processes necessary to achieve design
goals have been selected, detailed process equipment design can commence.
When possible, system selection or design should be based on scale-up
from treatability test results. For an ideal application of thermal desorption,
representative samples of the candidate waste would be subjected to each of
the three tiers of treatability tests described in Section 3.2 based on a specific
full-scale treatment system design. Tier 1 testing would consist of batch
tests and would be used to confirm the treatability of the waste by thermal
methods. Tier 1 testing would establish a range of soil treatment tempera-
tures and residence times at which the soil treatment performance standards
could be achieved. Tier 1 testing would not simulate expected mass transfer
mechanisms or solid/gas/liquid relationships and would not be performed
with a continuous process.
Tier 2 testing would be used to more closely simulate a specific technol-
ogy and could be conducted using either a batch or a continuous reactor.
The equipment dimensions and the flow rates of the process streams through
each unit operation should be established based on ratios to the expected
sizes and flows in the full-scale treatment system. For example, ratios and
values such as drum length to diameter ratio, gas volume to solids mass ratio,
3.5
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Design Development
and gas flow velocities values should be maintained so that they are
constructable and operable after scale-up. Some parameters, such as the
method of heating the primary reactor or methods of handling ancillary process
streams may not simulate the full-scale system during Tier 2 testing.
Tier 3 testing would then be used to test the proposed technology in as
complete a fashion as possible. Tier 3 testing is conducted in systems rang-
ing from 1/100 up to 1/10 of the size of the full-scale system. In addition to
maintaining constructable, operable system ratios as established in Tier 2
testing, Tier 3 testing should mimic expected full-scale treatment equipment
in all respects but size. Equipment geometries should be at the same ratios
as those used in the full-scale system; gas/solid/liquid flow ratios should
approximate full-scale conditions, and ancillary unit operations should be in
place and operable in their proper relationship to the primary treatment unit.
In practice, few if any systems are designed or developed specifically for
a candidate waste through the rigors of three levels of treatability testing.
Selection of a full-scale system is typically made by evaluation of candidate
waste physical and chemical parameters, and in some instances Tier 1 and
Tier 2 treatability test data, relative to the characteristics of full-scale com-
mercial systems available from contractors. Evaluation of full-scale system
parameters such as maximum soil treatment temperature, solids residence
time, mass transfer mechanisms, gas/solid/liquid ratios, and gas velocities
relative to the. expected requirements for the candidate wastes typically re-
places Tier 3 treatability studies.
3.3.1 Heat and Mass Transfer
3.3.1.1 Heat Transfer
The most fundamental question that must be answered in the design and
selection of a thermal desorption system is the mode of heat transfer within
the primary chamber of the desorption system. Thermal desorbers are gener-
ally classified into two groups:
• directly-heated units; and
• indirectly-heated units.
Example schematic diagrams of both types of systems are presented in
Figure 3.1 and Figure 3.2, respectively.' Significant process differences and
advantages and disadvantages are associated with each type of system.
3.6
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Chapter 3
Figure 3.1
Directly-Heated Rotary Dryer Schematic
Offgas
t
Peed Soil •
Scale \
Rotary Dryer
Combustion
Chamber
T
Treated Soil
-Fuel
Air
O
x—-
Blower
Figure 3.2
Indirectly-Heated Rotary Dryer Schematic
Combustion
Gas
Furnace
1
Combustion
Gas
Combustion
Gas
Rotary
Dryer
Fuel and Air
Treated Soil
3.7
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Design Development
Directly-heated thermal desorbers incorporate a propane, natural gas, or
fuel oil burner inside of a chamber that is attached to the end of the thermal
desorber shell. Hot gas from the burner chamber discharges into the thermal
desorber shell. Directly-heated units primarily transfer heat through radia-
tion and convection from the gas to the solids. Contaminants are volatilized
and swept from the thermal desorber by the combustion products from the
burner and exhausted to the emission control system for further treatment.
Directly-heated units are typically more energy- and cost-efficient than
indirectly-heated units. Directly-heated units are generally less expensive to
construct, have high solids throughput capabilities in the range of 9 to 45
tonne/hr (10 to 50 ton/hr), and lower unit operating costs ($/ton) compared
to indirectly-heated units. However, they are typically restricted to treating
materials with maximum heating values in the range of 222 to 556 cal/g (400
to 1,000 Btu/lb) and relatively low (<25%) moisture content. Since
directly-heated units expose the solids to oxidizing conditions, excessive
heat can be released from high heating value waste which results in process
gas temperatures or flows exceeding the gas handling capacity of the emis-
sion control system. Directly-heated units also have significantly higher
offgas volumes per mass of solids processed than do indirectly-heated units.
Therefore, the emission control systems require relatively large equipment
unit operations.
Indirectly-heated thermal desorbers transfer heat through the thermal
desorber shell by conduction or provide heat by electrical resistance heaters
to heat the soil. The contaminants are volatilized and exhausted to the emis-
sion control system. The combustion products from the auxiliary fuel fired
burners do not mix with the volatilized contaminants and are exhausted
through a separate set of stacks. Since the combustion products from a
burner are not mixed with the volatilized contaminants, the volume of gas
generated from heating the soil is very low.
Indirectly-heated units, which rely on conductive and radiation heat trans-
fer, are typically less sensitive to waste heating value and potential
heat-release than directly-heated units. Solids throughput rates are in the
range of 1.8 to 13.6 tonne/hr (2 to 15 ton/hr). Such units can be designed to
eliminate exposure of the waste to oxidizing conditions during treatment and
avoid potential regulatory sensitivities to waste oxidation. Some types of
indirectly-heated units, such as thermal screws, are well-suited for treating
high moisture content sludges because of their positive solids transport
3.8
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Chapter 3
mechanisms. Indirectly-heated units have very low offgas volumes per mass
of solids processed as compared to directly-heated units. Therefore, emis-
sion control unit operations require relatively small equipment.
3.3.1.2 Mass Transfer
Mass transfer of contaminants from the solid phase to the gas phase is
affected by size of the feed materials, typically less than 51 cm (2 in.), the
degree of mixing and the depth of the solids bed in the thermal desorb'er, the
particle size of the feed material, and the permeability of the feed material.
Mixing breaks up large particles and reduces the distance that molecules
must diffuse from the center of a particle to the outer surface. The rate of
removal of organic compounds from a solid matrix is improved by reducing
the depth of solids bed. Many thermal desorbers use lifters inside of the
thermal desorber which pick up material and shower it through the hot gas.
Mass transfer through a soil particle is inhibited by materials that have low
permeability such as highly-plastic clays.
3.3.2 Reliability and Performance
Reliability is expressed as an operating factor, which is defined as the
fraction of time that a system operates compared to the scheduled operating
hours. For example, if a system operated for 45 hours during a scheduled
operating period of 60 hours, the operating factor would be 75%. Typical
operating factors for thermal desorption systems are in the range of 70 to
85%. The operating factor generally increases as a project progresses and
site-specific operating problems are resolved.
Most reliability problems occur in the feed or treated solids material han-
dling operations or in handling the liquid or sludge residual products rather than
in the thermal desorber or emissions control system. Feed materials must be
sized, screened, and conveyed while treated solids must be cooled, moisturized,
and conveyed. These processes often represent a considerable challenge de-
pending upon the material and type of equipment used. Wet scrubber
blowdown and condensate recovered during desorption must be treated to re-
move organics and particulates. These ancillary treatment processes are often
less reliable than the thermal desorption and emissions control equipment.
Performance results from various full-scale units are included in Appendix
A. As stated earlier, systems with diverse designs have consistently demon-
strated performance complying with regulatory- and project-specific standards.
3.9
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Design Development
3.3.3 Regulatory Considerations
Regulations governing thermal desorption applications vary depending
upon the regulatory basis for the project, location of the site, types of con-
taminants, waste matrix, and type or thermal desorption system being used.
Therefore, practitioners should work closely with regulatory personnel to
define regulatory requirements early in the process.
RCRA or TSCA regulations can be Applicable or Relevant and Appropri-
ate Requirements (ARARs) if a remediation project is performed under
CERCLA. ARARs may be chemical-specific (risk.based standards for spe-
cific compounds), location-specific (floodplains, wetlands, etc.), or
action-specific (technology-based performance standards). ARARs are de-
termined on a case-by-case basis. The nature of the system used
(directly-heated or indirectly-heated) and the type of emission control equip-
ment (recovery-type or destructive-type) used can affect which regulatory
requirements apply to a CERCLA project.
The process of selecting a remedy for a site under CERCLA is
well-defined. A Remedial Investigation identifies the types, concentrations,
and distribution of contaminants. A Baseline Risk Assessment is conducted
to determine which media and contaminants constitute an unacceptable risk
level and require remedial action. A Feasibility Study evaluates various
remediation alternatives and their ability to comply with nine criteria speci-
fied in CERCLA. These criteria include: (1) overall protection of human
health and the environment; (2) compliance with ARARs; (3) long-term
effectiveness and permanence; (4) reduction of toxicity, mobility, or volume;
(5) short-term effectiveness; (6) implementability; (7) cost; (8) community
acceptance; and (9) state acceptance. A Record of Decision (ROD), which
specifies a selected remedy, is then written by the US EPA Regional Office
staff. The Record of Decision becomes the basis for a Consent Decree or
Unilateral Administrative Order. A Statement of Work, which is prepared as
an attachment to the Consent Decree or the Unilateral Administrative Order,
defines specific requirements for developing a remedial design and conduct-
ing a remedial action.
For many CERCLA sites, state air, solid waste, or water quality regula-
tions may also be ARARs. Many states have air toxics standards that require
ambient concentration of contaminants of concern resulting from stack
3.10
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Chapter 3
emissions to remain below a threshold level. Compliance is determined by
performing a stack test to measure mass emission rates, running a dispersion
model to calculate ambient concentrations resulting from stack emissions,
and comparing the predicted ambient concentrations with the state standards.
3.4 Process Configurations
Various process configurations of thermal desorption technologies were
discussed in Chapter 3 of the companion volume Innovative Site
Remediation Technology— Thermal Desorption (Lighty et al. 1993). As
discussed in that monograph, thermal desorption is not a single technology,
but instead, encompasses a range of mechanical equipment that performs
similar functions. Rotary dryers, thermal screws, paddle dryers, anaerobic
thermal processors, batch vacuum systems, and belt conveyor systems are all
used in thermal desorption systems. Emission control systems can be
broadly categorized as either destructive-type or recovery-type systems.
Destructive-type systems, which use a thermal oxidizer to destroy organic
contaminants, are normally used in conjunction with baghouses, cyclones,
and wet scrubbers to remove particulates and acid gases. Recovery-type
emission control systems typically involve wet scrubbing, condensation, and
granular activated carbon adsorption to remove organic contaminants from
the offgas stream.
Because of the number of types of thermal desorption systems available,
this monograph does not provide detailed process information for all of the
available types of systems. However, typical photographs, process-flow
diagrams, and plant layout drawings are presented for two example systems:
(1) directly-heated rotary dryer with destructive-type emission control sys-
tem (Figures 3.3, 3.4, and 3.5), and (2) indirectly-heated thermal desorber
with recovery-type emission control system (Figures 3.6, 3.7, and 3.8). Sim-
plified process-flow diagrams for other selected thermal desorption systems
are presented in the Phase I Monograph and in several of the case histories
presented in Appendix A.
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Design Development
to
I
Q
3 o:
.^"D
u. O
"o
o
o
2
S
3.12
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I i
Figure 3.4
Directly-Heated Rotary Dryer System Process-Flow Diagram
CO
CO
Cyclone r^
Paniculate* \ /
to Mixing ^ V
Conveyor
Fuel-
Air |
Blower
Ruel
Air |
?—
Blower
Offgas
Afterburner
It Scale ly
Combustion
Chamber
Rotary Dryer
<
r
Treated
Soil
*/
Vapors
Bughouse
Water
ID Fan
Particulates to
Mixing Conveyor
Exhaust G,
JL
Stack
Co
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Design Development
E
a
I
3
(D
co
= ..; i
o
-------
Chapter 3
Figure 3.6
Indirectly-Heated Rotary Dryer System
Reproduced courtesy of OHM Corporation
3.5 Prefreatment Processes
Pretreatment operations can include feed storage in buildings or stock-
piles, debris removal, size reduction (screening, crashing, shredding), blend-
ing, drying, dewatering, pH adjustment, conveying, and weighing.
3.5.1 Feed Storage
Most contractors perform excavation only during the day shift, hence the
contaminated feed material needs to be stored to provide an adequate feed
supply during other operating shifts. Excavated material is stockpiled to
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Design Development
CD
o
Ct
I
I
I-
a.
•^
-------
Chapter 3
provide an adequate feed supply for continuous operation of the treatment
facility if excavation operations are temporarily suspended. The stockpiled
material should be covered to exclude rainfall and to minimize fugitive emis-
sions. If the contaminated material is stored in an enclosed structure, fugi-
tive emissions control and/or building ventilation requirements must be con-
sidered. The storage area should be designed to control precipitation run-on
and runoff. The optimum size of the feed stockpile depends on site-specific
weather conditions with "typical" stockpiles containing a minimum 5-day
inventory of feed materials, with a 7 to 14-day inventory preferred.
Figure 3.8
Indirectly-Heated Rotary Dryer System Layout
Control
Trailer
Aqueous Phase
Carbon Adsorbers
Water Storage Tfcnks
36m
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Design Development
3.5.2 Debris Removal
Screens and magnetic separators are used to remove debris from the feed
to avoid jamming mechanical equipment. The RCRA debris rule (40 CFR
Part 268.45) requires that material separated from a RCRA hazardous waste
which is greater than 60 mm (2.36 in.) in size must be treated according to
specific technological standards, or the debris must be treated to a
waste-specific treatment standard.
3.5.3 Size Reduction
The maximum range of particle size that can be treated in most thermal
desorbers is 51 to 64 mm (2 to 2.5 in.), primarily because of materials han-
dling and heat transfer limitations. Large particles are either screened,
shredded, and/or crushed before treatment. Oversized debris that is removed
can be decontaminated and disposed of off-site or returned to the site. Metal
objects that pass through the screening operation are sometimes removed by
a magnetic separator suspended over the belt feeder.
3.5.4 Blending
The type and concentration of contaminants and the moisture content in
the waste feed are key considerations in treating contaminated materials.
Blending with less-contaminated feed material, treated solids, or other mate-
rials may be required because of process safety or material handling consid-
erations.
For directly-heated systems, the maximum concentration of organics in
the feed material must be limited to prevent exceeding LEL criteria in the
offgas. Additional discussions of this topic are presented in Sections 2.2.2.4
and 3.8.
Materials handling limitations are another consideration for wastes con-
taining heavy, tar-like contaminants that tend to stick to surfaces and jam
mechanical equipment. The material is generally not uniformly contami-
nated. In some cases, material with higher levels of contamination can be
blended with other, less-contaminated material to make the feed more uni-
form. Blending is typically accomplished with conventional materials han-
dling equipment such as backhoes or with pugmills. However, blending is
difficult, and a uniform feed does not always result.
3.18
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Chapter 3
3.5.5 Drying/Dewatering
Moisture affects the amount of energy required to heat the medium, as
well as the handling characteristics of fine-grained soils. Drying and dewa-
tering methods include blending with drier material, gravity draining, air
drying, mixing with treated solids, or using centrifuges or filter presses. The
moisture content of the feed should be appropriate for the specific type of
thermal desorption system that is being used. Thermal screws and paddle
dryers are specifically designed to dry wet materials and can operate well on
materials with moisture contents of up to 60%. Other types of thermal
desorbers typically operate best on feed materials with a moisture content of
less than 25%. If water is removed by mechanical means, it will typically
require posttreatment since it may contain a significant concentration of
contaminants.
3.5.6 pH Adjustment
Some thermal desorption systems are made of carbon steel and there-
fore cannot tolerate pH extremes. To limit equipment corrosion, highly
acidic media can be treated with lime, cement kiln dust, or other alkaline
materials to obtain a pH above 5. Lime can be mixed with the feed ma-
terial by using conventional excavating equipment (such as backhoes) or
blended in a pugmill. However, low and high pH materials are rarely
encountered in thermal desorption applications. Therefore, pH adjust-
ment is seldom required.
3.5.7 Conveying
For thermal desorbers that operate in a continuous mode, material must be
fed on a controlled basis. A variety of types of equipment can be included in
the feed conveying system such as hoppers, belt conveyors, and screw au-
gers. Hoppers should be designed with steep (>60 degree) slopes so that the
material will flow freely. In some instances, hopper vibrators are required to
convey material out of the hopper. Belt conveyors generally require scrapers
to prevent the buildup of material on the belt. Screw augers are best suited
for free-flowing materials such as silts and sands, however, they tend to plug
when handling cohesive clays.
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Design Development
3.5.8 Weighing
Regulatory compliance usually entails continuous monitoring and record-
ing of the feed rate of waste material to a thermal desorber. This is typically
accomplished by a weigh scale installed on a belt feed conveyor or by weigh
cells installed on a feed hopper.
Payment for treatment services is normally based on weight measure-
ments of feed materials. These measurements can be obtained either from
the feed monitoring system or a separate truck scale. Track scales are usu-
ally more accurate, but add to the cost of the project. For large projects with
greater than 45,500 tonne (50,000 ton) of feed material, the increased accu-
racy of the truck scales may justify their installation and operating expense.
3.6 Posttreatment Processes
Posttreatment of the treated solids and the gas stream leaving the desorber
is required. In addition, posttreatment of liquids and sludges is required in
systems that use a wet scrubber or condenser.
3.6.1 Solids Posttreatment
Treated solids exiting a thermal desorber are hot and dusty. Posttreatment
of treated solids typically entails water quenching to cool the solids and
control dust. The solids leaving the desorber usually drop into a screw con-
veyor, pugmill, or rotary mixer where water is added. Water addition greatly
improves material handling characteristics and is required for optimal com-
paction. Steam and particulates generated by solids quenching operations
must be collected and controlled. Other solids posttreatment operations
include stockpiling, sampling, and analysis. Stockpiles should be con-
structed to control run-on, runoff, and fugitive emissions. The design must
allot sufficient area to stockpile the treated solids while samples are being
analyzed to confirm adequate treatment. The required storage volume of the
soil stockpile area depends on the soil processing rate and the treated soil
analysis turn around time. The material is backfilled if analytical results
indicate that the treated material meets applicable performance standards and
retreated if it does not meet applicable standards.
3.20
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Chapter 3
3.6.2 Gas Posttreatment
The gas posttreatment system removes pollutants from the gas stream
before it is discharged. These gases may consist of the original contami-
nants, the combustion gas products, products of incomplete combustion
(PICs), paniculate matter, and acid gases. The gas posttreatment system for
a directly-heated thermal desorber requires a relatively large emission con-
trol system because the combustion products from the heat source are mixed
with the desorbed contaminants. Typical stack gas flows for directly-heated
thermal desorption systems with afterburners are in the range of 600 to 2,000
dscm/tonne (19,250 to 64,160 dscf/ton) of feed solids. Emission control
equipment normally used for gas posttreatment for directly-heated systems
includes cyclone separators, thermal oxidizers, baghouses, evaporative cool-
ers, and wet scrubbers.
Conversely, the gas posttreatment system for an indirectly-heated thermal
desorber requires a relatively small emission control system because the
combustion products from the heat source are not mixed with the desorbed
contaminants. Typical stack gas flows for indirectly-heated thermal desorp-
tion systems are in the range of 13 to 450 dscm/tonne (417 to 14,436 dscf/
ton) of feed solids. Emission control equipment commonly used for the gas
posttreatment process for indirectly-heated systems includes evaporative
coolers, wet scrubbers, condensers, and carbon adsorption systems. Some of
the unit operations used to control organics and remove acid gases and par-
ticulates are described below.
3.6.2.1 Organics Control
Destructive-Type Systems. Thermal oxidizers are used with
directly-heated thermal desorption systems to control organic emissions,
primarily, because of their robustness and relatively low cost. The thermal
oxidizer is a refractory-lined metal chamber that provides sufficient gas resi-
dence time, temperature, and mixing to destroy organic compounds. Ther-
mal oxidizers typically operate between 871 to 982°C (1,600 to 1,800°F),
with a 0.5 to 2.0 sec gas-phase residence time. Thermal oxidizers can be
used before or after paniculate control devices.
Recovery-Type Systems. Recovery-type emission control systems typi-
cally use combinations of wet scrubbers, condensers, and carbon adsorption
to remove organic contaminants. Wet scrubbers cool the gas and remove
heavy organic contaminants that would potentially plug downstream
3.21
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Design Development
equipment. Condensers operate at gas exit temperatures in the range of 4 to
49°C (40 to 120°F). Carbon adsorption typically serves as a final polishing
step to remove low concentrations of organic compounds from the gas phase.
Activated carbon collection efficiency varies with the types and concentra-
tions of organic compounds in the process gas, relative humidity of the pro-
cess gas, and the organic loading on the carbon. Carbon beds are often in-
stalled in series so that if breakthrough occurs in the first bed, a second bed
is available to capture contaminants. The spent carbon must be periodically
sent off-site for regeneration or disposal.
The important design parameters for carbon adsorption units include the
inlet gas temperature, inlet gas relative humidity, the organics loading, the
empty bed contact time, and the superficial gas velocity. The temperature of
the inlet process gas should be less than 60°C (140°F), and the gas should be
preconditioned to less than 50% relative humidity by cooling it or mixing it
with drier air. Above these values, organics removal efficiency deteriorates.
Activated carbon systems in vapor phase applications can typically achieve
loadings in the range of 0.05 to 0.15 kg of organic per kg of carbon (0.05 to
0.15 Ib of organic per Ib of carbon). These guidelines can be used to esti-
mate the operating period before breakthrough. The empty bed contact time
is the ratio of empty bed volume to the volumetric gas flow rate through the
bed. The superficial gas velocity (or empty bed velocity) is the ratio of the
volumetric gas flow rate to the cross-sectional area of the bed. One report
suggests a typical empty bed contact time of 4.2 sec and a superficial gas
velocity of 0.3 m/sec (1.0 ft/sec)(PRC Environmental Management, Inc.,
Versar, Inc., and Radian Corporation 1991). In reports of other applications
of carbon adsorption, the contact time is as low as 2 sec, and superficial gas
velocities range from 0.08 to 0.46 m/sec (0.25 to 1.5 ft/sec). Before a spe-
cific application is undertaken, an engineering study or treatability test to
generate engineering data is recommended.
3.6.2.2 Acid Gas Removal
Most thermal desorbers do not produce significant quantities of acid
gases. However, systems that use a thermal oxidizer as part of the emission
control system will produce hydrogen chloride and/or sulfur dioxide if com-
pounds containing chlorine and/or sulfur are present in the thermal desorber
offgas. Therefore, hydrogen chloride and sulfur dioxide may have to be
removed from the offgas, depending on the types of contaminants present in
3.22
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Chapters
the feed solids and the thermal desorption system operating temperatures.
Acid neutralization reduces corrosive attack on steel and other materials
throughout the system, including the stack.
Venturi Scrubbers. Conventional venturi scrubbers have been used to
remove sulfur dioxide and hydrogen chloride. A benefit of the venturi scrub-
ber is its capability to also remove particulates from the gas stream. The
heart of the venturi scrubber is a venturi throat where gases pass through a
reduced cross-sectional area and reach velocities in the range of 61 to 183 m/
sec (200 to 600 ft/sec). Typically, 8 to 45 L (2 to 12 gal) of water per 28
dscm (1,000 dscf) of gas is injected into the venturi throat section. As the
high velocity gas stream shears the injected liquid, many fine water droplets
are formed that remove gases, particles, and droplets from stack gases by
absorption and impaction. Cyclonic or chevron-type demisters are usually
installed downstream of the venturi scrubber to remove the entrained liquid
droplets. High-efficiency venturi scrubbers have a pressure drop of 19 to 56
mm Hg (10 to 30 in. w.c.). A potential problem with venturi scrubbers is
the erosive effect of the gas/liquid mixture passing through the throat sec-
tion, which is exacerbated by the high turbulence in this section. Purge wa-
ter and/or sludge streams from the scrubber must be also be treated.
Packed Scrubbers. A few systems use a packed scrubber which consists of a
horizontal or vertical vessel filled with packing. Water is sprayed on the top of
the packing in the column, and the packing provides a large surface area for
absorption of acid gases. The scrubbers are usually designed to.use a stoichio-
metric ratio of alkali reagent to acid gas of slightly over one to one. Sodium
hydroxide is often used for pH adjustment; normally, the scrubbers operate
within a pH range of 5 to 7. At higher pH levels, insoluble forms of calcium
carbonate and sodium bicarbonate can form and foul scrubber internals.
3.6.2.3 Particulate Removal
Paniculate control devices include dry cyclones, baghouses, high effi-
ciency paniculate filters (HEPA), and venturi scrubbers.
Dry Cyclones. The dry cyclone is an inertial separator in which particles
entrained in the gas stream enter the cyclone, are directed into a vortex flow
pattern, collect on the wall of the separator because of inertial effects, and
eventually drop to the receiver in the bottom of the unit. Cyclone separators
are most efficient at removing larger particles (>15 jam) from the gas stream.
Particulate collection efficiencies increase proportionally with inlet gas
3.23
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Design Development
velocities; this effect is limited, however, by the allowable pressure drop of
the cyclone. A typical inlet velocity is approximately 25 m/sec (82 ft/sec)
and typical pressure drops range from 3.7 to 13.0 mm Hg (2 to 7 in
w.c.)(PRC Environmental Management, Inc., Versar, Inc., and Radian Cor-
poration 1991).
Baghouses. A baghouse contains fabric filters that collect particulates.
Baghouses contain a set of permeable bags that allow the passage of gas, but
not particulate matter. Baghouses are highly efficient at removing particles
>1 urn in diameter. A number of design factors must be considered when
selecting a baghouse, including: the degree of filtration required, type of bag
filter material, air-to-cloth ratio, gas inlet temperature, bag life, bag cleaning
capability, gas and particulate distribution, and particulate removal. Typical
air-to-cloth ratios range from 0.61 to 1.51 mVmin per m2 (2 to 5 acfm per
ft2). Typical filter fabrics and suggested maximum continuous operating
exposure temperatures are as follows (BHA 1996):
• Nomex® 190°C (375°F);
• P84 260°C (500°F);
• Fiberglass, woven 260°C (500°F); and
• Teflon® 260°C (500°F).
The collected particles must be removed from the bags periodically to
avoid a high-pressure drop. Pulsed air is the most commonly used bag
cleaning method on thermal desorption systems. A short-duration jet of
compressed air at 3.44 to 6.88 bar (50 to 100 psig) is pulsed inside of a
row of bags. The jet of air momentarily expands the bag and dislodges
the dust cake from the outside of the bag. The dust is collected in a
hopper and discharged from the hopper through an airlock. Typically,
operating pressure drops across baghouses are in the range of 3.72 to
11.16 mm Hg (2 to 6 in. w.c.).
For baghouses to operate properly, the temperature of the gas entering the
baghouse must be kept above the dew point of the gas to prevent condensa-
tion and plugging of the bags and potential corrosion of the housing. Typical
gas inlet temperatures range from 149 to 232°C (300 to 450°F), although
higher temperature baghouses are available. External insulation of the
baghouse is also recommended to avoid corrosion of the housing.
3.24
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Chapters
HEPA Filters. High Efficiency Paniculate Filters (HEPA) are disposable,
extended medium, dry-type filters with a rigid casing supporting the media.
HEPA filters have a minimum particle removal efficiency of 99.97% for 0.3
jim diameter particles (Burchsted and Fuller 1970). A HEPA filter has a
maximum pressure drop of 1.86 mm Hg (1.0 in. of w.c.) when clean and
operated at the rated air flow.
Venturi Scrubbers. A discussion of venturi scrubbers is presented in
Section 3.6.2.1.
3.6.3 Emissions Control System Residuals Posttreatment
3.6.3.1 Aqueous Liquids
For systems using wet scrubbers, blowdown must typically be filtered and
treated with activated carbon before it is discharged. The treated water can
also be reused to cool and moisturize the treated solids. Blowdown streams
from systems using recovery-type emission control systems contain organic
compounds which must be removed before reusing the water to cool the
treated solids. Blowdown streams from systems using destructive-type emis-
sion control systems may contain concentrations of organic compounds low
enough so that no additional treatment is required before reusing the water to
.cool the treated solids.
Systems using condensers sometimes require phase separation of the
condensate to segregate aqueous liquids, organic liquids, and sludges. Aque-
ous liquids may subsequently be treated by filtration and activated carbon
adsorption. Granular media (sand) filters or bag filters are used to reduce
total suspended solids. Liquid-phase activated carbon adsorption removes
organics from the blowdown. Treated aqueous condensate is typically re-
used to cool and moisturize treated soil. If the blowdown is to be released to
a Publicly-Owned Treatment Works (POTW) or to a water body under a
National Pollutant Discharge Elimination System (NPDES) permit, other
parameters may apply. Potential parameters that may require treatment and/
or adjustment to meet POTW pretreatment requirements include pH, total
dissolved solids, biochemical oxygen demand, chemical oxygen demand,
metals, and temperature. Discharge under an NPDES permit is rarely used.
However, it would typically require meeting similar parameters to those
listed for discharge to a POTW plus whole-effluent toxicity.
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Design Development
3.6.3.2 Organic Liquids
Systems using condensers sometimes need multiple unit operations to
treat condensate. Phase separation, emulsion breaking, reverse osmosis, or
other chemical processes can separate aqueous liquids and organic liquids.
The separated aqueous liquids are typically treated by filtration and activated
carbon adsorption as described above. Organic liquids can be transported
directly off-site for treatment or disposal or they can be pretreated by physi-
cal/chemical processes, such as base-catalyzed decomposition, to reduce
toxicity prior to off-site treatment and disposal (US EPA 1993g).
3.6.3.3 Particulates
Particulates collected in dry control devices, such as cyclones and baghouses,
may be decontaminated or may require further treatment prior to disposal.
Typical methods of handling these streams include: (1) mixing them with hot
solids discharged from the thermal desorber and collecting vapors from the
mixer and routing them into the emission control system; (2) recycling them to
the thermal desorber; and/or (3) combining them with hot solids discharged
from the thermal desorber in the soil cooling and moisturizing system. Samples
of treated solids are typically collected at the discharge of the solids cooling
system to confirm that performance standards have been met.
3.6.3.4 Scrubber Sludge
Wet emission control devices, such as wet scrubbers and condensers, can
produce sludge streams. If the sludge stream is contaminated with organics,
it can be either recycled to the thermal desorber or sent off-site for treatment
or disposal. If the sludge is contaminated with inorganics at concentrations
above regulatory criteria, it may require further treatment by stabilization.
Stabilization.may be performed either on-site or at an off-site facility. If the
sludge is not contaminated, it can be combined with the treated solids. In
some cases, sludges require dewatering prior to further treatment.
3.6.3.5 Activated Carbon
Granular activated carbon may be used for treating aqueous condensate
and/or the thermal desorber exit gas. Activated carbon is typically regener-
ated or incinerated at a commercial off-site facility. The carbon should be
analyzed to determine if it exhibits RCRA hazardous characteristics before it
is disposed.
3.26
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Chapter 3
3.7 Process Instrumentation and Controls
Commercially-available thermal desorption systems use sophisticated
measurement and control instruments to monitor and adjust operation of the
desorption system. Control systems rely on measuring devices to provide
data and control instruments that can be programmed to adjust system opera-
tions according to that data. Data gathered in a thermal desorption system
include temperatures, pressures, fluid levels, and flow rates.
3.7.1 Measuring instruments
Temperature, Temperature, a critical parameter for system operation, is
normally measured by thermocouples in the fluid or matrix being monitored.
The exit temperature of the solids is a critical parameter in attaining solids
treatment standards. Temperature is often measured in at least one location
in every process stream for every system unit operation. This allows for
monitoring, adjustment, and control of the system and, more importantly,
provides critical data for troubleshooting (e.g., for a heat balance).
Pressure. Pressure is normally measured relative to atmospheric pressure
by one or more differential pressure cells. Desorption systems are usually
operated at pressures slightly below atmospheric pressure; however, some
types of systems operate under vacuums as high as 635 mm Hg (25 in. w.c.).
Operating under even a slight vacuum minimizes fugitive emissions from the
thermal desorption system. Centrifugal fans or positive displacement blow-
ers evacuate gases from the system and develop a vacuum. Critical areas for
measurement of vacuum are the thermal desorber chamber and the emission
control system. It is helpful to measure pressure upstream and downstream
of unit operations that are susceptible to fouling or blocking such as
baghouses, condensers, quench towers, cyclone separators, and activated
carbon beds. Measuring pressure at many locations facilitates troubleshoot-
ing if operational problems develop.
Fluid Levels. Fluid levels are often measured with bubbler systems,
which determine the pressure necessary to overcome the head pressure
of the fluid being measured. Scrubbing systems, condensing system
reservoirs, fuel storage vessels, and water treatment systems should all
include such devices.
3.27
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Design Development
Flow Rate. Flow rate is measured on a mass or volumetric basis for dif-
ferent process streams. Waste feed rate is typically measured on a mass
basis with a scale and speed idler installed on the feed conveyor. Alterna-
tively, waste feed mass can be measured on a "batch" basis on a platform
scale before the feed is loaded into the feed system. The flow rate is then
calculated based on the time interval between weight measurements. Other
process flow rates measured include the flow rate of liquid process streams,
such as wet scrubber makeup or blowdown water, cooling water circulation
rates, and condensate blowdown rates. These streams are typically measured
on a volumetric basis by rotometers or by measuring differential pressure
across orifices of known dimensions.
3.7.2 Control and Monitoring Instrumentation
The data collected by measuring instruments are normally transmitted to a
central location for monitoring purposes, and if appropriate, transmitted to
control instruments. Control instruments are often programmable logic
controllers (PLCs), or personal computers (PCs) which accept digital inputs
from measuring instruments and provide digital outputs as a function of the
input received. With proper design and programming, a thermal desorption
system can be configured to operate in a largely automatic mode whereby
the control instruments receive output from the measuring devices, evaluate
the input, and send an output signal that causes adjustment to the operation
of the system.
Personal computers are able to store the operating data in an electronic
format. This useful capability provides a history of operation which is valu-
able in documenting compliance with regulatory standards and allows for
troubleshooting or diagnosis of a system problem that has caused a compo-
nent or unit operation to fail.
3.7.3 Control Logic
The logic programmed into the control instruments is designed to provide
safe, efficient operation of the system in a manner that complies with project
standards. Additional programming features shut down various equipment,
or even the entire system, under pre-defined circumstances. Many of these
measurements or controls can be required as conditions for operation under
permits or regulatory approvals. Examples of control loops that may be used
in a desorption system are discussed below.
3.28
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Chapter 3
Burner Firing Rate. Based on solids temperature measurements in the
thermal desorber, control instruments increase or decrease the burner firing
setting to achieve a target solids treatment temperature or "setpoint." The
burner firing rate is typically interlocked with temperature measurements in
the downstream process gas.
System Pressure. Based on measurement of differential pressure relative
to atmosphere in the thermal desorber, the control instruments increase or
decrease centrifugal fan speed or open or close dampers to achieve a target
vacuum setpoint.
Fluid Level. Based on measurement of fluid level in the wet scrubber, the
control instruments open or close a valve that allows water to fill the wet
scrubber to achieve a target fluid level setpoint.
Automatic Waste Feed Cutoffs. Thermal desorption systems normally
have provisions for the actuation of an automatic waste feed cutoff
(AWFCO) system. This involves monitors and controls that are interlocked
with the feed system components. These control instruments should be pro-
grammed to discontinue waste feed under operating conditions that may
result in inadequate treatment or release of contaminants to the environment.
The instruments that initiate an AWFCO vary depending on the thermal
desorber's specific design and operating parameters. Typical interlock pa-
rameters include oxygen concentration, negative pressure, mechanical func-
tion of key materials handling equipment, and critical temperatures, pres-
sures, or flows in the system that affect the quantity or concentration of stack
emissions. Other process parameters may be appropriate as well. The
AWFCO system description and parameter specifications are normally key
items in the operating approval or permit equivalency for a thermal desorber.
3.8 Safety Requirements
An operational hazards evaluation should be conducted on a site-by-site
basis to identify potential hazards associated with the thermal desorption
system and specific waste feed materials. The following section discusses
general safety issues. However, the system operator should analyze each
project to identify and develop plans for dealing with site-specific situations.
3.29
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Design Development
A number of standard safety precautions are required and should be
observed for thermal desorption systems. All systems must comply with
Occupational Safety and Health Act (OSHA) requirements. These in-
clude, but are not limited to, confined space entry procedures, fire pro-
tection, and spill protection. Precautions relating to hot operating equip-
ment, such as warning signs, barriers, and safety shields, must be imple-
mented. Conveyors and other mechanical and electrical equipment must
have adequate lock-out/tag-out safety mechanisms to prevent inadvertent
operation during maintenance.
In the pretreatment process, adequate ventilation of storage buildings
must be provided to prevent fire and explosion hazards from fugitive organic
emissions. Personnel monitoring should be conducted to select appropriate
Personal Protective Equipment (PPE) to prevent excessive exposure to fugi-
tive emissions. To control fugitive emissions, thermal desorbers are operated
under slight- to high-negative pressures.
In directly-heated thermal desorption systems that are operated with ex-
cess oxygen, the concentration of contaminants in the feed must be limited
so that the concentration of organics in the process gas do not exceed safe
levels. In good design and operating practice for directly-heated systems,
the concentration of organics in the process gas is limited to less than 25% of
the LEL unless continuous LEL monitoring and control instrumentation is
provided (NFPA 1990). If continuous monitoring and control instrumenta-
tion is provided, the concentration of organic vapors can not exceed 50% of
the LEL (NFPA 1990). Tables of LEL values for specific compounds can be
found in the literature (Sax 1989; Turner and McCreery 1981; Lide 1990).
In gas posttreatment, process configurations in which the baghouse is
located before the primary organic emission control device present a
potential fire hazard in the baghouse if high boiling point organics are in
the feed material. Heavy organics can be volatilized in the thermal
desorber and condense when the offgas cools as it passes through the
emission control system. Hydrocarbons or other combustible materials
may collect on the filter bags and constitute a fire hazard. Condenser
systems pose the same kind of concern as any other system that gener-
ates a concentrated hazardous liquid such as level controls and second-
ary containment. The condensate must be handled using procedures that
are appropriate for hazardous or toxic substances.
3.30
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Chapter 3
Special precautions must be observed to contain the heating media in
indirectly-heated systems so as to avoid fires and personnel injury. Adequate
control of pressure is required where heated media, such as steam and other
heat-transfer fluids are circulated at elevated pressure. Where electrically-
heated fluids are used, special attention to high voltage electrical safety pre-
cautions are required.
Safety hazards are system specific and a general characterization of sys-
tem hazards is not possible. Therefore, every system must be evaluated prior
to operation to identify system-specific safety hazards. However, examples
of types of system hazards follow.
• Failure of high temperature rotary seals on indirectly-heated
systems using an organic heat-transfer fluid. Such failure can
allow heat-transfer fluid to leak and contaminate solids during
treatment, and can cause a potential fire hazard.
• Buildup of participates and slag in thermal oxidizers. Accumula-
tion of these materials must be checked periodically. Paniculate
and slag removal hazards include the potential for burns since
these materials can retain heat for a long period of time and the
potential for injury from slag falling from the walls of the com-
bustion chamber. Removal of these materials requires working
under confined space entry operating procedures.
• Mechanical failure of posttreatment material handling equipment.
Shaft failures in augers or pugmills are common and can go un-
noticed by equipment operators. Material handling equipment
failure can lead to an accumulation of hot solids in the primary
treatment device.
In addition to the safety of personnel and equipment, environmental
safety is also a key consideration. Secondary containment of liquids is nec-
essary for the handling, storage, and treatment locations. Tanks or contain-
ers storing hazardous material should be installed in a bermed area with
sufficient volume to contain precipitation plus the material resulting from a
tank or container failure. Secondary containment systems must be designed
to comply with the requirements of relevant regulations. Precipitation wa-
ters from the treatment and handling areas should be collected for analysis
and treatment if necessary.
3.31
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Design Development
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3.32
-------
Treatment Cost Elements
Co
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33-11 Biological Treatment
33-12 Chemical Treatment
33-13 Physical Treatment
33-14 Thermal Treatment
-01 Solids Preparation and Handling
-02 Liquid Preparation and Handling
-03 Vapor/Gas Preparation and Handling
-04 Pads/Foundations/Spill Control
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Untreated solids screening, size reduction, dewatering, moisture control, mixing, stockpiling, sampling
and analysis; thermal treatment of contaminated solids; treated solids cooling, moisturizing, stockpiling,
sampling and analysis, loading, transporting, backfilling
Collection, storage, treatment, release, disposal (POTW or surface discharge) of condensed liquid
organics, process water, decontamination water, and stormwater. Typical unit operations include phase
separation, granular activated carbon, metals precipitation, suspended solids filtration.
Paniculate filtration, wet or dry acid gas scrubbing, condensation, adsorption onto activated carbon
Materials and construction of process equipment foundations, pads, sumps
Equipment transportation, off loading, staging, and erection.
Equipment shakedown, startup, pretests, performance test sampling, analysis and reporting, regulatory
review and approval
OSHA and/or job specific training
Operations labor, bulk chemicals (NaOH, lime), activated carbon purchase, fuel, electricity, water,
maintenance supplies, health and safety supplies, spare parts
Operations labor, bulk chemicals (NaOH, lime), activated carbon purchase, fuel, electricity, water;
maintenance supplies, health and safety supplies, spare parts. Note: Most thermal remediation projects
require less than three years of operations.
Equipment amortization, leasing, profit, insurance, taxes, overhead
Included in WBS Item 33-17
Included in WBS Item 33 -21
-------
Design Development
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3.34
-------
Chapter 3
3.9 Specification Development
Specifications for a given application should focus on the overall remedial
objectives for the project. Specifications that focus on performance stan-
dards, rather than performance methods, allow the largest degree of flexibil-
ity to the contractor and generally result in the most efficient, lowest cost
remedy for a site. Primary standards for a project should include stack emis-
sion standards, ambient air quality standards, treated solids standards, and
process water discharge standards. Development of specifications should be
closely coordinated with regulatory agencies to ensure that all ARARs are
addressed. The requirements from any approved work plan or permit should
be identical to the requirements in the performance standards.
Other areas that warrant consideration in the development of project specifi-
cations include: material handling, site drainage and stormwater control, fugi-
tive emissions control, noise limitations, hours of operation, project schedule,
waste throughput requirements, and equipment mechanical availability.
3.10 Cost Data
Thermal desorption treatment is generally performed by contractors who
operate transportable equipment as an on-site service. A list of cost elements
which should be considered in evaluating full-scale thermal desorption
projects is presented in Table 3.1. This work breakdown structure has been
developed using Work Breakdown Structure (WBS) guidelines prepared by
the interagency Federal Remediation Technologies Roundtable (Federal
Remediation Roundtable 1995a). Using this WBS, costs are categorized as
before-treatment, treatment, and after-treatment costs. Costs for each of
these elements are highly site- and technology-specific and depend on the
scope of work for the application.
In general, before-treatment and after-treatment costs are primarily a
function of the size and mobility of the thermal treatment equipment and the
scope of services to be provided. For example, mobilization and demobili-
zation costs are relatively high for large systems that need many trucks to
transport the equipment and require extensive infrastructure to erect the unit
such as foundations, utilities, and temporary structures. Conversely, small
3.35
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Design Development
systems that can be transported on 3 to 5 trucks have relatively low mobili-
zation, setup, and demobilization costs.
Treatment costs are related to the waste throughput capacity of the equip-
ment. Unit treatment costs ($/tonne) are generally lower for large systems
than for small systems because of the economy of scale. Key factors that
affect unit treatment costs include the waste throughput capacity, system
operating factor, soil type, feed solids moisture content, type of Contaminant,
and solids treatment criteria.
Example turnkey unit costs versus site size are presented in Figure 3.9 for
three different sizes of rotary dryer systems with destructive-type emission
control systems. Although the absolute cost values are different for other
types of thermal desorption systems, all technologies demonstrate similar
trends of decreasing total unit costs with increasing site size.
Figure 3.9
Example Turnkey Treatment Cost vs. Site Size
400
10,000 20,000 30,000 40.000 50,000
Site Size (tonne)
• 10tonne/hr rotary dryer
• 20 tonne/hr rotary dryer
A 30 tonne/hr rotary dryer
3.36
-------
Chapter 3
An example breakdown of the total turnkey unit cost ($/tonne) for a
30,000 tonne (27,272 ton) project using a 30 tonne/hr (27.3 ton/hr) rotary
dryer system is presented in Figure 3.10. The relative percentage of the total
costs for each of the individual items are technology-specific and also de-
pend upon the amount of waste to be processed.
Figure 3.10
Example Breakdown of Turnkey Unit Cost
Planning & Design 3.4% site Work 8.2% Equipment
Site Restoration 9.6% ^x. / Mobilization
Demobilization 2.7% "_
Performance
Testing
3.4%
Excavation/
Thermal Operations 45.2%
Cost Basis: 30,000 tonne site; 30 tonne/hr rotary dryer
Total Unit Cost: $121.67/tonne
A summary of historical cost data for full-scale thermal desorption
projects on hazardous substance applications is presented in Figure 3.11
(Cudahy and Troxler 1991, updated 1996). The data represent projects
awarded between 1985 and 1996. All costs have been adjusted to a June,
1996 basis by using the Chemical Engineering Plant Cost Index to adjust for
inflation (Chemical Engineering 1996). These data are based on contract
values and feed material quantities for projects in which the primary treat-
ment technology was thermal desorption. In Figure 3.11, the data show a
significant amount of scatter; prices range from less than $110/tonne ($1007
ton) to approximately $440/tonne ($400/ton). The scatter in the data can
mainly be attributed to differences in the scope of work for the various
projects. For example, projects at the higher end of the cost range typically
represent turnkey services including remedial action work plans, excavation,
3.37
-------
Design Development
stockpiling, pretreatment of feed materials, backfilling, sampling and ana-
lytical services, ambient air monitoring, and community relations, as well as
thermal treatment services. Some of the data points at the low end of the
cost range represent only the thermal operations services (hopper-to-hopper)
cost component of the total project cost. Note that the costs presented in this
section are only for projects involving treatment of hazardous substances,
primarily CERCLA and RCRA applications. Costs for treating petroleum-
contaminated soils with thermal desorption technologies are typically less
than $55/tonne ($50/ton) as discussed in Appendix B.
Figure 3.11
Thermal Desorption Historical Unit Cost Data
Thermal Treatment Project Costs ($/tonne)
o o o § §
1
— S
•5
i
"
' .
.
"
m
*
*
i
•
B
10,000 20,000 30,000 40,000
Site Size (tonne)
50,000 60,000 70,000
Source: Cudahy and Trader 1991 (updated 1996)
3.77 Design Validation
Designs must be validated for each site to evaluate safety criteria, confirm
the capability of the thermal desorption system to meet the performance
3.38
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Chapters
standards for the project, and estimate the processing capacity of the equip-
ment as a function of the characteristics of the feed material. Design valida-
tion should be performed using a combination of health and safety criteria,
engineering analysis, and, in some cases, treatability testing.
Key safety criteria are controlling fugitive dust and VOC emissions to
acceptable levels. Acceptable levels must be determined based on an analy-
sis of personnel exposure and ambient air impacts. These factors are gener-
ally evaluated during the remedial design planning phase as part of the de-
velopment of a site-specific Health and Safety Plan and/or Ambient Air
Monitoring Plan. A second criterion is to ensure, for systems that operate
with excess oxygen in the process gas, that the concentration of organic
materials in the process gas does not exceed LEL guidelines. This factor is
discussed in Section 3.8.
The capability to meet solids treatment standards for a project should be
estimated based on the boiling point of the contaminants, the maximum
solids temperature and residence time in the thermal desorber, and analytical
considerations. As a rule of thumb, organic contaminants can be removed
from a solid matrix at commercially-viable rates if the matrix is heated to a
temperature typically within ±56 to 111°C (100 to 200°F) of the boiling
point of the contaminant. However, the capability to meet solids treatment
standards is a function of the maximum solids treatment temperature in the
thermal desorber, the residence time of the solids in the desorber, the operat-
ing vacuum in the desorber, and the degree of mixing in the desorber. Each
combination of conditions should be assessed based on the characteristics of
the particular thermal desorber that is being evaluated. In some cases,
laboratory-scale treatability testing is required to determine the optimal com-
binations of process conditions to meet treatment standards. Since solids
treatment standards are typically established by risk assessment procedures,
standards may be below analytical detection limits for the matrix being ana-
lyzed. Treatability testing and analyses should be conducted to determine
the analytical detection limits that can be achieved for the waste matrix.
Stack emissions estimates should be developed using a mass and energy
balance approach. The concentration of contaminants of concern (organics,
metals, etc.) in the feed material should be estimated, and an estimated con-
trol efficiency should be applied to each unit operation in the process train.
Estimated control efficiencies are best determined from full-scale empirical
data from similar applications. The estimated stack emissions should then
3.39
-------
Design Development
be compared to the performance standards to determine if further analysis or
modification of the process equipment is required. An evaluation may also
be needed for constituents that are not contaminants of concern in the feed
material but are potentially formed in the thermal desorption process. Ex-
amples of such constituents may include total non-methane hydrocarbons,
carbon monoxide, dioxin/furans, nitrogen oxides, hydrogen chloride, and
sulfur dioxide. In some cases, laboratory-scale treatability testing is useful
for estimating performance characteristics of full-scale thermal desorption
systems. However, laboratory-scale treatability test results for stack emis-
sion parameters should only be considered useful for order of magnitude
estimates. Because of the number of unit operations, range of operating
conditions, and geometric configurations of emission control devices, careful
attention must be given to scale-up factors in designing treatability tests.
The processing capacity of the equipment as a function of the characteris-
tics of the feed material should be determined by an engineering mass and
energy balance approach. Key parameters that should be considered in the
evaluation are the heat transfer capacity of the thermal desorber, the moisture
content of the feed material, the geotechnical characteristics of the feed ma-
terial, the required solids treatment time and temperature, and the solids
treatment criteria. The gas handling capacity of emission control unit op-
erations can also dictate maximum waste processing capacity. Factors that
must be considered include the fraction of solids entrained in the process
gas, gas residence time and velocity in unit operations, thermal capacity of
the thermal oxidizer (if used), and the capacity of the induced draft fan.
3.72 Permitting Requirements
Permitting requirements vary depending upon the applicable regulatory
program. If a remediation project is conducted as part of a RCRA corrective
action, the design and operation of the facility may be subject to the condi-
tions in the facility's RCRA permit. However, most thermal desorption
projects involving hazardous substances are conducted under CERCLA or
state Superfund programs. Permits are not required for on-site actions under
CERCLA; however, the work must be done in compliance with the substan-
tive requirements of ARARs. The Record of Decision broadly defines the •
3.40
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Chapter 3
ARARs, and the details regarding implementation of the ARARs are devel-
oped during the remedial design process. Regulations that are commonly
determined to be relevant and appropriate include RCRA Subpart O Incin-
eration Standards (for units that use a thermal oxidizer) or RCRA Subpart X
Miscellaneous Units Standards (for indirectly-heated units that use a
recovery-type emissions control system and directly-heated units that do not
use a thermal oxidizer). If the material to be treated is derived from material
that has a PCB concentration of greater than 50 mg/kg, TSCA requirements
can be ARARs. Other ARARs that sometimes impact operations are:
• RCRA waste identification, manifesting, transportation, and land
disposal restrictions for hazardous wastes that are transported
off-site for disposal;
• NPDES permitting requirements for wastewater discharges; and
. " • state air and solid waste regulations.
Compliance with regulatory programs is documented by developing Re-
medial Design and Remedial Action Work Plans that incorporate the sub-
stantive requirements of ARARs, Example components of Remedial Action
Work Plans are listed in Table 3.1. These documents are submitted to the US
EPA for review and approval prior to the initiation of field activities. Once
field activities are initiated, US EPA typically provides a remedial action
oversight contractor at the site who verifies compliance with the require-
ments in the Remedial Design and Remedial Action Work Plans.
A key component of regulatory compliance for a thermal desorption sys-
tem is conducting a proof-of-process test, which confirms that all perfor-
mance standards can be achieved. A detailed discussion of proof-of-process
testing is presented in Section 3.13.
3.13 Performance Measures
The ultimate measure of performance for a thermal desorption system is
the quality of the process streams that exit the equipment. Process streams
which are measured or analyzed for comparison against performance stan-
dards usually include exit gases, treated solids, and aqueous discharges.
Contaminants of concern, excavation standards, and solids treatment
3.41
-------
Design Development
standards are usually defined in the ROD for CERCLA projects. Perfor-
mance standards for other media, such as stack gas emissions and wastewa-
ter discharges, are developed during the remedial design and are largely
influenced by the regulatory requirements for a given project. Because it is
impractical to measure compliance relative to all performance standards
continuously, compliance is normally measured during rigorous testing in
the initial operation of the desorption equipment on a project. This testing is
referred to as proof-of-process testing. Ongoing compliance is then demon-
strated by monitoring and operating within the limits of process parameters
established during the proof-of-process testing.
3.13.1 Proof-of-Process Testing
Proof-of-process testing occurs after equipment has been installed on a
site and has gone through start-up and shakedown procedures. Mechanical
and instrumentation tests are conducted during the shakedown period using
uncontaminated feed material. Normally, the equipment is operated for a
limited period of time (typically 240 to 720 operating hours) on contami-
nated feed material to allow for equipment adjustments to achieve optimal
operations. Process monitoring is conducted during this period to determine
optimum operating conditions. Proof-of-process testing is normally com-
pleted over a three- to ten-day period during which the equipment is oper-
ated at target conditions anticipated to meet the project performance stan-
dards. Three runs at the same feed and process operating conditions nor-
mally constitute one test. Multiple tests should be conducted if there are
substantial differences in feed materials at the site or if the contractor antici-
pates operating under multiple sets of operating conditions. Operating con-
ditions for production operations are either explicitly defined in the Reme-
dial Action Work Plan or they are negotiated with regulatory agencies based
on the monitoring results from the proof-of-process test.
Testing requirements are normally established on a site-by-site basis.
Examples of tests that may be necessary include:
• exit gas sampling for organic compound contaminants of concern
and possibly PICs, dioxins/furans, and principal organic hazard-
ous constituents (POHCs);
• exit gas sampling for inorganic compounds, including paniculate
matter, metals, and hydrogen chloride and chlorine;
3.42
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Chapter 3
• waste feed for total chlorides;
• continuous emissions monitoring for oxygen, carbon dioxide,
carbon monoxide, total hydrocarbons, sulfur dioxide, and oxides
of nitrogen with selection of parameters based on a case-by-case
analysis depending on the types of contaminants and the type of
thermal system used;
• waste feed and treated solids sampling for organic contaminants
of concern and possibly metals and dioxins/furans; and
• aqueous blowdown sampling and analysis for contaminants of
concern.
In addition to the sampling and analysis of streams exiting the system,
extensive process monitoring is done on streams within the system. This
monitoring includes such factors as temperatures, pressures, flow rates, and
fluid levels at critical points within the system. Operating conditions for
production operations are either explicitly defined in the Remedial Action
Work Plan or they are negotiated with regulatory agencies based on the
monitoring results from the Performance Test. Compliance can be deter-
mined by comparing the results of the analyses to the allowable conditions
specified in the Remedial Action Work Plan.
It is not normally practical, or even possible, to duplicate the sampling
and analysis of a proof-of-process test on a routine or ongoing basis. There-
fore, the process monitoring data collected in conjunction with the samples
taken during the proof-of-process test are used to establish allowable system
conditions for future operation. The objective is to define an acceptable
"window" of system operating conditions that fall within the range of oper-
ating conditions demonstrated during successful testing. The variables to be
monitored must be suitable for "real time" analysis and must relate directly
to system performance. Typical variables used to define acceptable operat-
ing conditions include minimum solids treatment temperature, maximum
solids feed rate, maximum exit gas total hydrocarbon content, and maximum
thermal desorber pressure.
Following completion of proof-of-process testing, the analytical data and
monitoring data are compiled, and operating conditions are defined. The
desorption system must be configured to provide routine monitoring of the
relevant conditions and allow for suitable correction when the system
3.43
-------
Design Development
operation moves outside the defined boundaries. Section 3.7 describes
the process instrumentation and controls that are often used in compli-
ance monitoring.
3.13.2 Sampling and Analysis
In addition to routine monitoring of system performance through the sys-
tem instrumentation .and controls, periodic sampling and analysis of process
discharge streams are necessary. Treated solids must be sampled and ana-
lyzed for contaminants of concern on a periodic basis. Grab samples of
treated solids are usually collected on a time or mass basis, such as once
every four hours or once every 45 tonne (50 ton) of waste treated. The grab
samples are then combined into a composite sample. The composite sample
typically represents either a specified mass of material, typically 90 to 681
tonne (100 to 750 ton) or the solids treated during a period of time, typically
8 to 24 operating hours. The composite sample is then analyzed to confirm
that the treated waste meets the performance standard. If water is discharged
from the system, it is also sampled and analyzed for contaminants of concern"
on a batch basis to verify compliance with discharge standards.
3.44
-------
Chapter 4
IMPLEMENTATION AND OPERATION
This chapter consists of a brief review of the typical procurement methods
and contract types for the implementation of thermal desorption technolo-
gies. It also includes a more thorough review of implementation and opera-
tions procedures including requirements for project planning, startup, operat-
ing plans, operating and maintenance manuals, operating practices, opera-
tions monitoring, and quality assurance and quality control.
4.1 Implementation
4.1.1 Procurement Methods
Two common methods for procuring thermal desorption services are turn-
key and thermal operations services (hopper-to-hopper). These types of
procurement methods are described in the following subsections.
4.1.1.1 Turnkey Contracts
Turnkey contracts are most commonly used for procuring thermal desorp-
tion services. A thermal treatment contractor serves as a general contractor
and either performs all required remediation services with its own work
forces or contracts directly with subcontractors to perform selected tasks.
This type of service encompasses all of the tasks necessary for the successful
completion of site remediation, including preparing project work plans, site
preparation, equipment mobilization, setup, startup, performance testing,
excavation, feed storage and preparation, thermal desorption operations,
equipment demobilization, sampling and analysis, residuals treatment and
disposal, backfilling of treated solids, and site restoration. These types of
contracts frequently include other tasks, such as building demolition, off-site
4.1
-------
Implementation and Operation
disposal of demolition waste materials, or utility rerouting, which are not
related to the thermal treatment operations.
4.1.1.2 Thermal Operations Service Contracts
In a thermal operations service type of contract, the thermal treatment
contractor serves as a subcontractor to a general contractor and typically
performs only services directly related to the thermal treatment operation.
Such a "hopper-to-hopper" contract often covers equipment mobilization,
setup, startup, performance testing, operations, and demobilization of the
thermal desorption system and related equipment. The general contractor is
responsible for integrating these services into the overall operations at the
site. The general contractor or other subcontractors usually perform other
tasks such as site preparation, feed excavation and stockpiling, backfilling,
sampling and analysis, etc.
4.1.2 Contract Terms
The most common methods for paying for remediation services are lump
sum, fixed unit price, time and materials, and cost plus fixed fee. For most
applications, a combination of payment methods are used in a single contract
to stimulate cost competition, allocate risk equitably between the contractor
and the client, and enhance the cost-effectiveness of the cleanup. The fol-
lowing subsections contain a discussion of the payment methods and the
situations in which they may be applied.
4.1.2.1 Lump Sum
Items with clear-cut tasks that are primarily within the contractor's con-
trol (i.e., mobilization, setup, startup, performance testing, and demobiliza-
tion) are typically bid as lump sum items. Lump sum payment items require
a well-defined scope of work and few interfaces with other parties. The
remediation contractor agrees to complete the given task and assumes all of
the inherent risks in return for a lump sum payment. The specifications
should describe the work in detail, including any acceptance tests that must
be completed as part of the scope of work.
4.2
-------
Chapter 4
4.1.2.2 Unit Price
The unit price ($/ton) payment mechanism is best suited for items associ-
ated with some uncertainty regarding material quantities or characteristics
prior to the start of the project, but which can be measured as the project
progresses. For unit price items, the contractor bids a fixed unit price based
on area, weight, or volume for each type of work being done (e.g., clearing
and grubbing in dollars per acre of grubbed area, thermal treatment in dollars
per ton of soil, concrete demolition in dollars per cubic yard of concrete,
etc.). When work is done on a unit price basis, the specifications should
describe how the units will be measured. The specifications should also
include any limitations on material characteristics, such as percent moisture
for waste feed material. In some cases, unit prices are established on a slid-
ing scale as a function of feed characteristics.
4.1.2.3 Time and Materials
Work that involves professional services, such as community relations, is
commonly procured using time-and-material payment schedules.
Time-and-materials type payment items are based on pre-established rate
schedules for personnel and equipment. Reimbursement is based on the
actual time required to perform services, multiplied by the personnel or %
equipment rates. The rate schedule normally includes a definition of ex-
penses that are directly reimbursable and those included as overhead in the
personnel and equipment rates.
4.1.2.4 Cost Plus Fixed Fee
In the cost plus fixed fee payment method, the contractor is paid for ac-
tual costs to perform services, an allocation for overhead, and a fixed per-
centage fee on the cost plus overhead. These contracts are typically struc-
tured with an incentive-based performance target, such as feed processing
rate. If the contractor varies from the performance target, the fee percentage
may either be increased or decreased accordingly.
4.1.3 Project Planning
Usually, the first task in project planning is to thoroughly review histori-
cal project documents, including Remedial Investigation/Feasibility Studies,
the Record of Decision, Consent Decree or Unilateral Administrative Order,
4.3
-------
Implementation and Operation
and the Remedial Design Plan. The remediation contractor is often required
to prepare a number of plans as part of the remedial action phase of the pro-
gram. Examples of the types of plans include Remedial Action Work Plan,
Health and Safety Plan, Contingency Plan, Quality Assurance/Quality Con-
trol (QA/QC) Plan, Ambient Air Monitoring Plan, Performance Standards
Verification Plan, Performance Test Plan, Construction QA/QC Plan, Opera-
tions and Maintenance Plan, and Community Relations Plan.
A frequent criticism of waste treatment facilities is that the affected
public has little, if any, input into the monitoring and operation of the
facility. Facility design engineers and operations managers should be
aware that communities often desire input into the remediation technol-
ogy that is selected and where it will be located; need information on
performance testing plans; seek access to the facility (control room or
other nonhazardous areas) to be knowledgeable of daily operations and
to confirm adherence to monitoring requirements; and require education
to understand and appreciate the effectiveness of the facility operation
and treatment process. Well-conceived and well-executed public in-
volvement and participation plans/strategies are intrinsic to the success-
ful implementation and operation of thermal desorption technologies.
4.2 Start-up Procedures
The actual startup of the project in the field is broken down into several
tasks including site preparation, equipment mobilization/setup, and equip-
ment startup. A detailed work breakdown structure for a thermal desorption
project is presented in Table 3.1.
4.2.1 Site Preparation
Generally, site preparation should be performed before the thermal treat-
ment equipment is moved to the site. Site preparation activities include
clearing, grubbing, grading and drainage work; installing fences, roads, and
parking areas; routing and connecting utilities; constructing feed and treated
solids handling pads or structures; constructing secondary containment ar-
eas; and building pads or foundations for the process equipment.
4.4
-------
Chapter 4
4.2.2 Mobilization/Setup
Mobilization involves transporting equipment to the site and off-loading it
into a lay-down area. Setup includes installing the equipment on pads or
foundations, connecting and installing all auxiliary equipment including
process piping, utilities, electrical wiring, and control systems.
4.2.3 Equipment Startup
Following the mobilization/setup phase of the project, the thermal desorp-
tion system is ready for startup. The start-up phase includes several tasks,
such as operational training, testing equipment operability, operating with
clean feed material, and.pre-operational testing with contaminated feed ma-
terial. Operational training requirements, as defined by OSHA, call for
training of the operators for routine and non-routine tasks to ensure operator
safety, environmental protection, and reliable system operation. All system
and auxiliary system components should be checked out to verify proper
installation and operation in accordance with manufacturers' specifications.
The first step in system startup is a check-out of mechanical systems,
instrumentation, and controls to verify proper operation of all system com-
ponents, including motors, control systems, system interlocks, and emer-
gency shutdown systems. Standard operating procedures with check lists are
normally used to accomplish these tasks in the proper sequence. Instruments
are calibrated and the data acquisition system is checked. The second testing
step should be conducted using uncontaminated solids to check the material
handling operations and process equipment operations.
The last phase in the start-up sequence is pre-operational testing using
contaminated material under operating conditions that have been approved
by the regulatory agency. This phase includes shakedown tests to optimize
system performance and establish target operating conditions for the pretest.
A pretest can be conducted at the same process operating conditions that will
be used during the proof-of-process test. The goal of the pretest is to con-
firm that all performance test objectives can be achieved at the chosen oper-
ating conditions and that all test methods, roles, responsibilities, and inter-
faces are well-defined.
4.5
-------
Implementation and Operation
4.2.4 Performance Verification
Performance verification typically consists of two components, (1)
proof-of-process test; and, (2) compliance monitoring during production
operations. A detailed discussion of proof-of-process testing is presented in
Section 3.13.1 and a discussion of sampling and analysis during production
operations is presented in Section 3.13.2.
4.3 Operations Practices
Operations practices include a large variety of tasks such as the excava-
tion of the material to be treated, stockpiling and pretreatment of the exca-
vated material, run-on/runoff control, wastewater treatment, fugitive emis-
sions control, the operation of the thermal desorption system, sampling and
analysis of treated solids and other residuals, and backfill of the treated ma-
terial. Each task has a specific set of operating criteria and practices that are
typically described and defined in the Remedial Action Work Plans.
Specific operating practices are typically prepared for tasks which include:
• Earthwork
• excavation,
• stockpile management,
• debris management,
• backfilling, and
• equipment decontamination;
• Process Operations
• performance standards verification for solids, offgas, and
process operating limits,
• automatic waste feed cutoff interlocks,
• continuous emission monitor calibration,
• treated solids sampling and analysis,
• data and records management,
4.6
-------
Chapter 4
• wastewater management,
• secondary containment,
• stormwater management,
• wastewater treatment,
• wastewater sampling and analysis, and
• disposal of treated wastewater and treatment residues;
Equipment Decontamination and Demobilization
• equipment disassembly,
• decontamination,
• decontamination sampling and analysis, and
• demobilization.
4.4 Operations Monitoring
Thermal desorption system operating parameters, including flows, levels,
temperatures, and pressures, must be regularly monitored and recorded as
necessary to ensure that the system can achieve the following goals:
• protect the safety of site personnel, equipment, the environment,
and the public health of the community;
• minimize upset, alarm, and automatic waste feed shutdown con-
ditions; and
• comply with performance standards.
4.4.1 Process Monitoring
The contractor's proof-of-process test plan typically defines the specific
process parameters that will be monitored and recorded. Examples of pro-
cess parameters that are monitored include, but are not limited to, the follow-
ing; waste feed rate, solids exit temperature, thermal desorber pressure,
emissions control equipment pressure differential, quench gas exit tempera-
ture, stack gas total hydrocarbons concentration, stack gas carbon monoxide
4.7
-------
Implementation and Operation
concentration, process water flow, recycle water flow, burner operations,
induced draft fan operations, and power failure modes. Not all parameters
apply to all types of thermal desorption systems.
Some type of continuous emissions monitoring system is normally re-
quired. Stack gas parameters should be measured and recorded on a con-
tinuous basis. For some parameters, records can be stored on a 60-minute
rolling average basis.
Process monitoring should also be conducted to record the equipment
operating factor. The operating factor is the fraction of time that the
equipment actually operates compared to the planned operating sched-
ule. Operating factors are typically derived by using records from the
waste feed system recorder.
4.4.2 Instrument Testing and Calibration
Testing and calibrating the process and emissions monitoring equipment
described in Section 3.7 must be conducted in compliance with manufactur-
ers' specifications and at the intervals defined in the Operations and Mainte-
nance Plan.
4.5 Qualify Assurance/Qualify Control
The Quality Assurance/Quality Control (QA/QC) Plan, which is prepared
as an attachment to the Remedial Action Work Plan, is the guiding document
for all project-related sampling and analytical QA/QC activities. This docu-
ment defines the data quality objectives for each sample and analytical pa-
rameter. The contents of a typical QA/QC plan prepared according to US
EPA guidelines are described in Table 4.1 (US EPA 1994c). Each section of
the QA/QC plan should include example forms for documenting each of the
required tasks.
4.8
-------
Chapter 4
Table 4.1
QA/QC Plan Content Requirements
Section # Topic
1 Title Page
2 Table of Contents
3 Project Description
4 Project Organization and Responsibility
5 QA Objectives for Precision, Accuracy, Completeness, Representativeness, and Comparability
6 Sampling Procedures
7 Sample Custody
8 Calibration Procedures and Frequency
9 Analytical Procedures
10 Data Reduction, Validation, and Reporting
11 Internal Quality Control Checks
12 Performance and System Audits
13 Preventive Maintenance
14 , Specific Routine Procedures Used to Assess Data Precision, Accuracy, and Completeness
15 Corrective Action
16 Quality Assurance Reports to Management
Source: US EPA 1994c
4.9
-------
-------
Chapter
AND
DATA
5.7 Overview
A number of different types of mechanical equipment are used as thermal
desorbers. Types of thermal desorbers that are commercially available in-
clude rotary dryers, thermal screws, paddle dryers, anaerobic thermal proces-
sors, conveyor belts, batch vacuum systems, and mercury retort systems.
Table 5.1 lists applications of thermal desorbers, giving the contractor's
name, site name, contaminants treated, site size, type of thermal desorber
used, and type of emission control system used (Cudahy and Troxler 1991,
updated 1996). Additional information is available through the Innovative
Treatment Technology (ITT) database on US EPA's CLU-In Web Page
(http://www.clu-in.com) which is updated periodically. To download the
current ITT database and a user's manual, select the alphabetical listing and
click on the letter "V".
A brief process description of each general type of thermal desorber is
presented below, followed by a project case history summary. The informa-
tion presented below is not a comprehensive discussion of all of the thermal
desorption systems that are commercially available; rather, it is a synopsis of
selected information that is readily available in the literature. Appendix A
contains detailed case histories for five projects which include process de-
scriptions, detailed performance data, and selected cost data. Case histories
were chosen that represent a variety of types of technologies, contaminant
types, and site conditions.
5.1
-------
Case Histories and Performance Data
tn
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59-
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5.2
-------
MaxymilUan
McLaren Hart
McLaren Hart
McLaren Hart
McLaren Hart
McLaren Hart
McLaren Hart
McLaren Hart
McLaren Hart
Mercury Recovery
. Services
OHM
OHM
OHM
Oi
Co OHM (RUST)
OHM (RUST)
OHM (RUST)
OHM (RUST)
OHM (RUST)
Purgo, Inc.
Purgo, Inc.
Purgo, Inc.
Purgo, Inc.
Purgo, Inc.
Seaview Thermal
Systems
Smith (Canonie)
Smith (Canonie)
Dragstrip
PCX
Letterkenney
Potters Pit
AMAX/US Metals
Azon Labs
Borg-Warner
Otis Air Base
Rogers Seed
Multiple
Confidential
Confidential
Hooper Sands
Ciba-Geiby
Re-Solve
Sand Creek
Sangamo Weston
Waldick Aerospace
Air National Guard
Confidential
Confidential
Confidential
Garland RD
PSE&G Patterson
Arlington Blending
Canon Bridgewater
Glen Falls
Washington
Chambersburg
Leland
Carteret
Millerton
Vernon
Cape Code
Twin Falls
New Brighton
Confidential
Chocolate Bayou
South Berwick
Mclntosh
North Dartmouth
Commerce City
Pickens
Wall Township
Martinsburg
East Rutherford
Carteret
East Rutherford
West Milton
Patterson
Arlington
Bridgewater
NY
NC
PA
NC
NJ
NY
' CA
NY
ID
PA
KY
TX
ME
AL
MA
CO
sc
NJ
WV
NJ
NJ
NJ
OH
NJ
TN
MA
PCBs
Pesticides
VOCs
PAHs/VOCs
VOCs
VOCs
Mercury
VOCs
Pesticides
Mercury
PAHs
VOCs
VOCs
Pesticides
PCBs
Pesticides
PCBs
VOCs,TPH
VOCs
PCBs, PAHs
VOCs
VOCs
VOCs
PAHs
Pesticides
VOCs
13,818
19,091
19,091
54,545
7,273
2,273
2,045
19,091
545
3,636
6,818
4,545
1,545
136,364
40,909
14,091
40,909
5,498
3,164
6364
1,818
11,818
12,273
1,818
37,475
10,909
Indirect Rotary Dryer
Infrared Vacuum-200
Infrared Vacuum- 100
Infrared Vacuum- 100
Infrared Vacuum- 100
Infrared Vacuum- 100
Infrared Vacuum-200
Infrared Vacuum- 100
Infrared Vacuum-200
Mercury Report Retort
Rotary Dryer
Indirect Rotary Dryer
Rotary Dryer
Rotary Dryer
Indirect Rotary Dryer
Rotary Dryer
Indirect Rotary Dryer
Rotary Dryer
Rotary Diyer
Indirect Rotary Dryer
Indirect Rotary Dryer
Rotary Dryer
Rotary Dryer
Thermal Screw
Rotary Dryer
Rotary Dryer
Recovery
Recovery <
Recovery
Recovery
Recovery
Recovery
Recovery
Recovery
, Recovery
Recovery
Recovery
' Recovery
Destructive
Destructive
Recovery
Recovery
Recovery
Destructive
Destructive
Recovery
Recovery
Destructive
Destructive
Recovery
Recovery
Recovery
S
>«
u
Oi
-------
Contractor*-1"
Smith (Canonie)
Smith (Canonie)
Smith (Canonie)
Smith (Canonie)
Smith (Canonie)
SoilTech
SoilTech (Smith)
SoilTech (Smith)
SoilTech [Kimmins]
Southwest Soil
Remediation
Southwest Soils
[IT Corp.]
Southwest
Soil/Geomatrix
Southwest
Soil/Parsons
Engineering
SRS [OHM]
SRS [OHM]
Thermal Remed.
Corp.
Thermal Remed.
Corp.
Site Name
McKin
Old Marsh Aviation
Ottati & Goss
South Keamy Site
Spencer Kellog
Waukegan Harbor
Pristine
Smith's Farm
Wide Beach
Confidential
Aberdeen
Confidential
Confidential
Hilton Davis
Pester Refinery
Crop Prod. Services
Estevan Coal
Thermal
Site Location
Gray
Utchfield Park
Kingston
South Keamy
Newark
Waukegan
Reading
Bullitt
Brant
Turlock
Aberdeen
Mettler
Phoenix
Cincinnati
El Dorado
Brawley
Estevan
Table 5.1
cont.
Desorptlon Applications
State
ME
AZ
NH
NJ
NJ
IL
OH
KY
NY
CA
NC
CA
AZ
OH
KS
CA
CAN
Contaminants
VOCs/PAHs
Pesticides
VOCs
VOCs
PAHs/VOCs
PCBs
PAHs
PCBs
PCBs
Pesticides
Pesticides
Pesticides
Pesticides
VOCs
PAHs
Pesticides
PAHs
Site Size
(tonnes)
15,909
49,091
6,818
14,545
5,909
11,818'
11,673
30,909
38,182
2,182
86,364
3,636
1,909
22,727
54,545
636
7,727
Thermal Desorber
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Anaerobic Thennal Processor
Anaerobic Thennal Processor
Anaerobic Thermal Processor
Anaerobic Thermal Processor
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Thennal Screw (2)
Thermal Screw
Conveyor Thennal Desorber
Conveyor Thermal Desorber
Offgas
Treatment
Recovery
Recovery
, Recovery
Recovery
Recovery
Recovery
Recovery
Recovery
Recovery
Destructive
Destructive
' Destructive
Destructive
Recovery
Recovery
Destructive
O
Q
c/>
CD
I
o"
13.
CJ>
Q
a
TJ
CD
3
3
O
CD
O
Q
Destructive
-------
Oi
Westinghouse
Weston
Weston
Weston
Williams
Environmental
Services
Williams
Environmental
Services
Williams
Environmental
Services
Williams
Environmental
Services
Williams
Environmental
Services
Williams
Environmental
Services
Williams
Environmental
Services [Sevenson]
Williams |
[Four Seasons]
ACME
Anderson Dev Co
Arnold Air Force
Base
Tinker AFB
American Thermostat
Letterkenney
Metaltec Aerospace
Stauffer
T.H. Agri. & Nutrition
Woods Industries
Lipari
Reilly Tar
Rockford
Adrian
Tullahoma
Oklahoma City
Cairo
Chambersburg
Franklin Borough
Tampa
Albany
Yakima
Pitman
Indianapolis
IL
MI
TN
OK
NY
PA
NJ
FL
GA
WA
NJ
IN
PCBs
VOCs
VOCs
VOCs
VOCs
.
VOCs
VOCs
Pesticides
Pesticides
Pesticides
VOCs
PAHs
6,818
8,182
7^73
909
13,636
24,899
6,909
2,864
3,818
23,616
72,838
11,045
Infrared Vacuum-100
Thermal Screw
Thermal Screw
Thermal Screw
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Recovery
Recovery
Recovery
Recovery
Destructive
Destructive
Destructive
Recovery
• Recovery
Destructive
Destructive
Destructive
'Name in parentheses indicates company that completed project and then was acquired by another firm.
"Name in brackets indicates prime contractor.
Source: Cudahy and Troxler 1991 (updated 1996)
,
-V
Chapter 5
-------
Case Histories and Performance Data
5.2 Rotary Dryer
As shown in Table 5.1, several contractors provide rotary dryer sys-
tems. Detailed discussions of rotary dryer design features and operating
practices are presented in Sections 3.4 and 3.5 of the companion mono-
graph, Innovative Site Remediation Technology — Thermal Desorption
(Lighty et al. 1993).
Rotary dryers can be either co-current (soil and process gas flow in the
same direction) or counter-current (soil and process gas flow in opposite
directions) and can be either directly-heated or indirectly-heated. Schematic
diagrams of directly-heated and indirectly-heated rotary dryers are shown in
Figures 3.1 and 3.2, respectively. Process-flow diagrams for directly-heated
and indirectly-heated rotary dryers and emission control systems are shown
in Figures 3.4 and 3.7, respectively.
Directly-heated dryers incorporate a propane, natural gas, or fuel oil
burner mounted inside a combustion chamber that discharges hot gas
into the dryer shell. The hot gas heats the soil, and contaminants are
volatilized and swept from the thermal desorber by the combustion prod-
ucts from the burner.
Indirectly-heated rotary dryers consist of a horizontal cylindrical shell
rotating inside of a furnace. A series of burners are fired into the space be-
tween the outside of the dryer shell and the inside of the furnace wall. Heat
is transferred through the dryer shell to the contaminated solids. The con-
taminants are volatilized and exhausted to the emission control system. The
combustion products from the burners do not mix with the volatilized con-
taminants and are exhausted through a separate set of stacks.
Directly-heated rotary dryers may use either destructive-type or recovery-
type emission control systems while indirectly-heated rotary dryers use only
recovery-type emission control systems. Destructive-type emission control
systems typically use a cyclone, thermal oxidizer, baghouse, and wet scrub-
ber. A recovery-type emission control system uses wet scrubbers and con-
densers to remove organic compounds from the offgas, followed by a final
carbon adsorption step. In some recovery-type systems, a fraction of the
process gas is recycled back through the thermal desorber. Case histories for
various types of rotary dryers, emission control systems, and waste applica-
tions are presented below.
5.6
-------
Chapter 5
5.2.1 Old Marsh Aviation Site
The Old Marsh Aviation Site in Litchfield, Arizona, was formerly an
aerial pesticide applicator's airstrip which was adjacent to residential devel-
opments and a large resort (Miller 1994; US EPA 1993b; US EPA 1995).
The site had been leased to a pesticide aerial applicator from 1940 to 1974.
During pesticide application operations, spills and disposal of pesticides,
pesticide mixtures, and pesticide containers contributed to contamination
of soils at the site. The soil was primarily contaminated with dichloro-
diphenyltricholoroethane (DDT), toxaphene, and lesser amounts of ethyl
parathion, methyl parathion, dieldrin, endrin, endosulfan, dibromo-
chloropropane, and ethylene dibromide.
Smith Environmental Services (formerly Canonie Environmental Ser-
vices) used a directlyrheated rotary dryer to treat 49,090 tonne (54,000 ton)
of pesticide-contaminated soil at the site. The project was conducted be-
tween May, 1992 and October, 1993. The project was significant because it
was the first application of a rotary dryer system with a recovery-type emis-
sion control system for treating pesticide-contaminated soils.
The thermal desorption system consisted of feed hoppers and conveyors,
a directly-heated rotary dryer, soil cooling pugmill and soil discharge con-
veyor, cyclone, baghouse, induced draft fan, venturi scrubber, two parallel
vapor-phase activated carbon adsorption systems, and a stack. The .rotary
dryer used a propane- or fuel oil-fired burner to produce a hot gas that was
contacted with the contaminated soil. Optimal conditions for the project
were a feed soil moisture content of approximately 5%, rotary dryer soil
discharge temperature of 371 to 399°C (700 to 750°F), and a soil feed rate of
32 to 41 tonne/hr (35 to 45 ton/hr).
A Superfund Innovative Technology Evaluation (SITE) Demonstration test
was conducted which consisted of three sampling runs. Average concentrations
of DDT and toxaphene in the feed soil were 19.5 and 19.7 mg/kg, respectively.
Average concentrations of DDT and toxaphene in the treated soil were 0.0014
and 0.020 mg/kg, respectively. Measured removal efficiencies of DDT and
toxaphene from the soil were 99.99 and 99.90%, respectively.
One objective of the SITE Demonstration was to determine if breakdown
products were produced from organic compounds during the thermal treat-
ment process. Some VOCs and S VOCs were formed as products of thermal
transformation! Demonstration test results indicated that the thermal
5.7
-------
Case Histories and Performance Data
desorption system did not generate polychlorinated dibenzo para-dioxins
(PCDDs) or polychlorinated dibenzofurans (PCDFs). The concentration of
2,3,7,8 tetra-chlorodibenzo-para-dioxin toxicity equivalence (TCDD TEQ) in
the stack gas was 0.0022 ng/dscm corrected to 7% oxygen, a factor of approxi-
mately 2 orders of magnitude less than the proposed Clean Air Act Maximum
Achievable Technology Standard (MACT) of 0.2 ng/dscm for combustion
sources. The scrubber liquid contained measurable quantities of DDT,
dichlorodiphenyl-dichloroethane (DDD), and dichlorodiphenyldichloroethylene
(DDE). DDE was present in the vapor-phase activated carbon. The average
emission rate for compounds detected at quantifiable levels in the stack gas
included 4,4'-DDE at 0.000019 kg/hr (0.000043 Ib/hr), chloromethane at 0.009
kg/hr (0.02 Ib/hr), benzene at 0.024 kg/hr (0.053 Ib/hr), and toluene at 0.0036
kg/hr (0.008 Ib/hr).
At a soil feed rate of 32 tonne/hr (35 ton/hr), the total turnkey project
costs were approximately $163/tonne ($148/ton) for treating 49,090 tonne
(54,000 ton) of soil. The total turnkey project cost included several activities
that were not directly associated with the thermal treatment operations, such
as off-site disposal of some contaminated solids.
5.2.2 Harbor Point Site
The Harbor Point Site in Utica, New York, was a former manufactured
gas plant (MGP) owned by the Niagara Mohawk Power Company
(Maxymillian, Warren, and Neuhauser 1994; US EPA 1994a). The site pro-
duced energy for lighting and heating by converting coal into a gas product.
The manufactured gas plant produced a variety of types of residues includ-
ing coal tar, purifier wastes, water gas plant wastes, coke plant wastes. The
primary contaminants from the site operations included benzene, toluene,
ethylbenzene, and xylene (BTEX), PAHs, ferric cyanide compounds, ar-
senic, and lead. The PAH compounds included naphthalene, 2-methylnaph-
thalene, acenaphthylene, acenaphthene, fluorene, phenathrene, anthracene,
fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene,
benzo(k)fluoranthene, benzo(a)pyrene, indeno(l,2,3-cd)pyrene,
dibenzo(a,h)anthracene, and benzo(g,h,i)perylene.
Maxymillian Technologies (formerly Clean Berkshires Inc.) used a
directly-heated rotary dryer with a destructive-type emission control system
to conduct a demonstration program to treat a total of 6,363 tonne (7,000
ton) of various types of wastes at the site. The demonstration project was
5.8
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Chapters
conducted in November and December of 1993. The project was significant
because it demonstrated that rotary dryer technology could be used to suc-
cessfully treat a variety of types of MGP wastes. A complete case history
for the project is presented in Appendix A.
The thermal desorber is a directly-heated, co-current rotary dryer. Soil
exiting the rotary dryer, cyclone particulates, and baghouse particulates were
combined and then cooled and moisturized in a pugmill equipped with water
sprays. The emission control system consisted of a cyclone, thermal oxi-
dizer, partial quench system, baghouse, induced draft fan, and stack.
A total of 28 demonstration test runs were conducted on various types of
wastes, including tar emulsion soil, purifier waste, coke plant soil, purifier
soils, water gas plant soils, and harbor sediments. Rotary dryer soil dis-
charge temperatures ranged from 315 to 454°C (600 to 8506F), at soil feed
rates of 12 to 23 tonne/hr (13 to 25 ton/hr). The thermal oxidizer was oper-
ated at an average exit gas temperature of 987°C (1,810°F) and average gas
residence time of 0.85 seconds.
The concentration of total PAHs in the feed soil during the demonstration
tests ranged from 73 to 2,522 mg/kg with an average of 1,030 mg/kg. The
concentration of total PAHs in the treated soil ranged from non-detect (< 3.0
mg/kg) to 65 mg/kg with an average of <8.5 mg/kg. The concentration of
total cyanide in the feed solids ranged from 15 to 2,000 mg/kg with an aver-
age value of 547 mg/kg. The concentration of total cyanide in the treated
solids ranged from 0.83 to 213 mg/kg with an average value of <33.3 mg/kg.
Stack testing was conducted for a number of parameters including naph-
thalene, xylene, particulates, cyanide, arsenic, and lead. Continuous emis-
sions monitoring was conducted for THCs, nitrogen oxides, sulfur dioxide,
carbon monoxide, oxygen, and carbon dioxide. Average stack emission
results were as follows:
Particulates 75 mg/m3 (0.033 gr/dscf);
Carbon monoxide 2.5 ppm ;
Nitrogen oxides 100 ppmv;
Sulfur dioxide 404 ppm ;
Total hydrocarbons 2.2 ppm ;
Arsenic 15.5 jog/m3; and
Lead 35.3
5.9
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Case Histories and Performance Data
Destruction and removal efficiency values for napthalene ranged from
99.7218 to 99.9994% with 15 of 16 tests recording DRE values of >99.99%.
DRE tests results for total xylene ranged from 99.99 to 99.9992%. Stack
emissions were generally in compliance with applicable standards; however,
sulfur dioxide emissions were above regulatory limits since the system did
not include a wet scrubber for removal of acid gases.
The estimated cost to remediate 18,144 tonne (20,000 ton) of contami-
nated soils is $144/tonne ($13 I/ton) based on achieving a 90% operating
factor. This cost includes system erection, operation, consumables, facility
modifications, repair and replacement; disassembly, and site restoration.
5.2.3 Re-Solve Superfund Site
The Re-Solve Superfund Site in North Dartmouth, Massachusetts, was a
former solvent recycling facility which operated from 1956 to 1980 (Palmer
1993; Ayen, Matz, and Meyers 1994; US EPA 1993a). The facility operated
a distillation process and disposed of the hazardous byproducts from this
process on-site in surface impoundments and a land farming area. In the
1980s, contaminated sediments, highly contaminated soil from the land
farm, and process equipment and drums were removed from the site. PCB-
contaminated soils remained on-site for subsequent thermal treatment.
OHM Corporation's (formerly Rust Remedial Services) X*TRAX® sys-
tem was used to treat 45,455 tonne (50,000 ton) of PCB-contaminated soil at
the site between May, 1992 and July, 1994. A detailed case history on an
application of the system at the Re-Solve Site is presented in Appendix A.
Extensive data from laboratory-scale treatability tests are also available for
the system (Palmer 1993).
The thermal desorber was an indirectly-heated, co-current rotary dryer
that operated at a soil discharge temperature of approximately 232 to 454°C
(450 to 850°F) at a waste feed rate of approximately 4.5 to 9 tonne/hr (5 to
10 ton/hr). The thermal desorber offgas was treated through a wet scrubber,
two condensers, mist eliminator, and a reheater. Most of the purge gas
stream was then recycled back to the desorber with about 5-10% of the gas
passing through a HEPA filter and carbon adsorption system before being
discharged to the atmosphere. The flow rate of the recycled purge gas was
approximately 19.8 mVmin (700 acfm) and the flow rate of the vent gas
which was discharged to the atmosphere was approximately 1.05 mVmin
5.10
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Chapter 5
(37 acfm). The system included a scrubber water treatment system consist-
ing of a phase separator, filter press, filtrate tank, and organic liquid storage
tank. The condensate from the condensers was treated in a second phase
separator. The organic liquid phase was stored in a tank and the water was
treated through activated carbon and used to cool and moisturize the treated
soils. Residuals, including aqueous-phase activated carbon, liquid-phase
activated carbon, and organic liquids, were disposed off-site.
A proof-of-process test and a SITE Demonstration test of the system were
conducted in May, 1992. During the SITE Demonstration test, soil was fed
at an average rate of 4.5 tonne/hr (4,9 ton/hr). The soil was heated to an
average temperature of 389°C (732°F) for a residence time of 2 hours. PCB
concentrations in the feed ranged from 181 to 515 mg/kg and treated soil
samples all contained less than 1 mg/kg PCBs with an average of 0.25 mg/
kg. The average PCB removal efficiency from soil was 99.9%. No PCBs
were detected in the gaseous emissions from the process, demonstrating a
DREof>99.9999996%.
5.2.4 T H Agriculture & Nutrition Site
The TH Agriculture & Nutrition Company, Inc. (THAN) property in Al-
bany, Georgia, was used by several companies for the formulation and stor-
age of agricultural chemicals from the mid-1950s until 1978. The site is
approximately 7 acres in size and is located in a light industrial and residen-
tial area. During a removal action, 3,818 tonne (4,200 ton) of a cohesive
clay soil were excavated and stockpiled. This soil was prohibited from land
disposal under RCRA regulations because of designation as a California list
waste (i.e., materials having organic chlorine concentrations >1,000 mg/kg).
The contaminants of concern included 14 organochlorine (OCL) pesticides,
with DDT and toxaphene being the primary constituents. The average total
concentration of OCL pesticides in the feed soil was in the range of 400 to
600 mg/kg.
Williams Environmental Services used a directly-heated, counter-current
rotary dryer system with a recovery-type emission control system to remediate
3,818 tonne (4,200 ton) of pesticide-contaminated soil at the site between June,
1993 and October, 1993 (Goh, Troxler, and Cleary 1995; Troxler, Goh, and
Dicks 1993; Federal Remediation Technologies Roundtable 1995b). A case
history for this application is presented in Appendix A.
5.11
-------
Case Histories and Performance Data
The thermal desorption system consisted of feed hoppers and conveyors,
a directly-heated rotary dryer, soil cooling pugmill and soil discharge con-
veyor, baghouse, induced draft fan, quench chamber, gas conditioner, two
parallel vapor-phase activated carbon adsorption systems, and-a-stack. The
rotary dryer used a propane-fired burner to produce a hot gas that was con-
tacted with the contaminated soil.
A demonstration test consisting of three test runs was conducted in which
treated soil discharge temperatures ranged from 445 to 582°C (833 to
1,080°F) at a soil feed rate of 6.5 to 8.5 tonne/hr (7.2 to 9.5 ton/hr). Pesti-
cides were removed from the soil at efficiencies ranging from 97.88 to
99.86% for all of the pesticide contaminants of concern except for DDE.
The average removal efficiency for DDE was skewed by one low value re-
corded during the performance test run with the lowest soil treatment tem-
perature. Additional investigation indicated that DDE was produced within
the thermal process by the dehydrochlorination of DDT. However, data from
subsequent full-scale production operations indicated that DDE was consis-
tently removed from the soil at an efficiency of greater than 95%.
Stack parameters and average test results were as follows:
Stack gas flow 306 dscm/min (10,804 dscf/min);
Pesticides noii-detect;
Particulates l .35 mg/m3 (0.0006 gr/dscf);
Hydrogen chloride/chlorine 0.05 kg/hr (0.12 Ib/hr);
Total hydrocarbons 11.9 ppmv; and
Carbon monoxide 156 ppmv.
Concentrations of all fourteen OCL pesticides in the stack gas were below
detection levels during all test runs. All DRE values were greater than
99.99% with some values as high as 99.9999%.
Summa canisters were used by an US EPA contractor to collect gas
samples at the exit of the vapor-phase activated carbon beds. Summa canis-
ters were analyzed for concentrations of 27 volatile organic compounds to
determine if they were produced as degradation products of the thermal
process. Concentrations of 23 of the compounds were below analytical
quantitation limits. Compounds which were detected at low concentrations
included chloromethane (41.3 to 92.5 ppbv), chloroethane (11.6 to 21.1
5.12
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Chapter 5
ppbv), methylene chloride (4.1 to 4.6 ppbv), and benzene (1.9 ppb ) An
emission estimate for the treatment of 3,818 tonne (4,200 ton) of soil was
developed by deriving an emission factor per tonne of soil treated. Based on
this analysis, the estimated mass emission of all identified VOCs over the
entire prpject was 2.0 kg (4.4 Ib).
Hopper-to-hopper treatment costs, including site work, the performance
test, and thermal treatment operations, were $200/tonne ($182/ton) of soil
treated. Engineering design, project oversight, and ambient air monitoring
performed by a third party added $79/tonne ($72/ton) of soil treated to the
nmifr't f^nat-
project cost.
§.3 Thermal Screw
As shown in Table 5.1, several contractors provide treatment services
using thermal screw systems. A detailed discussion of thermal screw design
features and operating practices is presented in Section 3.6 of the companion
monograph (Lighty et al. 1993).
A thermal screw consists of a screw auger mounted inside a trough In
many systems, multiple screws are used in parallel and/or in series A hot
fluid, typically hot oil or steam, circulates through the shell and/or shaft and
flights of the screw The waste is fed into one end of the system, transported
by the rotation of the screw, and discharged at the opposite end. The heating
medium used in the screw limits the maximum soil discharge temperature of
the system to about 56°C (100°F) below the maximum service temperature
of the heat transfer fluid.
5.3.1 Anderson Development Company Site
The Anderson Development Company manufacturing facility was used
MKOrllKa1197910 manufacture ^'-methylene bis(2)chloroaniline
(MBOCA), a hardening agent used in the manufacture of polyurethane plas-
tics Wastes, including both volatile and semivolatile organic compounds
had been discharged on-site into an unlined 2,000 m2 (0.5 acre) lagoon. '
n ™ *R Wf°n US6d th™ L°W TemPerature Thermal Treatment System
(LI ) thermal screw system to treat 8,182 tonne (9,000 ton) of sludge
5.13
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Case Histories and Performance Data
contaminated with both VOCs and S VOCs (US EPA 1992a; Federal
Remediation Technologies Roundtable 1995b). The project was conducted
between October, 1991 and October, 1993. The project is described in detail
in Appendix A, which contains a case history for the project.
Feed preparation for the sludge included lime and ferric chloride addition
followed by dewatering in a filter press to a moisture content of 14 to 44%.
The thermal desorber used two jacketed troughs, one above the other with
solids from the top trough discharging into the bottom trough. Each trough
contained four parallel heated screw augers. An oil heating system heated a
heat transfer oil to an operating temperature about 56°C (100°F) higher than
the desired solids discharge temperature. The combustion gases released
from the oil heater burner were used as sweep gas in the thermal screw. Ex-
haust gas from the thermal screws was treated through a baghouse, air-
cooled condenser, refrigerated condenser, reheater, and vapor-phase acti-
vated carbon. Condensate streams were treated in a three-phase separator
with the aqueous phase further treated through activated carbon.
A series of six performance test runs was conducted as part of a SITE
Demonstration test (US EPA 1992a). The contaminated sludge was fed to
the unit at a rate of 1.91 tonne/hr (2.1 ton/hr) and heated to a temperature of
260°C (500°F) with a total solids residence time of 90 minutes. Tests
showed that all VOCs were removed to below the detection limit of 0.06 mg/
kg. MBOCA removal efficiencies were greater than 88% with concentra-
tions in the treated sludge ranging from 3.0 to 9.6 mg/kg. Stack emissions of
non-methane total hydrocarbons ranged from 6.7 to 11 ppmv with a maxi-
mum emission rate of 0.09 kg/day (0.2 Ib/day). The maximum stack particu-
late emission rate was 0.09 kg/day (0.2 Ib/day).
No project-specific actual costs were reported. However, Appendix A
contains detailed cost estimates for pretreatment, thermal treatment, and
posttreatment activities for a 2,727 tonne (3,000 ton) site for materials at
moisture contents of 20,45, and 75% (US EPA 1992a). These estimated
costs are $410/tonne, $590/tonne, and $796/tonne ($373/ton, $536/ton and
$724/ton), respectively.
5.14
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Chapter 5
5.4 Dryer
A paddle dryer is similar in operating principle to a thermal screw except
that a series of paddles is mounted on a shaft in the thermal desorber rather
than using a screw type conveyor. A hot fluid is circulated through the
trough and/or paddle shaft.
5.4.1 Chemical Plant Site
ETG Environmental Inc. treated 855 tonne (950 ton) of dewatered sludge
from two wastewater tanks and a separator at a chemical plant in Baltimore,
Maryland, using a paddle dryer system (ETG Environmental Inc. 1995).
The sludge was dewatered using a plate and frame filter before it was ther-
mally treated. The sludge was contaminated with benzene.
The system is indirectly heated by a hot fluid circulating through the
trough of the paddle dryer. The unit is designed to achieve solids tempera-
tures of up to 510°C (950°F). Depending upon the feed material characteris-
tics, feed rates of 4.5-9.0 tonne/hr (5-10 ton/hr) can be achieved. Vapors
generated by the process were captured and recycled to the client's vapor
recovery system.
The feed material, which was contaminated with benzene, exhibited a low
flash point and was a RCRA D001 hazardous waste because of flammability.
The paddle dryer was used to drive off the VOCs, thereby increasing the
flash point above the threshold for the D001 waste classification. The vol-
ume of material was reduced by approximately 50%.
5.5 Anaerobic Thermal Processor
The anaerobic thermal processor system is a unique indirectly-heated
rotary dryer that consists of four zones: preheat, retort, combustion, and
cooling. The offgas from the retort zone is treated using a cyclone and con-
densation system to remove most of the organic compounds. The condenser
is a direct contact condenser that may use either oil or water as the cooling
medium. Noncondensable gas exiting the condensers is recycled back
through the burners in the combustion zone of the unit.
5.15
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Case Histories and Performance Data
The SoilTech Anaerobic Thermal Processor has been used at numerous
sites (Lighty et al. 1993; Johnson and Dirgo 1994; US EPA 1992b; US EPA
1992c). A detailed discussion of the SoilTech system features and operating
conditions is presented in Section 3.7 of the companion monograph (Lighty
et al. 1993).
5.5.1 Pristine Superfund Site
The Pristine, Inc. Superfund Site in Reading, Ohio was used for manufac-
turing sulfuric acid prior to 1970 (Mutton and Trentini 1994). From 1977 to
1981, a liquid waste incinerator operated at the site. Due to spills and a large
inventory of materials at the site, incineration operations were discontinued
in 1981. Soils and sediments were determined to be contaminated with
volatiles, semivolatiles, pesticides, metals, and sulfur. Concentrations of
volatiles were up to 0.140 mg/kg; semivolatiles up to 130 mg/kg; 4,4'-DDT
up to 8.2 mg/kg; and lead up to 1,100 mg/kg.
SoilTech used their anaerobic thermal processor to treat 11,673 tonne
(12,840 ton) of contaminated soil at the site. The project was conducted in
1993 and 1994. A complete case history for the application.of the anaerobic
thermal processor at the Pristine Superfund Site is presented in Appendix A.
The anaerobic thermal process consisted of seven main process units: a
pretreatment system, a feed system, a processor unit, a vapor recovery sys-
tem, a flue gas treatment system, a treated soil handling system, and a waste-
water treatment system. A detailed description of the process components of
the system is presented in Appendix A. The soil treatment temperature in
the retort zone ranges from 510 to 649°C (950 to 1,200°F) and soil through-
put is approximately 9 tonne/hr (10 ton/hr).
A performance test consisting of four test runs was conducted. Con-
centrations of contaminants in the treated soil were not detected except
for 4,4'-DDT (9.6 |ig/kg), dieldrin (4.9 |ig/kg), benzene (9.0 Jig/kg), and
chloroform (9.0 |ig/kg). The compounds 1,2,3-trichlorobenzene and
benzyl chloride were used as surrogate Principal Organic Hazardous
Constituents (POHCs). ORE values for 1,2,3-trichlorobenzene ranged
from 99.9954 to 99.999967%. DRE values for benzyl chloride ranged
from 99.99931 to 99.99979%. Stack sampling during the performance
test was conducted for various parameters. Stack parameters and aver-
age test results were as follows:
5.16
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Chapter 5
Stack gas flow
Particulates
2,3,7,8 TCDDTEQ
Oxygen
Hydrogen chloride/chlorine
Sulfur dioxide
Total hydrocarbons
Carbon monoxide
106 dscm/min (3,750 dscf/min);
1.35 mg/m3 (0.0006 gr/dscf) @
7% oxygen;
0.013 ng/dscm @ 7% oxygen;
7.8%;
0.005 kg/hr (0.01 llb/hr);
56ppnr;
7 ppmv; and
989 ppm.
5.6 Conveyor Belt
A conveyor belt thermal desorber uses a mesh or open metal belt to trans-
port solids through the thermal desorber. Soil is normally fed into the unit
and distributed across the belt in a 12 to 50 mm (0.5 to 2 in.) thick layer.
Conveyor belt systems are either directly-heated using natural gas burners or
indirectly-heated using a series of silicon carbide electric heating elements.
5.6.1 Acme Solvents Superfund Site
The Acme Solvents Superfund Site is located near Rockford, Illinois.
From 1960 to 1973, the site was used for disposing paints, oils, and still
bottoms from a solvent recovery plant owned by Acme Solvents Reclaiming,
Inc. Wastes were dumped into depressions created by previous quarrying
operations or by scraping overburden from the near-surface bedrock to form
berms (O'Brien and Rouleau 1993, 1995). Ethylbenzene, tetrachloroethene,
xylenes, trichloroethene, bis(2-ethylhexyl)phthalate, naphthalene and PCBs
were the major contaminants of concern in the soil at the site.
Westinghouse used a 3-megawatt indirectly-heated conveyor belt thermal
desorber to treat approximately 6,818 tonne (7,500 ton) of soil at the site.
The project was conducted between June and September, 1994. This project
was the first application of a conveyor belt thermal desorption system.
5.17
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Case Histories and Performance Data
The thermal desorption system consisted of a feed system, primary heat-
ing chamber, treated soil cooling and handling system, emission control
system, and water treatment system. The soil was fed into the primary heat-
ing chamber which operated at a slight negative pressure in an oxygen defi-
cient environment. The soil was evenly distributed on a belt carrying the soil
beneath a series of silicon carbide electric heating rods. The rods heated the
soil to the target soil treatment temperature via infrared radiation. Typical
operating parameters included a soil layer thickness ranging from 12 to 51
mm (0.5 to 2.0 in.), soil residence time of 5 to 60 min, soil feed rate of 4.5 to
9 tonne/hr (5 to 10 ton/hr), and soil discharge temperatures ranged from 204
to538°C(400tol,0000F).
The volatilized contaminants were captured by a sweep gas and transferred
to the emission control system. This system consisted of a wet scrubber, venturi
scrubber, knockout vessel, mist eliminator, chiller, and a vapor-phase carbon
system. The stack gas flow rate ranged from 6.2 to 7.4 dscm/min (219 to 260
dscf/min). Condensed water and organic contaminants from the wet scrubber,
venturi scrubber, knockout vessel, and chiller were fed to the water treatment
system. The water treatment system consisted of a phase separator and an air/
water cooler. Condensed organics were separated and disposed of off-site.
Water was cooled in the air/water cooler and 95% of the water was recycled to
the scrubber. The remaining 5% of the water was treated through a bag filter
and activated carbon and used to cool and moisturize the treated soil.
A proof-of-performance test consisting of 10 test runs was conducted at
an average soil feed rate of 6.3 tonne/hr (6.9 ton/hr). Maximum concentra-
tions of total xylenes and bis (2-ethylhexyl) phthalate in the feed soil were
1,500 and 1,300 mg/kg, respectively. Maximum concentrations of the same
components in the treated soil were 1.5 mg/kg and 23.3 mg/kg, respectively.
Average stack gas performance results were as follows:
Stack gas flow 7.0 dscm/min (247 dscf/min);
PCB DRE 99.9993%;
Particulates 3.7 mg/m3 (0.0016 gr/dscf);
2,3,7,8 TCDD TEQ 0.061 ng/dscm;
Oxygen 2.3%;
Methane, acetylene, ethane 3%; and
Carbon monoxide 3.8%.
5.18
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Chapter 5
5.7 Batch Vacuum System
Several contractors have developed batch thermal desorption systems that
operate under vacuum conditions. Mechanical configurations include both
rectangular furnaces into which trays of soil are placed with a forklift and
rotary dryers that operate in a batch mode.
5.7.1 PCX Site
The PCX Site in Washington, North Carolina, was a former pesticide
storage and formulating facility. The pesticides most prevalent at the site
included chlordane, methoxychlor, DDT, DDE, and other OCL pesticides.
McLaren Hart Environmental Engineering Corporation used a batch
vacuum thermal desorption unit to treat approximately 19,091 tonne (21,000
ton) of pesticide-contaminated soils at the site (ETS Inc. 1995). A detailed
description of the system is presented in another reference (Walsh 1995).
The project was conducted in 1994 and 1995.
The McLaren Hart high vacuum system consists of a rectangular chamber
with doors on one side. The two hinged doors are opened and two trays of
soil are inserted into the chamber. The system operates under a vacuum of
508 to 635 mm Hg (20 to 25 in. Hg) which allows contaminants to boil at a
lower temperature. The unit is heated by infrared radiation generated by a
series of propane-fired radiant heaters with a total thermal capacity of 1.48
gigajoules/hr (1.4 MM Btu/hr). The soil is typically heated to a temperature
ranging from 149 to 232°C (300 to 450°F). The system has a total operating
capacity of 3.8 m3 (5 yd3) of soil in the two trays. Typical cycle times for
each batch range from 2 to 4 hours/Vacuum conditions in the chamber are
maintained by using a vacuum pump. The gas exhausted from the system is
treated by a condenser, and a carbon system polishes the gas.
A performance test was conducted which consisted of three test runs with
the following stack sampling trains: Run 1, US EPA Method 0030 (VOCs);
Run 2, Method 23 (dioxins/furans, pesticides, and SVOCs); and Run 3,
Method 0050, (hydrogen chloride and particulates). The average concentra-
tions of toxaphene and DDD in the feed soil were 1,056 and 37 mg/kg, re-
spectively. Average concentrations of toxaphene and DDD in the treated soil
were non-detected and 0.002 mg/kg, respectively. Selected stack sampling
results are presented below:
5.19
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Case Histories and Performance Data
Stack gas flow
Particulates
2,3,7,8 TCDD TEQ
Hydrogen chloride
Oxygen
Aldrin
4,4'-DDD
4,4'-DDE
gamma-chlordane
Heptachlor
6.68 dscm/min (236 dscf/min);
2.2 mg/m3 (0.001 gr/dscf);
0.37 ng/dscm @ 7% oxygen;
0.0066 kg/hr (0.003 Ib/hr); -
18.5%;
0.08 ug/m3;
2.27ug/m3;
2.31 Mg/m3;
0.10|Jg/m3;and
0.02 ug/m3.
5.8 Mercury Retort
The mercury retort system incorporates three batch furnaces. The process
is a two-stage, medium-temperature desorption process that has a low tem-
perature "hold" at 100°C (212°F) followed by a high temperature hold at
649°C (1,200°F). The feed material is shredded, blended with an additive,
and then heated to the initial temperature in a low-velocity air stream. The
vapor from this stream is then treated using condensation and activated car-
bon adsorption. The material is then heated at the higher temperature, again
in an air stream. The vapor is condensed to recover the mercury, and a car-
bon adsorption system is used to polish the offgas.
5.8.1 Fixed Base Commercial System
Mercury Recovery Services, Inc. has treated mercury-contaminated
soil at both the pilot- and commercial-scale (Weyand, Rose, and Zugates
1995). At the commercial-scale, soils contaminated at mercury concen-
trations ranging from 500 to 1,000 mg/kg were treated to less than 1 mg/
kg total residual mercury at batch cycle times of 2 hours. Mercury
TCLP values were consistently below detection limits of 0.002 mg/L.
The unit operated at a soil feed rate of 11 tonne/day (12 ton/day). The
mercury recovered during the process had 99% purity and was sold for
5.20
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Chapter 5
refining and reuse. The process exhaust consistently had mercury levels
below the OSHA respirator limit of 0.05 mg/m3.
5.9 Performance Data ~ Dloxln
Application of thermal desorption systems typically requires an evalua-
tion of the capability to meet performance standards for residual dioxins/
furans in the treated soil, concentration of stack gas emissions, or ambient
standards based on stack gas emissions. Generally, such data are presented
as concentrations of 2,3,7,8 TCDD TEQ. A summary of available data is
presented below.
5.9.1 Soil Residuals
A typical performance standard for 2,3,7,8 TCDD TEQ in treated soil is
1.0 JJg/kg. Figure 5.1 presents concentrations of 2,3,7,8 TCDD TEQ in feed
soil and treated soil from nineteen different sites. The data includes results
of bench-, pilot-, and full-scale studies. Data plotted at a temperature of
15.6°C (60°F) represents feed soil samples (where available). The data indi-
cate a strong correlation of decreasing residual concentration with increasing
soil treatment temperature. In general, all samples which were treated at a
temperature in excess of 371°C (700°F) resulted in residual concentrations of
2,3,7,8 TCDD TEQ of less than 1.0 jog/kg in the treated soil. Approximately
67% of the samples treated at temperatures of less than 371°C resulted in
residual concentrations of 2,3,7,8 TCDD TEQ of less than 1.0 fig/kg.
5.9.2 Stack Emissions
Stack emission concentrations of 2,3,7,8 TCDD TEQ for full-scale appli-
cations of three types of thermal desorption systems were compiled:
• directly-heated thermal desorbers with destructive-type systems
(6 data points);
• directly-heated thermal desorbers with recovery-type emission
control systems (2 data points); and
• indirectly-heated thermal desorbers with recovery-type emissions
control systems (6 data points).
5.21
-------
Case Histories and Performance Data
Figure 5.1
2,3.7,8-TCDD TEQ Values vs. Soil Treatment Temperature
100 e
10
=6
O.l
0.001
0.0001
•57
D
[]
[U
1
O
100
200 300 400
Soil Treatment Temperature ("C)
a
500
600
• Sital •Site 2 A Site 3 # Site 4 O Site 5 * Site 6 "M" Site 7
Q Site 8 ^Site9 *Site10 ft Site 11 <>Site12 * Site 13 + Site 14
X Site 15 •Site 16 O Site 17 A Site 18 V Site 19
Source: Cudahy and Trader 1991 (updated 1996)
Figure 5.2 presents minimum, average, and maximum values recorded
for each type of configuration. The average stack emission 2,3,7,8
TCDD TEQ concentrations for the three types of systems are 0.0198,
0.0281, and 0.2437 ng/dscm corrected to 7% oxygen, respectively. As a
benchmark for comparison, the proposed MACT standard for combus-
tion sources is 0.20 ng/dscm corrected to 7% oxygen. Therefore, the
average performance of directly-heated systems with both destructive-
and recovery-type emission control systems is approximately one order
5.22
-------
Chapter 5
of magnitude below the proposed MACT standard. While the average
concentrations measured for indirectly-heated systems with recovery-
type emission control systems were slightly above the proposed MACT
standards, these types of systems typically have a factor of 5 to 100
times less stack gas flow than directly-heated systems.
Figure 5.2
2,3,7,8-TCDD TEQ Stack Emission Concentration
C
*£
t—
a
a
0.01 =f
0.001 =
0.0001
Direct/Destructive Direct/Recovery Indirect/Recovery
I—I Low value
Esa Average value
E2S3 High value
Source: Cudahy and Troxler 1991 (updated 1996)
Directly-heated thermal desorption systems with both destructive- and
recovery-type emission control systems showed relatively little variation
range among the data points. In general, design and operating parameters
for these types of systems are well established and fall within a relatively
narrow range. For example, afterburners typically operate at exit gas
5.23
-------
Case Histories and Performance Data
temperatures of 927 to 1,093°C (1,700 to 2,000°F). Conversely, performance
data for indirectly-heated thermal desorbers with recovery-type emission
control systems showed much greater variability between the highest and
lowest values. The design and operating parameters for these types of sys-
tems tend to be contractor-specific and also exhibit wide ranges in values.
In order to compare the three types of thermal desorption systems on an
equivalent mass emission basis, a 2,3,7,8 TCDD TEQ stack emission factor
was developed with units of ng of emissions per ton of feed soil. The results
of this analysis are presented in Figure 5.3. As shown in Figure 5.3, average
stack emission factors for all three types of systems fall within a very narrow
range, with average values of 14.9, 5.3, and 17.3 ng/ton of feed soil, respec-
tively, for the three types of thermal desorption systems described above.
Figure 5.3
2,3,7,8-TCDD TEQ Stack Emission Factor
o
•§>
u.
c
o
§
0.01
Direct/Destructive Direct/Recovery Indirect/Recovery
i—i Low value
•• Average value
ES3 High value
Source: CudahyandTroxler 1991 (updated 1996)
5.24
-------
Appendix A
CASE HISTORIES*
Appendix A contains case histories for selected thermal desorption appli-
cations. Case histories were selected to represent a variety of types of tech-
nologies, waste types, and site conditions. Table A.O includes a list of
projects for which case histories are presented.
Table A.O
Case History Summary
Case #
1
2
3
4
5
Contractor
Maxymillian
OHM Corp.
Roy F. Weston
SoilTech
Williams
Site Name
Harbor Point
Re-Solve
Anderson
Development
Company
Pristine
TH Agriculture
& Nutrition
Site Size
(tonnes)
4,500
45,400
8,200
11,600
3,800
Contaminants
PAHs
PCBs
VOCs
PAHs
Pesticides
Equipment Type
Rotary Dryer/Afterburner
Indirect-Rotary Dryer
Thermal Screw
Anaerobic Thermal Process
Rotary Dryer/GAC
*Editor's Note: The case histories presented in Appendix A have been electronically tran-
scribed from the original source reports as published. No editorial changes were made to the
text of the report or the data reported therein. However, tables and figures were renumbered
and some values were provided in English or metric equivalents to conform to the format of
this monograph.
A.I
-------
Case Histories
Case 1 — Thermal Desorption of Coal Tar
Contaminated Soils from Manufactured
Gas Plants (NealA. Maxymillion and Stephen A.
Warren, Maxymillian Technologies, Inc. and Edward F.
Neuhauser, Ph.D., Niagara Mohawk Power Corporation)
Executive Summary
Maxymillian Technologies (MT) was selected to operate a full-scale dem-
onstration test of its thermal desorption technology on contaminated manu-
factured gas plant (MGP) soil at the Harbor Point Site in Utica, NY. The test
was conducted by Niagara Mohawk Power Corporation in cooperation with
the U.S. Environmental Protection Agency's Superfund Innovative Technolo-
gies Evaluation (US EPA SITE) Program. The MT transportable Thermal
Desorption System (TDS) consists of a rotary dryer with pollution control
equipment to destroy and remove volatilized contaminants. During the
Demonstration, the desorber was operated with rotary dryer soil exit tem-
peratures of 288-454"C (550-850°F), an afterburner exit temperature of
9828C (1,800°F) and a throughput of 11-23 tonne/hr (12-25 ton/hr). The
TDS proved to be effective in remediating MGP wastes including soil con-
taminated with PAHs, VOCs and cyanide. Throughout the Demonstration,
TDS emissions remained within acceptable limits. The TDS decontaminated
soil from four different waste streams to below detection limits and achieved
DREs of at least 99.99%.
Niagara Mohawk is Conducting a Demonstration Program
Niagara Mohawk Power Corporation (NMPC), in New York State, is
taking a responsible role in investigating, and where necessary, remediating
MGP sites. Through a research and development project, the company is
testing remediation technologies to find the most appropriate, cost-effective
method to remediate these sites.
A.2
-------
Appendfx A
MGP History
From the 1850s through the early 1960s, MGPs produced energy for
lighting and heating by converting coal into a gas product. The gas was then
processed to remove tar and other chemical compounds before it was piped
to homes and businesses. MGPs became obsolete after a network of pipe-
lines provided widespread availability of natural gas. The MGP process
generated residues that remain in the soil and water resources at the sites.
These wastes, according to the US EPA, primarily include coal tar, water-gas
tar, oil-gas tar, oils, tar-oil-water emulsions, and waste sludges. The con-
taminants in the soil are primarily volatile organic compounds (VOCs), poly-
nuclear aromatic hydrocarbons (PAHs), cyanide (CN), arsenic and lead.
Research and Development Project
NMPC is conducting a full-scale research and development project to
evaluate technologies to remediate MGP waste sites. The demonstration
program is being conducted with the support of the US EPA, the New York
State Department of Environmental Conservation (NYSDEC), and various
utility groups such as EPRI and GRI, who are co-funding the project.
Throughout the project NYSDEC played an important role in overseeing
and monitoring this program. Together, NMPC and NYSDEC conducted a
well-organized demonstration which included public involvement. NMPC
implemented a public participation program that involved voluntary public
meetings and an informational hot-line. This effort increased public aware-
ness of the demonstration and helped obtain local support.
For the program, NMPC selected the Harbor Point Site, in Utica, New
York, for its size, location, and variety of pollutants found at the site. NMPC
constructed a new research facility at the 65 acre site, where, over the next
few years, NMPC will conduct a series of remediation demonstrations. The
results of the project will be used to determine the best method for
remediation of MGP sites, both on NMPC property and elsewhere.
For the program, NMPC is contracting with technology vendors to dem-
onstrate their full-scale remediation systems. NMPC will evaluate each
vendor's technology through the use of an oversight engineering firm. Addi-
tionally, NMPC has enlisted the support of the US EPA SITE program,
which will perform an independent evaluation of select technologies.
A.3
-------
Figure A. 1.1
Maxymillian Technologies' Thermal Desorption System
-------
Appendix A
Maxymillian Technologies Demonstrated
its Thermal Desorption System
Maxymillian Technologies was selected by Niagara Mohawk to demon-
strate its full-scale thermal desbrptioh technology on MGP wastes. Refer to
Figure A. 1.1, a photograph of the desorber as it appeared at NMPC's demon-
stration facility. The Maxymillian Technologies Thermal Desorber was
evaluated by NMPC and its consultants, and selected for the demonstration
program in early 1993. The technology was also accepted into the US EPA
SITE program in 1993.
The Maxymillian Technologies Thermal Desorption System (TDS) is
based on rotary dryer technology to decontaminate soils. The thermal treat-
ment process involves two steps: volatilization of contaminants followed by
treatment of the volatilized gases. During the volatilization step, contami-
nated materials are exposed to high temperatures in a co-current flow rotary
dryer, causing contaminants to volatilize to the gas phase. The clean soils
are then discharged and stockpiled for testing. The gas stream passes to the
downstream pollution control equipment, where contaminants are destroyed
prior to release to the atmosphere.
The TDS was modified to operate at the Harbor Point Site. One signifi-
cant modification was reconfiguring the burners to operate on natural gas
instead of fuel oil. The burners were successfully converted, and the utility
usage results are presented in Table A. 1.1.
The Maxymillian Technologies TDS components
The Maxymillian Technologies TDS system is made up of a series of
separate components, linked together and centrally controlled by an operator
in the process control room. Refer to Figures A. 1.2 and A, 1.3, a Process-
Flow Diagram and a Plan View of the TDS. The system consists of the fol-
lowing components:
• computer controlled feed system;
• rotary dryer;
• cyclone;
• afterburner;
• quench tower;
A.5
-------
Thermal
Run#
TE-068
TE-069
TE-070
TE-071
CG-057
CG-058
CG-059
CG-060
CG-076
CG-077
CG-078
PS-061
PS-062
PS-063
PS-064
PS-065
PS-079
PS-080
PS-081
Date
Tues. 11/9
Tues. 1 1/9
Tues. 1 1/9
Wed. 11/10
Tues. 1 1/2
Tues. 1 1/2
Tues. 11/2
Wed. 11/3
Tues. 11/16
Tues. 11/16
Wed. 11/17
Thurs. 1 1/4
Thurs. 11/4
Thurs. 11/4
Thurs. 11/4
Fri. 11/5
Thurs. 11/18
Thurs. 11/18
Fri. 11/19
Waste
Stream
Tar mixed
w/50% clean
Tar mixed
w/33% clean
Tar mixed
w/33% clean
Tar mixed
w/33% clean
Coke Plant
Coke Plant
Coke Plant
Coke Plant
Coke Plant
Coke Plant
Coke Plant
Purifier Soils
Purifier Soils
Purifier Soils
Purifier Soils
Purifier Soils
Purifier Soils
Purifier Soils
Purifier Soils
Phase
Experimental
Experimental
Experimental
Experimental
; ;j
Experimental
Experimental
Experimental
Experimental
Formal
Formal
Formal
Experimental
Experimental
Experimental
Experimental
Experimental
Formal
Formal
Forma]
Thruput
(ton/hr)
15
15
15
14
13
18
18
12
15
15
15
15
15
25
25
20
20
20
20
Table A. 1.1
Desorption System Utility Usage
Temp. Start
(*F) Time
700 09:07
800 11:27
700 12:50
800 08:50
600 10:37
600 12:30
550 14:40
600 15:00
600 09:30
600 15:50
600 10:27
600 10:00
700 11:33
600 13:10
550 14:50
800 09:55
850 09:13
850 15:00
850 09:00
Stop Natural Gas Electricity
Time (cf) (gas/ton) (kWh) (kWh/ton)
10:23 56,000
12:25 55,000
13:50 52.000
12:42 220,000
12:05 79,000
13:40 63,000
15:45 64,000
18:50 202,000
13:40 116,000
19:20 199,000
14:06 203,000
11:15 54,000
12:38 51,000
14:25 69,000
15:31 48,000
14:25 236,000
13:27 205,000
1838 180,000
12:30 179,000
3,340.06 300
4,438.43 300
4,958.27 300
4,167.06 UOO
4,331.42 600
2,858.47 300
3,480.76 600
4,254.79 1,200
1,777.06 1400
3,628.06 1,200
3473.78 1,200
2,909.82 300
3,128.34 300
2,242.85 300
2,864.66 600
2,64940 1400
2,625.38 900
2,574.04 900
2,59747 900
17.89
24.21
28.61
22.73
32190
13.61
32.63
25.28
22.98
21.88
21.13
16.17
18.40
9.75
35.81
16.84
1143
12.87
13.06
Water
(gal/min) (gal/ton)
77.93
70.03
72.82
8422
70.65
67.%
74.46
77.07
82.14
8846
89.11
63.81
70.71
80.37
81.20
83.08 '
91.74
9Z70
87.38
353.23
327.75
41649
370.11
340.88
215.85
263.23
373.38
314.60
339.05
343.55
257.89
281.93
195.93
198.68
251.84
298.43
288.99
Case Histories
266.29
-------
HS-088
HS-089
HS-090
HS-091
HS-092
HS-093
HS-094
WG-084
WG-085
WG-086
WG-087
WG-095
WG-096
WG-097
Wed. 12/1
Wed. 12/1
Wed. 12/1
Thurs. 12/2
Tues. 12/7
Tues. 12/7
Wed. 12/8
Mon. 11/29
Mon. 11/29
Mon. 11/29
Tues. 11/30
Thurs. 12/9
Thurs. 12/9
Fri. 12/10
Harbor
Sediments
Harbor
Sediments
Harbor
Sediments
Harbor
Sediments
Harbor
Sediments
Harbor
Sediments
Harbor
Sediments
Water Gas
Plant
Water Gas
Plant
Water Gas
Plant
Water Gas
Plant
Water Gas
Plant
Water Gas
Plant
Water Gas
Plant
Experimental
Experimental
Experimental
Experimental
Formal
Formal
Formal .
Experimental
Experimental
Experimental
Experimental
Formal
Formal
Formal
15
15
15
17
17
17
17
14
17
18
18
18
18
18
600
700
800
750
750
750
750
700
800
850
800
800
800
800
09:37
11:20
13:15
09:31
10:43
15:47
08:35
10:00
11:30
13:00
09:21
/ 08:30
13:15
16:05
10:57
12:09
15:20
13:01
14:15
19:21
12:13
11:00
12:30
14:00
13:40
11:57
16:45
19:45
81,000
108,000
87,000
223,000
221,000
206,000
222,000
65,000
71,000
56,000
177,000
161,000
157,000
179,000
3,829.47
8,525.33
2366.94
3359.14
4,146.07
3,388.45
3,811.77
4,594.62
3,996.40
3,230.03
2,353.48
2,896.47
2,617.31
3,10739
600
600
600
1,200
1,200
1300
1,200
300
600
300
1,200
900
900
1,200
28.37
47.36
17.70
19.15
2231
19.74
20.60
21.21
33.77
17.30
15.96
16.19
15.00
20.83
91.48
89.35
87.64
92.11
92.22
9130
93.04
83.14
80.72
84.78
88.28
88.02
88.12
85.78
345.99
345.60
323.21
308.73
366.79
322.10
348.26
352.61
272.60
293.39
304.02
327.77
307.03
327.64
1
9?
»
i>
-------
Case Histories
• baghouse;
• ID fan and exhaust stack;
• multi-stage dust suppression system; and
• process control room.
Soil Decontamination
The process begins when prepared soils are loaded into the feed bin of the
waste feed system. The computer controlled feed system includes four 18
tonne (20 ton) storage bins which provide temporary residence for the waste
feed materials. Material that is fed to the rotary dryer comes from a stock-
pile which has been tested to determine the average contaminant concentra-
tion. A feed belt at the base of the bin delivers soil to an incline conveyor
belt that leads to the drum volatilizer. The incline conveyor belt is equipped
with a weigh scale in the control center, where the Plant Operator controls
the feed rate.
Soil is fed from the incline conveyor belt into the rotary dryer, where the
contaminants are thermally transferred from the soil into the gas stream.
This thermal transfer takes place as the soil is exposed to heat from the direct
fire natural gas burner located at the feed end of the rotary dryer. Quick
moisture removal permits longer soil residence times at optimum volatiliza-
tion temperatures. The rotary dryer burner firing rate can be varied accord-
ing to desired soil exit temperatures. The rotary dryer and burner system can
support soil exit temperatures ranging from 149 to 538°C (300 to 1,000°F).
Special steel alloys are used to line the rotary dryer, providing for a wide
.range of soil exit temperatures without the use of refractory.
The rotary dryer is inclined and rotates to convey the soils from the feed
end to the discharge end. The parallel flow of soils and gases in the rotary
dryer results in desired heat exchange between the two media. Parallel flow
also ensures that all airborne dust particles are thoroughly decontaminated
as they travel the length of the rotary dryer. The transfer of contaminants
into the gas phase is driven by three factors: turbulence, temperature, and
residence time. Turbulence is provided by the rotation of the rotary dryer
and is enhanced by flights affixed to the drum's interior surface. These
flights lift and veil the soil, thus exposing greater surface area to the hot
gases for improved volatilization. Soil exit temperature is controlled by the
firing rate of the burner.
A.8
-------
Figure A. 1.2
Process-Flow Diagram of Maxymillian Technologies Thermal Desorption System
-Atomizing Air
Rotary
Dryer
one
/
,..>
Afterburner
Jnt
Quench
Tower
Multi-Stage Dust
Suppression System
Baghouse
Makeup
Exhaust
Stack
Monitoring Points:
1 Soil Feed Rate 4 Soil Discharge Temperature 7 Quench Exit Temperature 10 Stack Gas Flow Rate
2 Dryer Entry Pressure 5 AB Gas Exit Temperature 8 Baghouse Differential Pressure 11 CEM (O2. CO2, CO, NOX, SO2, THC)
3 Dryer Gas Exit Temperature 6 Quench Water Flow 9 ID Fan Differential Pressure
!
0.
-------
Figure A. 1.3
Plan View of Maxymillian Technologies Thermal Desorption System
>
O
129 MM Btu/hr Direct Fired Burner
Control
Room
110 MM Btu/hr
Direct Fired Burner
' Thermal Relief Vent
Quench
o
Q
I
I
CD
-------
Appendix A
Residence time is a function of the incline angle of the rotary dryer, and
the rotation speed of the drum. Residence time for all soil is approximately
five (5) minutes to ensure that soils reach required exit temperatures. De-
contaminated soil exits from the drum to the soil discharge cooler, the first
stage in the multi-stage dust suppression system.
In the multi-stage dust suppression system the soil is mixed with residual
paniculate matter removed from the gas stream and a controlled volume of
water. Water is sprayed onto and blended into the soil to cool the soil and to
control fugitive dust. Soil is discharged from a radial stacking conveyor and
stored temporarily prior to testing. Processed soils are sampled and ana-
lyzed to verify attainment of the target cleanup levels.
Pollution Control
Heated gases which cause the volatilization of contaminants travel simul-
taneously and co-currently with soils. The entire system, from the rotary
rotary dryer to the induced draft (ID) fan, operates under negative pressure.
Negative pressure prevents fugitive emissions of gases and particulates from
the closed system to the atmosphere.
Gases are drawn from the drum volatilizer through ductwork into the
cyclone. Within the cyclone, large particulate matter entrained in the gas
stream is removed by centrifugal force. The particulate matter drops through
an air lock at the base of the cyclone and is discharged to the multi-stage
dust suppression system. Gases and remaining fine particulates exiting the
cyclone are drawn through ductwork into the afterburner.
The afterburner subjects the contaminated gases to high temperatures to
destroy the contaminants. The afterburner is designed to achieve 99.99%
Destruction and Removal Efficiency (DRE). Destruction of contaminants in
the afterburner is a factor of turbulence, temperature, and residence time.
Turbulence is created by tangential entry of the gases into the swirling flame
of the gas fired burner. Temperature and residence time of the gases are
controlled by the burner firing rate and the volume of air flow. Exit gas
temperature can range from 871 to 1,093°C (1,600 to 2,000°F) and is main-
tained at 982°C (1,800°F). A programmable controller ensures the after-
burner operates at a sufficiently high temperature to destroy contaminants in
the process gases. Data from the Continuous Emissions Monitor are moni-
tored to ensure that proper destruction takes place.
A. 11
-------
Case Histories
Gases are drawn by the ID fan from the afterburner through a refractory
lined duct to the quench tower. Hot process gases pass through highly atom-
ized water mists. This cooling protects the baghouse from high tempera-
tures. The baghouse is a dry filtering device that contains a series of four-
teen compartments, each of which contains forty-eight Triloft filtering bags.
Gases are drawn from the exterior surface of the bags to the interior, leaving
any remaining particles and dust on the outside surface of the bags.
A pulse jet air cleaning system, operating sequentially through the com-
partments, causes the particles to fall from the exterior surface of the bags to
a drag slat conveyor at the bottom of the baghouse. The drag slat conveyor
carries the paniculate matter to the multi-stage dust suppression system,
where the material is mixed with soil from the rotary dryer. Cleaned gases
exit the baghouse and are released through the stack where exhaust exit tem-
peratures range from 149 to 204°C (300 to 400°F).
The Demonstration Test
The Thermal Desorption Demonstration Project was conducted at the
NMPC MGP Remediation Technologies Facility at Harbor Point. A work plan
was developed for five separate waste streams from five separate areas of the
site, including: Coke Plant, Tar Emulsions, Purifier Wastes, Water Gas Plant
and Harbor Sediments. However, the MGP activities which created the Tar
Emulsions waste source are not indicative of most MGP sites; thus the Tar
Emulsions waste stream was not included in the Formal demonstration. Addi-
tionally, Purifier Wastes contain high levels of sulfur which would lead to short
term increases in SO2 stack emissions. To simplify the Demonstration Test, the
Desorber was not configured with a scrubber. As a result, Purifier Soils were
chosen to replace Purifier Waste — Purifier Soils are from the same waste
source area but have significantly less sulfur content.
Approximately 907 tonne (1,000 ton) of soil from each source area was
excavated and transported to an on-site materials processing area. The
source materials were then physically processed to achieve uniformity of
size and contaminant levels and subsequently stored in temporary structures.
The Project Followed a Two Phased Approach
The demonstration program included an Experimental phase followed by
a Formal phase. The Experimental phase was designed to identify the TDS's
A.12
-------
Appendix A
operational parameters that produce satisfactory soil cleanup and stack emis-
sions levels. For each specific waste stream, Experimental testing consisted
of processing at different soil exit temperatures and feed rates while main-
taining constant afterburner temperatures. The Formal phase of testing in-
volved performing three replicate runs for each waste stream. The TDS
operational parameters selected were based on results from the Experimental
phase. Table A. 1.2 provides a summary of run parameters.
The Demonstration Test Involved Several Engineering Firms
Atlantic Environmental Services (AES) served as the prime contractor to
oversee the Demonstration Test. AES performed extensive soil sampling
using their on-site screening laboratory. Maxymillian Technologies con-
tracted Tighe & Bond Laboratory Services to perform soil sampling TRC
Environmental was contracted by AES and Maxymillian Technologies to
perform stack sampling and analysis. SAIC Corporation served as the US
EPA contractor for the SITE program and contracted IT Corporation to per-
form stack sampling and analysis for the SITE program.
A Sampling and Analytical Plan was Designed to Evaluate Results
Extensive sampling of feed soil, processed soil, and stack gas was con-
ducted for each operational parameter to evaluate TDS performance (refer to
Table A. 1.3). During the Experimental phase, samples of processed soil at
each temperature setpoint were analyzed overnight by AES's on-site screen-
ing lab to determine an optimum temperature for toluene, ethylbenzene and
xylenes (TEX) and PAH removal Confirmatory soil samples taken by Tighe
& Bond were sent off-site for more detailed and sensitive analysis
Throughout Experimental tests, stack emissions were continuously moni-
tored for CO, C02, 02, THC, NOx and SO2. Also, a volumetric sample was
analyzed for cyanide.
Once the optimum soil exit temperature for each waste stream was deter-
mined, an additional test run at optimum temperature was performed Dur-
ing this 3-hour run the waste stream was spiked with a measured amount of
naphthalene. Stack emissions sampling was expanded to include sampling
trains for volatiles, semivolatiles, metals and particulate. Results from this
expanded Experimental test included a calculation of Destruction and Re-
moval Efficiency (ORE) for naphthalene.
A.13
-------
Case Histories
Table A. 1.2
Summary of IDS Runs and Parameters
During the Harbor Point Demonstration
Waste Stream
Coke Plant
-
Purifier Soils
Harbor Sediments
Water Gas
Demonstration Phase
Experimental
Experimental
Experimental
Experimental
Formal
Formal
Formal
Experimental
Experimental
Experimental
Experimental
Experimental
Formal
Formal
Formal
Experimental
Experimental
Experimental
Experimental
Formal
Formal
Formal
Experimental
Experimental
Experimental
Experimental
Formal
Formal,
Formal
Run Number
CG-057
CG-058
CG-059
CG-060
CG-076
CG-077
CG-078
PS-061
PS-062
PS-063
PS-064
PS-065
PS-079
PS-080
PS-081
HS-088
HS-089
HS-090
HS-091
HS-092
HS-093
HS-094
WG-084
WG-085
WG-086
WG-087
WG-095
WG-096
WG-097
Throughput Soil Exit Temperature
(ton/hr) CF)1
13
18
18
12
15
15
15
15
15
25
25
20
20
20
20
15
15
15
17
17
17
17
14
17
18
18
18
18
18
600
600
550
600
600
600
600
600
700
600
550
800
850
850
850
600
700
800
750
750
750
750
700
800
850
800
800
800
800
'Afterburner exit temperature 1800T
A.14
-------
Appendix A
Table A. 1.3
Schedule of Sampling and Analysis — Experimental and Formal Phases
Matrix
Sample Frequency
Analytical Parameter'
Atlantic Environmental
\
InfeedSoil
Outfeed Soil
one composite per run
one composite per run
PAHs, TEX, % solids, cyanide
PAHs, TEX, % solids, cyanide
' Tighe&Bond
InfeedSoil
Outfeed Soil
one composite per run
one composite per run
PAHs
BTEX
% solids
total solid cyanide
total As
total Pb
PAHs
BTEX
% solids
total solid cyanide
TCLP metals
TRC Environmental
Stack Gas
Continuous Emissions Monitor (CEM)
one per run for 240 min
three per run for 40 min
one per run for 60 min
one per run for 60 min
one per run for 120 min
O2/CO2
CO
NOX
SO2
THC
PAHs and other SVOCs
BTEX and other VOCs
paniculate
HCN
As and Pb
SAIC
Infeed Soil 4 /run for 30 min
I/test condition
8 /run for 30 min
I/test condition
4 /run for 30 min
4 /run for 30 min
I/run
I/run
I/test condition
I/test condition
1 /test condition
I/test condition
I/test condition
PAHs
other SVOCs
BTEX
other VOCs
moisture
cyanide
As and Pb
particle size
ultimate
proximate
ash fusion temperature
ash mineral analysis
percent chlorine
A.15
-------
Case Histories
Table A. 1.3 cont.
Schedule of Sampling and Analysis — Experimental and Formal Phases
Matrix Sample Frequency
Analytical Parameter1
SAIC
Outfeed SoU 4Aun for 30 min
I/test condition
8/run for 30 min
I/test condition
I/run
4 Ann for 30 min
I/run
I/test condition
-
PAHs
other SVOCs
BTEX
other VOCs
moisture
cyanide
As and Pb
TCLP
particle size
IT Corporation
Stack Gas Continuous Emissions Monitor (CEM)
I/run
3/run
I/run
I/run
I/run
cyco2
CO
NOX
SOj
THC
PAHs and other SVOCs
BTEX and other VOCs
paniculate
cyanide
As
Pb
'The following polynuclear aromatic hydrocarbons (PAHs) were analyzed for Naphthalene, 2-Methylnaphthalene, 1 -
Methylnaphthatene, Acenaphthylene, Acenaphthene, Fluorsne, Phenanthrene, Anthracene, Fluoranthene, Pyrene,
Benzo(a)anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, lndeno(1,2,3-
cdjpyrene, Dibenzo(a,h)anthracene, Benzo(g,h,i)perylene.
The Formal phase was comprised of three replicate runs based on the
operational parameters determined in the Experimental phase. The US EPA
SITE program provided independent analysis and evaluation of the TDS
performance. The Formal phase test runs involved sampling and analysis by
SAIC and IT Corporation that duplicated tests performed by AES, Tighe &
Bond and TRC during the Experimental phase. Refer to Table A. 1.3, Sched-
ule of Sampling and Analysis.
A.16
-------
Appendix A
The Demonstration Test Provided Excellent Results
The demonstration test was conducted over the course of six weeks, in
November and December, 1993. Each waste stream was processed at a vari-
ety of parameters during the Experimental phase. MT then determined pa-
rameters for the Formal stack testing phase by evaluating screening results
and operational observations from the Experimental phase. In both the Ex-
perimental and Formal phases, the TDS successfully remediated contami-
nated soils with infeed PAH concentrations of 100-3,300 mg/L to outfeed
PAH concentrations of non-detect to 50 mg/L. Refer to Table A. 1.4 for the
percent of contaminants removed from soil.
Table A. 1.4
Percent Removal of Contaminants from Soil
Coke Plant
Purifier Soils
Tar Emulsions
Harbor Sediments
Water Gas Plant
Total PAHs
(%)
99.32
97.94
99.72
99.48
99.76
BTEX
<*)
89.49
53.37
100.00
99.88
99.70
Cyanide
(%)
84.87
96.69
85.65
43.53
59.07
Materials Handling Was a Significant Factor
Excavation activities from the source areas took place under an accel-
erated schedule during the fall of 1993. Due to time constraints, mate-
rial processing was limited to size reduction and contaminant mixing.
Adequate time for dewatering and moisture content reduction was not
available. To compensate for limited dewatering, MT decided to con-
duct a Material Handling Shakedown test for each waste stream to as-
sess the physical properties of the soil. This Shakedown test provided
valuable information which helped MT determine best operating
A.17
-------
Case Histories
parameters for each waste stream and prepare for the erratic moisture
content of the soil. The most significant conclusion of the Materials
Handling Shakedown was the direct link between soil feed consistency
and moisture content, and the ability to maintain stable TDS operations.
Further, the Demonstration test illustrated appropriate materials han-
dling procedures for a full-scale remediation by thermal desorption.
Tar Emulsions Soil
Tar Emulsions soil was not used in the Formal test, but it was tested in the
Materials Handling Shakedown and Experimental phases to determine the
feasibility of thermally desorbing this waste stream. Tar Emulsions soil had
13-28% moisture content and was very cohesive, forming clumps up to 61
cm (24 in.) in diameter. In this state, Tar Emulsions soil was very difficult to
feed uniformly into the TDS, resulting in inconsistent operations. Tar Emul-
sions soil was easy to desorb once it was fed into the TDS.
MT recommended mixing Tar Emulsions with a drier, less cohesive
material to provide uniform feed. During a full-scale remediation, this
waste stream would be mixed with another waste stream. For the pur-
pose of this test, clean, dry soil was mixed with Tar Emulsions at various
ratios to simulate blending with granular, yet contaminated material.
MT concluded that the optimum mixture for handling was 50% Tar
Emulsions to 50% granular soil.
Purifier Waste
Purifier Waste was not used in the Formal demonstration. Purifier Waste
were intended for the Demonstration, however, high sulfur contents contrib-
uted to the formation of high short term levels of SO2. For full-scale
remediation, pollution control equipment designed for scrubbing SO2 would
have been utilized for this waste stream. Purifier Waste is a non-cohesive
matrix with high wood chip content which processes easily through the TDS.
Coke Plant Soil
Coke Plant soil was of uniform gradation and low moisture content (13-
19%) with some clay content. It tended to stick slightly at the feed bins and
shaker screen requiring one person to be stationed at each location to assist
in maintaining a uniform feed rate.
A.18
-------
Appendix A
For full-scale remediation, minimal modifications could be made to pro-
vide a uniform feed and eliminate the need for these technicians. Partial
drying of the soil and/or strategically placed vibrators would assist in feed-
ing Coke Plant material. Coke Plant soil could potentially be blended with
more cohesive waste streams to help them feed more uniformly.
Purifier Soils
Purifier Soils material was of uniform gradation with a moisture content
of 13-25% and a small percentage of wood chips. Feed rates of 18 to 23
tonne/hr (20 to 25 ton/hr)(design maximum for TDS) were uniform and
consistent.
Similar to Purifier Waste, the granular Purifier Soils blended well with
wet, cohesive waste streams to make them more manageable to feed. MT
also discovered that the higher throughput entrained much more paniculate
in the steam from the soil discharge system. Additional water sprays and
frequent cleaning of particulate knockout devices kept the particulate from
becoming a problem.
Harbor Sediments
Harbor Sediments were of uniform gradation and somewhat granular
but had a moisture content ranging from 19 to 28% with pockets of
much wetter material. Due to the high moisture content, this flowing
soil would not hold an angle of repose. Consequently, the initial shake-
down runs included blending the material with first 50% then 40%
clean, dry soil. Blending with dry soil made Harbor Sediments more
cohesive in the feed system. When a pocket of much higher moisture
content (estimated 35%) was fed into the system, it flowed rapidly out
of the feed bin, surged into the feed system and upset the rotary dryer
temperature. Harbor Sediments would benefit from air drying and from
thorough blending of stockpiles for a uniform moisture content.
Water Gas Plant Soil
Water Gas Plant soil was cohesive with moisture contents ranging from
13 to 30%. The soil had areas with high "asphalt-like" sheens and areas
with strong odors. The cohesive material caused some waste feed blockage,
requiring technicians at the cold feed bin and the rotary dryer feed chute.
A.19
-------
Case Histories
Table A. 1.5
Summary of IDS Soil Analytical Results
from the Harbor Point Demonstration
Infced
Moisture Infeed
Run Content Total
Number1 (%) PAH2
CG-057-E
CG-058-E
CG-059-B
CG-060-E
CG-076-F
CG-077-F
CG-078-F
PS-061-E
PS-062-E
PS-063-E
PS-064-E
PS-065-E
PS-079-F
PS-080-F
PS-081-F
HS-088-E
HS-089-E
HS-090-E
HS-091-E
HS-092-F
HS-093-F
HS-094-F
WG-084-E
WG-085-E
WG-086-E
WG-087-E
WG-095-F
WG-096-F
WG-097-F
15
16
13
13
18
18
19
13
18
17
17
19
22
23
25
24
24'
19
28
28
26
28
21
13
16
18
30
29
26
2089.55
539.30
478.79
433.11
98.10
99.90
7180
749.46
825.88
772.73
1220.10
879.48
692.00
243.90
303.00
893.56
710.13
849.12
893.84
795.60
954.00
812.00
2261.02
1770.70
2522.68
2083.80
1375.00
1448.00
1610.00
Outfeed
Total '
PAH2
ND
ND
22.23
3.55
ND
ND
ND
33.63
9.42
9.54
64.55
ND
ND
ND
ND
4.92
4.46
ND
12.86
2.23
3.82
2.54
3.48
ND
ND
4.88
7.29
10.14
4.93
Infeed
Total
BTEX2
ND
ND
ND
ND
0.48
0.36
0.44
ND
ND
ND
ND
ND
0.31
0.11
0.30
32.52
22.32
22.18
25.60
8.36
10.37
20.50
188.78
126.87
122.24
163.77
84.40
93.50
52.00
Outfeed Infeed
Total Total
BTEX2 Cyanide3
ND
ND
ND
ND
0.10
ND
0.04
ND
ND
ND
ND
ND
0.11
0.13
0.09
ND
ND
ND
ND
0.17
ND
ND
ND
ND
ND
ND
0.94
1.07
0.38
164.49
166.31
264.85
172.89
160.00
170.00
190.00
1046.70
1212.71
1164.89
1319.74
1363.58
2100.00
2900.00
2300.00
15.78
36.61
24.75
15.19
< 50.00
< 50.00
< 60.00
32.75
32.15
40.39
97.36
< 60.00
< 60.00
< 50.00
Outfeed
Total
Cyanide3
26.94
32.79
1.67
42.58
< 20.00
39.00
32.00
52.07
8.48
81.93
213.98
7.48
< 30.00
< 30.00
< 20.00
6.75
0.83
2.83
2.09
< 40.00
< 40.00
< 50.00
0.80
0.85
0.89
ND
< 50.00
< 50.00
< 50.00
Outfeed
TCLP for As
andPb4
ND
ND
5.5 mg/L (Pb)
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AH values reported in mg/kg, except where otherwise noted.
ND Non detectable
'•£" denotes experimental phase runs, "P denotes formal phase runs.
2Experimental phase results from AES's on-site screening lab, detection limit of 3,00 mg/kg. Formal phase results from
TTghe & Bond's off-site lab, detection limit of 0.010-1.000 mg/kg.
"Experimental phase results from AES's on-site screening lab. Formal phase results from Tighe & Bond's off-site lab.
••Results from Tighe & Bond's off-site lab with detection limit of 1 mg/L.
A.20
-------
Appendix A
Technicians in close proximity to the Water Gas Plant soil were required to
wear respirators due to the volatiles.
Water Gas Plant soil had slugs of high contamination that were not visibly
detectable, but caused temperature surges in the TDS. These surges, result-
ing from the fuel value of the contaminants, caused the rotary dryer tempera-
ture to vary. Further mixing of the waste feed stockpile improved the unifor-
mity, however, temperatures continued to vary. In order to maintain positive
system control, MT blended approximately 15% clean soil with-Water Gas
Plant soil. This blending served to minimize temperature surges. For full-
scale remediation with this waste stream, MT recommends more advance
analysis of the soil to predict the fuel contribution from the contaminants.
Thermal Desorption is an Effective Technology for MGP Sites
MT demonstrated that the TDS effectively remediated MGP wastes in-
cluding soil contaminated with PAHs, VOCs and cyanide. Refer to Table
A. 1.5 for soil analytical results and to Table A. 1.6 for stack gas analytical
results. Throughout the Demonstration, stack emissions remained within
acceptable limits. Refer to Table A. 1.7 for a list of Continuous Emissions
Monitoring results. The TDS decontaminated soil from four different waste
streams to below detection limits and achieved DREs of at least 99.99% in
all cases except one Water Gas Plant Formal phase run. Since these con-
taminants are found at many MGP sites, the results indicate that thermal
desorption would be an effective technology for other sites.
Cost Estimate
Due to the relatively small volume of material processed and the added labor
and equipment costs associated with a large-scale, multiple waste stream, mul-
tiple sampling subcontractor demonstration test, costs recorded for TDS opera-
tions at the Harbor Point Site Demonstration are inherently higher than produc-
tion operations for remediation of a site. Therefore, to provide an estimate of
expected costs associated with cleanup of an MGP site, MT projected costs for
TDS production operations using the operations experience and costs recorded
for the Harbor Point Site Demonstration as a basis.
MT's assumptions for this cost estimate include full TDS production
operations on a 18,142 tonne (20,000 ton) site within a 402.3 km (250 mil)
radius of our Pittsfield, MA office. MT assumes a TDS soil feed rate of 23
A.21
-------
Case Histories
tonne/hr (25 ton/hr), 90% on-line efficiency, and operations 10 hr/day, 5 days
per week processing MGP contaminated soils with a 15% moisture content.
Refer to Table A. 1.8 for a comparison of items included in and excluded
from each cost category. Refer to Table A. 1.9 for a breakdown of costs.
Table A. 1.6
Summary of IDS Stack Gas Analytical Results
from the Harbor Point Demonstration 1
Run#2
CG-060-E
CG-076-F
CG-077-F
CG-078-F
PS-065-E
PS-079-F
PS-080-F
PS-081-F
HS-091-E
HS-092-F
HS-093-F
HS-094-F
WG-087-E
WG-095-F
WG-096-F
WG-097-F
Naphthalene
ORE
(%)3
99.9980
99.9931
99.9954
99.9978
99.9983
99.9969
99.9944
99.9959
99.9994
99.9991
99.9993
99.9981
99.9985
99.7232
99.9935
99.9987
PAH
Emission
Rate
(Ib/hr)
1.15E-03
8.64E-04
6.08E-04
3.15E-04
2.61E-04
3.85E-04
5.91E-04
4.39E-04
1.57E-04
3.80E-04
2.70E-04
4.65E-03
5.03E-04
1.46E-01
3.00E-03
2.57E-03
Paniculate
Emissions
(gr/dscf)4
0.034
0.042
0.025
0.021
0.016
0.018
0.024
0.027
0.037
0.035
0.030
0.037
0.030
0.031
0.036
0.044
HCN
Emission
Rate
(Ib/hr)5
0.004
0.010
0.015
0.015
0.037
0.025
0.073
0.057
0.011
0.003
0.003
0.009
0.008
0.013
0.025
0.011
Arsenic
Emission
Rate
(Ib/hr)6
<2.72E-04
<9.62E-04
<4.93E-04
<3.66E-04
<6.91E-04
< 1.07E-03
< 1.38E-03
1.38E-03
<1.42E-04
< 2.40E-04
<2.12E-04
2.27E-04
<3.12E-04
<2.66E-04
< 2.98E-04
3.44E-04
Lead
Emission
Rate
(Ib/hr)7
9.85E-04
<8.27E-04
<2.80E-04
<4.94E-04
<1.72E-03
<5.34E-04
<2.18E-03
2.64E-03
4.41E-04
8.17E-04
8.09E-04
1.03E-03
1.79E-03
2.42E-03
2.17E-03
2.65E-03
'Sampling, analysis and calculations by TRC Environmental Consultants, Inc.
^E" denotes experimental phase runs, "P denotes formal phase runs.
"Spiking with naphthalene at 10 Ib/hr. ORE calculations account (or native concentrations of naphthalene in infeed soil.
•Corrected to 7% oxygen.
5Maximum allowable emission rate per NYS air regulations 0.3 Ib/hr.
•Maximum allowable emission rate per NYS air regulations 2.5E-03 Ib/hr.
'Maximum allowable emission rate per Boiler and Industrial Furnace regulations 6.4E-01 Ib/hr.
A.22
-------
Table A. 1.7
Continuous Emissions Monitoring Averages of Demonstration Processing Daily Averages
Date Start
Waste Stream (1993) Time
Tar w/33% clean 11/9 '09:20
Tar w/33% clean 11/10 08:30
Coke Plant 11/2 10:20
Coke Plant 11/3 15:00
Coke Plant 11/16 15:40
Coke Plant 11/17 09:20
Purifier Soils 11/4 10:00
Purifier Soils 11/5 08:10
Purifier Soils 11/18 08:40
> Purifier Soils 11/18 14:50
k> Purifier Soils 11/19 08:40
00 Harbor Sediments 12/1 09:30
Harbor Sediments 12/2 09:20
Harbor Sediments 12/7 10:00
Harbor Sediments 12/7 15:31
Harbor Sediments 12/8 08:10
Water Gas Plant 11/29 10:00
Water Gas Plant 11/30 09:00
Water Gas Plant 12/9 08:43
Water Gas Plant 12/9 13:10
Water Gas Plant 12/10 15:30
Stop
Time
14:10
13:00
15:40
19:00
19:30
14:20
16:10
14:50
13:50
18:40
12:50
15:50
14:00
14:40
19:50
13:00
14:20
14:00
12:46
17:15
20:10
Moisture
45
45
45 -
45
43
NA
45
45
NA
NA
NA
NA
NA
49
' NA
NA
NA
NA
NA
NA
NA
3)
10.85
10.29
10.72
11.26
10.75
10.71
9.00
8.10
8.60
8.45
8.20
8.88
8.10
7.95
8.07
8.85
9.19
8.78
8.12
8.25
8.95
C02
6.30
6.63
6.43
6.10
6.52
6.49
7.70
8.25
8.43
8.52
8.48
8.65
8.80
7.66
8.44
7.78
8.51
8.37
8.86
8.50
7.66
CO
(ppm)
19.34
8.37
3.36
2.40
1.86
0.69
6.70
9.02
2.35
3.23
3.72
0.83
1.63
0.09
0.08
0.42
1.93
0.61
5.52
4.31
3.88
(ppm)
77.10
83.47
99.43
86.77
101.18
97.76
94.91
83.41
94.37
86.89
88.48
79.25
88.29
8653
87.17
. 82.90
97.41
102.83
105.69
111.24
114.74
SO2
(ppm)
26.34
32.67
186.69
125.92
196.22 .
163.70
727.80
916.83
1,024.67
1,180.14
1,046.73
60.04
6852
74.75
97.77
77.45
140.93
139.03
327.39
298.09
265.61
THC
(ppm)
0.15
0.02
0.50
0.05
0.11
0.06
0.50
0.33
-0.11
-0.12
0.17
0.18
0.06
.0.55
0.31
-0.10
0.35
0.41
0.76
0.00
0.05
CO
(Ib/hr)
1.51
0.61
0.26
0.21
0.14
NA
0.60
0.46
0.18
0.25
0.28
0.07
0.12
0.11
0.01
0.03
0.13
0.11
0.43
0.32
0.30
NOX
(Ib/hr)
9.89
10.77
12.40
1255
13.05
NA
13.70
6.99
12.01
10.87
11.07
10.77
10.42
10.91
10.97
10.67
11.14
1250
13.60
1352
14.52
SO2 THC
(Ib/hr) (Ib/hr)
4.70 0.01
5.86 ' 0.00
32.39 0.04
25.34 0.00
35.22 0.01
NA NA •
146.50 0.05
106.96 0.02
181.57 -0.00
205.59 -0.01
182.35 0.01
11.36 0.00
11.25 0.00
13.12 0.05
17.13 0.01
13.88 -0.00
22.45 0.35
2353 0.00
58.67 0.02
50.45 0.00
46.80 0.00
O., > 3%
CO < 100 ppmv (dry) or < 5.64 Ib/hr
NO „ < 250 ppmv (dry) or < 23.2 Ib/hr
SO2 < 3,000 ppm instantaneous or < 1,900 ppm, 10 min average
THC < 50 ppmv (dry) or < 4.44 Ib/h'r as propane
Temporary emissions standards authorized by NYSDEC based on short term duration ol project or as recommended in "Air Permit Emissions Estimate," Focus Environmental, Inc., July 15,
1994, Revision 2.
T3
T>
CD
I
-------
Case Histories
Table A. 1:8
Description of Cost Categories
Cost Categories
Included
Excluded
Site Preparation
Startup
Performance Test
TDS Production
Operations
Labor
Materials Excavation
and Preparation
Demobilization
blacktop pad with an impervious liner, '
6 in. gravel, 2 1/2 in. blacktop, sealer,
and 4 in. curb
stormwater collection and removal
from pad
mobilization and assembly (4 weeks)
transportation of 5 oversize and 9 legal
size trailers
equipment including 45 ton crane, 60 ft
manlift, fork truck
labor for mobilization and assembly
utility connections
piping and electrical connections
shakedown (2 weeks)
testing and calibration
processing clean soil
sampling and analysis for soil and stack
emissions including CEM
writing Performance Test Report
use of the TDS
two front-end loaders
utility usage
spare parts and regular maintenance
component interior decontamination
crew of 7 for shakedown and
production operations
operations of 10 hr/day, 5 days/week
fully burdened wages and living
expenses
excavation 8 hr/day, 5 days/week
dust control (water sprays)
1 backhoe
1 front-end loader
3 10-wheel dump trucks
screening for oversize
decontamination
disassembly and demobilization
(3 weeks)
equipment includes 45 ton crane, 60 ft
manlift, fork truck
crew of 4
site access
site security
submittals (work plans, etc.)
site preparation (access roads, utilities,
site survey)
stormwater treatment
utility installation to the site
sampling and analysis
sidewall stabilization
additional dust and odor control
additional materials preparation
dewatering
washwater treatment and disposal
A.24
-------
Appendix A
Table A. 1.9
Thermal Desorption Cost Estimate
Item
Details
Item ($) $/ton
Site Preparation
TDS Pad
2. Startup
TDS Mobilization/Assembly
Shakedown
2 1/2 in. blacktop, sealed, liner below 6 in. 40,000 2.00
gravel, 4 in. curb
Not included: permitting, submittals, -
surveys, site access, utility connections,
buildings, site clearing, health and safety,
analytical
Total Site Preparation 40,000 2.00
4 weeks 175,000 8.75
2 weeks 50,000 2.50
Total Startup 225,000 11.25
3. Performance Test
4. TDS Production Operations
TDS Equipment
Utilities
Natural Gas
Electricity
Water
5. Labor — Shakedown and
TDS Operations
6, Materials Excavation and
Preparation
Assume 3 replicate runs at one test
condition — reduced scale of Harbor
Point Demonstration. Estimated costs
may be +100% to -50% based on site
specific testing requirements
Total Performance Test
(based on Harbor Point usage)
(based on Harbor Point usage)
(based on Harbor Point usage)
Total TDS Operations
2 Supervisors @ $75/hr; 2 Operators @
$SO/hr; 3 Technicians @ $45/hr;
$65/person/day per diem; 20 weeks @ 40
hr+lOhrOT
Total Labor
Assume site conditions similar to Harbor
Point, including sizing (screening), but
excluding crushing/shredding, dredging,
or temporary structure
Total Excavation/Preparation
200,000 10.00
200,000 10.00
600,000 30.00
110,600
42,000
7,000
759,600
458,300
458^00
500,000
5.53
2.10
0.35
37.98
22.92
22.92
25.00
500,000 25.00
7. Demobilization
TDS Decontamination
TDS Disassembly/Demobilization
Total Demobilization
Total Estimate
30,000
125,000
155,000
2337,900
1.50
6.25
7.75
116.90
Assumptions: Site within 250 mi, 20,000 ton MGP soil, 15% moisture content, 25 ton/hr TDS, 90% on-line, 10 hr/day, 5
days/week
A.25
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Case Histories
Conclusions
Materials Handling Observations and Lessons Learned
TDS Successfully Processed a Wide Range of Material Types. The
waste streams MT processed through the TDS exhibited a wide variety of
characteristics. For example, Tar Emulsions, and to a lesser extent Coke
Plant soils, were very cohesive. Similarly, Harbor Sediments and Water Gas
Plant soils had high moisture contents. The TDS was able to achieve steady
state operations and thereby effectively desorb all waste streams. MT dem-
onstrated DREs for PAHs in excess of 99.99% on all waste streams.
Materials Handling is Key to TDS Operations. MT learned that crush-
ing/shredding/screening and mixing soil greatly affected TDS operations.
Decreasing material cohesiveness led to more consistent feed. Similarly,
mixing soil to achieve uniform moisture content and Btu value also provided
consistent feed which yielded steady operating conditions. An example is
moisture content. The optimum moisture content for TDS operations is
10%-15%. However, the TDS demonstrated that it can effectively desorb
waste streams with much higher moisture contents (>28%) particularly if the
moisture content remains relatively uniform throughout the run.
Blending Waste Types Improves Feed Characteristics. Blending dry,
granular material with cohesive, wet waste streams makes them easier to
feed into TDS and yields steadier operating conditions. For purposes of this
Demonstration, the waste streams were kept segregated and clean sand/stone
was used for blending. For a production-scale project, various waste streams
could be blended together to improve feed characteristics. Granular Purifier
Soils could be blended with cohesive Tar Emulsions to breakup tar clumps.
Similarly, dry waste streams could be blended with the wet Harbor Sedi-
ments. However, wet waste streams were effectively treated through the
TDS provided that the moisture content remained relatively uniform
throughout the run.
A.26
-------
Appendix A
Thermal Processing Observations and Lessons Learned
The TDS Successfully Remediated MGP Wastes. The TDS demonstrated
that it can successfully remediate MGP wastes using the selected afterburner
exit temperature and residence time. The TDS consistently achieved DREs
in excess of 99.99% for PAHs for all waste streams. Comparing soil infeed
to outfeed concentrations, the TDS effectively removed PAHs and BTEX
from all waste streams. The TDS also effectively removed and destroyed
cyanide.
TDS Emissions Can Be Maintained Within Acceptable Limits. As sum-
marized in Table A. 1.6, particulate, HCN, lead and arsenic emissions were
maintained within acceptable limits per NYSDEC Guidelines and Boiler and
Industrial Furnace Regulations. Purifier Waste had a high-sulfur content
which yielded high SO2 emissions. For a commercial-scale MGP
remediation, the TDS could be fitted with a scrubber to reduce SO2 emis-
sions to acceptable levels.
Different Waste Streams Cleanup at Different Temperatures. Because
different waste streams had different characteristics (cohesiveness, moisture
content, Btu value, etc.) the temperature at which PAHs were effectively
desorbed varied. MT determined that the following rotary dryer exit tern- -
peratures were effective in cleaning up each indicated waste stream:
Tar Emulsions 427°C (800°F);
Coke Plant 316°C (600°F);
Purifier Soils 454°C (850°F);
Harbor Sediments 399°C (750°F); and
Water Gas Plant 427°C (800°F).
The TDS is a Cost-Effective Technology for MGP Remediation. On a
full-scale commercial MGP remediation project, the TDS decontaminates
soil at an estimated cost of $128.46 tonne/hr ($116.90/ton). Thermal Des-
orption is a cost-effective technology that permanently eliminates the liabil-
ity associated with MGP wastes.
A.27
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Case Histories
Case 2 — Thermal Desorption Of PCB-
Contaminated Soil at the Re-Solve
Superfund Site (Richard J. Ayen, Ph.D. and. Carl R.
Palmer, Rust Federal Services Inc., 100 Technology Drive,
Anderson, SC 29625, (803) 646-2413 and Paul Mafz and
Gregg S. Meyers, Rust Remedial Services Inc., 7250 West
College Avenue, Palos Heights, IL 60463, (708) 361-8400)
Abstract
Full-scale operation of the X*TRAX® thermal desorption process was
initiated in June, 1993 at the Re-Solve Superfund Site in North Dartmouth,
Massachusetts. This was preceded by a very successful full-scale proof-of-
process pilot demonstration in May, 1992. The X*TRAX system separates
organic contaminants from soil and sludge by heating the solids in a sealed,
indirectly fired rotary dryer. The Re-Solve Site was the location ofa solvent
recycling facility, and 45,359 tonne (50,000 ton) of PCB contaminated soil
required treatment by the X*TRAX unit. Although the site treatment stan-
dard was 25 mg/kg, the soil was routinely treated to less than 2 mg/kg PCBs.
PCB levels in the feed soil ranged from 25 mg/kg to 13,000 mg/kg, with the
average being from 300 to 700 mg/kg. The X*TRAX unit was operated at
continuous feed rates of up to 10 tonne/hr (11 ton/hr) and routinely achieved
an on-line factor of over 80%. An US EPA SITE demonstration was also
carried out in May, 1992. For this demonstration, PCB levels in the feed
ranged from 181 to 515 mg/kg; treated soil samples all contained less than 1
mg/kg PCB, with an average of 0.25 mg/kg. Soil treatment progressed as
planned at Re-Solve, and treatment operations were concluded in July, 1994.
In early 1995, preparations were begun to move the system to the Sangamo
Superfund Site in South Carolina, again for the remediation of PCB-con-
taminated soil.
Introduction
OHM Corporation (formerly Rust Remedial Services) offers a low tem-
perature thermal desorption process for the removal of organic contaminants
from soils, sludges and filter cakes. The X*TRAX® process has been
A.28
-------
Appendfx A
, patented. It is capable of removing a wide variety of contaminants, includ-
ing PCBs, solvents, pesticides and pesticide intermediates, as well as mer-
cury (Palmer 1993). The development of the process has been documented
previously (Swanstrom 1991a; Swanstrom 1991b). This process was se-
lected for the remediation of PCB-contaminated soil at the Re-Solve
Superfund Site in North Dartmouth, Massachusetts.
Site History
The Re-Solve Superfund Site is located in a rural area in southeastern
Massachusetts on a 11.5 acre parcel. The site was operated as a waste
chemical reclamation facility from 1956 to 1980. A variety of hazardous
materials were handled at the site including PCB oil, waste oils, solvents,
organic liquids, organic solids, acids, alkalies, inorganic liquids, and inor-
ganic solids.
In 1981 all buildings, drums, and debris were removed by the owner, and
the site was covered with an unknown quantity of sand. The contents of the
four on-site lagoons were not removed, and the building foundations along
with several loading and unloading pads were left in place. Later that year,
the Massachusetts Department of Environmental Quality Engineering sub-
mitted a request to the US EPA that the site be placed on the National Priori-
ties List (NPL). The site was placed on the NPL in December of 1982.
Over the next two years a number of site investigations and studies were
conducted by the US EPA, including a Remedial Investigation and Feasibil-
ity Study (RI/FS), leading to a Remedial Action Master Plan (RAMP) and a
Record of Decision (ROD). The investigations characterized and identified
the sources of contamination, as well as defined the scope of remedial ac-
tion. The remedial action that was implemented identified approximately
11,468 m3 (15,000 yd3) of waste which required disposal. The remedial
action was carried out under the direction of the U.S. Army Corps of Engi-
neers from September of 1984 to January of 1987.
During the removal activities, extensive soil contamination was detected
which went beyond the scope of the remedial action defined in the original
ROD. Additional testing was done, and these tests showed that PCB con-
tamination existed at concentrations greater than 50 mg/kg in soils up to ten
feet below the seasonal low groundwater. An off-site RI/FS that was con-
ducted during the removal activities indicated that soil and sediment con-
tamination by PCBs was present in the off-site wetland areas as well.
A.29
-------
Case Histories
In February of 1987 a supplemental on-site remedial investigation was
completed to address the additional contamination that was detected. In
September of 1987 the US EPA issued the final ROD which included two
phases of remediation; the Source Control Remedy (SCR) which focused on
the remediation of soil in the unsaturated zone, and the Management of Mi-
gration which focused on the remediation of groundwateir.
In 1989 the US EPA, the Massachusetts Department of Environmental
Protection, and over 200 potentially responsible parties (PRPs) signed a
consent decree requiring the PRPs to direct and help pay for the cleanup
work specified in the ROD. In October of that year Rust was awarded the
contract for the SCR.
The supplemental ROD identified PCB-contaminated soils and sediments
as posing the greatest environmental risks from the Re-Solve Site. The SCR
phase of the project called for the excavation of more than 15,291 m3
(20,000 yd3) of contaminated soil and sediment, on-site treatment of what is
found to be contaminated, and finally placement of the clean material back
on-site. The cleanup requirement for soils removed from the unsaturated
zone prior to replacement was 25 mg/kg or less; for the soils and sediments
removed from the wetland areas, the requirement was 1 mg/kg or less.
The supplemental ROD also specified that the soil and sediments be
treated in a "mobile dechlorination facility", and required that a "practical
scale" (proof-of-process) demonstration of the dechlorination technology be
performed prior to the full-scale treatment. In order to meet all of the re-
quirements of this "practical scale" demonstration Rust elected to mobilize
it's X*TRAX thermal desorption process, and demonstrate the dechlorina-
tion process on the concentrated PCB waste stream which would be recov-
ered by X*TRAX.
In June of 1990 Rust began preparation of the site. The first major under-
taking involved characterizing the site to define the areas of PCB contamina-
tion. The data generated during the original SCR was found to be inad-
equate, so additional sampling was done. The site was extensively sampled,
and all of this information was then used to generate a computer model
which delineated the contaminated areas of the site.
The X*TRAX and dechlorination units were brought on-site in March of
1992. All of the equipment was assembled and tested in five weeks. The
proof-of-process test was performed over a ten day period in May of 1992.
This was immediately followed by a US EPA SITE demonstration.
A.30
-------
Appendix A
One of the major post-demonstration decisions was to eliminate the re-
quirement for dechlorination of the waste. While the technology was suc-
cessful in treating the waste, it generated additional waste to be disposed of.
In an effort to minimize the amount of waste being shipped off-site for incin-
eration, the requirement was removed.
In June of 1993, almost a full year after the pilot demonstration, approval
to begin the full-scale remediation was secured. The full-scale remediation
phase proceeded without interruption until July of 1994 when the last of the
45,359 tonne (50,000 ton) was treated by the X*TRAX unit. Other than
scheduled maintenance outages, the site was operational for 24 hours a day,
7 days a week.
The final phase of the SCR, the demobilization of the equipment, began
immediately upon completion of thermal processing in July of 1994. This
phase of the project was projected to be completed in the fall of 1994, pav-
ing the way for the startup of the Management Of Migration Phase. This
phase of the project is expected to last for the next ten to fifteen years.
Process Description
The X*TRAX® Model 200 Thermal Desorption System is a low tempera-
ture desorption process designed to remove organic contaminants from soils,
sludges, and other solid media. The X*TRAX Model 200 is fully transport-
able and consists of a rotary dryer, gas treatment system, liquid processing
system, one control room trailer and various pieces of moveable equipment.
The equipment can be assembled and staged in an area of about 38.1 m by
38.1 m (125 ft by 125 ft). The X*TRAX process flow is. shown in Figure
A.2.1 and is described below.
The X*TRAX system is a thermal/physical separation process. Contami-
nated materials are fed into an externally heated dryer in which water and or-
ganic contaminants are volatilized from the solids. Processed solids exit the
dryer at between 232 and 454°C (450 and 850°F) and are cooled with water to
eliminate dusting. The treated solids can be returned to their original location
and compacted in place. At Re-Solve, consistent operation was achieved with
the product temperature between 260 and 399°C (500 and 750°F).
The organic contaminants and water vapor that are volatilized from the
solids are transported out of the dryer by an inert carrier gas. The carrier gas
is ducted to the gas treatment system, where it passes through a cyclone (for
A.31
-------
Case Histories
fine particulate removal) and then a high-energy eductor scrubber. The
scrubber removes high boiling point organic compounds, cooling the gas to
82°C (180°F). Carrier gas exiting the scrubber then passes through two con-
densers in series where it is cooled to less than 10°C (50°F).
Figure A.2.1
X*TRAX® Process-Flow Diagram
Organic* •<•
Sludge
1
\*J
EAii
Scni
i
toe
Jber
Primary
Condenser
^ 1 t
VdOflfliffliiV
1
Water >
Recycle Cond<
Secondary
Condenser
1 T
HSSBBfllffiiy
1 '
unsafe
Vent Gas* —
,ow Temperas
let
Carbon Drums
Makeup
Tanks
Dry Product
Solids Feeder
Most of the conditioned carrier gas is reheated and recycled to the dryer.
Approximately 10% of the carrier gas is vented through a high efficiency
particulate air (HEPA) filter and a carbon adsorption train before it is dis-
charged. Because indirect firing and carrier gas recycle are used, emissions
from the process are very small; only 30-50 fWmin. This discharge (600
times less than an equivalent capacity incinerator) helps maintain a small
negative pressure within the system and prevents the release of potentially
contaminated gases. Makeup nitrogen is added to the system to keep oxygen
concentrations low (typically less than 1%). This is done to insure that no
combustion takes place within the system.
A.32
-------
Appendix A
The X*TRAX Model 200 full-scale system was completed in late 1989.
This unit is completely transportable and can be set up on-site in less than
four weeks. Site requirements are for a firm, level surface to set the equip-
ment. Housekeeping pads are then poured to facilitate operations. Propane
fuel and nitrogen are provided from storage tanks. The unit can be fired on
natural gas if it is available. Electrical service of 700 amp, 480 V, three
phase is required and can be provided by a diesel generator if necessary. The
unit is completely self contained and, if required, can derive essentially all
of its process water requirement from the soil being treated.
Proof-of-Process Demonstration Test
. The X*TRAX® Model 200 was mobilized to the Re-Solve Site in late
March, 1992. Within 5 weeks the Model 200 and the pilot-scale dechlorina-
tion system were installed and functionally tested, confirming the mobility
of the equipment. The proof-of-process pilot demonstration test was per-
formed over a ten day period in May, 1992. During the demonstration test
over 454 tonne (500 ton) of PCB-contaminated soil were processed through
the X*TRAX unit. The PCBs removed from the contaminated soil by the
X*TRAX system were concentrated into an organic liquid which was then
processed through the dechlorination system.
The performance of the X*TRAX unit was outstanding. Treated soil had
PCB residual levels consistently below 2 mg/kg, well below the 25 mg/kg
treatment standard established for the site. This excellent performance was
achieved while the unit was being operated at nearly 145 tonne/day (160 ton/
day), 20% more than the design throughput capacity.
An US EPA SITE demonstration was performed in conjunction with the
proof-of-process demonstration test in May, 1992. Extensive samples were
taken to fully characterize the operation of the X*TRAX unit. Three sam-
pling intervals of six hours each were employed over a two day period.
Samples were taken of the feed and treated soil as well as the aqueous, or-
ganic, and solid residuals from the process. The air emissions from the pro-
cess vent were also sampled before and after the carbon.adsorption units.
PCBs, volatile organics, semivolatile organics, and PCDD/PCDFs (dioxins
and furans) were all analytical parameters. The results were reviewed by the
US EPA's Center for Environmental Research Information and summarized
in a demonstration bulletin (US EPA Demonstration Bulletin 1993).
A.33
-------
Case Histories
During the SITE test, PCB levels in the feed ranged from 181 to 515 mg/kg.
All of the treated soil samples had less than 1 mg/kg PCB, and the average
was 0.25 mg/kg, demonstrating a PCB removal efficiency of 99.9%. No
PCB's were detected in the process vent. The SITE demonstration results
indicated PCDD/PCDFs were not formed within the X*TRAX system.
Even though PCDD/PCDFs were present at low levels in the feed soil, they
were not detected in the process vent. Total hazardous air pollutant emis-
sions from the unit were negligible at 0.4 g/day.
Full-Scale Production
Full-scale production began on June 21,1993 and was completed on July
16,1994. During the first month of full-scale operation, data were collected
so that a detailed mass balance could be calculated. This was the only time
other than during the initial site characterization that samples of the un-
treated soil were collected. The results of that mass balance are included in
Table A.2.1, and demonstrate almost complete recovery of the PCBs that
were fed to the unit.
Table A.2.1
Mass Balance Results
PCB Input 7914 Ib
PCB Output
Treated Soil 63 Ib
Primary Phase Separator Filter Cake 3121 Ib
Condensate Phase Separator Filter Cake 2384 Ib
Untreated Condensate Water 565 Ib
Condensed Oil in Storage Tank 1511 Ib
Condensed Oil in System 50 Ib
Total PCBs 7694 Ib
Percent Recovery of PCBs 97%
A.34
-------
Appendix A
Figures A.2.2 and A.2.3 show system availability and throughput, respec-
tively, for June, 1993 through July, 1994, the last month of operation. All
throughput tonnages in Figures A.2.2 and A.2.3 have been adjusted to a 1%
moisture basis. System availability was low during the first two months of
operation, primarily due to mechanical problems with the product handling
system. Several modifications were made to the system between June and
November of 1993, which resulted in gradual improvement in system avail-
ability and throughput.
Figure A.2.2
XTRAX® Availability at Re-Solve Superfund Site
•a
6/93 7/93 8/93 9/93 10/9311/9312/93 1/94 2/94 3/94 4/94 5/94 6/94 7/94
Month/Year
In December, the system went through a major turnaround, and several
modifications were implemented which subsequently provided increased
reliability. After this turnaround, system availability was consistently above
80%, peaking at 93% for the month of March, 1994.
Monthly throughput trended upward with availability; With the exception
of January, February and March of 1994, when cold winter weather and
precipitation reduced treatment rates. Daily throughput rates peaked during
A.35
-------
Case Histories
June, 1994, the last full month of operation, when 5,339 tonne (5,885 ton)
were treated, for an average 177 tonne/day (195 ton/day) on a 1% moisture
basis. If the system availability of 90% is taken into account and the
throughput rate adjusted to the as-fed average moisture content of 15.5%, the
daily throughput was 227 tonne (250 ton) per available machine day. This
well exceeds the original design goal of 113-136 tonne (125-150 ton) per
available machine day. In early 1995, planning was begun to move the sys-
tem to the Sangamo Superfund Site in Pickens, South Carolina. The project
will involve the removal of PCBs from 45,359 tonne (50,000 ton) of soil.
Figure A.2.3
X'TRAX® Treated Tons at Re-Solve Superfund Site
6,000
5,000
.2 4,000
s
I 3.000
f2
"§ 2,000
1,000
6/93 7/93 8/93 9/93 10/93 11/9312/93 1/94 2/94 3/94 4/94 5/94 6/94 7/94
Month/Year
Conclusions and Key Results
1. "Proof-of-process" Test and "SITE" Demonstration Test
Note: These conclusions were made by the US EPA and re-
viewed by the US EPA's Center for Environmental Research.
A.36
-------
Appendix A
• X*TRAX successfully removed PCBs from feed soil
and met the site-specific treatment standard of 25 mg/kg
for treated soils. PCB concentrations in all treated soil
samples were less than 1.0 mg/kg and the average con-
centration was 0.25 mg/kg. The average PCB removal
efficiency was 99.9%.
• Polychlorinated dibenzo-p-dioxins (PCDD) and polychlori-
nated dibenzofurans (PCDF) were not formed within the
X*TRAX system.
• Organic air emissions from the X*TRAX process vent
were negligible (0.4 g/day). PCBs were not detected in
vent gases.
• X*TRAX effectively removed other organic contaminants
from feed soil. Concentrations of tetrachloroethene, total
recoverable petroleum hydrocarbons, and oil and grease
were all reduced to below detectable levels in treated soil.
• Metals concentrations and soil physical properties were not
altered by the X*TRAX system.
2. Full-Scale Production Highlights
• On its first project, the availability of the X*TRAX thermal
desorption system reached a peak level of 93% during
March, 1994. Availability was consistently at 80% or
above during the final six months of operations.
• Daily throughput rates of 227 tonne/day (250 ton/day) were
consistently demonstrated, with peaks in excess of 272
tonne/day (300 ton/day) and no appreciable drop in the
treatment standard.
• The average of all the treated soil samples was 2.9 mg/kg
for PCBs. This corresponds to overall removal of PCB
efficiency for the entire project of 99.2%. (Based on an
average contamination level of 365 mg/kg from the site
characterization data).
A.37
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Case Histories
References
1. Palmer, C. 1993. Experience with the X*TRAX® Thermal Des-
orption System. Presented at the Conference on Remediation of
Contaminated Sites. Vancouver, British Columbia. May 28.
2. Swanstrom, C. 1991b. Thermal Separation of Solids Contami-
nated with Organics. Presented at HazMat'91. West Long
Beach, CA. November
3. Swanstrom, C. 1991a. Determining the Applicability of
X*TRAX® for On-Site Remediation of Soil Contaminated with
Organic Compounds. Presented at HazMat Central '91.
Rosemont, IL. April.
4. US EPA Demonstration Bulletin: X*TRAX® Model 200 Ther-
mal Desorption System. 1993. EPA/540/MR-93/502. February.
Cose 3 — Thermal Desorption at the
Anderson Development Company
Superfund Site Adrian, Michigan,
March 1995
Executive Summary
This report presents cost and performance data for a thermal desorption
treatment application at the Anderson Development Company (ADC) Site
located in Adrian, Lewanee County, Michigan. Between 1970 and 1979, the
ADC Site was used for the manufacture of 4,4-methylene bis(2-chloro-
aniline) or MBOCA, a hardening agent used in plastics manufacturing. Pro-
cess wastewaters were discharged to an unlined lagoon. A subsequent reme-
dial investigation determined that soil and sludges in and around the lagoon
were contaminated. Contaminated soils and sludges were excavated, dewa-
tered, and stockpiled. A Record of Decision (ROD), signed in September
1991, specified thermal desorption as the remediation technology for the
excavated soil. Soil cleanup goals were established for MBOCA and spe-
cific volatile and semivolatile organic constituents.
A.38
-------
Appendix A
Thermal desorption using the Roy F. Weston LT3® system was performed
from January 1992 to June 1993. The LT3® thermal processor consisted of
two jacketed troughs, and operated with a residence time of 90 minutes and a
soitfsludge temperature of 260-277°C (500-530°F) in this application. Hol-
low-screw conveyors moved soil through the troughs, and acted to mix and
heat the contaminated soil. The thermal processor discharged treated soil to
a conditioner where it was sprayed with water. Thermal desorption achieved
the soil cleanup goals specified for MBOCA and all volatile organic con-
stituents. Seven of eight semivolatile organic constituents met cleanup
goals; analytical problems were identified for bis(2-ethylhexyl)phthalate.
Information on costs for this application were not available at the time of
this report. Originally, the treated soils were to be used as backfill for the
lagoon. However, the state required off-site disposal of treated soils due to
the presence of elevated levels of manganese.
Site Information
Identifying Information
Anderson Development Company, Adrian, Michigan
CERCLIS# MID002931228
ROD Date: September 30,1991
Treatment Application
Type of Action: Remedial
Treatability Study Associated with Application? Yes (see Supplement A)
US EPA SITE Program Test Associated with Application? Yes
(see US EPA 1992a)
Period of Operation: 1/92-6/93
Quantity of Material Treated During Application: 4,627 tonne (5,100
ton) of soil and sludge
A.39
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Case Histories
Background (US EPA 1991; Simon Hydro-Search 1994; US EPA
1990b; Hahnenburg 1995)
Historical Activity that Generated Contamination at the Site: Chemi-
cal Manufacturing — plastics hardener
Corresponding SIC Code: 2869 (Industrial Organic Chemicals, Not
Elsewhere Classified)
Waste Management Practice that Contributed to Contamination:
Surface Impoundment/Lagoon
Site History: The Anderson Development Company (ADC) is a specialty
chemical manufacturer located in Adrian, Lewanee County, Michigan, as
shown on Figure A.3.1. The ADC Site covers approximately 12.5 acres of a
40 acre industrial park Residential areas surround the industrial park. Fig-
ure A.3.2 shows a layout of the ADC Site.
Between 1970 and 1979, ADC manufactured 4,4-methylene bis(2-
chloroaniline), or MBOCA. MBOCA is a hardening agent used in the
manufacture of polyurethane plastics. As part of the manufacturing process,
process wastewaters containing MBOCA were discharged to an unlined 0.5
acre lagoon.
In May 1986, Anderson Development Company (ADC) entered into an
Administrative Order by Consent with US EPA to conduct a Remedial Inves-
tigation/Feasibility Study (RI/FS). The remedial investigation determined
that soil and sludge in and around the lagoon were contaminated, and con-
taminated soils and sludges were excavated, dewatered, and stockpiled.
Regulatory Context: A 1990 ROD selected in situ vitrification (ISV) as
the remediation technology. An amended ROD was issued in September
1991 which specified thermal desorption as the remediation technology, with
ISV as a contingent remedy if thermal desorption was found to be not effec-
tive. In August 1991, ADC signed a consent decree to conduct a Remedial
Design/ Remedial Action (RD/RA) to remediate the site according to the
specifications in the 1991 Record of Decision (ROD).
Remedy Selection: Thermal desorption was selected based on a re-
view of the results from a bench-scale thermal desorption study. The
performance data from the bench-scale test indicated that thermal des-
orption was capable of meeting the MBOCA cleanup levels. Addition-
ally, the costs projected for thermal desorption treatment were lower
than costs projected for other technologies.
A.40
-------
Appendix A
Figure A.3.1
Site Location
Anderson Development
Superfund Site
Adrian, Michigan
Source: US EPA 1991
Site Logistics/Contacts
Site Management: PRP Lead
Oversight: US EPA
Remedial Project Manager:
Jim Hahnenburg (HSRW-6J)
U.S. EPA Region V
77 West Jackson Boulevard
Chicago, IL 60604
(312)353-4213
A.41
-------
Case Histories
State Contact:
Brady Boyce
Michigan Department of Natural Resources
Knapp's Office Centre
P.O. Box 30028
Lansing, MI 48909
(517) 373-4824
Treatment System Vendor:
Michael G. Cosmos
Weston Services
1 Weston Way
West Chester, PA 19380
(610) 701-7423
Figure A.3.2
Site Layout
N
A
LT3® Process Equipment Area
Feed Soil Staging Building
Adapted from US EFA1991
A.42
-------
Appendix A
Matrix Description
Matrix Identification
Type of Matrix Processed Through the Treatment System: Soil (ex-
situ)/Sludge (ex-situ)
Contaminant Characterization
Primary Contaminant Groups: Halogenated and nonhalogenated vola-
tile organic compounds and polynuclear aromatic hydrocarbons
The contaminants in the lagoon area identified during the remedial inves-
tigation included volatile organic compounds (VOCs), phthalates, phenols,
and polynuclear aromatic hydrocarbons (PAHs). The primary constituent of
concern was 4,4-methylene bis(2-chloroaniline)(MBOCA). Other VOCs
present included toluene and degradation products of MBOCA. High levels
of metals (e.g., manganese at levels up to 10%) were also present at the site
(US EPA 1991; Simon Hydro-Search 1994).
Matrix Characteristics Affecting Treatment Cost or Performance
Listed in Table A.3.1 are the major matrix characteristics affecting cost or
performance for this technology.
s
Treatment System Description
Primary Treatment Technology Type:
Thermal Desorption
Supplemental Treatment Technology Types (Simon Hydro-
Search 1994):
Pretreatment (Solids): Shredding/Screening/Dewatering
Posttreatment (Air): Baghouse, Condenser, Carbon
Posttreatment (Water): Oil-Water Separator, Filter, Carbon Adsorber
A.43
-------
Case Histories
Table A.3.1
Matrix Characteristics
Parameter Value Measurement Procedure
Soil Classification A-7-6 Soil Group ASTM (no further description
available'at this time)
Clay Content and/or Particle-Size Arithmetic mean diameter of Not Available
Distribution untreated sludge was 765 microns
Moisture Content Soil: Not Available Not Available
Sludge: 56-70% (before dewatering)
Sludge: 41-44% (after dewatering)
pH <7 (before dewatering) Not Available
10.9-11.2 (after dewatering)
Oil and Grease or Total Petroleum Not Available
Hydrocarbons
Bulk Density Not Available
Lower Explosive Limit Not Available
Source: USEPA1992a
Thermal Desorption System Description and Operation
The following treatment technology description is an excerpt from the
Applications Analysis Report (US EPA 1992a):
"The LT3® system consists of three main treatment areas: soil treatment,
emissions control, and condensate treatment. A block-flow diagram of the
system [see Figure A.3.3] is described below.
Soil is treated in the LT3® thermal processor. The thermal processor con-
sists of two jacketed troughs, one above the other. Each trough houses four
intermeshed, hollow-screw conveyors. A front-end loader transports feed
soil (or sludge) to a weigh scale before depositing the material onto a feed
conveyor. The feed conveyor discharges the soil into a surge hopper located
above the thermal processor. The surge hopper is equipped with level sen-
sors and provides a seal over the thermal processor to minimize air infiltra-
tion and contaminant loss. The conveyors move soil through the upper
trough of the thermal processor until the soil drops to the lower trough. The
A.44
-------
Figure A.3.3
Simplified Sectional Diagram Showing the Four Internal Zones
To Atmosphere
A
Sweep Gas
Contaminated
Soil or Sludge
>
r
Preprocessing
(as needed)
j Hot Oil Burner Offgases
Hot Oil , 1 ,
* F<
*~ Corf
1 I
Oversized
-ed
reyor
k
>,
Surge
Hopper
Dust
Y
Co
Thermal
Processo
01 Oil . ™™
r
i
V
Fabric Filter
Baghouse
^ Fuel/Combustion Air
^ Conditioner
*^ Conveyor
i
'
Disci
Com
Spray Water
targe
eyor
>. Processed Soil
Truck or Pile
Material or
Wastewater
Air-Cooled
Condenser
y
Refrigerated
Condenser
t
Carbon Vapor
Pac
Oil- Water
Separator
>
Organ!
1 ,
55 gal
Drum
\
:s
Paper
Filter
i
Carbon
Adsorber
i
Water Tank
Disposal
To Discharge
*• or Off-Site
Disposal
To Atmosphere
•<— Solids Flow
•«— Aqueous Flow
•<-• Vapor Flow
Source: Hastings 1992c
I
x"
>
-------
Case Histories
soil then travels across the processor and exits at the same end that it entered.
Hot oil circulates through the hollow screws and trough jackets and acts as a
heat transfer fluid. During treatment in the processor, each hollow-screw
conveyor mixes, transports, and heats the contaminated soil. The thermal
processor discharges treated soil into a conditioner, where it is sprayed with
water to cool it and to minimize fugitive dust emissions. An inclined belt
conveys treated soil to a truck or pile.
A burner heats the circulating oil to an operating temperature of 204 to
3438C (400 to 650°F)(about 38°C [100°F] higher than the desired soil treat-
ment temperature). Combustion gases released from the burner are used as
sweep gas in the thermal processor. A fan draws sweep gas and desorbed
organics from the thermal processor into a fabric filter. Dust collected on the
fabric filter may be retreated or drummed for off-site disposal. Exhaust gas
from the fabric filter is drawn into an air-cooled condenser to remove most
of the water vapor and organics. Exhaust gas is then drawn through a sec-
ond, refrigerated condenser, which lowers the temperature further and re-
duces the moisture and organic content of the offgases. Electric resistance
heaters then raise the offgas temperature back to 21°C (70°F). This tempera-
ture optimizes the performance of the vapor-phase, activated carbon column,
which is used to remove any remaining organics. At some, sites, caustic
scrubbers and afterburners have been employed as part of the air pollution
control system, but they were not used at the ADC Site.
Condensate streams from the air-cooled and refrigerated condensers are
typically treated in a three-phase, oil-water separator. The oil-water separa-
tor removes light and heavy organic phases from the water phase. The aque-
ous portion is then treated in the carbon adsorption system to remove any
residual organic contaminants; after separation and treatment, the aqueous
portion is often used for soil conditioning. The organic phases are disposed
of off-site. When processing extremely wet materials like sludge, the oil-
water separation step may not be appropriate due to the high volume of con-
densate generated. In such cases, aqueous streams from the first and second
condensers may be pumped through a disposable filter to remove particulate
matter prior to carbon adsorption treatment and off-site disposal."
System Operation. At ADC, contaminated soil and sludge were exca-
vated and screened. Additionally, sludges were dewatered with a filter press
to reduce the moisture content to levels sufficient for thermal treatment.
A.46
-------
Appendix A
The soil and dewatered sludge were then stockpiled in the feed soil staging
building prior to thermal treatment. No information is available at this time
on the disposition of water extracted by the filter press (Simon Hydro-
Search 1994).
Treated soils, sludges, and fly ash were sent off-site for disposal at the
Laidlaw Landfill, a Type II facility located in Adrian, Michigan. The ROD
originally called for backfilling the excavated lagoon with the treated soil,
sludge, and fly ash. However, due to high manganese levels, off-site dis-
posal was required. Second-time fly ash, which is fly ash generated during
the treatment of fly ash through the LT3® system, did not meet the estab-
lished guidelines, and could not be disposed in the landfill. Instead, the
second-time fly ash was barreled and incinerated at Petrochem Processing,
Inc. in Detroit, Michigan.
Operating Parameters Affecting Treatment Cost or Performance
Table A.3.2 lists the major operating parameters affecting cost or perfor-
mance for this technology and the values measured for each.
Table A.3.2
Operating Parameters*
Parameter Value
Residence Time 90 min
System Throughput 2.1 ton/hr
Temperature (Soil/Sludge) 500'-530T
'Values reported during SITE Demonstration
Source: USEPA19928
A.47
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Case Histories
Timeline
A timeline of key activities for this application is shown in Table A.3.3.
Table A.3.3
Timeline
Stan Date
End Date
Activity
5/86 Administrative Order by Consent entered by PRP to conduct Rl/FS
8/91 Administrative Order by Consent entered by PRP to conduct RD/RA
9/8/83 Site Placed on NPL
9/28/90 ROD signed
9/30/91 ROD amendment signed
- 9/91 Thermal Desorption Treatability Study conducted
9/91 - Contract let to Weston Services for site remediation
10/91 - LT3® mobilized to Anderson Development Company Site
11/91 12/91 Dewatering activities for high water content sludges
11/91 - 1st LT3® Operations test (delayed due to transportation problems)
12/91 - 2nd LT3* Operations test (required because results from 1st test were
destroyed in a fire)
12/91 - Results from 2nd LT3a> Operations test received
1/92 - LT3* Operations started
5/92 - LT3® operations stopped to assess operability of the process and to review
potential problems with the analytical method for MBOCA
6/92 8/92 Evaluation of QAPP, resampling of treated materials, evaluation of operating
temperatures via pilot plant test
9/92 - Restart of LT3® operation
6/93 - LT3* operations complete
10/93 - LT3* removed from site
3/24/93 - Memo from MDNR to EPA indicating that all ARARs have been activated and
delisting process can proceed
Source: Simon Hydro-Search 1994
A.48
-------
Appendix A
Treatment System Performance
Cleanup Goals/Standards
The Consent Decree and ROD amendment identified cleanup goals for
volatile organic compounds (VOCs) and semivolatile organic compounds
(SVOCs) in treated soil and sludge, including an MBOCA cleanup standard
of 1.684 mg/kg. Cleanup goals for VOCs and SVOCs in soil and sludge
were identified as the Michigan Environmental Response Act (MERA)
Number 307, Regulation 299.5711, Type B criteria for soil. Cleanup goals
were not identified for metals. The specific constituents from the MERA
307 list with which ADC was required to comply are not available at this
time. In addition, no information is shown on any air emission standards in
the references available at this time (US EPA 1991; Simon Hydro-Search
1994; U.S. District Court 1991)
Additional Information on Goals
The cleanup goal for MBOCA, as specified in the ROD, is based on US
EPA guidance documentation and is based on the excess lifetime cancer risk
level of 1 • 10"6.
Treatment Performance Data
During treatment, treated soils and sludges were placed in eight compos-
ite soil piles (piles A through H). All eight soil piles were approved by US
EPA for off-site disposal. Tables A.3.4, A.3.5, and A.3.6 show the range of
concentrations for MBOCA, VOCs, and SVOCs for piles B through G, re-
spectively. No data are available at this time on the concentration of these
analytes in the soils and sludges prior to treatment or on the concentrations
of these contaminants in piles A or H. Table A.3.7 shows the range of con-
centrations for 13 metals in treated soil piles B and G (Hastings 1992a).
Chlorinated dibenzo-p-dioxins (CDDs) and furans (CDFs) were measured
during the SITE Demonstration in the untreated and treated sludge, filter
dust, liquid condensate, exhaust gas from refrigerated condenser, and stack
gas. The results for 11 specific CDDs and CDFs measured in these locations
are shown in Table A.3.8 (US EPA 1992a)
A.49
-------
Case Histories
Table A.3.4
Range of 4,4-Methylene Bis(2-Chloroaniline)(MBOCA)
Concentrations in Treated Soil Piles
Cleanup PfleB PileC PileD PileE PileF PUeG
Constituent Goal 9/17-11/22 11/30-12/12 12/13-1/7 1/7-1/22 1/26-2/13 4/8-4/30
MBOCA (mg/kg) 1.684 BDL-1.63 0.55-1.52 0.28-1.66 0.21-1.67 0.36-1.60 < 0.05-1.59
BOL Below detection limit (detection limit not reported)
Source: Hastings 1992a
As shown in Tables A.3.4, A.3.5, and A.3.6, MBOCA, other VOCs, and
SVOCs met the cleanup goals for 6 soil piles treated, with 2 exceptions. In
soil pile B, bis(2-ethylhexyl)phthalate (BEHP) was measured as 300 Mg/kg,
and the cleanup goal was 40 }Jg/kg. BEHP is a common laboratory contami-
nant, and its presence was attributed to analytical problems rather than pres-
ence in the treated soil (Hastings 1992a).
As shown in Table A.3.6, isophorone was initially measured in soil pile B
at levels ranging from 200-600 jog/kg, and the cleanup goal was 160 jig/kg.
Additional samples from soil pile B showed that isophorone and other
SVOCs were measured at levels below the detection limit. The RPM stated
that, prior to disposal, soil at this site had to be retreated until all cleanup
goals were met. Soil from pile B was disposed off-site. It is not known at
this time if soil from pile B that showed the elevated levels of isophorone
was retreated.
As shown in Table A.3.7, the treated soils contained concentrations of
manganese ranging from 6,700 mg/kg to 22,000 mg/kg. Due to these high
concentrations of manganese, ADC was required to dispose of these residu-
als in an off-site landfill, instead of being backfilled on-site.
As shown in Table A.3.8, dioxins and furans were present in some treat-
ment residuals. The fabric filter dust contained the highest concentrations of
dioxins/furans and was the only solid residual containing measurable
amounts of 2,3,7,8-TCDD.
A.50
-------
Table A.3.5
Range of VOC Concentrations in Treated Soil Piles
Constituent
Acetone (fig/kg)
Benzene (ng/kg)
Methylene Chloride (Ug/kg)
2-Butanone (ng/kg)
1,1,1,-Trichloroethane ((ig/kg)
Toluene (fig/kg)
Cleanup Goal
14,000
20
100
8,000
4,000
16,000
PileB
9/17-11/22
100-5,400
NA
. 10-20
100-200
NA
20-110
PileC
11/30-12/12
NA
NA
NA
NA
NA
NA
PileD
12/13-1/7
100-300
NA
10-20
100
NA
20
PileE
1/7-1/22
100-300
NA
0-20
NA
NA
. NA
KleF
1/26-2/13
500
NA
10-20
NA
10
NA
PileG
4/8-4/30
100-600
20
10-20
100
NA
NA
NA Not available
Source: Hastings 1992a
-------
>
£S
Table A.3.6
Range of SVOC Concentrations in Treated Soil Piles
Constituent
Chrysene (fig/kg)
Phenanthrene (Hg/kg)
Pyrene (ng/kg)
Benzo(k)Fluoranthene (ng/kg)
Phenol (ng/kg)
Benzo(b)Fluoranthene (|ig/kg)
Fluoranthene (Hg/kg)
. Bis(2-Ethylhexyl)-Phthalate (jig/kg)
Isophorone (Hg/kg)
4-Methyl Phenol (jig/kg)
Qeanup Goal
330
Not Identified
4,000
330
80,000
330
6,000
40
160
8,000
PileB
9/17-11/22
BDL(200)-
BDL(1,100)
200-300
200-300
NA
200-14,000
NA
200-300
300
200-600
600
PileC
11/30-12/12
NA
300
200
NA
3,300-5,700
NA
200
NA
NA
NA
PileD
12/13-1/7
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
PileE
1/7-1/22
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
PifeF
1/26-2/13
BDL(700)-
BDL(5,300)
400-1,800
300
NA
4,700-5,900
NA
200-300
NA
NA
NA
PUeG
4/8-4/30
BDL(3,900)-
BDL(12,000)
700-3,200
700-2300
300
300-1,000
200-300
200-300
NA
NA
NA
BDL Below detection limit (value In parentheses is reported method detection limit)
MA Not available
Source: Hastings 1992a
o
Q
0
0>
CO
-------
Appendix-A
Table A.3.7
Range of Metals Concentrations in Treated Soil Piles
Constituent
Antimony (mg/kg)
Arsenic (mg/kg)
Barium (mg/kg)
Cadmium (mg/kg)
Chromium (mg/kg)
Copper (mg/kg)
Lead (mg/kg)
Manganese (mg/kg)
Mercury (mg/kg)
Selenium (mg/kg)
Silver (mg/kg)
Thallium (mg/kg)
Zinc (mg/kg)
Cleanup Goal
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
Not Identified
PfleB
9/17-1 1/22
BDL-11
BDL-25
67-110
BDL-8.6
BDL-31
23-48
13-39
8,700-18,000
BDL-0.3
0.2-3,5
BDL-3.4
3-38
3.2-14,000
PileG
4/8-4/30
0.5-3.6
16-31
61-130
4.1-7.7
16-46
30-1150
26-140
6,700-22,000
<0.1-<0.2
< 0.5-140
1.2-3
26-54
4,000-8,500
BDL Below detection limit (detection limit not reported)
Source: Hastings 1992a
Performance Data Completeness
Data are available on the concentrations of MBOCA, VOCs, and SVOCs
in six of eight treated soil piles; these data are adequate for comparison with
cleanup goals. Data are also available on the concentrations of CDDs and
CDFs in six sampling locations.
Performance Data Quality
EPA SW-846 methods were used for sampling soil piles at ADC; no infor-
mation is available at this time on the analytical methods used.
Analytical problems were identified by the PRP for chrysene, BEHP, and
isophorone in soil pile B. For chrysene, analytical data sheets were identi-
fied incorrectly; problems for BEHP and isophorone are described under
"Performance Data Assessment."
A.53
-------
Case Histories
Table A.3.8
Arithmetic Mean Concentrations of CDDs and
CDFs Measured During SITE Demonstration
Sampling Location
Parameter
23,7,8-TCDD
TCDD
TCDF
PeCDD
PeCDF
HxCDD
HxCDF
HpCDD
HpCDF
OCDD
OCDF
Untreated
Sludge
(ng/kg)
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
0.21
BDL
Treated
Sludge
(ng/kg)
BDL
0.987
2.42
0.534
0.066
BDL
BDL
BDL
BDL
BDL
BDL
Filter
Dust
(ng/kg)
0.1
6.54
19.8
5.98
2.49
0.81
0.5
1.38
0.14
3.20
0.04
Liquid
Condensate
(ng/L)
BDL
119
697
60
47.7
BDL
2.8
BDL
BDL
BDL
BDL
Exhaust Gas
from
Refrigerated
Condenser
(ng/dscm)
0.01
0.137
0.178
02
0.14
0.002
0.0004
0.023
0.005
0.121
0.0067
Stack Gas
(ng/dscm)
0.001
0.0087
0.066
0.0089
BDL
BDL
0.0003
0.017
0.0012
0.025
0.0024
All CDDs and CDFs shown as Below detection limit (BDL) are assigned a value of 0. Detection limits in untreated
sludge ranged from 0.04 to 0.80 ng/g. Detection limits in treated sludge ranged from 0.07 to 1.6 ng/g. Detection limits in
fabric filter dust ranged from 0.14 to 9.6 ng/g. Detection limits in the liquid condensate ranged from 1.4 to 17 ng/L.
Source: US EPA 1992a
Treatment System Cost
Procurement Process (Simon Hydro-Search 1994)
The PRPs contracted with nine firms to provide support services for the
ADC remediation. Weston Services served as the primary contractor for soil
excavation and treatment at ADC. Table A.3.9 lists each contractor and their
role in this cleanup. No information is available at this time on the competi-
tive nature of these procurements.
A.54
-------
Appendix A
Table A.3.9
ADC Remediation and Support Contractors
Contractor
Activity
Weston Services
Clayton Environmental Consultants
Chester LabNet
Laidlaw Waste Systems
Simon Hydro-Search
OHM
Environmental Science and Engineering
Clean Harbors
Environmental Management Control, Inc.
Soil excavation and treatment
Analytical services
Analytical services
Transport and disposal of treated soils, sludge, and fly ash
Environmental consultants, project management
Dewatering of high moisture content sludges
Installation of groundwater monitoring wells
Disposal of wastewater and contaminated stormwater
Backfilling the excavated lagoon
Source: Simon Hydro-Search 1994
Treatment System Cost
No information is available at this time on the costs for the thermal des-
orption treatment application at ADC.
Projected Cost
The Applications Analysis Report (US EPA 1992a) includes cost projec-
tions for using the LT3® system at other sites. As shown in Tables A.3.10,
A.3.11, and A.3.12, costs are divided into 12 categories and are reported as
cost per ton of soil treated, for three different soil moisture contents. The
values are based on using an LT3® system similar to the system used at the
Anderson Site (US EPA 1992a).
The costs are shown in Tables A.3.10, A.3.11, and A.3.12 according to the
format for an interagency Work Breakdown Structure (WBS). The WBS
specifies 9 before-treatment cost elements, 5 after-treatment cost elements,
and 12 cost elements that provide a detailed breakdown of costs directly
associated with treatment. Tables A.3.10, A.3.11, and A.3.12 present the
cost elements exactly as they appear in the WBS, along with the specific
activities, and unit cost and number of units of the activity (where appropri-
ate), as provided in the Applications Analysis Report.
A.55
-------
Cose Histories
-•
Table A.3.10
Projected Costs for Activities Directly Associated with Treatment
Cost per Ton of Soil Treated ($)•
Soil Moisture Content
Cost Categories
20%
45%
75%
Startup/Tcsting/Permits
Startup Costs11
Mobilization
Assembly
Shakedown
Total Startup Costs
$10.00
25.00
15.00
50.00
$10.00
25.00
15.00
50.00
g
g
g
g
Operation (Short-term — Up to 3 years)
Labor Costs0
Operations Staff
Site Manager
Maintenance Supervisor
Site Safety Officer
Total Labor Costs
Supply and Consumable Costs
PPEC
PPE Disposable Drums0
Residual Waste Disposal Drums
Activated Carbon'
Diesel Fuel"
Calibration Gases'
Total Supply and Consumable Costs
Utility Costs
Natural Gas (@ $1.43/1,000 ft3)
Electricity (@ $0.18/kWh)
Water (@ $1.00/100 gal)
Total Utility Costs
Equipment Repair and Replacement Costs
Maintenance
Design Adjustments'
Facility Modifications f
Total Equipment Repair and Replacement Costs
39.00
21.60
7.20
7.20
75.00
6.00
0.50
1.20
8.00
0.62
0.35
16.70
7.80
2.10
0.60
10.50
11.70
0.00
0.00
11.70
A.56
79.50
4430
14.60
14.60
153.00
10.00
1.00
1.20
24.00
1.00
1.10
38.30
26.00
6.30
0.60
32.90
19.80
0.00
0.00
19.80
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
g
-------
Appendix A
Table A.3.10 cont.
Projected Costs for Activities Directly Associated with Treatment
Cost per Ton of Soil Treated ($)'
Soil Moisture Content
Cost Categories
20%
45%
75%
Cost of Ownership
Equipment Costs
LT3® Rental0
Support Equipment Rental
Dumpstersc
Wastewater Storage Tanks"
Steam Cleaner
Portable Toilet1
Optional Equipment Rental c
Total Equipment Costs
Total
13.00d
0.70
1.00
0.10
0.10
12.00
26.90
$190.80
22.00
1.35
2.00
0.20
0.20
20.00
45.65
$339.65
g
g
g
g
g
g
g
g
"Cost per ton of soil treated; figures rounded and have been developed for a 3,000 ton project.
"Fixed cost not affected by the volume of soil treated.
c Costs are incurred for the duration of the project.
"Feed rate is double that of soils with 45% moisture content.
"Costs are incurred only during soil treatment activities.
'Cost included in the cost of renting the LT38 system.
'Soil moisture content of 75% is too wet to be treated and is outside the economically-viable range. Therefore, the
material was dewatered to 45% moisture content prior to treatment.
Source: US EPA 1992a
Observations and Lessons Learned
Cost Observations and Lessons Learned
• No information is available at this time on the costs for the ther-
mal desorption treatment application at ADC.
• Projected costs for treatment activities ranging from $190 to
$340 per ton of soil treated were identified by the SITE program
based on the results of a demonstration test. The SITE program
identified moisture content as a key parameter affecting costs.
A.57
-------
Cose Histories
Table A.3.11
Projected Costs for Pretreatment Activities
Cost per Ton of Soil Treated ($)»
Soil Moisture Content
Cost Categories 20% 45% 75%
Mobilization and Preparatory Work
Site Preparation Costs
Administrative $11.00 $11.00 $11.00
Fencing 0.40 0.40 0.40
Construction 0.70 0.70 0.70
Dcwatering NA NA 187.90
Total Site Preparation 12.10 12.10 200.00
Permitting and Regulatory Costs
Permit 3.30 3.30 3.30
Engineering Support 80.00 80.00 80.00
Total Permitting and Regulatory Support 83.30 83 JO 83.30
Monitoring, Sampling, Testing, and Analysis
Analytical Costs
Treatability Studyb 10.00 10.00 10.00
Sample Analysis for VOCs 4.20 12.00 12.00
Total Analytical Costs 14.20 22.00 22.00
Total $109.60 $117.40 $30530
NA Not applicable
•Cost per ton of soil treated; figures are rounded and have been developed for a 3,000 ton project.
"Foced cost not affected by the volume of soil treated.
Source: US EPA 1992a
Performance Observations and Lessons Learned
• Cleanup goals for treated soil and sludge in this application were
specified for 4,4-methylene bis(2-chloroaniline) and six other
VOCs, and nine SVOCs. Cleanup goals ranged from 20 pg/kg
(e.g., for benzene) to 80,000 pg/kg (e.g., for phenol).
A.58
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Appendix A
Analytical data for six treated soil piles show that MBOCA and
all other VOCs met the cleanup goals. Eight of nine SVOCs met
cleanup goals; analytical problems were identified for BEHP.
Elevated levels of manganese were measured in the treated soil;
as a result, ADC was required to dispose of treated soils in an
off-site landfill.
SITE program data indicate that dioxins and furans were present
in some treatment residuals; of all solid residuals, the fabric filter
dust contained the highest concentrations of dioxins and furans.
This cleanup of 4,627 tonne (5,100 ton) of soil and sludge was
completed in a 17 month period, which included several months
of system downtime.
Table A.3.12
Projected Costs for Posttreatment Activities
Cost per Ton of Soil Treated ($)"
Soil Moisture Content
Cost Categories 20% 45% 75%
Disposal (Commercial)
Residual Waste and Waste Shipping, Handling, and
Transportation Costs
Oversized Material (2% of feed soil) $5.40 $5.40 $5.40
Drums 27.00 27.00 27.00
Wastewater 7.20 14.40 14.40
Total Residual Waste and Waste Shipping, 39.60 46.80 46.80
Handling, and Transportation Costs
Demobilization
Site Demobilization Costs 33.00 33.00 33.00
Total $72.60 $79.80 $79.80
•Cost per ton of soil treated; figures are rounded and have been developed for a 3,000 ton project.
Source: USEPA1992a
A.59
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Case Histories
Other Observations and Lessons Learned
• The technology, tested in the testability study was not used in the
full-scale application; the reason for this is not available at this time.
References
1. US EPA. 1991. Superfund Record of Decision: Anderson
Development (Amendment), MI. EPA/ROD/ROS-91/177. Of-
fice of Emergency and Remedial Response, Washington, DC.
September 30.
2. Simon Hydro-Search. 1994. Final Remedial Action Report,
Anderson Development Company Site. Houston, TX. April.
3. Anderson Development Company. 1992. NPL Public Assis-
tance Database (NPL PAD). EPA ID#MID002931228.
Adrian, MI. March.
4. US EPA. 1993f. Superfund Preliminary Close Out Report,
Anderson Development Company Site, Adrian, MI. Region V.
Chicago, IL. September 24.
5. US EPA. 1990b. Superfund Record of Decision, Anderson
Development, MI. EPA/ROD/R05-90/137. Office of Emer-
gency and Remedial Response, Washington, DC. September.
6. U.S. District Court. 1991. Consent Decree, United States of
America vs. Anderson Development Co. Washington DC. Au-
gust 19.
7. US EPA. 1992e. Public Meeting, Explanation of Significant
Differences for Remedial Activities at the Anderson Develop-
ment Company Site. October 21.
8. Weston Services, Inc. 1991. Thermal Treatment Systems Pro-
posal, Remediation ofMBOCA Contaminated Sludge and Un-
derlying Soil at the Adrian, Michigan Facility for Anderson
Development Company. August 8.
9. US EPA. 1992. Applications Analysis Report — Low Tempera-
ture Thermal Treatment (LT3®) Technology, Roy F. Weston, Inc.
EPA/540/AR-92/019. Office of Research and Development,
Washington, DC. December.
A.60
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Appendix A
10. Canonie Environmental Services Corp. 1990. Treatability
Study Report and Remedial Contracting Services Proposal.
September.
11. Hahnenburg, Jim. 1995. Comments on 30 November 1994
Draft Report from Jim Hahnenburg, RPM. Received January
18,1995.
12. Hastings, Mark. 1992a. Memorandum from Mark Hastings,
Anderson Development Company, to James J. Hahnenburg, US
EPA, regarding Off-site disposal of Composite Soil Pile B.
December 3.
13. Hastings, Mark. 1992b. Memorandum from Mark Hastings,
Anderson Development Company, to James J. Hahnenburg, US
EPA, regarding Off-site disposal of Composite Soil Pile B,
Additional Semivolatile Analytical Data. December 14.
14. Hastings, Mark. 1992c. Memorandum from Mark Hastings,
Anderson Development Company, to James J. Hahnenburg, US
EPA, regarding Off-site disposal of Composite Soil Pile C.
December 22.
15. Hastings, Mark. 1993a. Memorandum from Mark Hastings,
Anderson Development Company, to James J. Hahnenburg, US
EPA, regarding Off-site disposal of Composite Soil Pile D.
January 20.
16. Hastings, Mark. 1993b. Memorandum from Mark Hastings,
Anderson Development Company, to James J. Hahnenburg, US
EPA, regarding Off-site disposal of Composite Soil Pile E.
February 18.
17. Hastings, Mark. 1993c. Memorandum from Mark Hastings,
Anderson Development Company, to James J. Hahnenburg, US
EPA, regarding Off-site disposal of Composite Soil Pile F.
March 10.
18. Hastings, Mark. 1993d. Memorandum from Mark Hastings,
Anderson Development Company, to James J. Hahnenburg, US
EPA, regarding Off-site disposal of Composite Soil Pile G
May 13.
A.61
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Case Histories
Analysis Preparation
This case study was prepared for the US EPA's Office of Solid Waste and
Emergency Response, Technology Innovation Office. Assistance was pro-
vided by Radian Corporation under US EPA Contract No. 68-W3-0001.
Supplement A to Case 3 — Treatability Study Results
Treatabilily Study Objectives
Canonie conducted a bench-scale treatability study using their Low Tem-
perature Thermal Aeration (LTTA) process on contaminated soil from the
Anderson Site. The study had the following objectives (Canonie Environ-
mental 1990):
• determine the effectiveness of the LTTA process to reduce MBOCA
concentrations in contaminated sludge and clay from the Anderson
Site to levels below the cleanup goal of 1.684 mg/kg;
• optimize the operating parameters, especially bed temperature
and residence time; and
• develop cost estimates for the full-scale treatment application.
Treatability Study Test Description
The treatability study consisted of six runs. A bench-scale thermal des-
orption system was used during the study to simulate the full-scale LTTA
system. The bench-scale system utilized a batch process, and consisted of a
hollow rotating cylinder with a metal shell which simulated the rotary drum
dryer in the LTTA system. The shell was heated externally, which in turn
heated the soil fed into the cylinder. In the full-scale design, heat transfer is
accomplished directly, and includes a continuous feed of soil.
Offgases from the soil were carried from the dryer by induced air flow
through the rotating cylinder. Air flow was induced through the cylinder at a
rate of 0.25 to 0.3Q ftVmin. The amount of air flow per mass of soil in the
dryer was much smaller than in the full-scale unit. Because of the relatively
lesser amount of particulates produced, a baghouse was not included in the
design of the bench-scale unit.
A.62
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Appendix A
The offgases from the bench-scale unit were first vented through a
series of water cooled condensers, which simulated the Venturi scrubber
in the full-scale system. This unit condensed water vapor and some
volatile and semivolatile organics, including MBOCA. For the fifth and
sixth run, the condenser offgas was vented through Tenax or polyure-
thane foam (PUF) tubes, respectively, to sample for volatile or
semivolatile compounds which remained in the offgas. This measured
the amount of volatiles and semivolatiles which would enter the vapor
phase carbon unit in the full-scale system.
The first four runs of the treatability study were preliminary runs, while
the last two were system optimization runs. Canonic performed the runs on
contaminated sludge and clay from the Anderson Site. The clay was shred-
ded to a particle size of less than one-half inch and then dried. The proce-
dure used for the treatability study follows:
1. Contaminated wet sludge and shredded, dried clay were mixed at
a ratio of approximately one to three or one to four (weight-to-
weight basis).
2. Between 1,300 and 1,400 g were batch fed into the preheated
dryer cylinder for each run.
3. Air was induced through the dryer cylinder at a flow rate be-
tween 0.2 and 0.3 ft3/min.
4. The residence time was 10.0 minutes for the first, second, and
sixth runs, and 12.5 minutes for the third, fourth, and fifth runs.
The cylinder was rotated at 6 rpm for all six runs.
5. Offgas from the process was vented through a series of condens-
ers, and a glass container was used to collect the condensate.
6. During the fifth run, a portion of the offgas was vented through
Tenax tubes to sample for volatiles. During the sixth run, the
offgas was passed through PUF tubes to sample for semivolatiles.
In both runs, the offgas passed through the tubes after it had
passed through the condensers.
7. The soil inside the cylinder was heated to temperatures (bed tem-
perature) between 249 and 371°C (480 and 700°F)(Canonie Envi-
ronmental 1990).
A.63
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Case Histories
Treatability Study Performance Data
Untreated and treated soil samples from each run were analyzed for
MBOCA. The operating parameters and the MBOCA data for the six runs
are presented in Table A.3.13. The results show that runs with a bed tem-
perature of greater than 316°C (600°F)(runs 1 and 2) had a removal effi-
ciency of greater than 99.99%, removing MBOCA to concentrations of less
than 0.05 mg/kg. Runs 3 and 4 showed that when the bed temperature was
below 600°F and untreated soil concentrations were relatively high (300 mg/
kg or higher), large concentrations of MBOCA remained in the treated soils.
Table A.3.13
MBOCA Concentrations in Pre- and Posttreatment
Soil and Relative Test Run Conditions
Test
Run#
1
2
3
4
5
6
MBOCA
Pre treatment
570
1100
300
320
92.
81
(mg/kg)
Posttreatment
<0.05
<0.05
13
240
<0.05
0.23
Test Run Conditions
% Reduction
in MBOCA
99.99
99.99
95.67
25
99.45
99.72
Median Bed Temperature
(T)
700
(500
500
480
520
520
Run Time
(min)
10
10
12.5
12.5
12.5
10.0
Samples from Runs 5 and 6 were analyzed for concentrations of volatile
and semivolatile organics. The results, shown in Table A.3.14, show that
volatile and semivolatile soil concentrations were relatively low before treat-
ment, and that the technology reduced concentrations of toluene. Other
compounds showed no decrease or an increase in concentration. Results of
the condensate analysis are presented in Table A.3.15.
A.64
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Append)* A
Table A.3.14
Summary of Volatile and Semivolatile
Organics in Pre- and Posttreatment Soil
Test
Run # Compound Detected
5 Volatiles
Acetone
Benzene
Chlorobenzene
Methyl Chloride
Tetrachloroethene
Toluene
Xylenes (Total)
Semivolatiles
Bis(2-Ethylhexyl)Phthalate
4-Methylphenol
6 Volatiles
Acetone
Benzene
Methyl Chloride
Toluene
Xylenes (Total)
Semivolatiles
Bis(2-EthylhexyI)Phthalate
4-Methylphenol
Concentration <|ig/kg>
• Pretreatment Sample
1,900
ND
40
ND
40
1,800
40
1,000
2,600
ND
ND
ND
720
ND
1300
2,100
Posttreatment Sample
1,900
8
ND
58
ND
54
5
1,200
2,100
2,600
12
200
98
12
ND
ND
ND Not detected
Results of the offgas analysis show that no Semivolatiles were present and
only low levels of volatiles were present. Of the volatiles, acetone and ac-
etaldehyde were present at the greatest concentrations, at 20 Mg/kg and 6
kg, respectively. The offgas analytical data is presented in Table A.3.16
(Canonic Environmental 1990).
A.65
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Case Histories
Table A.3.15
Summary of Volatile and Semivolatile Organics in Condenser Offgas
Test Run # Compound Detected Concentration (Jig/kg)
5 VolanTesOnly*
C4HgHydrocarbon 0.2
• ,
Acetaldehyde *
CjH10Hydrocarbon 0-1
CsHuHydrocarbon 0.07
CsHgHyrdrocarbon °-08
Furan °-08
Carbon Disulfide 0.7
Propanol 3
Acetone 20
C,;H12Hydrocarbon 0.9
Acetonitrile O-3
C6H14Hydrocarbons 3
Methyl Acetate 02
Methyl Propanol + C 6H12Hydrocarbon 0.8
Methyl Propanol 0.1
C6HIOHydrocarbon + C6H12Hydrocarbon - 0.07
Unknown Compound 0.08
Butanol °-9
Unknown Compound 0.03
6 Scmivolatiles Only*
None Detected
The GC Column was not heated during VOC analyses, hence the list presented may not include all the volatile
compounds present In the sample.
A.66
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Appendix A
Table A.3.16
Summary of Condensate Analyses
Compound Detected
Concentration (ftg/L)
MBOCA
Volatiles
Acetone
Toluene
Acetaldehyde
Methyl Ester of Methyl Propeonic Acid
Semivolatiles
4-Chloroaniline
4-MethyIphenol
Phenol
Aniline
Pyridine
Furancaiboxaldehyde
Dimethyl Pyridine
Benzaldehyde
Bromophenol + Acetophenone
Chloroaniline Isomcr
Benzothiazole
Chloromethyl Benzeneamine
Bromophenol
Unknown Nitrogen Compound
Dibromophenol
Chloro Methoxy Pyrimidinamine
Unknown Nitrogen Compound
860
30,000
600
1,000
300
1,500
12,000
5,100
20,000
800
900
800
2,000
900
20,000
1,000
1,000
900
1,000
3,000
8,000
3,000
A.67
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Case Histories
Canonic estimated that they could perform the full-scale remediation for a
fixed price of $810,000. This estimate was based on a maximum of 1,814
tonne (2,000 ton) of soil. This estimated cost does not include site prepara-
tion, electrical costs, or waste disposal.
Treotability Study Lessons Learned
• Canonie's LTTA technology was effective in reducing concentra-
tions of MBOCA to levels below the cleanup goal of 1.684 mg/
kg, when operated at temperatures of 271 "C (520°F) or greater.
• The vendor specified that optimal operating parameters for the
full-scale system would be a residence time of 10 minutes at 316
to 343°C (600 to 650°F), and a system throughput of 32 to 36
tonne/hr (35 to 40 ton/hr). Under these conditions, the system
would be effective in meeting the cleanup goals.
• According to the vendor, the full-scale LTTA system would achieve
a greater removal efficiency than the bench-scale system due to the
direct heating and the greater air flow in the full-scale unit.
• Canonie estimated that they could perform the full-scale
remediation for a fixed price of $810,000. This estimate was
based on a maximum of 1,814 tonne (2,000 ton) of soil. This
estimated cost does not include site preparation, electrical costs,
or waste disposal.
Cose 4 — Thermal Desorption at the
Pristine, Inc. Superfund Site, Reading, Ohio
Executive Summary
This report presents cost and performance data for a thermal desorption
treatment application at the Pristine, Inc. Superfund Site, located in Reading,
Ohio. Pristine, Inc. performed liquid waste disposal operations at the site
from 1974 to 1981 and operated as a sulfuric acid manufacturing facility
prior to 1974. As a result of spills and on-site disposal of wastes, soils at the
Pristine Site became contaminated with volatile and semivolatile organics,
A.68
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Appendix A
polynuclear aromatic hydrocarbons (PAHs), pesticides, and inorganic
metals. The soils also contained high levels of elemental sulfur (greater
than 2%).
SoilTech's 9 tonne/hr (10 ton/hr) mobile Anaerobic Thermal Processor
(ATP) system was used for treating contaminated soil at the Pristine Site.
The ATP system included a feed system, the ATP unit (rotary dryer thermal
desorber), a vapor recovery system, a flue gas treatment system, and a tail-
ings handling system. Wastewater from the vapor recovery system was
treated in an on-site wastewater treatment system.
The ATP system was operated at the site from November 1,1993 until
March 4,1994 and was used to treat approximately 11,612 tonne (12,800
ton) of contaminated soil. The ATP System treated contaminants in soil to
levels below the cleanup goals. Levels of six of the 11 target constituents
were reduced to concentrations at or below the reported detection limits. All
stack gas air emission performance standards were met in this application.
Average throughput was approximately 5.9 tonne/hr (6.5 ton/hr), and aver-
age on-line availability was approximately 62% in this application. This
application was notable for treating soil with a wide range of pH and mois-
ture conditions. Treated soil was backfilled on-site.
No information on treatment system cost was available at the time of
this report.
Site Identifying information
Identifying Information
Pristine, Inc. Superfund Site, Reading, Ohio
CERCLIS#: OHD076773712
ROD Date: 30 March 1990
Treatment Application
Type of Action: Remedial
Treatability Study Associated With Application? No
US EPA SITE Program Test Associated With Application? No
Period of Operation: November 1993 to March 1994
A.69
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Case Histories
Quantity of Material Treated During Application: Approximately
11,612 tonne (12,800 ton) of soil
Background
Historical Activity that Generated Contamination at the Site: Liquid
waste storage, disposal, and treatment operations
Corresponding SIC Code: 4953 W - Waste Management; Refuse Sys-
tems (Waste Processing Facility, miscellaneous)
Waste Management Practice that Contributed to Contamination:
Storage — Drums/Containers; Waste Treatment Plant
Site History: Pristine, Inc., a former liquid waste disposal facility that
operated from 1974 to 1981, is located on a 3-acre site in Reading, Ohio, as
shown in Figure A.4.1. Prior to 1974, the Pristine Site was the location of a
sulfuric acid manufacturing facility. Between 1974 and 1981, the Pristine
facility accepted a variety of bulk and drummed liquid waste products, in-
cluding acids, solvents, pesticides, and PCBs. The types of wastes stored at
Figure A.4.1
Site Location
Pristine, Inc.
Supcrfund Site
Reading, Ohio
Source: US EPA 1987a
A.70
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Appendix A
Pristine are shown in Table A.4.1. These wastes were treated by acid neu-
tralization or incineration; and disposed on-site. In December 1977, the
Ohio Environmental Protection Agency modified Pristine's operating permit
to require that Pristine reduce the amount of waste maintained at the site to
the equivalent of no more than 2,000 drums (US EPA 1987a; Pristine, Inc.
unknown; Ecology and Environment, Inc. 1986).
Table A.4.1
Types of Wastes Stored at Pristine
Mixed paint sludges
Acid-contaminated soil
Neutralized acid sludge
DDT and other pesticides
Contaminated soap, cosmetics, coin syrup, and fatty acid
Dimethyl sulfate
Hydrazine
Flammable solvents
Cyanide wastes
Chlorinated solvent sludge
Sulfuric and nitric acid
PCB-contaminated solvents
Ink solvent
Neutralized acid
PCB-contaminated soybean oil
Sulfuric acid sludge
Chrome wastes
Scrubber process waste
Sodium
Adipoyl chloride
Kepone
Acetomethoxane (originally listed as dioxin)
Inorganic peroxides
Tetrahydrofuran
Amines
Biological waste
Pharmaceutical waste
Freons
Adhesives
Mercaptans
Alcohols
Cadmium and plating waste
Phenolic plastics and resins
Phosphorus
Picric acid
Laboratory packs
Source: Ecology and Environment, Inc. 1986
A.71
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Case Histories
In 1979, an on-site inspection of Pristine's facilities by the Ohio EPA
found 13 bulk storage tanks that each contained from 1,893 to 37,853 L (500
to 10,000 gal) of liquid waste material and as many as 10,000 drums on-site.
As a result of state enforcement actions, which cited Pristine's failure to
comply with the terms of its waste incinerator operating permit and viola-
tions of water pollution control regulations, Pristine, Inc. ceased disposal
activities at the site in 1981. Samples taken on and near the Pristine Site
during Remedial Investigation/Feasibility Study (RI/FS) indicated that soils
and sediment at the site were contaminated with volatile organic compounds
(VOCs), semivolatile organic compounds, including polynuclear aromatic
hydrocarbons (PAHs), pesticides, compounds, and inorganic metals (US
EPA 1987a; Pristine, Inc. unknown).
Regulatory Context: A Record of Decision (ROD) was signed in De-
cember 1987 and amended in 1990. An Explanation of Significant Differ-
ences (ESD) amended the 1990 ROD and specified thermal desorption to
remediate site soils. Thermal desorption was selected based on its ability to
remove PAHs and pesticides from the site soil (US EPA 1987b; US EPA
1990a; Pristine, Inc. undated).
Site Logistics/Contacts
Site Management: PRPLead
Oversight: US EPA
Remedial Project Manager:
Mr. Tom Alcamo
USEPA Region V
230 South Dearborn Street
Chicago, Illinois 60604
(312) 886-7278
Vendor:
Mr. Thomas J. Froman
Project Engineer
Canonic Environmental Services Corp. (prime contractor)
800 Canonic Drive
Porter, IN 46304
(219) 926-8651
A.72
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Appendix A
Mr. Joseph H. Mutton
Smith Environmental Technologies Corp.
304 Inverness Way
Englewood, CO 80112
(303) 790-1747
Matrix Description
Matrix Identification
T^pe of Matrix Processed Through the Treatment System: Soil (ex-
situ), sediment (ex-situ)
Contaminant Characterization
Primary Contaminant Groups: Volatiles, semivolatiles (primarily poly-
nuclear aromatic hydrocarbons), pesticides, metals, and sulfur.
To characterize soils for thermal desorption, composite samples were
collected from twelve separate areas across the Pristine Site. Concentrations
of volatile organics ranged from non-detect to 140 Mg/kg, semivoiatile organ-
ics ranged from non-detect to 130 mg/kg, lead ranged from 26 mg/kg to
1,100 mg/kg, and 4,4'-DDT ranged from 110 jig/kg to 8,200 |jg/kg. Samples
analyzed for PCBs were all non-detect. One composite sample was col-
lected from the area near the former waste incinerator and analyzed for diox-
ins and furans. Laboratory analytical results for this sample indicated that
concentrations of furans ranged from 26.7 parts per trillion to 722 parts per
trillion, and concentrations of dioxins ranged from 3.0 parts per trillion to
792 parts per trillion (Conestoga-Rovers & Associates 1993).
The soil was also determined to contain sulfur in excess of 2% by weight
(Mutton and Trentini 1994).
Table A.4.2 presents the concentrations of 17 contaminants in the
untreated soil that was fed to the desorber during the three-day proof-of-
process test (Canonic Environmental Services 1993-1994; Mutton and
Trentini 1994).
A.73
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Case Histories
Table A.4.2
Feed Soil Concentrations
Constituent
Bcnzo(a)Anthracene
Benzo(a)Pyiene
Benzo(b)Fluoranthene
Benzo{k)Fluoranthene
Chrysenc
Dibenzo(a,h)Anthracene
Indcno( 1 ,2,3-cd)Pyrene
Aldrin
4,4'-DDT
Dkldrin
2,3,7,8-TCDD (equivalent)
Benzene
Chloroform
1,2-Dichloroethane
1 , 1 -Dichloroethene
Tetrachloroethene
Trichloroethene
Number of
Samples
3
3
3
3
3
3
3
3
3
3
4
3
3
3
3
3
3
Minimum Concentration
(ME/kg)
5301
420J
980
290J
790
ND (380)
290J
ND(460)
3,200
160J
9.93 E-04
ND(6)
3J
5J
ND(6)
11
ND(6)
Maximum Concentration
(HE/kg)
1,100
750
1,900
440
890
ND (770)
370J
ND (2,300)
4,800
ND (2,300)
1.06E-02
ND(6)
ND(6)
8
ND(6)
70
6
J Result is an estimated value below the reporting limit
ND Not detected (detection limit shown in parentheses)
Source: Canonie Environmental Services 1993-1994; Mutton and Trantini 1994
Matrix Characteristics Affecting Treatment Cost or Performance
Table A.4.3 presents the major matrix characteristics affecting cost or
performance for this application.
A.74
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Appendix A
Table A.4.3
Matrix Characteristics
Parameter
Value
Measurement
Procedure
Soil Classification
Clay Content and/or Particle-Size Distribution
Bulk Density
Lower Explosive Limit
Moisture Content
P"
Oil and Grease or Total Petroleum Hydrocarbons
Silty clays with some sand
Not Available
53-104 lb/ft3
Not Available
15-20%
1-2 for some feed soils
Not Available
Not Available
Not Available
Not Available
Not Available
Source: Conestoga-Rovers & Assoc. 1993; Hutton and Trentini 1994
Treatment System Description
Primary Treatment Technology
Thermal Desorption
Supplemental Treatment Technology
Posttreatment (Air): cyclone, quench, baghouse, carbon adsorption,
condenser, and gas-oil-water separators.
Posttreatment (Water): oil/water separation (using a gravity separator, a
coalescing plate system, an oleophilic membrane packing, and a dissolved
air flotation system), hydrogen peroxide oxidation, sand filtration, and acti-
vated carbon filtration.
SoilTech ATP Thermal Desorption System Description and
Operation
System Description. The SoilTech Anaerobic Thermal Processor, shown in
Figure A.4.2, is a mobile treatment system consisting of six main process units,
including a soil pretreatment system, a feed system, an anaerobic thermal
A.75
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Case Histories
o
Cl =£•
-------
Appendix A
processor unit, a vapor recovery system, a flue gas treatment system, a tailings
handling system, and a wastewater treatment system. (Canonic Environmental
Services Corp. 1994; Hutton and Shanks 1994; Mutton andTrentini 1994).
The feed system consists of two feed hoppers and a conveyor belt. One
feed hopper contains the contaminated soil and the other contains clean
sand. The sand is fed to the ATP unit during system startup and shutdown
periods, and acts as a heat carrier (Canonic Environmental Services Corp.
1994; US EPA 1993e).
The ATP unit is a rotary dryer which contains four separate internal zones
separated using proprietary sand seals. As shown in Figure A.4.3, these include
the preheat, retort, combustion, and cooling zones. The feed enters the preheat
zone where it is heated to approximately 232°C (450°F) and mixed, vaporizing
water, volatile organics, and some semivolatile organics. The solids then enter
the retort zone where they are heated to a target temperature range of 510 to
649°C (950 to 1,200°F), causing vaporization of heavy oils and some thermal
cracking of hydrocarbons, resulting in the formation of coked solids and decon-
taminated solids. The solids from the retort zone then enter the combustion
zone where coked solids are combusted. A portion of the decontaminated sol-
ids are recycled to the retort zone via a recycle channel. The recycling of these
solids helps to maintain an elevated temperature in the retort zone. The decon-
taminated solids remaining in the combustion zone enter the cooling zone
where they are cooled to a specified exit temperature (Canonie Environmental
Services Corp. 1994; US EPA 1993e).
The vapor recovery system consists of two parallel systems. One system
condenses water and vapors from the preheat zone of the ATP unit and con-
sists of a cyclone, a condenser, and a gas-oil-water separator. The other
system condenses water and vapors from the retort zone and consists of two
cyclones, a scrubber, a fractionator, a condenser, and a gas-oil-water separa-
tor. Condensed water from the vapor recovery system is treated in an on-site
wastewater treatment system which consists of the following processes:
• oil/water separation (using a gravity separator, a coalescing plate
system, an oleophilic membrane packing, and a dissolved air
flotation system);
• hydrogen peroxide oxidation;
• sand filtration; and
• carbon adsorption.
A.77
-------
o
Figure A.4.3
Simplified Sectional Diagram Showing the Four Internal Zones
I
>
00
SandSeal
Low Temperature
Steam and Hydrocarbon
Vapors Flow
Hydrocarbon
>• XandSteam
Vapors Flow
Hot Sand Recycle - SrSS?"
Coked Sand ^ j
Treated Solids
Kiln End Seals (Typ.)
Source: Canonie Environmental Services Corp. 1994
-------
Appendix A
The flue gas treatment system consists of a cyclone with fines conveyor,
flue gas quencher chamber, baghouse with dust conveyor, acid gas scrubber,
and activated carbon unit. This system removes particulates and trace hydro-
carbons from the flue gas exiting the combustion zone of the ATP. Fines
from the baghouse and cyclone are mixed with the treated solids exiting the
ATP unit. The treated flue gas is released to the atmosphere (Canonic Envi-
ronmental Services Corp. 1994; US EPA. 1993e).
The tailings (treated solids) handling system is used to cool and re-
move treated solids from the ATP. The treated solids exiting the ATP are
quenched with process and scrubber water and transported to storage
piles using belt and screw conveyors (Canonic Environmental Services
Corp. 1994; US EPA 1993e).
Treated soil was backfilled on-site. The soil was backfilled in uniform
lifts across the site. The vendor stated that this area will be capped (SoilTech
1995; Alcamo 1995).
The primary innovative features of this ATP unit are the four internal
zones and the use of proprietary sand seals at each end of the retort zone
which are designed to maintain an oxygen-free environment in the retort
zone. The oxygen-free environment in the retort zone helps to prevent the
oxidation of hydrocarbons and coke (Canonie Environmental Services Corp.
1994; US EPA 1993e).
System Operation. SoilTech conducted a proof-of-process performance
test prior to full-scale operation to demonstrate compliance with soil treat-
ment cleanup goals and stack gas emission performance standards. Four test
runs (sampling windows) were completed during the proof-of-process test
(Hutton and Trentini 1994).
Sulfur dioxide (SO2) control was a particular concern in this application
because of potential SO2 emissions and the impact of SO2 on corrosion of
process equipment and on the pH of aqueous condensate streams. Several
SO2 control methods were used during the proof-of-process and full-scale
operations, including lime (calcium oxide) addition, caustic solution, desorp-
tion, recovery of elemental sulfur under anaerobic conditions, and wet scrub-
bing of ATP flue gases (Hutton and Trentini 1994).
During full-scale operation of the ATP system, 11,647 tonne (12,839 ton)
of soil and sediment were treated. Average throughput was approximately
5.9 tonne/hr (6.5 ton/hr), and average on-line availability was approximately
A.79
-------
Cose Histories
62%. The wastewater from this system was treated and used as process
water for cooling the treated soil (Hutton and Shanks 1994; Hutton and
Trentini 1994).
Operating Parameters Affecting Treatment Cost or Performance
(Canonie Environmental Services Corp. 1994; Hutton and
Trentini 1994)
Table A.4.4 lists the major operating parameters affecting cost or
performance for this technology. Values measured for these parameters
during the proof-of-process period are included in this table. Automatic
waste feed shutoff controls were used for key operating parameters,
including retort and combustion zone temperatures and preheat, retort,
and combustion zone pressures.
Table A.4.4
Operating Parameters
Parameter
Value
Measurement Procedure
Preheat and Retort Zone
Residence Time
Preheat Zone Temperature
Retort Zone Temperature
Combustion Zone Temperature
Cooling Zone Temperature
System Throughput
Preheat Zone Pressure
Retort Zone Pressure
Combustion Zone Pressure
Stack Gas Exit Temperature
Stack Gas Flow Rate
Approximately 5 min Engineering design calculations
412-446'F
1,010-1,034'F
U86-1.412T
624-689T
7.84-lOton/hr
-0.10 in. water column
-0.12 in. water column
-0.08 in. water column
135'F
8,200 acfm @ 450T
Thermocouples in preheat zone
Thermocouples in retort zone
Thermocouples in combustion zone
Thermocouples in cooling zone
Weight of untreated solids measured
using a truck scale
Pressure to electrical transducer
Pressure to electrical transducer
Pressure to electrical transducer
Thermocouples in stack
Orifice Plate Flowmeter
Source: Canonte Environmental Services Corp. 1994; Hutton and Trsntini 1994
A.80
-------
Appendix A
The data collected during the proof-of-process period indicated that the
ATP system met all established performance criteria for flue gas stack emis-
sions and for treated soil. Based on these results, US EPA approved the
continued operation of the ATP system at these target operating conditions.
Timeline
The timeline for this application is presented in Table A.4.5.
Table A.4.5
Timeline
Start Date End Date Activity
12/82 - Pristine added to National Priorites List
'87 RI/FS conducted
W& - ROD signed
3/90 - ROD amended
11/93 3/94 Thermal desorption completed
U/93 11/93 Three day Proof-of-Process Test conducted
Source: US EPA 1987b; US EPA 1990a; Canonie Environmental Services Corp. 1994
Treatment System Performance
Cleanup Goals/Standards
An Explanation of Significant Differences (ESD), which amended the
1990 ROD, identified the cleanup goals shown in Table A.4.6 for treatment
of on-site soils and sediments at the site.
While the ROD and ESD did not specify stack gas emission standards,
standards for stack gas emissions were established for the proof-of-process
period during project planning. Table A.4.7 lists performance standards for
stack gas emissions. In addition, a Destruction and Removal Efficiency
A.81
-------
Case Histories
Table A.4.6
Cleanup Goals
Constituent
Total Carcinogenic PAHs*
Aldrin
DDT
Dieldrin
2,3,7,8-TCDD (equivalent)**
Benzene
Chloroform
1 ,2-Dichloroethane
1 , 1 -Dichloroc thane
Tetrachloroethane
• Trichlororethane
Cleanup Goal (jig/kg)
1,000
IS
487
6
0.990
116
2,043
19
285
3244
175
Total Carcinogenic PAHs are defined as the total of benzo(a)anthracene, benz(a)pyrene, benz(b)fluoranthene,
benz(k)fluorantf)ene. chrysene, dibenzo(a,h)anthracene, and indeno(1,2,3-cd)pyrene.
"Cleanup goal for 2.3,7,8-TCDD (equivalent) taken from Treated Soil Analytical Results (Canonie Environmental
Services Corp. 1993-1994).
Source: Pristine, Inc. undated
Table A.4.7
Proof-of-Process Tests Stack Gas Emissions Performance Standards
Parameter Performance Standard
Particulates 0.015 gr/dscf corrected to 1% O2
Opacity . £20%
Total Dioxin and Furan Emissions < 30 ng/dscm @ 7% O2
Hydrogen Chloride S41b/hr
Total Hydrocarbons (THC) £ 20 ppm corrected to 7% O 2
Sulfur Dioxide 16.6 g/sec
Source: Mutton and Trentini 1994
A.82
-------
Appencffx A
(DRE) of 99.99% was required to be demonstrated for PAHs and pesticides
in this application (Hutton and Trentini 1994).
Treatment Performance Data (Canonie Environmental Services
Corp. 1994; Hutton and Trentini 1994)
Table A.4.8 summarizes the results of the analysis of treated soil from 40
of the 44 piles. Data on the minimum and maximum constituent concentra-
tions are presented; data on analysis by soil pile is included in Table A.4.9.
Sampling was performed between November 1, 1993 and March 4, 1994. No
data were reported for four of the piles (nos. 34-37).
Performance standards and analytical results for selected parameters in
stack gas emissions during the proof-of-process tests as presented in Table
A.4.10. Air modeling using the ICST-2 model was conducted to assess
ground level concentrations of specific metals and other compounds.
To assess compliance with the 99.99% DRE for PAHs and pesticides
during the proof-of-process period, surrogate organic compounds were
added to the feed soil in window numbers 2, 3, and 4 of the proof-of-process
test. 1,2,3-Trichlorobenzene was used as a surrogate to represent PAHs, and
chloromethyl-benzene (benzyl chloride) was used as a surrogate for pesti-
cides. The results of the testing showed a 99.99% (four-nines) DRE for
1,2,3-trichlorobenzene in windows 2 and 3 (six-nines in window 4) and
99.999% (five-nines) DRE for benzyl chloride in windows 2, 3, and 4.
Performance Data Assessment
A review of the treatment performance data in Table A.4.8 indicates that
the cleanup goals for all constituents were met for the 40 piles of treated soil
that were analyzed. The performance data show that the technology re-
moved six of the 11 targeted constituents to levels at or below the detection
limit. Only 4,4'-DDT, dieldrin, 2,3,7,8-TCDD (equivalent), benzene, and
chloroform remained in the treated soil above the detection limit, at maxi-
mum concentration levels of 4.8 to 9.6 Hg/kg.
For the seven PAH constituents analyzed, this technology was effective in
removing these constituents to the reported detection limit (400 JJg/kg).
A review of the stack gas emissions sampling results, presented in Table
A.4.10, show that during the proof-of-process tests, all stack gas emissions
performance standards were met. Occasional THC spikes were measured at
A.83
-------
Case Histories
levels greater than the performance standard of 20 ppm. The vendor attrib-
uted these THC spikes to burner malfunction which caused uncombusted
propane fuel to be emitted from the stack.
Table A.4.8
Treatment Performance Data
Constituent
Benzo(a)Anthracene
Beozo(a)Pyrene
Benzo(b)Fluotanthene
Benzo(k)Fluoiantbene
Chiysenc
Dibcnzo{a,h)Anthraccne
Indeno(l,2,3-cd)Pyrene
Total Carcinogenic PAHs
Aldrin
4.4'-DDT
Dieldrin
2,3,7,8-TCDD (equivalent)
Benzene
Chloroform
1 ,2-Dich)oroe thane
1 , 1 -Dichloroethane
Tetrachloroe thane
Trichloroc thane
Number of
Soil Piles
Analyzed
40
40
40
40
40
40
40
40
40
40
40
40
40
40
40
40
40
40
Cleanup
Goal
(Hgftg)
ND(370)
ND(370)
ND (370)
ND (370)
ND (370)
ND (370)
ND (370)
1,000
15
487
6
0.99
116
2,043
19
285
3,244
175
Minimum
Concentration
Oigftg)
ND (370)
ND (370)
ND (370)
ND (370)
ND (370)
ND (370)
ND (370)
ND
ND (4.3)
ND (8.6)
ND (4.0)
0.000028
ND(5)
ND(5)
ND(5)
ND(5)
ND(5)
ND(5)
Maximum
Concentration
(Hg/kg)
ND(400)
ND(400)
ND(400)
ND (400)
ND(400)
, ND(400)
ND(400)
ND
ND (4.9)
96
4.8
0.0123
9
9
ND(6)
ND(6)
ND(6)
ND(6)
ND Not detected (detection limit shown in parentheses)
Source: Canonie Environmental Services Corp. 1993-1994
A.84
-------
Table A.4.9
Summary of Analytical Results for the Treated Soil Piles at the Pristine Superfund Site
Pile Number
Sample Date
US EPA Method 8270
Benzo(a)Anthracene
Benzo(a)Pyrene
Bcnzo(b)Fluoranthene
Beazo(k)Fluroanthene
Chrysene
Dibenzo(a,h)Anthracene
Indeno(l,2,3-cd)Pyrene
Total PAHs
US EPA Method 8080
3> Aldrin
0° 4,4'-DDT
Dieldrin
US EPA Method 8290
2,3,7,8-TCDD (equivalent)
US EPA Method 8240
Benzene
Chloroform
1,2-DichIoroethane
1,1-Dichloroethene
Tetrach loroethene
Trichloroethene
Cleanup
Goals
1,000
15
487
6
0.99
116
2,043
19
285
3,244
175
1
11/1/93
370 U
370 U
370 U
370 U
370 U
370 U
370 U
BDL
4.5 U
8.9 U
4.5 U
0.0123
6U
6U
6U
6U
6U
6U
2
1 1/8/93
370 U
370 U
370 U
370 U
370 U
370 U
370 U
BDL
4.5 U
9.1 U
4.5 U
0.00221
6U
6U
6U
6U
6U
6U
3
11/9/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.6 U
9.2 U
4.6 U
0.00371
6U
6U
6U
6U
6U
6U
4
11/11/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.6 U
9.1 U
4.6U
0.0013 U
61F
6U
6U
6U
6U
6U
5
11/12/93
380 U
380 U
380 U
380 U
380 U
380 U
380U
BDL
4.5 U
9U
4.5 U
0.00126 U
6U
6U
6U
6U
6U
6U
6
11/15/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.6 U
9.3 U
4U
0.000575
6U
6U
6U
6U
6U
6U
7
11/17/93
370 U
370 U
370 U
370 U
370 U
370 U
370 U
BDL
4.4 U
8.9 U
4.4 U
0.000635
6U
6U
6U
6U
6U
6U
8
11/18/93
380 U
380 U
380 U
380 U
380 U
380U
380U
BDL
45 U
9.1 U
45 U
0.0000277
6U
6U
6U
6U
6U
6U
9
11/20/93
380 U
380 U
380U
380 U
380 U
380 U
380 U
BDL
45 U
9U
45 U
0.000275
9
5U
5U
5U
5U
5U
10
11/25/93
370 U
370 U
370 U
370U
370 U
370 U
370 U
BDL
4.5 U
9U
45 U
0.00104
6U
6U
6U
6U
6U
6U
Data reported In ug/kg for all constituents
BDL Below detection limit
NA Not available
U Constituent was not detected above limit specified. The detection limit is Influenced by several factors, including initial sample size, dilution factor, matrix Interferences, and
Instrument response; therefore, the detection limit may vary from sample to sample.
Source: Canonie Environmental Services Corp. 1993-1994
-------
Table A.4.9 cont.
Summary of Analytical Results for the Treated Soil Piles at the Pristine Superfund Site
S
82
Pile Number
Sample Date
US EPA Method 8270
Benzo(a)Anthracene
Benzo(a)Pyrene .
Benzo(b)Fluoranthene
Benzo(k)Fluroanthene
Chrysene
Dibenzo(a,h)Anthracene
Indeno(l ,2,3-cd)Pyrene
Total PAHs
US EPA Method 8080
Aldrin
4,4'-DDT
Dieldrin
US EPA Method 8290
2,3,7,8-TCDD (equivalent)
US EPA Method 8240
Benzene
Chloroform
1,2-Dichloroethane
1,1-DicWoroethene
Tetrachloroethene
Trichloroethene
Cleanup
Goals
1,000
15
487
6
0.99
116
2,043
19
285
3,244
175
11
11/29/93
370 U
370 U
370 U
370 U
370 U
•370 U
370 U
BDL
4.5 U
9U
4.5 U
0.000105 U
5U
5U
5U
5U
5U
5U
12
11/3093
360 U
360 U
360 U
360 U
360 U
360 U
360 U
BDL
4.3 U
8.6 U
4.3 U
0.000405
7
6U
6U
6U
6U
6U
13
12/2/93
390 U
390 U
390 U
390 U
390 U
390 U
390 U
BDL
4.7 U
9.4 U
4.7 U
0.000562
6U
6U
6U
6U
6U
6U
14
12/3/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.5 U
9.1 U
4.5 U
0.000296
6U
6U
6U
6U
6U
6U
15
12/6/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.6
92
4.6
0.000225
6U
6U
6U
6U
6U
6U
16
12/7/93
370 U
370 U
370 U
370 U
370 U
370 U
370 U
BDL
4.5 U
9.1 U
4.5 U
0.0000715
6U
6U
6U
6U
6U
6U
17
12/12/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.6 U
9.2 U
4.6 U
0.000208
6U
6U
6U
6U
6U
6U
18
12/14/93
400U
400U
400U
400U
400U
400U
400U
BDL
4.8 U
9.6
4,8
0.0000859
6U
6U
6U
6U
6U
6U
19
12/17/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.7 U
9.3 U
4.7 U
0.000204
6U
6U
6U
6U
6U
6U
20
12/20/93
370 U
370 U
370 U
370 U
370 U
370 U
370 U
BDL
4.5 U
8.9 U
4.5 U
0.000434
6U
6U
6U
6U
6U
6U
Data reported in ug/kg for all constituents
BDL Below detection limit
NA Not available
U Constituent was not detected above limit specified. The detection limit Is Influenced by several factors, Including initial sample size, dilution factor, matrix interferences, and
Instrument response; therefore, the detection limit may vary from sample to sample.
i
Source: Canonle Environmental Services Corp. 1993-1994
-------
Table A.4.9 cont.
Summary of Analytical Results for the Treated Soil Piles at the Pristine Superfund Site
00
Pile Number
Sample Date
US EPA Method 8270
Benzo(a)Anthracene
Benzo(a)Pyrene
Benzo(b)Fluoranthene
Benzo(k)Fluroanthene
Chrysene
Dibenzo(a,h)Anthracene
Indeno(l ,2,3-cd)Pyrene
Total PAHs
US EPA Method 8080
Aldrin
4,4'-DDT
Dieldrin
US EPA Method 8290
2,3,7,8-TCDD (equivalent)
US EPA Method 8240
Benzene
Chloroform
1,2-Dichloroethane
1 , 1 -Dichloroethene
Tetrachloroethene
Trichloroethene
Cleanup
Goals
1,000
15
487
6
0.99
116
2,043
19
285
3,244
175
21
12/20/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.4 U
8.9 U
4.4 U
0.00016
6U
6U
6U
6U
6U
6U
22
12/22/93
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.5 U
9U
4.5 U
0,000514
6U
9
6U
6U
6U
6U
23
1/3/94
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.5 U
9U
4.5 U
0.000413
6U
6U
6U
6U
6U
6U
24
1/3/94
390 U
390 U
390 U
390U
390 U
390 U
390 U
BDL
4.7 U
9.4 U
4.7 U
0.0000705
5U
5U
5U
5U
5U
5U
25
1/5/94
400U
400U
400U
400U
400U
400U
400U
BDL
4.7 U
9.3 U
4.7 U
0.000595
6U
6U
6U
6U
6U
6U
26
1/10/94
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.6 U
9.2 U
4.6 U
0.000733
6U
6U
6U
6U
6U
6U
26(dup.)
1/10/94
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.6 U
9.2 U
4.6 U
0.000415
6U
6U
6U
6U
6U
6U
27
1/12/94
400U
400U
400U
400U
400U
400U
400U
BDL
4.8 U
9.1 U
4.8 U
0.000114
6U
6U
6U
6U
6U
6U
28
1/14/94
370 U
370 U
370 U
370 U
370 U
370 U
370 U
BDL
4.6 U
9.1 U
4.6 U
0.000189
6U
6U
6U
6U
6U
6U
29
1/17/94
410 U
410 U
410 U
410 U
410 U
410 U
410 U
BDL
4.9 U
9.7 U
4.9 U
0.0000542
6U
6U
6U
6U
6U
6U
Data reported in ug/kg for all constituents
BDL Below detection limit
MA Not available
U Constituent was not detected above limit specified. The detection limit is influenced by several factors, including initial sample size, dilution factor, matrix interferences, and
instalment response; therefore, the detection limit may vary from sample to sample.
Source: Canonie Environmental Services Corp. 1993-1994
-------
00
00
Table A.4.9 cont.
Summary of Analytical Results for the Treated Soil Piles at the Pristine Superfund Site
Pile Number
Sample Date
US EPA Method 8270
Benzo(a)Anthracene
Benzo(a)Pyrene
Benzo(b)Fluoranthene
Benzo(k)F1uroanthene
Chrysene
Dibenzo(a,h)Anthracene
Indeno( 1 ,2,3-cd)Pyrene
Total PAHs
US EPA Method 8080
Aldrin
4,4'-DDT
Dieldrin
US EPA Method 8290
2,3,7,8-TCDD (equivalent)
US EPA Method 8240
Benzene
Chloroform
1 ,2-Dichloroe thane
1,1-Dichloroethene
Tetrachloroethene
Trichloroethene
Cleanup
Goals
1,000
15
487
6
0.99
116
2,043
19
285
3,244
175
30
1/18/94
400U
400U
400U
400U
400U
400U
400U
BDL
4.8 U
9.8 U
4.8 U
0.0000436
6U
6U
6U
6U
6U
6U
31
1/20/94
370 U
370 U
370 U
370 U
370 U
370 U
370 U
BDL
4.5 U
9U
4.5 U
0.00023
6U
6U
6U
6U
6U
6U
32
1/24/94
380 U
380 U
380 U
380U
380 U
380 U
380 U
BDL
4.6 U
9.1 U
4.6 U
0.00138
6U
6U
6U
6U
6U
6U
33
1/31/94
380 U
380 U
380 U
380 U
380 U
380 U
380 U
BDL
4.5 U
9U
4.5 U
0.000679
6U
6U
6U
6U
6U
6U
34
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA'
NA
NA
NA
NA
NA
NA
NA
NA
NA
35
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
36
NA
NA
NA
NA
NA
NA
NA
NA
NA .
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
37
NA
'NA
NA
NA
NA
NA
NA
NA
BDL
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
38
2/22/94
038 U
038 U
0.38 U
0.38 U
038 U
0.38 U
0.38 U
BDL
4.6 U
9.1 U
4.6 U
0.00024 U
6U
6U
6U
6U
6U
6U
39
2/22/94
0.38 U
0.38 U
. 0.38 U
038 U
038 U
0.38 U
0.38 y
BDL
4.5 U
9U
4.5 U
0.0000659 U
6U
6U
6U
6U
6U
6U
Data reported in ug/kg for all constituents
BOL Below detection limit
NA Not available
U Constituent was not detected
above limit specified. The detection limit is influenced by several factors, includin
g initial sampli
3 size, dilutii
an factor, rr
latrix interferes
MS. and
o
8
o>
§.
ffi
instrument response; therefore, the detection limit may vary from sample to sample.
Source: Canonie Environmental Services Corp. 1993-1994
-------
Appendix A
Table A.4.9 cont.
Summary of Analytical Results for the Treated
Soil Piles at the Pristine Superfund Site
Pile Number
Sample Date
Cleanup
Goals
40
2/22/94
41
2/26/94
42
2/28/94
42
(dup.)
2/28/94
43
3/1/94
44
3/4/94
US EPA Method 8270
Benzo(a)Anthracene
Benzo(a)Pyrene
Benzo(b)Fluoranthene
Benzo(k)Fluroanthene
Chrysene
Dibenzo(a,h)Anthracene
Indeno( 1,2,3-cd)Pyrene
Total PAHs
US EPA Method 8080
Aldrin
4,4'-DDT
Dieldrin
US EPA Method 8290
2,3,7,8-TCDD
(equivalent)
US EPA Method 8240
1,000
15
487
6
038 U
038 U
0.38 U
0.38 U
038 U
0.38 U
0.38 U
BDL
4.6 U
9.2 U
4.6 U
0.36 U
0.36 U
0.36 U
0.36 U
0.36 U
0.36 U
0.36 U
BDL
4.3 U
8.6 U
4.3 U
038 U
0.38 U
0.38 U
038 U
0.38 U
0.38 U
0.38 U
BDL
4.5 U
9.1 U
4.5 U
0.38 U
0.38 U
•038U
038 U
038 U
038 U
0.38 U
BDL
4.5 U
9.1 U
4.5 U
037 U
0.37 U
0.37 U
037 U
037 U
037 U
0.37 U
BDL
4.4 U
8.8 U
4.4 U
Data reported in us/kg for all constituents.
BDL
NA
U
0.37 U
0.37 U
037 U
0.37 U
0.37 U
0.37 U
0.37 U
BDL
4,4 U
8.9 U
4.4 U
0.99 0.000175 U 0.000152 U 0.000136 0.00021 0.0000629 0.000144
Benzene
Chloroform
1 ,2-Dichloroe thane
1,1-Dichloroethene
Tetrachloroethene
Trichloroethene
116
2,043
19
285
3,244
175
6U
6U
6U
6U
6U
6U
5U
5U
5U
5U
5U
5U
6U
6U
6U
6U
6U
6U
6U
6U
6U
6U
6U
6U
5U
5U
5U
.5U
5U
5U
5U
5U
5U
5U
5U
5U
Below detection limit
Not available
Constituent was not detected above limit specified. The detection limit is influenced by several factors, including initial
sample size, dilution factor, matrix interferences, and! nstrument response; therefore, the detectkjn limit may vary from
sample to sample.
Source: Canonie Environmental Services Corp. 1993-1994
Performance Data Completeness
Treatment performance data are available for assessing the concentrations
of individual constituents in 40 of 44 soil piles treated, and for assessing the
concentrations in feed soil and stack gas air emissions from the proof-of-
process test.
A.89
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Cose Histories
Table A.4.10
Stack Gas Emissions Results from Proof-of-Process Tests
Parameter Performance Analytical Results
Particulates 0.015 gr/dscf corrected to 7% O2 < 0.00078 gr/dscf @ 7% O2
S2096 £20%
Total Dioxin and < 30 ng/dscm @ 7% O2 0.26 ng/dscra ® 7% O, (window #1)
Furan Emissions
2,3,7,8 TCDD equivalent 2.3,7,8 TCDD equivalent = 0.013
ng/dscm @ 7% O2
Hydrogen Chloride fi 4 Ib/hr 0.0085 1 -0.0 1 44 Ib/hr
Total Hydrocarbons (THC) £ 20 ppm corrected to 7% O 2 5.6-8.8 ppm '
(occasional spikes over 20 ppm*)
Sulfur Dioxide _ 16.6 g/sec < 1 g/sec
•Waste feed to the ATP was discontinued when THC concentrations exceeded 20 ppm. THC spikes above 20 ppm
were attributed by the vendor to burner malfunctions causing uncombusted propane fuel to be emitted from the stack.
Source: Hutton and Trentlnl 1994
Performance Data Quality
Project specifications were prepared for this application by Conestoga-
Rovers Associates (CRA). The remedial action was monitored by CRA for
the PRPs.
Soil samples were analyzed using SW-846 Methods 8270, 8080, 8290,
and 8240. No exceptions to the QA/QC objectives were noted by the vendor
for this application.
Treatment System Cost
Procurement Process
The PRPs contracted with Canonic Environmental Services Corp. to ther-
mally treat soil and sediment at this site. • Canonic contracted with SoilTech
to perform the thermal treatment portion of the project. Conestoga-Rovers
Associates was selected by the PRPs to monitor the remedial action (Hutton
and Trentini 1994). No additional information is available on the competi-
tive nature of the procurement process.
A.90
-------
Appendix A
Treatment System Cost
No information was available on treatment system cost at the time of this
report's preparation.
»
Vendor Input
According to the treatment vendor, in general, the costs for treatment
using the SoilTech ATP system vary depending on the character of the waste
material, with treatment costs ranging from $165 to $275/tonne ($150 to
$250/ton) for a 9 tonne/hr (10 ton/hr) ATP system. The factors identified by
the vendor that affect costs include:
• moisture content of feed material;
• particle size;
• hydrocarbon content;
• material handling characteristics; and
• chemical characteristics.
Vendor estimates for mobilization and demobilization costs for a 9 tonne/
hr (10 ton/hr) system range from $700,000 to $1.5 million (Hutton and
Shanks 1994).
Observations and Lessons Learned
Performance Observations and Lessons Learned
• Thermal desorption using the ATP system was effective in treat-
ing contaminants in soil at the Pristine Site to levels below the
cleanup goals. In addition, levels of six of the 11 targeted con-
stituents were reduced to concentrations at or below the reported
detection limits.
• Thermal desorption using the ATP system was also effective in
reducing levels of seven additional constituents to the reported
detection limit of 400 jjg/kg.
• All stack gas emission performance standards were met in this
application, including standards for particulates, opacity, dioxins
and furans, hydrogen chloride, THC, and SO2. Surrogate com-
pounds were used to verify compliance for a 99.99% DRE for
A.91
-------
Case Histories
PAHs and pesticides (1,2,3-trichlorobenzene for PAHs and
chloromethylbenzene for pesticides).
• Occasional THC spikes were measured at levels greater than the
performance standard; the vendor attributed these spikes to
burner malfunctions.
Other Observations and Lessons Learned
• Because SO2 control was a particular concern in this application,
several methods were used to control SO2 during this application,
including chemical addition and wet scrubbing.
References
1. US EPA. 1987a. Feasibility Study Completed for the Pristine,
Inc. Site. Office of Public Affairs, Region V. November.
2. Pristine, Inc. Source unknown.
3. Ecology and Environment, Inc. 1986. Remedial Investigation
Followup Work Plan for Pristine, Inc., Reading, OH. TDD
R05-8607-01. September.
4. US EPA. 1987b. Superfund Record of Decision, Pristine,
OH, First Remedial Action — Final. EPA/ROD/R05-88/060.
December.
5. US EPA. 1990a. Superfund Record of Decision, Pristine, OH,
First Remedial Action (Amendment) — Final. EPA/ROD/R05-
90/132. March.
6. Pristine, Inc. undated. Explanation of Significant Differences
for the Pristine, Inc. Superfund Site, undated.
7. Pristine, Inc. 1992. NPL Publications Assistance Database, US
EPA, Region V. EPAID#OHD076773712. Ohio. March.
8. US EPA. 1989b. Draft Proposed Plan, Pristine, Inc. Superfund
Site, Reading, OH. February.
9. Conestoga-Rovers & Associates. 1993. Final Design Report,
Thermal Treatment of Soil and Sediment (100% Design) Pris-
tine, Inc. Site, Pristine, OH. Ref. No. 3250 (25). July.
A.92
-------
Appendix A
10. Camp Dresser & McKee, Inc. et al. 1986. Performance of
Remedial Response Activities at Uncontrolled Hazardous Waste
Sites (REMII), U.S. EPA Contract No. 68-01-6939, Final Re-
medial Investigation Report, Pristine, Inc. Site, Reading, OH.
REM H Document No. 115-RIL-RT-CMKQ-l. July.
11. Canonic Environmental Services Corp. 1993b. Soil Excavation
and Handling Plan, Pristine, Inc., Reading, OH. 92-171-03.
August.
12. Canonie Environmental Services Corp. 1993a. Health and
Safety Plan, Pristine, Inc., Reading, QH. 92-171-03. August.
13. Canonie Environmental Services Corp. 1993c. Treated Soil
Handling, Sampling, and Analysis Plan, Pristine, Inc., Reading,
OH. 92-171-03. September.
14. Canonie Environmental Services Corp. 1994. SoilTech ATP
System Proof of Process, Pristine, Inc. Site, Reading, OH. 92-
171-03. February.
15. US EPA. 1993c. Letter from US EPA, Region V, to Pristine
Trustees. May 4.
16. Canonie Environmental Services Corp. 1993-1994. Treated
Soil Analytical Results. Letters from Canonie Environmental
Services Corp. to Conestoga-Rovers & Associates Limited.
December 1993 through March 1994.
17. Mutton, J. and R. Shanks. 1994. Thermal Desorption of PCB-
Contaminated Waste at the Waukegan Harbor Superfund Site.
Remediation. Spring.
18. US EPA. 1993e. Draft Applications Analysis Report for the
SoilTech Anaerobic Thermal Processor at the Wide Beach De-
velopment and Waukegan Harbor Superfund Sites. Risk Reduc-
tion Engineering Laboratory, Cincinnati, OH. May.
19. PRC Environmental Management, Inc. 1994. Results from the
SITE Demonstration of the SoilTech ATP Process at the OMC
Site in Waukegan, Illinois; Volume I — Draft Report. Chicago,
IL. September 16.
A.93
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Case Histories
20. Button, J.H. and AJ. Trentini. 1994. Thermal Desorption
of Polynuclear Aromatic Hydrocarbons and Pesticides Con-
taminated Soils at an Ohio Superfund Site: A Case Study.
94-FA155.05. Paper presented at the 87th Annual Meeting
of 1994 Air and Waste Management Association. Cincin-
nati, OH. June 19-24.
21. SoilTech. 1995. Comments on Draft Report from SoilTech.
Received February 16.
22. Alcamo, Tom. 1995. Personal communication, Tom Alcamo,
RPM, to Jim Cummings, EPA/TIO. February 14.
Analysis Preparation
This case study was prepared for the US EPA's Office of Solid Waste and
Emergency Response, Technology Innovation Office. Assistance was pro-
vided by Radian Corporation under US EPA Contract No. 68-W3-0001.
Cose 5 — Thermal Desorption at the
T H Agriculture & Nutrition Company
Superfund Site, Albany, Georgia
Executive Summary
This report presents cost and performance data for a thermal desorption
treatment application at the T H Agriculture & Nutrition (THAN) Company
Superfund Site in Albany, Georgia. Stockpiled soil contaminated with orga-
nochlorine (OCL) pesticides was treated as part of a removal action. This
project is notable for being one of the first full-scale thermal desorption
treatment applications of soil containing a mixture of OCL pesticides at a
Superfund Site.
The THAN Site, used from the 1950s to 1982 for pesticide formulation
and storage, was placed on the National Priorities List (NPL) in 1989. In
March 1992, US EPA issued a Unilateral Administrative Order (UAO) to
THAN for a soil and debris removal action at the site. Approximately 3,917
A.94
-------
Appendix A
tonne (4,318 ton) of soil with concentrations of total OCL pesticides equal to
or greater than 1,000 mg/kg was excavated and stockpiled at the site. Ini-
tially, the stockpiled soil was to be transported to an off-site incinerator for
treatment. However, because the actual volume of stockpiled soil was over
four times the initial estimate of 907 tonne (1,000 ton), on-site thermal des-
orption, with subsequent placement of treated soils on-site, was used.
The UAO established a treatment goal of less than 100 mg/kg for total
OCL pesticides in the treated subsurface soil. A treatability variance, re-
ceived in October 1992, allowed the treated soil to be placed on-site after
treatment and required a minimum reduction of 90% in the concentration of
specific OCL pesticides. Air emission limits for the thermal desorber stack
gas were based on complying with Georgia Air Toxics Guidelines ambient
air standards.
The full-scale thermal desorption system operated from July to October
1993 and was used to treat 3,917 tonne (4,318 ton) of contaminated soil.
Total OCL pesticide concentrations in the treated soil at THAN ranged from
0.009 to 4.2 mg/kg during the full-scale operation, with an average concen-
tration of 0.51 mg/kg. Average removal efficiencies achieved for the four
target OCL pesticides were greater than 98%.
Prior to full-scale operation, a process shakedown and proof-of-process
performance test were conducted to verify the effectiveness of the operating
conditions. In addition, a shakedown pretest was conducted to evaluate the
materials handling portion of the system.
Based on a petition for reimbursement, the cost for thermal desorption at
THAN was approximately $1.1 million, including approximately $850,000
in costs directly attributed to treatment activities (corresponding to $182/
tonne [$200/ton] of soil treated).
Site Information
Identifying information
T H Agriculture & Nutrition Company Superfund Site, Albany, Georgia
Action Memorandum Date: Not available
A.95
-------
Case Histories
Treatment Application
Type of Action: Removal
Treatability Study Associated with Application? Yes (See Supplement A)
US EPA SITE Program Test Associated with Application? No
Duration of Action: March 1992-February 1994
Period of Operation: July to October 1993
Quantity of Soil Treated During Application: 3,917 tonne (4,318 ton)
Background
Historical Activity that Generated Contamination at the Site: Agricul-
tural Pesticides Formulation and Storage
Corresponding SIC Code: 2879 (Pesticides and Agricultural Chemicals,
Not Elsewhere Classified)
Waste Management Practice that Contributed to Contamination:
Formulating and blending process
Site History: The 7-acre T H Agriculture & Nutrition Company
(THAN) facility is located in Albany, Georgia, as shown in Figure A.5.1.
From the mid-1950s until 1967, the site was used by other companies
for the storage and formulation of pesticides. Typical activities for for-
mulating pesticides included preparation of dry and liquid formulations
and blending pesticides with solvents. THAN purchased the site in 1967
and continued pesticide formulation operations until 1978. The site was
used by THAN as a storage and distribution center until 1982 (Williams
Environmental Services, Inc. 1993b).
In 1982, the Georgia Environmental Protection Division (GEPD) deter-
mined that the soil and groundwater at the site were contaminated primarily
with OCL pesticides and solvents as a result of site activities. The site was
placed on the National Priorities List (NPL) in March 1989 (Williams Envi-
ronmental Services, Inc. 1993b).
Regulatory Context: In response to a UAO issued by US EPA in March
1992 for a soil and debris removal action, THAN excavated soil from areas
where concentrations of total OCL pesticides exceeded 50 mg/kg in surface
soils and 100 mg/kg concentration in subsurface soils. A total of 26,308
tonne (29,000 ton) of contaminated soil and debris were excavated from
A.96
-------
Appendix A
these areas. Approximately 3,917 tonne (4,318 ton) of excavated soil was
stockpiled on-site for further treatment. Initially the stockpiled soil was to
be transported to an off-site incinerator for treatment. However, because the
actual volume of stockpiled soil was over four times greater than the initial
estimate of 907 tonne (1,000 ton), on-site thermal desorption, with subse-
quent placement of treated soils on-site, was used. The stockpiled soil was
identified as containing listed hazardous wastes with RCRA waste codes
P037 (dieldrin), P123 (toxaphene), U061 (DDT and metabolites), U129
(lindane), and U239 (xylenes). The remaining 22,407 tonne (24,700 ton)
were disposed off-site (Williams Environmental Services, Inc. 1993b).
Figure A.5.1
Site Location
TH Agriculture and Nutrition
Superfund Site
Albany, Georgia
A.97
-------
Case Histories
A treatability variance, received from US EPA Region IV on October 27,
1992, set treatment standards for on-site thermal desorption of the stockpiled
soils and approved a plan to place and cover thermally treated soils on-site
with a minimum of 0.61 m (2 ft) of clean soil. In addition, air emissions
limits were established for the thermal desorber stack gas (Williams Envi-
ronmental Services, Inc. 1993b).
Prior to approval of the full-scale remediation work plan, THAN was
required to demonstrate proof-of-process in a performance test. A
shakedown pretest was performed to evaluate the materials handling
portion of the system. The proof-of-process performance test was run in
July 1993. Based on the proof-of-process performance test results, US
EPA Region IV provided the required approval to conduct full-scale
treatment activities in August 1993. Full-scale treatment activities be-
gan in August 1993 and concluded in October 1993. Demobilization of
the unit was completed in January 1994 (Focus Environmental, Inc.
1993a; Focus Environmental, Inc. 1994; US EPA 1993d).
Site Logistics/Contacts
Site Management: PRP Lead
Oversight: US EPA
On-Scene Coordinator:
R. Donald Rigger
U.S. Environmental Protection Agency
Region IV
345 Courtland Street, N.E.
Atlanta, Georgia 30365
(404)347-3931
Contractor:
Mark Fieri
Project Manager
Williams Environmental Services, Inc.
2076 West Park Place
Stone Mountain, Georgia 30087
(770)879-4075
A.98
-------
Appendix A
Project Oversight:
William L. Troxler, P.E.
Focus Environmental, Inc.
9050 Executive Park Drive, Suite A-202
Knoxville, Tennessee 37923
(423)694-7517
Matrix Description
Matrix Identification
Type of Matrix Processed Through the Treatment System: Soil (ex-situ)
Contaminant Characterization
Primary Contaminant Groups: Halogenated Organic Pesticides
THAN conducted an RI between December 1990 and September 1991
including sampling of soil, groundwater, and other media. Constituents
identified at the site included organochlorine (OCL) pesticides, organophos-
phorus (OP) pesticides, polychlorinated biphenyls (PCBs), chlorinated herbi-
cides (CHs), volatile and semivolatile organics, as well as inorganics (Focus
Environmental, Inc. 1993b). The OCL pesticide constituents were analyzed
using US EPA Method 8080.
Matrix Characteristics Affecting Treatment Cost or Performance
Table A.5.1 lists the major matrix characteristics affecting cost or perfor-
mance and the values measured for each.
Specific particle-size distribution data were measured for the stockpiled
soil and are provided in Table A.5.2. The soil was described as containing
large clumps of clay. The impact of high clay content material on the system
operation is discussed in the Thermal Desorption System Description and
Operation section of this report.
Treatment System Description
Primary Treatment Technology Type
Thermal Desorption
A.99
-------
Case Histories
Table A.5.1
Matrix Characteristics
Parameter
Soil Classification
Clay Content and/or Particle-Size Distribution
Bulk Density
Lower Explosive Limit
Moisture Content
PH
Total Organic Carbon (TOC)
Oil and Grease or Total Petroleum Hydrocarbons
Value
Type CH Clay
Sec Table A.5.2
126tol30Ib/ft3
Not Available
13 to 19%
5.7 to 6.2
0.2 to 0.23%
Not Available
Measurement Method
-
•
Not Available
-
ASTM D2216
ASA #9
Not Available
-
Source: T H Agriculture & Nutrition Company 1994
Table A.5.2
Particle-Size Distribution of Stockpiled Soil
Partic!e Size (mm)
0-0.074
0.074-0.149
0.149-0.297
0.297-0.590
0.590-1.19
1.19-2.38
Distribution (%)
0.8-1.2
5.6-8.0
18.4-20.4
21.2-22.0
12.2-12.4
36.8-41.0
Source: T H Agriculture & Nutrition Company 1994
A. 100
-------
Appendix A
Supplemental Treatment Technology Types
Pretreatment (Solids): Screening
Posttreatment (Air): Baghouse, Quench, Air Cooler, Reheater Induced
Draft Fan, Carbon Adsorption
Posttreatment (Solids): Quench
Posttreatment (Water): Carbon Adsorption
Thermal Desorptlon Treatment System Description and
Operation (Focus EnvironmentaUnc. 1994;Troxler 1994)
The Williams Environmental Services, Inc. Thermal Desorption Process-
ing Unit (TPU) #1 was used to treat soils at the THAN Site. As shown in
Figure A.5.2, it consisted of a feed system, a counter-current rotary desorber,
and a cooling system for the treated soil. Offgases were routed through a
baghouse, a water quenching unit, a mixing chamber, a reheater, and a va-
por-phase carbon adsorption bed, as shown in Figure A.5.2. Quench water
was routed through a liquid-phase carbon adsorption bed. Treated solids
from the system were mixed with baghouse fines and redeposited on-site.
Offgases were vented to the atmosphere through a stack, after treatment in
the air pollution control (APC) unit. The activated carbon beds were regen-
erated off-site.
An interlock process control system was utilized to maintain operation of
the TPU #1 system within allowable limits. In the event that any of the lim-
its were breached, the interlock system was designed to automatically shut
down the feed system. Parameters monitored on either an instantaneous or
rolling average basis and automatic waste feed cutoff conditions for the in-
terlock system are shown in Table A.5.3.
A process change was made prior to full-scale treatment activities based
on automatic cutoffs during the proof-of-process performance test. Insuffi-
cient fan capacity triggered several cutoffs which occurred based on the
maximum rotary dryer pressure of 0.00 in. of water. Therefore, the fan was
replaced prior to conducting full-scale treatment activities.
The TPU #1 feed system consisted of a shaker screen, a conveyor belt,
and an automated load cell that was connected to the interlock system. The
shaker screen removed clay clumps and other material greater than 1.91 cm
A.101
-------
Figure A.5.2
Williams Environmental Services, Inc. Thermal Desorption Unit.TPU #1 Used at THAN Facility, Albany, Georgia
Process
Water
Untreated
Soil
8
co
(D
I
i
T
Treated Solids
Source: Focua Environmental, Inc. 1994
-------
Appendix A
Table A.5.3
Interlock System Cutoff Conditions
Interlock System Process Parameter
Cutoff Condition
Type of Monitoring and/or Cutoff
Minimum Desorber Exit Gas
Temperature
Maximum Desorber Exit Gas
Temperature
Maximum Soil Feed Rate
Minimum Treated Soil Exit Temperature
Minimum Quench Recycle Liquid
Pressure
Maximum Quench Exit Gas
Temperature
Minimum Baghouse Differential Pressure
Power Failure
Maximum Stack Gas Total
Hydrocarbons
250T
510'F
7.8 ton/hr
875'F
5psi
200°F
1 in. water column
100 ppmv
1 min time delay
Instantaneous, vent opens, automatic
waste feed shutoff
20 min rolling average
20 min delay
S min time delay
Instantaneous, vent opens, automatic
waste feed shutoff
Instantaneous
Instantaneous, vent opens
20 min rolling average
Source: US EPA 1993d
(0.75 in.) in size from the soil stockpile. These clay clumps were crushed
using a front-end loader and re-introduced into the desorber.
The TPU #1 soil treatment unit consisted of a counter-current flow rotary
dryer, a propane-fired burner unit, and a soil quench system. The desorber
was a directly-heated, rotating, inclined cylindrical drum 1.5 m (5 ft) in di-
ameter and 6.7 m (22 ft) in length, and was constructed from a combination
of carbon steel and stainless steel. The primary burner was rated at 22.1
gigajoules/hr (21 MM Btu/hr) and was fired with propane. A centrifugal fan
maintained a negative pressure through the desorber with an average flow of
424.3 mVrnin (15,000 acfm). The burner gas enhanced the volatilization and
transport of organic contaminants from the soil. Desorption was enhanced
by the drum's rotation as well as internal flights that lifted and spilled soils
through the hot gases flowing through the dryer. Actual soil exit tempera-
tures during the performance test ranged between 445 and 585°F (833 and
1,085°F). Treated soils exited at the burner end of the unit and discharged to
A.103
-------
Case Histories
a screw conveyor where they were mixed with fines from the baghouse and
quenched with process water to suppress dust emissions. A negative
pressure was maintained throughout the transport system to capture va-
pors from the quenching process. The screw conveyor discharged the
treated solids to a stacking conveyor for stockpiling. The treated soil
was deposited on-site.
The TPU #1 exhaust gas treatment system consisted of a baghouse, a
quench chamber, a mixing chamber, a reheater, an induced draft fan, and a
vapor-phase carbon adsorption system. The rotary dryer offgases were fed
into a pulse jet baghouse to remove particulates. The baghouse operated at
temperatures up to 260°C (500°F) with a maximum air-to-cloth ratio of 5:1.
The baghouse fines were discharged from the hoppers via a conveyor system
to the treated soils transport unit. The baghouse offgases were then
quenched by flash evaporation of water in a quench chamber, which cooled
the gas to the adiabatic saturation temperature of 74°C (165°F). The exhaust
gas from the quench unit was passed through a demister, and then cooled to
60°C (140"F) by mixing with ambient air. To control potential condensation,
the gases were then reheated to 66°C (150°F) and fed through parallel carbon
adsorption beds with capacities of 5,443 kg (12,000 Ib) of carbon per bed.
The treated offgases were then vented to the atmosphere through a 13.7 m
(45 ft) vertical stack.
A portion of the quench water was recycled back to the spray nozzles in
the spray tower at a rate of approximately 113.6 L/min (30 gal/min). This
recycle was monitored for pH. Sodium hydroxide (50% NaOH) was added
when neutralization was necessary. The remaining quench water was treated
with a liquid-phase carbon adsorption system and then stored for use in cool-
ing treated soils. Both the liquid- and vapor-phase carbon adsorption beds
were regenerated off-site at Westates Carbon in Parker, Arizona.
Prior to full-scale system operation, a shakedown pretest and proof-of-
process performance test were conducted using 243 tonne (268 ton) of the
stockpiled soil. The shakedown pretest was used to evaluate the materials
handling portion of the system. During the pretest, large clumps of clay
were found in the soil stockpile, and were identified as a potential problem
for obtaining good heat transfer in the desorber. A shaker screen was added
to the system to limit materials to 1.91 cm (0.75 in.) in size prior to the
proof-of performance test (Focus Environmental, Inc. 1994).
A. 104
-------
Appendix A
The proof-of-process performance test was conducted at the THAN facil-
ity on July 22, 23, and 25,1993. Four runs were conducted on approxi-
mately 138 tonne (152 ton) of the stockpiled soils to demonstrate that the
soil could be treated to the target residual pesticide levels while not exceed-
ing air emissions standards. On average, the soil feed rate was 7.5 tonne/hr
(8.3 ton/hr) at a soil treatment temperature of 537°C (1,000°F). The results
indicated that all treated soil target pesticide concentrations could be met
while not exceeding the air standards.
Full-scale treatment activities at the THAN facility began on August 12,
1993, and continued until October 1993. Sampling and analysis of soils
beneath the stockpile area and in the area around the thermal desorption
system occurred after the full-scale treatment was completed to verify that
all soils on-site above US EPA's action levels had been treated.
The treated soils were placed on-site as was stipulated in the treatability
variance. Personal protective equipment, debris, and construction waste
were landfilled at a Chemical Waste Management facility in Carlyss, Louisi-
ana. Demobilization of the unit was completed in January 1994.
Operating Parameters Affecting Treatment Cost or Performance
(Focus Environmental, Inc. 1994; Troxler 1994)
Table A.5.4 lists the major operating parameters affecting cost or perfor-
mance for thermal desorption and the values measured for each during this
treatment application.
Timeline
A timeline for this application is shown in Table A.5.5.
Treatment System Performance
Cleanup Goals/Standards
Cleanup goals for the thermal desorption application at THAN were iden-
tified in a March 1992 UAO. An October 1992 treatability variance pro-
vided additional treatment requirements for the soil, and negotiations with
US EPA and the state of Georgia Department of Natural Resources (DNR)
established air emission standards for the project. The treatment require-
ments for both the proof-of-process performance test and full-scale treatment
A. 105
-------
Case Histories
Table A.5.4
Operating Parameters
Parameter . Value
Stack Gas Air Flow Rate 15,056 acfm (average)
Heating Chamber Maximum Operating Pressure 0.0 in. water column
Soil Residence Tune 15 min
Number of Passes 1
System Throughout 7-29 to 9.5 ton/hr
Temperature of Soil Exiting Heating Chamber 833 to 1,080T
Heating Chamber Exhaust Gas Temperature 284 to 332'F
Baghouse Differential Pressure 1.8 to 2.2 in. water column
Maximum Quench Exhaust Temperature 200T
Minimum Quench Recycle Liquid Pressure 5 psig
Carbon Adsorption Inlet Gas Temperature 141 to 150T
Minimum APC System Purge Rate 1 gal/min
Minimum APC System Water Supply Pressure 20 psig
Source: Focus Environmental, Inc. 1994;Troxler 1994
activities are shown in Table A.5.6 (US EPA 1992g; US EPA 1992f; US EPA
1993d). The constituents included in the parameter "Total OCL Pesticides"
include aldrin, alpha-BHC, beta-BKC, delta-BHC, gamma-BHC, chlordane,
DDT, DDD, DDE, dieldrin, endosulfan I, endosulfan II, endrin, and tox-
aphene (Williams Environmental Services, Inc. 1993b).
Air emission standards for stack gas THC, HC1, and particulates were estab-
lished in negotiations with US EPA and Georgia DNR, as shown in Table A.5.7.
Additional Information on Goals (Williams Environmental
Services, Inc. 1993b; US EPA 1993d)
Soil cleanup goals were developed in two stages. A goal of 100 mg/kg
for total OCL pesticides on a dry-weight basis was first provided in the
A.106
-------
Appendix A
Table A.5.5
Timeline
Start Date
End Date
Activity
Mid-1950s
October 1982
July 1984
March 1989
March 1992
April 1992
June 1992
October 1992
July 1993
August 1993
January 1994
1982
1989
September 1984
October 1993
Pesticide formulating and storage operations conducted at site
GEPD conducted initial site visits and identified soil and
groundwater contamination. THAN conducted studies to evaluate
the nature and extent of contamination
Removed and disposed of 10,400 ton of soil and debris at a
hazardous waste landfill
THAN placed on National Priorities List
US EPA issued an Unilateral Adminstrative Order for removal
action
Disposal of 24,700 ton of soil and debris at a hazardous waste
landfill
Bench-scale treatability study for thermal desorption
Treatability variance granted
Full-scale Proof-of-Process Performance Test
Full-scale treatment activity
Demobilization completed
Source: Focus Environmental, Inc. 1994
UAO. Additional goals for measured reductions in concentrations of target
constituents were then developed for a treatability variance based on
Superfund LDR Guide #6B — Obtaining a Soil and Debris Treatability Vari-
ance for Removal Actions (Directive 9347.3-06BFS). Soil cleanup standards
demonstrated during the proof-of-process performance test and full-scale
treatability activity included a minimum reduction of 90% in concentration
of BHC (alpha and beta), 4,4'-DDT, and toxaphene; and less than 100 mg/kg
total OCL pesticides in the treated soil. Since the stockpile had been charac-
terized and 90% reduction had been achieved during the performance test,
no feed samples were required for collection or analysis during the full-scale
operation, provided that the system operated within the proposed operating
conditions agreed upon by THAN and US EPA.
A. 107
-------
Case Histories
Table A.5.6
Treatment Requirements
Constituent/
Parameter
4,4'-DDT
Toxaphene
BHC-a!pha
BHC-beta
Total OCL
Pesticides
Soil Cleanup Goal
>90% measured
reduction in
concentration
>90% measured
reduction in
concentration
> 90% measured
reduction in
concentration
> 90% measured
reduction in
concentration
<100mg/kg
Required During Required During
Proof-of-Performance Full-Scale
Source Test Treatment Activity
Treatability
Variance
Treatability
Variance
Treatability
Variance
Treatability
Variance
Unilateral
Administrative
Order and
Treatability
Variance
/ /
/ /
/ /
/ /
/ /
Source: US EPA 1992; US EPA 1992g; US EPA 1993d
Air emission standards were developed through negotiations between
THAN, US EPA, and Georgia DNR. Stack gas particulates and HC1 emis-
sion rate limits were based on requirements in 40 CFR Part 264.343 (which
provides standards for incinerator emissions). A THC emission limit of 100
ppmv based on a 60-minute rolling average was developed by US EPA using
the following assumptions:
1. Feed soil containing approximately 1% total organic material,
such as humic materials;
2. A stack gas flow rate of 25,592 kg/hi- (56,420 lb/hr)(dry basis), or
1,947 mol/hr; and
3. The APC system achieving a removal efficiency of between 93%
and 96% for non-methane hydrocarbons.
A. 108
-------
Appendix A
Air emissions standards for toxaphene and DDT were developed based on
compliance with Georgia's Guidelines for Ambient Impact Assessment of
Toxic Air Pollutant Emissions. The attached graphs (Figures A.5.3 and
A.5.4) showing acceptable ambient concentrations for toxaphene and DDT
were developed based on site-specific air emissions modeling. The concen-
trations shown on the graphs are a function of the thermal treatment
contractor's operating schedule and air pollution control equipment removal
efficiency. For example, at the maximum operating schedule of 24 hours per
day, 7 days per week, the required removal efficiency shown on Figure A.5.3
for toxaphene is 96%.
Table A.5.7
Air Emission Standards
Constituent/
Parameter
Stack Gas Total
Hydrocarbons
Air Emissions
Standards
100 ppmv
Source
Negotiations with
US EPA
Required During
Proof-of-Performance
Test
'
Required During
Full-Scale
Treatment Activity
(Operating
parameter)
HC1 Mass
Emission Rate
Stack Gas
Particulates
Toxaphene
4.4'-DDT
<41b/hr
< 0.08 gr/dscf
As shown on
Figure A.5.3
As shown on
Figure A.5.4
40CFR /•
264 Subpart O
40CFR /
264 Subpart O
Georgia Guideline J
for Ambient Impact
Assessment of
Toxic Air Pollutant
Emissions
Georgia Guidelines J
for Ambient Impact
Assessment of
Toxic Air Pollutant
Emissions
Source: Focus Environmental, Inc. 1994
A.109
-------
Case Histories
Figure A.5.3
Toxaphene AAC Values vs. Operating Schedule
1.8E-03
1.6E-Q3
1.4&03
1.2E-03
O l.OE-03
8.0E-04
6.0E-04
4.0E-04
2.0E-04
8 hr/day, 5 days/week
12 hr/day, 5 days/week
12 hr/day, 7 days/week
24 hr/day, 5 days/week
24 hr/day, 7 days/week
_L
90 91 92 93 94 95 96 97 98 99 100
Required Toxaphene Removal Efficiency in APCE System
Treatment Performance Data (Focus Environmentaljnc. 1994)
Performance data for the thermal desorption treatment application at THAN
include proof-of-process performance test data results and full-scale treatment
activity data results. These data are presented in the following tables.
Soil data were obtained during the proof-of-process performance test by
collecting process samples of untreated and treated soil. One composite
untreated soil sample and one composite treated soil sample were collected
per run, consisting of grab samples collected at approximately 15-minute
intervals during treatment operations. The samples were collected using
procedures in US EPA SW-846, 'Test Methods for Evaluating Solid Waste,
Physical/Chemical Methods." Each composite sample was analyzed using
US EPA Method 8080 for OCL pesticides.
A.no
-------
Appendix A
Figure A.5.4
DDT AAC Values vs. Operating Schedule
5.QE-03
4.0E-03
1 3.0E-03
8
3
2.0E-03
l.OE-03
O.OE-00
8 hr/day, 5 days/week
12 hr/day, 5 days/week
12 hr/day, 7 days/week
24 hr/day, 5 days/week
^007-
90 91 92 93 94 95 96 97 98 99 100
Required-DDT Removal Efficiency in APCE System
Data presented in Table A.5.8 represent the averages of the four compos-
ite samples collected during the four runs conducted during proof-of-process
performance test.
Air emissions data for stack gas OCL pesticides from the proof-of-
process performance test were obtained using an US EPA Modified
Method 5 Sampling Train. Stack gas particulates and HC1 were mea-
sured using an US EPA Method 5 Sampling Train, and stack gas total
hydrocarbon concentrations were monitored with a continuous emission
monitoring (CEM) system using US EPA Method 25A. Data were col-
lected during each of the four runs from the proof-of-process perfor-
mance test, and are presented in Table A.5.9.
A.111
-------
to
Table A.5.8
Proof-of-Process Performance Test Soil
Constituent/Parameter
Aldrin
alpha-BHC
beta-BHC
delta-BHC
gamma-BHC
alpha-Chlordane
gamma-Chlordanc
4'4'-DDD
4'4'-DDE
4'4'-DDT
Dieldrin
Endosulfan I
Endosulfan II
Endrin
Toxaphene
Total OCL Pesticides
NA Not applicable
Source: Focus Environmental, Inc. 1994
Cleanup Goal
NA
> 90% reduction
> 90% reduction
NA
NA
NA
NA
NA
NA
> 90% reduction
NA
NA
NA
NA
> 90% reduction
< 100 mg/kg
Average Untreated
Soil Concentration
(mg/kg)
<1.7
1.8
42
<1.7
<1.7
<1.7
<1.7
<33
6.5
170
<33
6.6
<3.3
<3.3
160
371
Data
Average Treated
Soil Concentration
(mg/kg)
<0.03
<0.03
<0.08
<0.03
<0.03
<0.03
<0.03
<0.07
3.67
<0.25
<0.07
<0.03
<0.07
<0.07
<3.40
<7.9
r
Avenge Percent Removal
98.00
98.11
98.01
98.07
98.00
98.00
98.00
98.00
4354
99.86
98.00
99.48
98.00
98.00
97.88
97.87
o
Q
c/>
CD
5£
O
=3.
8
-------
Appendix A
Table A.5.9
Proof-of-Process Performance Test Air Emissions Data
Constituent/Parameter
Air Emission Average Emission Range of Emissions Rates
Standard Rate or Concentration or Concentrations
Stack Gas Total Hydrocarbons
HC1 Mass Emission Rate
Stack Gas Particulates
Toxaphene*
4,4'-DDT»
100 ppmv
<41b/hr
< 0.08 gr/dscf
1.48 ng/m3*)
2.96 ng/m3<">
11.9 ppmv
0.12Ib/hr
0.0006 gr/dscf
7.61 E-05 ng/m3
6.08E-06ng/m3
2.9 to 35.5 ppmv
0.12 to 0.13 Ib/hr
0.0005 to 0.0007 gr/dscf
(a)
(a)
ND Not detected
•Allowable Ambient Air Concentrations were developed based on Georgia's Guidelines for Ambient Impact Assessment
of Toxic Air Pollutant Emissions. Stack emissions tor DDT and toxaphene were non-detected for all runs. Ambient
concentrations calculated using one half of the detection limit.
"•Ambient standard
"Ambient impact
Source: Focus Environmental, Inc. 1994; Focus Environmental, Inc. 1995
Soil data were obtained during the full-scale treatment activities by col-
lecting and compositing samples of treated soils and are presented in Table
A.5.10. A total of 18 composite samples were collected and analyzed for
OCL pesticides using US EPA Method 8080.
Average untreated soil concentrations presented in Table A.5.10 are val-
ues from the proof-of-process performance test. Sampling and analysis of
untreated soil was not required during full-scale treatment activities, as
specified in US EPA's letter of approval following the proof-of-process per-
formance test. Treated soil concentrations shown in Table A.5.3 represent
the average concentration of the 18 samples collected. Average percent re-
moval was calculated by averaging the 18 separate values for percent re-
moval of that constituent. The average treated soil concentration of total
OCL pesticides of 0.5065 mg/kg represents the average of concentrations
that ranged from 0.009 mg/kg to 4.2 mg/kg.
A complete data set for the 18 samples collected and analyzed during the
full-scale treatment activity is provided in Table A.5.11.
A.113
-------
Table A.5.10
Full-Scale Treatment Activity Soil Performance Data
Constituent/Parameter
Aldrin
alpha-BHC
beta-BHC
delta-BHC
gamma-BHC
alpha-Chlordane
gamma-Chlordane
4'4'-DDD
4'4'-DDE
4'4'-DDT
Dieldrm
Endosulfan I
Endosulfan II
Endrin
Toxaphene
Total OCL Pesticides
Cleanup Goal
NA
> 90% reduction
> 90% reduction
NA
NA
NA
NA
NA
NA
> 90% reduction
NA
NA
NA
NA
> 90% reduction
< 100 mg/kg
Average Untreated
Soil Concentration*
(mg/kg)
<1.7
1.8
42
<1.7
<1.7
<1.7
<1.7
<3.3
&5
170
<3.3
6.6
<3.3
<3.3
160
371
Average Treated
Soil Concentration
(mg/kg)
< 0.037
< 0.040
< 0.038
< 0.038
< 0.037
< 0.037
< 0.037
< 0.070
< 0.441
< 0.071
< 0.070
< OX)37
< 0.070
< 0.070
< 3.646
< 0.507
Average Percent Removal
97.85
97.78
99.09
97.79
97.85
97.85
9735
9737
93.21
9956
97.87
99.45
97.87
97.87
97.72
99.86
in
(D
NA Not applicable
•Average from four pjns during performance tea!.
Source: Focus Environmental, Inc. 1994
-------
Appendix A
Air emissions data, other than monitoring of THC in stack gas, were not
required to be collected during the full-scale treatment activities. Because
THAN met the treatment and emission standards during the proof-of-process
performance test, US EPA was satisfied that the established operating pa-
rameters would ensure attainment of the additional air emission goals during
full-scale treatment activities.
Performance Data Assessment
The cleanup goal of 100 mg/kg total OCL pesticides in treated soils at the
THAN Site was achieved by the thermal desorption system. The average
total OCL pesticides concentration in the treated soil was 0.50 mg/kg during
the full-scale treatment activities.
Average OCL pesticide removal efficiencies measured during full-scale
treatment activities of the thermal desorption system (averaged from 18
composite sample results) were greater than 98.97% for BHC-alpha, 99.57%
for BHC-beta, 99.98% for 4,4'-DDT, and 99.29% for toxaphene. The indi-
vidual sample removal efficiencies ranged from 91.19% to 99.99%. The
treatment goal of 90% reduction of concentration established in the treatabil-
ity variance was achieved for the specified constituents.
The proof-of-process performance test results indicated that air emis-
sions from the thermal desorption system achieved the air emission stan-
dards for paniculate concentrations and HC1 emission rates, Acceptable
Ambient Concentrations for 4,4'-DDT and toxaphene developed from
Georgia's Air Toxics Guidelines, and US EPA-approved THC concentra-
tions in the stack gas.
Performance Data Completeness
Performance data available from the thermal desorption treatment appli-
cation at the THAN facility include soil performance test data from the
proof-of-process performance test and the full-scale treatment activities, and
air emissions data from the proof-of-process performance test. These data
characterize the treated soil matrix for OCL pesticides from the full-scale
treatment activities. In the proof-of-process performance test, constituent
concentrations for OCL pesticides in untreated soil are matched with treated
soil concentrations, and linked to specific operating conditions.
A. 115
-------
Case Histories
Full-Scale
Sample ID
816-TS-P
817-TS-P
819-TS-P
829-TS-P-l
830-TS-P
902-TS-P-l
906-TS-P-l
909-TS-P-l
911-TS-P-l
913-TS-P-l
915-TS-P-l
917-TS-P-l
919-TS-P-l
1005-TS-P1
100S-TS-P2
1006-TS-P1
1017-TS-P1
1020-TS-P1
# of Sample
Minimum
Average
Maximum
Standard
Deviation
Aldrin
(Hg/kg)
<6.8
<6.8
<1.7
<6.8
<34
<6.8
<68
<68
<8.5
<3.4
<1.7
<6.8
<1.7
<17
<340
<68
<8.5
<1.7
18
<1.7
<36.5
<340
77.2
alpha
BHC
(Hg/kg)
<6.8
<6.8
<1.7
<6.8
<34
<68
<68
<68
<8.5
<3.4
<1.7
<6.8
<1.7
<17
<340
«58
>8.5
<1.7
18
<1.7
<39.9
<340
77.2
Table A.5. 11
Treatment Activity Soil Data
beta
BHC
(Hg/kg)
<6.8
<6.8
<1.7
13
<34
30
«58
<68
<8.3
6.1
2.4
<6.8
<1.7
<17
<340
<68
<8.5
<1.7
18
<1.7
<38.3
<340
76.7
delta
BHC
(HE/kg)
<6.8
<6.8
<1.7
<6.8
<34
<6.8
<68
«58
<8.5
<3.4
<1.7
<6.8
<1.7
<17
<340
<68
29
<1.7
18
<1.7
<37.6
29
77.0
gamma
.BHC
(Jig/kg)
<6.8
<6.8
<1.7
<6.8
<34
<6.8
<68
<68
<8.5
<3.4
<1.7
<6.8
<1.7
<17
<340
<68
<8.5
<1.7
18
<1.7
<36.5
<340
112
alpha
Chlordane
(US/kg)
<6.8
<6.8
<1.7
<6.8
<34
<6.8
<68
<68
<&£
<3.4
<1.7
<6.8
<1.7
<17
<340
<68
<8.5
<1.7
18
<1.7
<36J
<340
77.2
gamma
Chlordane
(Hg/kg)
<6.8
<6.8
<1.7
<6.8
<34
<6.8
<68
<68
<8.5
<3.4
<1.7
<6.8
<1.7
<17
<340
<68
<8.5
<1.7
18
<1.7
<36.5
<340
77.2
Total OCL pesticides are calulated from detected values only.
Source: Focus Environmental,
Inc. 1994
A. 116
-------
Appendix A
Table A.5.11 cont.
Full-Scale Treatment Activity Soil Data
4'4'
ODD
(Hg/kg)
<13
<13
<3.3
<13
<66
<13
<130
<130
<16
<6.6
<3.3>
<13
<3.3
<33
<660
<130
<16
<3.3
18
<3.3
<70.3
<660
149.8
4.4-
DDE
(Hg/kg)
70
53
<3.3
600
260
490
820
480
57
36
20
96
13
11
4^00
670
55
8.8
18
<3.3
<441.3
4200
948.1
4'4'
DDT
(Hg/kg)
<13
<13
<3.3
27
<66
19
<130
<130
<16
<6.6
2.1
<13
<3.3
<33
<660
<130
9-5
<3.3
18
<3.3
<71.0
27
149.6
Dieldrin
(Hg/kg)
<13
<13
<3.3
<13
<66
<13
<130
<130
<16
<6.6
<3.3
<13
<3.3
<33
<660
<130
<16
<3.3
18
<3.3
<703
<660
149.8
Indosulfan I
(}ig/kg)
<6..8
<6.8
<1.7
<6.8
<34
<6.8
<68
<68
<8.5
<3.4
<1.7
<6.8
<1.7
<17
<340
<68
<8.5
<1.7
18
<1.7
<36.5
<340
77.2
Indosulfan n
<13
<13
<3J
<13
<66
<13
<130
<130
<16
<6.6
<3.3
<13
<3.3
<33
<660
<130
< 16
<3.3
18
<3J
<703
<660
149.8
Endrin
• (fig/kg)
<13
<13
<3.3
<13
<66
<13
<130
<130
<1.6
<6.6
<3.3
<13
<3.3
<33
<660
<130
<16
<3.3
18
<33
<70J
<660
149.8
Toxaphene
<680
<680
<170
<680
< 3,400
<680
< 6,800
< 6,800
<850
<340
<170
<680
<170
<1700
< 34,000
< 6,800
<850
<170
18
< 170.0
< 36,45.6
< 34,000
7,724.2
Total" OCL
Pesticides
(fig/kg)
70
53
ND
640
260
1,010
820,
480
57
42
25
96
13
11
4,200
670
55
9
A.117
-------
Case Histories
Performance Data Quality
All samples were analyzed using US EPA-approved methods and a frac-
tion of the data was validated. A QA/QC review was performed by Wood-
ward-Clyde consultants for THAN and by Roy F. Weston, Inc. for US EPA.
The results of this review indicated no technical data quality concerns. One
deviation from US EPA Method 8080 was noted; a wide-bore GC column
was used instead of a packed GC column.
A single-point calibration was first conducted on toxaphene but was then
reported with good agreement for a five-point calibration.
Treatment System Cost
Procurement Process
Eight vendors were contacted by THAN regarding the thermal desorption
project. THAN evaluated the cost estimates provided by each vendor for
mobilization/demobilization and per ton treatment, and also evaluated the
vendor's treatability study experience, the vendor's experience treating haz-
ardous waste (rather than petroleum contamination), vendor availability,
equipment types, and anticipated processing rates. Based on this assess-
ment, THAN contracted with Williams Environmental who prepared the
detailed work plans for the project.
Treatment System Cost
Treatment system costs were obtained from a Petition for Reimburse-
ment submitted by THAN to US EPA, as shown in Tables A.5.12 and
A.5.13. In order to standardize reporting of costs across projects, costs are
shown in Tables A.5.12 and A.5.13 according to the format for an inter-
agency Work Breakdown Structure (WBS). No costs were reported for the
following elements in the WBS: liquid preparation and handling; training;
cost of ownership; dismantling; site work; surface water collection and
control; groundwater collection and control; air pollution/gas collection and
control; solids collection and containment; liquids/sediments/ sludges col-
lection and containment; drums/tanks/structures/miscellaneous demolition
and removal; decontamination and decommissioning; disposal (other than
commercial); disposal (commercial); site restoration; or demobilization
(other than treatment unit).
A. 118
-------
Appendix A
Table A.5.12
Treatment Cost Elements
Cost Elements (Directly Associated with Treatment)
Estimated Cost
($)
Solids Preparation and Handling (equipment retrofit)
Vapor/Gas Preparation and Handling (equipment purchase, puffs)
Pads/Foundation/Spill Control (asphalt pad)
Mobilization/Set Up (mobilization)
Startup/Testing/Permits (performance test)
Operation (short-term; up to 3 years)(soil processing, air monitoring services, thermal
treatment oversight, final report)
Demobilization (demobilization)
Total Treatment Cost
30.000
4,885
26,373
50,000
30,000
698,738
10,000
849,9%
Average cost per ton: $849,996 + 4,318 ton = $200rton of soil treated
•Cost data were submitted by THAN in a Petition for Reimbursement, and have not been evaluated by US EPA as of
June 15, 1994.
Source: Rigger 1994
Table A.5.13
Pretreatment Cost Elements
Cost Elements
Estimated Cost
($)
Mobilization and Preparatory Work (Focus1 and Williams' work plan preparation, modeling) 148,263
Monitoring, Sampling, Testing, and Analysis (treatability study; untreated soil, treated soil, 104319
process water, and puff air samples; respirable dust analyses)
'Cost data were submitted by THAN in a Petition for Reimbursement, and have not been evaluated bv US EPA as of
June 15, 1994.
Source: Rigger 1994
A.119
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Case Histories
Cost Data Quality
An assessment of cost data quality has not been completed to date. Cost
data were submitted by THAN in a Petition for Reimbursement, and have
not been evaluated by US EPA Region IV as of June 15,1994.
Observations and Lessons Learned
Cost Observations and Lessons Learned
• Based on a petition for reimbursement, the cost for thermal des-
orption at THAN was approximately $1.1 million, including
approximately $850,000 for activities directly attributed to treat-
ment of 3,917 tonne (4,318 ton) of soil.
Performance Observations and Lessons Learned
• The cleanup goal of 100 mg/kg total OCL pesticides in treated
soils at the THAN site was achieved by the thermal desorption
treatment system. The average total OCL pesticides concentra-
tion in the treated soil was 0.51 mg/kg during the full-scale treat-
ment activities.
• Average removal efficiencies measured during full-scale treat-
ment activities of the thermal desorption system (averaged from
18 composite sample results) were greater than 98.97% for al-
pha-BHC, 99.57% for beta-BHC, 99.98% for 4,4'-DDT, and
99.29% for toxaphene. The individual sample removal efficien-
cies ranged from 91.19% to 99.99%. The cleanup goal of 90%
reduction of concentration established in the treatability variance
was achieved for the specified constituents.
• The proof-of-process performance test results indicated that air
emissions from the thermal desorption system achieved the air
emission standards for particulate concentrations and HC1 emis-
sion rates, Acceptable Ambient Concentrations for 4,4'-DDT and
toxaphene developed from Georgia's Air Toxics Guidelines, and
US EPA-approved THC concentrations in the stack gas.
• The proof-of-process performance test successfully demonstrated
that certain operating conditions (e.g., system soil throughput and
soil exit temperature) would meet the soil treatment goals and air
A. 120
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Appendix A
emission standards established for treating soil from the THAN
Site. Sufficient data were collected during the test to gain US
EPA's approval to conduct full-scale treatment activities.
The bench-scale treatability study accurately predicted a removal
efficiency of greater than 90% with effective removal of decom-
position products.
The bench-scale treatability study provided data required to sup-
port a treatability variance request submitted by THAN to US
EPA Region IV. The treatability variance, approved by US EPA
Region IV in October 1992, allowed THAN to place the treated
soils on-site. The treatability study also provided necessary data
to select the thermal desorption temperature used in the full-scale
treatment application.
References
1. Troxler, W.L., S.K. Goh, and L.W.R. Dicks. 1993. Treatment
of Pesticide-Contaminated Soils with Thermal Desorption
Technologies. Focus Environmental, Inc., Knoxville, TN.
AWMA Journal. 43: 1610. December.
2. Williams Environmental Services, Inc. 1992a. Treatability
Study for Pesticide Contaminated Soils from THAN. Prepared
for THAN. Submitted to US EPA Region IV. Stone Mountain,
GA. August.
3. Williams Environmental Services, Inc. 1993b. Thermal Des-
orption Work Plan THAN Facility, Albany, GA. Prepared for
THAN. Stone Mountain, GA. July.
4. Focus Environmental, Inc. 1993a. Interim Performance
Test Report THAN Facility, Albany, GA. Prepared for
THAN. August.
5. Williams Environmental Services, Inc. 1992b. Use of Thermal
Desorption for Treating Pesticide Contaminated Soils. Pre-
pared for THAN. Submitted to US EPA Region IV. Stone
Mountain, GA. July.
6. Focus Environmental, Inc. 1993b. Presentation Materials for
the THAN Site, Public Meeting, Albany, GA. February.
A.121
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Case Histories
7. Troxler, W.L. 1992. Thermal Desorption Treatment of Pesti-
cide Contaminated Soils, Project Initiation Meeting, Focus
Environmental, Inc. Knoxville, TN. June.
8. Focus Environmental, Inc. 1994. Appendix I, Removal Action
Report — Thermal Desorption, TH Agriculture and Nutrition
Company Facility, Albany, GA. Knoxville, TN. February.
9. US EPA. 1993d. Letter from Don Rigger to John P. Cleary,
P.E. Approval of Full-Scale Thermal Treatment at THAN Facil-
ity. August 12.
10. Troxler, W.L. 1994. Personal communication from William
Troxler to Jim Cummings, EPA/TIO. March 24.
11. US EPA. 1992g. Unilateral Administrative Order for Removal
Response Activities. Prepared for activities at THAN Facility.
March.
12. US EPA. 1992f. Treatability Variance for THAN Facility.
October.
13. Cleary, John P. 1994. Data sets provided by John P. Cleary,
P.E. from THAN. November 22.
14. Goh, Steve. 1995. Data provided by Steve Goh, Focus Envi-
ronmental; Inc. January 17.
15. Rigger, Don. 1994. Cost Breakdown for Thermal Desorption,
Albany, GA, provided by Don Rigger. June 15.
Analysis Preparation
This case study was prepared for the US EPA's Office of Solid Waste and
Emergency Response, Technology Innovation Office. Assistance was pro-
vided by Radian Corporation under US EPA Contract No. 68-W3-0001.
Supplement A — Treatability Study Results (Williams
Environmental Services, Inc. 1992a)
Treatability Study Objectives
Treatability Study Duration: 6/11/92 to 6/12/92
A. 122
-------
Appendix A
The purpose of the bench-scale treatability test was to determine the fea-
sibility of treating OCL pesticide-contaminated soils from the THAN Site
using thermal desorption (i.e., achieving greater than 90% removal) and to
evaluate the effects of varying temperature and residence time on pesticide
removal efficiency to determine an optimum operating range.
Treatability Study Test Description
The test was conducted by Williams Environmental Services at Deep
South Laboratories in Homewood, Alabama. Contaminated soils from the
THAN Site (100 g per batch) were treated in static trays at various residence
times and temperatures. The trays were shallow pans. The pans were placed
in a muffle furnace with nitrogen used as a purge gas to eliminate organic
vapor saturation in the furnace. Fifteen OCL pesticides and two OP pesti-
cides were analyzed to determine the removal effectiveness of thermal des-
orption treatment using soils from the THAN Site.
The ranges selected for the operating parameters were based on known
operating parameter limits of the rotary dryer and the physical characteristics
(boiling point and volatility) of the OCL pesticides present in the THAN Site
soils. The following temperatures were tested: 260°C (500°F), 371°C
(700°F), and 482°C (900°F). An initial temperature of 100°C (212°F) was
used to simulate the entrance of the soil into the rotary dryer, where the wa-
ter in the soils are first vaporized. The temperature was then increased at a
rate equivalent to the temperature gradient present in the rotary dryer. Resi-
dence times of 36 and 51 minutes were selected on the basis of the rotary
dryer's normal operating range of 15 to 45 minutes. (Table A.5.14)
Treatability Study Performance Data
At a residence time of 36 minutes, pesticide removal efficiencies were
greater than 99% at 371°C (700°F) and 482°C (900°F). At 260°C (500°F),
the pesticide removal efficiency was less than 90%. However, at a residence
time of 51 minutes, pesticide removal efficiencies greater than 90% were
achieved at all three test temperatures. Removal efficiencies were greater
than 99% at 371°C (700°F) and 482°C (900°F) and greater than 90% at
260°C (500°F). At a temperature of 260°C (500°F), concentrations of 4,4'-
DDE were greater in the posttreatment soils than in the pretreatment soils.
The vendor attributed this increase to thermal decomposition of 4,4'-DDT. It
A. 123
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Case Histories
was determined that at the higher temperatures this additional decomposition
product was removed as well.
Treatability Study Lessons Learned
The treatability test showed that thermal desorption was feasible for treat-
ment of pesticide-contaminated soils at the THAN Site. These results were
further validated in the full-scale remediation where the cleanup goals were
met using thermal desorption.
Table A.5.14
Treatability Study Results
Test Temperture
CF)
500
700
900
Total OCL Pesticide Removal Efficiency (%)
36-Minute Residence Time1
> 86.85
> 99.89
> 99.91
51 -Minute Residence Time*
> 90.28
> 99.90
> 99.91
•Residence time at target soil treatment was six minutes for both scenarios (Focus Environmental, Inc. 1994; US EPA
1993d)
A. 124
-------
Appendix B
TREATMENT OF NONHAZARDOUS
PETROLEUM-CONTAMINATED
SOILS BY THERMAL DESORPTION
TECHNOLOGIES*
Spills, leaks, and accidental discharges of petroleum products have con-
taminated soil at thousands of sites in the United States. One remedial ac-
tion technique for treating petroleum contaminated soil is the use of thermal
desorption technologies.
This paper describes key elements of a U.S. Environmental Protection
Agency (US EPA) report, Thermal Desorption Applications Manual for
Treating Nonhazardous Petroleum-Contaminated Soils (Troxler et al. 1993).
The applications manual describes the types, mechanical characteristics, and
operating characteristics of thermal desorption technologies that are com-
mercially available to treat petroleum-contaminated soils. It also provides
step-by-step procedures to rate the critical success factors influencing the
general applicability of thermal desorption at a particular site. These factors
include site characteristics, waste characteristics, soil characteristics, regula-
tory requirements, and process equipment design and operating characteris-
tics. Procedures are provided to determine the types of thermal desorption
systems that are most technically suitable for a given application and to de-
termine whether on-site or off-site treatment is likely to be the most cost
*Editor's Note: The case histories presented in Appendix B have been electronically tran-
scribed from the original source reports as published. No editorial changes were made to the
text of the report or the data reported therein. However, tables and figures were renumbered
and some values were provided in English or metric equivalents to conform to the format of
this monograph.
B.I
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
effective alternative. Key factors that determine process economics are iden-
tified, and estimated cost ranges for treating petroleum-contaminated soils
are presented. Spreadsheets are provided that can be used for performing
cost analyses for specific applications.
The aforementioned report is applicable only to the treatment of petro-
leum-contaminated soils that are exempt from being classified as hazardous
wastes under the Resource Conservation and Recovery Act (RCRA) or as
toxic materials under the Toxic Substances Control Act (TSCA). Although
much of the technical discussion in this paper is applicable to the treatment
of both nonhazardous and hazardous or toxic materials, permitting require-
ments and treatment costs are significantly different for the individual cat-
egories of waste materials.
Technology Overview
Thermal desorption includes a number of ex-situ processes that use either
direct or indirect heat exchange to heat a contaminated soil and volatilize
organic contaminants into an exhaust gas. Thermal desorption systems are
not generally effective in removing metals from contaminated soils, with the
exception of mercury. The term "thermal desorption system" in this docu-
ment refers to the thermal desorber and associated materials handling,
treated soil handling, exhaust gas treatment, and residuals treatment sub-
systems. A general block-flow diagram of a thermal desorption system is
presented in Figure B.I.
The "thermal desorber" is the unit operation that heats the soil to a suffi-
cient temperature to volatilize organic contaminants and remove them from
the heating chamber in a gaseous exhaust stream. The exhaust stream con-
veys the contaminants to an exhaust gas treatment system for further pro-
cessing. The exhaust stream conveying the organic contaminants may con-
sist of air, nitrogen, a combustion gas, or another inert gas. The maximum
temperature of the soil that can be achieved in a thermal desorber is gener-
ally limited by the materials of construction of the device and/or the charac-
teristics of the heat transfer fluid. Thermal desorbers typically operate at soil
discharge temperatures in the range of 149 to 316°C (300 to 600°F) for pe-
troleum contamination applications. However, systems are available that can
operate at soil discharge temperatures as high as 649°C (1,200°F).
B.2
-------
Appendix 6
Figure B.I
Thermal Desorption System Schematic Diagram
Exhaust Gas
to Atmosphere
A
Petroleum
Contaminated Soil
Soils to Disposal
Residuals to Treatment
or Disposal
After the exhaust gas exits the thermal desorber, it is treated by an exhaust
gas treatment system. The organic compounds in the exhaust gas may be
treated in an afterburner or collected by a physical/chemical treatment sys-
tem, which typically uses a condenser followed by an activated carbon ad-
sorption system. Particulates may be collected by using a cyclone,
baghouse, wet scrubber, or some combination of these devices.
Process Equipment Types
The four general types of thermal desorption systems that are commercially
available to treat petroleum-contaminated soils include: (1) rotary dryer, (2)
asphalt plant aggregate dryer, (3) thermal screw, and (4) conveyor furnace.
B.3
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
J*
Table B.I
Comparison of Thermal Desorption System
Features and Operating Parameters
Characteristic
Estimated Number
of Systems
Estimated Number
of Contractors
Mobility
Typical Feedstock
Quantity (ton)
Soil Throughput (ton/hi)
Maximum Feedstock
Size (in,)
Heat Transfer Method
Soil Mixing Method
Soil Discharge
Temperature (*F)
Soil Residence
Time (min)
Thermal Desorber
Exhaust Gas
Temperature (*F)
Thermal Desorber
Exhaust Gas Exit
Velocity (ft/sec)
Gas/Solids Flow
Operating Atmosphere
Afterburner Exit Gas
Temperature ('F)
Thermal Desorber
Thermal Duty
(MMBtu/hr)'
Afterburner Thermal
Duty (MM Bru/hr)
Rotary Dryer
100-120
60-70
Stationary/Mobile
300-25,000"
< 100-10,000"
5-100'
50-100"
2-3
Direct
Shell Rotation
and Lifters
300-600 <=
600-l,200e
3-7
300-500?
500-1, 000 h
5-15
Co-Current or
Counter-Current
Oxidative
1,400-1,600'
800-1,200"
5-50
5-50
Asphalt Plant
Aggregate Dryer
60-100
30-50
Stationary/Mobile
300-25,000'
< 100-10,000b
30-300"
30-300"
2-3
Direct
Shell Rotation
and Lifters
300-600
3-7
300-500
5-15
Counter-Current
Oxidative
1, 400-1, 600 'J
25-120
25- 100 J
Thermal Screw
20-25
8-12
Mobile
300-5,000"
NA
3-15
1-2
Indirect
Auger
300-500 d
250-350'
30-70
300-350
1-5
Not Applicable
Inert
No Afterburner
3-12
No Afterburner
Conveyor
Furnace
1
1
Mobile
300-5,000 '
NA
5-10
1-2
Direct
Soil Agitators
600-800
3-10
1,000-1,200
5-15
Counter-Current
Oxidative
1,400-1,800'
8
2
•Mobile systems
"Stationary systems
c Carbon steel materials of construction
"Hot oil heated system
•Alloy materials of construction.
'Steam heated system
"Counter-current systems
"Co-current systems
•Conventional afterburner
'Afterburners not included on all systems
'Catalytic afterburner
1 Excluding afterburner
B.4
-------
Appendix B
Mechanical design features and process operating conditions vary consid-
erably among the various types of thermal desorption systems. Table B.I
presents an overview of the key design features and process operating pa-
rameters for each type of thermal desorption system. A brief description of
each of these technologies is presented below.
Rotary Dryer
Rotary dryer systems are available as both mobile and stationary systems.
Treatment capacities range from 4.5 to over 91 tonne (5 to over 100 ton) of
contaminated soil per hour. A typical rotary dryer system contains the follow-
ing major process components: (1) feed pretreatment system, (2) feed hoppers
and conveyors, (3) rotary dryer (co-current or counter-current), (4) treated soil
cooling system, (5) cyclones, (6) baghouse, (7) induced draft (ID) fan, (8) after-
burner, and (9) stack.
A rotary dryer system uses a cylindrical metal reactor (drum) that is inclined
slightly to the horizontal. A natural gas, propane, or fuel oil fired burner located
at one end of the dryer provides heat to raise the temperature of the soil suffi-
ciently to desorb organic contaminants. The flow of solids may be either co-
current with or counter-current to the direction of exhaust gas flow. A series of
lifters inside the drum picks the soil up, carries it to near the top of the drum,
and drops it through the hot combustion gases from the burner. The intense
mixing that occurs in a rotary dryer enhances heat transfer by direct contact
with the hot gases and allows soils to be heated very rapidly. As the drum ro-
tates, soil is conveyed through the drum. The residence time of solids in the
drum is controlled by the rotational speed of the drum, the angle of inclination
of the drum, and the arrangement of internal lifters. The maximum soil tem-
perature that can be obtained in a rotary dryer depends on the materials of con-
struction of the dryer shell. Rotary dryers that treat petroleum-contaminated
soils are normally constructed of carbon steel and operate at soil discharge
temperatures of 149 to 316°C (300 to 600°F). Rotary dryers constructed of
alloys are available that can heat contaminated soils up to a temperature of
649°C (1,200°F). After the treated soil exits the rotary dryer, it is sprayed with
water for cooling and dust control. This water addition may be performed in
either a screw conveyor or a pugmill.
An example process-flow diagram of selected components of a counter-
current rotary dryer system is presented in Figure B.2. Counter-current ro-
tary dryers are typically followed by a cyclone, a baghouse, an ID fan, an
B.5
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
afterburner, and a stack. The exhaust gas temperature from a counter-current
rotary dryer with this downstream equipment arrangement is limited by the
materials of construction of the bags in the baghouse. This temperature
limitation is normally in the range of 177 to 260°C (350 to 500°F). A key
advantage of the counter-current system is that the exhaust gas can go di-
rectly to the baghouse without adding water or air for cooling; therefore, the
size of all process equipment downstream of the rotary dryer is minimized.
However, because of this relatively low baghouse operating temperature,
there is some potential for high molecular weight organics to condense in the
baghouse and contaminate the baghouse fines or to blind the bags. Contami-
nated fines may have to be recycled to the rotary dryer or mixed with the hot
soil discharge from the rotary dryer.
Figure B.2
Counter-Current Rotary Dryer System Process-Flow Diagram
B.6
-------
Appendix B
An example process-flow diagram of selected components of a co-current
rotary dryer system is presented in Figure B.3. The most common equipment
arrangement downstream of a co-current rotary dryer is a cyclone, an after-
burner, an evaporative cooler, a baghouse, an ID fan, and a stack. Rotary
dryers that operate in a co-current mode discharge exhaust gas at a tempera-
ture of 10 to 38°C (50 to 100°F) hotter than the soil discharge temperature.
This results in exhaust gas temperatures that may range from 204 to 538°C
(400 to 1,000°F). Since the afterburner is normally upstream of the baghouse,
any fines that are collected in the baghouse will be decontaminated. Therefore,
co-current rotary dryer systems can treat heavy petroleum products, such as
crude oil and No. 6 fuel oil, since baghouse blinding by condensed organic
compounds is not a major consideration.
Figure B.3
Co-Current Rotary Dryer System Process-Flow Diagram
Exhaust Gas
t
Fines to
Cooling
Conveyor Cyclone
Water -
<
ne
Fuel — > Afterburner
r-
Air
Exhaust Gas
!
1 Baghouse
"T .
»("*-
ID Fan
CookT fv/\/Y/vv\
Fines to Disposal
Rotary Dryer
B.7
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
Asphalt Plant Aggregate Dryers
Ba.tch mix asphalt plants use rotary dryers in the asphalt manufacturing
process to dry aggregate before it is mixed with asphalt. These systems are
currently being used to treat petroleum-contaminated soils, either as a recy-
cling process in which the treated soil is incorporated into the asphalt or as a
soil remediation process in which the treated soil is used for other puqposes.
Typical soil treatment capacities for batch mix asphalt plants range from 23
to 136 tonne/hr (25 to 150 ton/hr). Asphalt plant aggregate dryers are nor-
mally constructed of carbon steel and operate at soil discharge temperatures
of between 149 and 316°C (300 and 600°F).
Asphalt plant aggregate dryers typically use a counter-current rotary dryer
followed by a cyclone, baghouse, ID fan, and stack. Some asphalt plant
aggregate dryers have been retrofitted with afterburners. The equipment
arrangement is similar to the diagram shown in Figure B.2, except that some
asphalt plant aggregate dryers may not be equipped with afterburners.
Contaminated soils which are classified as either sands or gravels are
most suitable for incorporation into asphalt. In general, only limited quanti-
ties of silts and clays can used in the asphalt mix because the aggregate par-
ticle size distribution is a key pavement design parameter. The large surface
area of fine particulates, such as clays and silts, is not conducive to proper
mixing and coating of the aggregate material with asphalt. The total accept-
able quantity of minus 200 mesh (75 jam) material in the asphalt product is
generally less than 6% by weight (Porras 1990).
Thermal Screws
Thermal screws are available with soil treatment capacities ranging from
2.7 to 13.6 tonne (3 to 15 ton) of soil per hour. Thermal screw systems are
generally trailer-mounted. The number or trailers required depends on the
size and capacity of the system with two to four trailers being typical. A
diagram showing a typical process arrangement of a thermal screw and
exhaust gas treatment system is presented in Figure B.4. A typical thermal
screw system contains the following major components: (1) solids pretreat-
ment and feed system, (2) indirectly heated screw or paddle auger(s),
(3) heat transfer fluid heating system, (4) treated solids cooling conveyor,
(5) exhaust gas treatment system, and (6) water treatment system.
B.8
-------
Flue Gas
Figure B.4
Thermal Screw Dryer System Process-Flow Diagram
Cooling
Water
Vapor Phase
Activated Carbon
Exhatut Cm
Stack
Spent Carbon to Disposal
^Organics to Recycling or Disposal
Sludge to Disposal or
Recycle to Thermal Screw
>• Spent Carbon to Disposal
Cooled Soil
to Disposal
Q.
X'
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
Excavated solids are usually screened or crushed to remove rocks and debris.
The maximum size of soil particle that can be processed in a thermal screw
depends on the clearances between the screw or paddle auger and the auger
trough. Maximum soil particle sizes are typically in the range of 2.54 to 5.08
cm (1 to 2 in.).
The thermal screw processor may consist of from one to four screw or
paddle augers. Augers can be arranged in series to increase the solids resi-
dence time, or they can be configured in parallel to increase soil throughput
capacity. The auger system conveys, mixes, and heats contaminated soils to
volatilize moisture and organic compounds into an exhaust gas stream. Most
thermal screws systems are heated by a hot oil system or are heated with
process steam. Thermal screw systems circulate a hot heat transfer fluid (oil
or steam) through the jacketed trough in which each auger rotates. The heat
transfer fluid is also circulated through the hollow auger flights and returned
through the hollow auger shaft to the heat transfer fluid heating system.
The heat transfer fluid heating system may be fired with propane, natural
gas, or No. 2 fuel oil. The majority of the combustion gas does not contact
the waste material and can be discharged directly to the atmosphere without
emission controls. A fraction of the flue gas from the hot oil heating system
is recycled to the screw conveyor. This recycled flue gas maintains the ther-
mal screw exhaust gas exit temperature above 149°C (SOOT) so that volatil-
ized organics and moisture do not condense. The recycled flue gas has a low
oxygen content (less than 2% by volume O2) and provides an inert atmo-
sphere to minimize oxidation of organics.
The maximum soil temperature that can be attained in a thermal screw sys-
tem is limited by the temperature of the heat transfer fluid and the materials of
construction of the system. Hot oil heated systems can achieve soil tempera-
tures of up to 260°C (500°F) and steam-heated systems can heat soil up to
IITC (350°F).
After the treated soil exits the thermal screw, water is sprayed on the soil
for cooling and dust control. The water may be mixed with the hot soil in a
screw conveyor or a pugmill.
Vaporized organics, water, and the inert exhaust gas are drawn from the
screw conveyor under an induced draft and pulled through the exhaust gas
treatment system. A particulate control device, such as a venturi scrubber, is
commonly used directly downstream of the thermal screw. Most thermal
B.10
-------
Appendix B
screw systems use a single- or multi-stage condensation system combined
with other unit operations. Gases exiting the paniculate control device are
directed to a one-stage or two-stage water cooled condenser where the tem-
perature of the organic vapors and water are reduced to approximately 38 to
60°C (100 to 140°F). Brine cooled chillers may be provided as a second
treatment step. These devices can cool the exhaust gases to a temperature in
the range of -18 to 4°C (0 to 40°F). Noncondensable organics in the gas
exiting the last condenser may be treated by a vapor phase activated carbon
adsorption system.
Most of the moisture and organic compounds are condensed in the con-
denser and can be removed from the gas by a gas/liquid separator. Con-
densed liquid is pumped to a phase separator, where organics are drawn off
for recycling or disposal. The water fraction is treated in an aqueous-phase
activated carbon adsorption system and then used in the cooling conveyor to
humidify and cool the treated soil. Sludge from the bottom of the separator
may be disposed of or recycled to the thermal screw.
Since thermal screws are indirectly heated, the volume of exhaust gas
from the primary thermal treatment unit operation may be a factor of 2 to 10
times less than the volume from a directly heated system with an equivalent
soil processing capacity. Therefore, exhaust gas treatment systems consist of
relatively small unit operations that are well-suited to mobile applications.
Indirect heating also allows thermal screws to process materials with high
organic contents since the inert gas blanketing system prevents oxidation of
desorbed organic compounds.
Conveyor Furnace
One conveyor furnace system is being used to remediate petroleum-con-
taminated soils. The system is a mobile unit and is transported on three
trailers. The capacity of the conveyor furnace is in the range of 4.5 to 9
tonne (5 to 10 ton) of soil per hour. The conveyor furnace uses a flexible
metal belt to convey soil through the primary heating chamber. A 2.54 cm (1
in.) deep layer of soil is spread evenly over the belt. A series of burners fire
into a chamber above the belt to heat the soil. The conveyor furnace can
heat soils to temperatures ranging from 149 to 427°C (300 to SOOT). After
the treated soil exits the conveyor furnace, it is sprayed with water for cool-
ing and dust control.
B.11
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
The exhaust gas exits the conveyor furnace and is treated in an exhaust
gas treatment system that consists of an afterburner, quench chamber, and
venturi type scrubber. Water discharged from the scrubber is used to cool
the decontaminated soils.
Performance And Application Factors
Three key groups of factors affect the performance and applicability of
thermal desorption systems. These factors include equipment operating
parameters, contaminant characteristics, and soil characteristics. A discus-
sion of each of these groups of factors is presented below.
Equipment Operating Parameters
The primary process factors affecting thermal desorption performance
and applicability are the maximum soil temperature achieved, the soil treat-
ment time, the exhaust gas type, and the heating method. A discussion of
each of these factors is presented below.
Soil Temperature. The key parameter affecting the degree of treatment of
organic components by thermal desorption devices is the soil treatment tem-
perature. The soil treatment temperature achieved is a function of the mois-
ture content, heat capacity, particle size of the soil, and the heat transfer and
mixing characteristics of the thermal desorption device. The soil treatment
temperature required to treat a specific petroleum product in a thermal des-
orption system can be estimated from the original distillation temperature
range of the virgin product. Figure B.5 shows virgin petroleum product
distillation ranges versus typical thermal desorption system soil treatment
temperature ranges.
Treatment Time. The residence time of a solid in a thermal desorber
depends upon the physical configuration of the device, the rotational speed
of the soils-conveying mechanism (shell, auger, or belt), and the incline of
the thermal desorber. Total soil residence time in directly heated thermal
desorption devices (rotary dryers, asphalt kiln aggregate dryers, and the
conveyor furnace) is generally less than 10 min. Treatment times in indi-
rectly heated devices, such as thermal screws, may range from 30 to 90 min.
B.12
-------
AppenoTx 6
Figure B.5
Distillation Temperature vs. Thermal Desorber Temperature
Product Distillation Temperature Range
No. 6 Fuel Oil
Na4 Fuel Oil
Na3 Fuel Oil
No. 2FuelOil(diesel)
No. 1 Fuel Oil (kerosene)
Jet Fuel—A£P5)
Jet Fuel —B(JP4)
Automobile Gasoline
Naphtha (heavy)
MHaytiSi&aaiaiga
Aviation Gasoline
Naphthajlight)
Thermal Desorber Soil Discharge Temperature
Thermal Screw (steam heated)
Thermal Screw (hot oil heated)
Asphalt Plant Aggregate Dryer .
Rotary Dryer (carbon steel)
Conveyor Furnace
S
Rotary Dryer (alloy)
200 400 600 800
Temperature (*F)
1,000
1,200
Virgin product distillation temperature
Thermal desorber soil discharge temperature
B.13
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
Treatment time is a key parameter in determining the degree and cost of
decontamination that is achieved and the cost of treatment by a thermal des-
orption device.
Exhaust Gas Type. The exhaust gas may be oxidative or inert (nitrogen
or low oxygen content combustion gas). For a direct-fired system, the com-
bustion gas frpm the burner serves as an exhaust gas. This stream will al-
ways contain a significant amount of excess oxygen. -The organic content of
the feed material must generally be limited to less than 2 to 3% to stay below
the lower explosive limit if an oxidative exhaust gas is used. Thermal screws
may operate under an inert or very low (less than 2%) oxygen content atmo-
sphere. Thermal screw systems can process solids with 50% or more or-
ganic material since there is a very limited quantity of oxygen to support
oxidation of organic compounds.
Heating Method. Thermal desorption devices may be either direct-fired
or indirectly heated. In direct-fired systems, a burner is used inside of the
thermal desorption chamber and the gaseous combustion products from the
burner directly contact the waste materials. In indirectly heated systems,
heat is transferred to the soil through a metal shell or heated auger. The
flame from the heat-generating process does not contact the waste material.
The volume of exhaust gas from an indirectly heated thermal desorber may
be a factor of two to ten less than the exhaust gas volume from a directly
heated system with an equivalent soil throughput. Therefore, exhaust gas
treatment systems for indirectly heated systems are much smaller and more
mobile than those for directly heated systems. However, because of heat
transfer considerations, indirectly fired systems are generally limited in
physical size and have relatively low waste throughput capacities.
Contaminant Characteristics
The two key petroleum hydrocarbon contaminant properties that affect
the performance of a thermal desorber are the vapor pressure and the initial
concentration of hydrocarbons.
Vapor Pressure. The key parameter influencing the rate at which a contami-
nant is thermally desorbed is the vapor pressure of the compound. Vapor pres-
sure is the force per unit area exerted by a chemical in equilibrium with its pure
solid or liquid at a given temperature. Data presented in Figure B.6 show that at
typical thermal desorption operating temperatures (149 to 316°C [300 to
B.14
-------
Appendix B
Figure B.6
Vapor Pressure vs. Temperature
1,000,000 e?
100,000 5
10,000
1,000 5
I
0.01
0.001
200 400 600 800 1,000 1,200
Temperature (*F)
B.15
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
600"F]), the vapor pressure for a low molecular weight hydrocarbon, such as
benzene, is approximately three orders of magnitude higher than the vapor
pressure for a heavy hydrocarbon, such as phenanthrene. The boiling point of a
compound is the temperature at which its vapor pressure is equivalent to atmo-
spheric pressure (760 mm Hg at sea level). Figure B.6 shows that the boiling
points of the higher molecular weight hydrocarbons, such as phenanthrene, are
as much as 204 to 260°C (400 to 500°F) higher than the boiling points of lower
molecular weight compounds, such as benzene.
Concentration of Petroleum Hydrocarbons. The maximum concentra-
tion of petroleum hydrocarbons that can be treated by a thermal desorption
device depends upon the gas flow through the device, the oxygen content of
the exhaust gas, the type of hydrocarbon compounds present, and the exit
gas temperature. For safety reasons, the concentration of hydrocarbons in
the exhaust gas of some types of thermal desorbers are limited, to less than
25-50% of the lower explosive limit. The 25% value is applicable if the unit
does not include an continuous lower explosive limit (LEL) monitor. The
50% value is applicable if the unit includes an LEL monitor. These restric-
tions are applicable if the thermal desorber operates in an oxygen atmo-
sphere and the temperature of the exhaust gas is above the autoignition tem-
perature of the organic compounds. This safety precaution is normally
implemented by sampling and analyzing feed materials.
Lower explosive limits are typically in the range of 1 to 2% by vol-
ume for most hydrocarbons, and autoignition temperatures are in the
range of 260 to 649°C (500 to 1,200°F). Empirical guidelines on maxi-
mum allowable hydrocarbon concentrations in the feed material have
been established for directly heated rotary dryers. For these devices, the
maximum concentration of petroleum hydrocarbons that can be treated
is typically in the range of 2 to 3%. The maximum allowable concentra-
tion of hydrocarbons in the soil may also be limited in some cases by the
capacity of the afterburner to oxidize desorbed materials without ex-
ceeding temperature or gas residence time limitations.
Systems that operate in an inert atmosphere, such as a thermal screw, may
process materials with concentrations of hydrocarbons up to 50% or higher.
High concentrations of organics can be processed in inert blanketed systems
since there is a limited amount of oxygen available to support oxidation of
organic contaminants.
B.16
-------
Appendix B
Soil Characteristics
The key soil physical characteristics that influence the application of
thermal desorption include: (1) bulk density, (2) particle-size distribution,
(3) plasticity, (4) moisture content, and (5) humic content. A brief descrip-
tion of the impacts of each of these soil characteristics follows.
Bulk Density. Remedial investigation studies normally report soil vol-
umes in terms of yd3. However, performance characteristics of thermal des-
orption systems are determined by material mass flow rates rather than mate-
rial volume flow rates. For example, the amount of energy required to heat a
contaminated soil to a target treatment temperature is a function of the soil
heat capacity in Btus per pound. Similar relationships apply to the moisture
and. organic components of contaminated soils. Typical in-situ bulk densities
of soils range from 1,282 to 1,924 kg/m3 (80 to 120 lb/ft3). Excavated bulk
densities range from 75 to 90% of the in-situ bulk density.
Particle-Size Distribution. Soils are commonly classified according
to the Unified Soil Classification System (USCS)(Holtz and Kovacs
1981). There are four major divisions in the USCS: (1) coarse-grained,
(2) fine-grained, (3) organic soils, and (4) peat. The basis for the USCS
is that coarse-grained soils can be classified according to grain size dis-
tributions, whereas the engineering behavior of fine-grained soils are
primarily related to their plasticity. Classification is performed using
the materials that pass a 75 mm (2.95 in.) sieve. Coarse-grained soils,
such as sands and gravels, are those that have more than 50% material
retained on a 75 mm (2.95 in.) .sieve. Fine-grained soils are those hav-
ing 50% or more material that passes a 75 mm (2.95 in.) sieve. The
particle size distribution of soils can influence the performance of a
thermal desorption system because of the following reasons:
• pretreatment requirements to crush or screen soil;
• potential entrainment of particulates in the process gas; and
• material cohesion characteristics that influence heat transfer.
Thermal desorption devices normally require soils to be pre-treated to
a maximum size in the range of 2.54 to 5.08 cm (1 to 2 in.). Pretreat-
ment may require screening, crushing, or other unit operations. Size
limits depend upon the mechanical clearances in conveyor systems and
heat transfer considerations.
B.17
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
Fine-grained soil particles, such as silt and clays, may become entrained
in the process gas and pass through a thermal desorption device without
adequate residence time at the proper temperature. From 5 to 30% of fine-
grained soils fed to direct-fired thermal desorption devices may become
entrained in the gas stream. From 1 to 5% of fine-grained soils fed to indi-
rectly heated thermal desorption devices may become entrained in the gas
stream. Entrained material may have to be recycled back to the thermal
desorption unit, reducing the effective treatment capacity.
Material handling characteristics that affect heat transfer are affected by a
combination of both particle size and soil moisture characteristics as dis-
cussed below.
Plasticity. A plastic soil is defined as one that will deform without shear-
ing. Soil plasticity characteristics are measured using a set of parameters
known as the Atterberg limits. The plastic limit is the lowest moisture con-
tent at which a sample of the soil will deform without shearing. Thermal
desorption treatment of a fine-grained soil with a moisture content above the
plastic limit is extremely difficult. Plastic soils, when subjected to cornpres-
sive forces, can become molded into large particles that are difficult to heat
because of low surface area-to-volume ratios. Soils in a plastic state are also
difficult to pretreat to remove rocks and other debris and tend to stick to
materials handling equipment and cause jamming problems. Plastic soils
can also coat interior surfaces of thermal desorption systems and reduce heat
transfer efficiencies. In some cases, the moisture content of a soil must be
decreased below the plastic limit prior to thermal treatment. Pretreatment
methods may include air drying, mixing the waste material with drier soil or
other inert solids, or mechanical size reduction using power screens or crush-
ing operations.
Moisture Content. The moisture content of contaminated soils may
range from 5 to 30% or higher with typical moisture concentrations in
the range of 10 to 20%. The moisture may be either absorbed to the
surface of soil particles or chemically bound as a hydrate. Moisture
content of a soil will affect both the amount of energy required to heat
the soil to the target treatment temperature and the physical handling
properties of fine-grained soils as previously discussed. The soil pro-
cessing rate, and consequently the operating cost, of a thermal desorp-
tion device is strongly influenced by the soil moisture content. Mois-
ture can be the major heat sink in a thermal desorption system treating
B.18
-------
Appendix B
contaminated soils. Steam stripping is also an important thermal des-
orption removal mechanism for some compounds. One study has indi-
cated that the presence of moisture in the waste material significantly
affects the removal efficiency for p-xylene (Lighty and Pershing 1988).
Humic Content. Humic material is naturally occurring organic matter
that has been formed by the decay of vegetation. High quality agricultural
soils may contain between 5 and 10% organic material. Natural organic
material in soil begins to decompose at temperatures above 302°C (575°F)
(Helsel, Fox, and Troxler 1987). Studies of the thermal decomposition of
humic materials indicate that pyrolysis products (alkanes, phenols, and poly-
nuclear aromatic hydrocarbons) are formed at 399 to 499°C (750 to 930°F)
(Helsel, Fox, and Troxler 1987). Pyrolysis of humic materials can also gen-
erate carbon monoxide. Soil humic materials can also cause analytical inter-
ferences in both total petroleum hydrocarbon (TPH) and benzene, toluene,
ethylbenzene, xylene (BTEX) analytical tests (Pederson, Curtis, Fan 1991).
Naturally occurring compounds can yield positive values for TPH and BTEX
even if there is no petroleum contamination.
Regulatory Considerations
This document was developed for petroleum-contaminated soils that are
exempt from RCRA and TSCA regulations but are subject to various state or
local regulations. State and local regulations are generally significantly less
complicated than RCRA and TSCA regulations from the standpoint of waste
manifesting requirements, permitting documentation requirements, permit-
ting cost and schedule requirements, performance testing requirements and
cost, and testing and disposal of residuals. This document describes the
following regulatory-related items:
• procedures to determine if a petroleum-contaminated soil is ex-
empt from RCRA and TSCA regulations;
• overview of federal, state, and local regulatory requirements;
• current state regulatory criteria for treated soils; and
. • common analytical methods that are used in the regulation of
petroleum-contaminated soils.
B.19
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
Federal Regulations
" The three key federal regulations that impact the application of ther-
mal desorption for treating petroleum-contaminated soil are: (1) RCRA
underground storage tank corrective action regulations; (2) RCRA exclu-
sion of petroleum-contaminated media and debris, and (3) RCRA recy-
cling exemptions.
RCRA Underground Storage Tank Corrective Action Regulations. 40
CFR 280 describes standards that apply to the design, construction, installa-
tion, notification, operation, release detection, release reporting, release
investigation, release response, release corrective action, and closure for
underground storage tanks. Subpart F of 40 CFR 280 describes corrective
action requirements for UST's that have leaked. Corrective action require-
ments include initial response, initial abatement measures and. site check,
initial site characterization, free product removal, investigations for soil and
groundwater cleanup, corrective action plan, and public participation. Cor-
rective action plans must describe soil remediation methods and procedures
for disposing of treated soil.
RCRA Exclusion. RCRA regulations define certain wastes that are ex-
cluded from being hazardous wastes [40 CFR 261.4(b)(10)]. Petroleum-
contaminated media and debris that fail the test for the Toxicity Characteris-
tic of 40 CFR 261.24 (Hazardous Waste Codes DO 18 through D043 only)
and that are subject to the underground storage tank Corrective Action Regu-
lations under 40 CFR Part 280 are exempt from being hazardous wastes.
Toxicity characteristic DO 18 is benzene, which is a common petroleum prod-
uct constituent. Therefore, this exclusion eliminates most petroleum-con-
taminated soils generated during the remediation of underground storage
tanks from being RCRA regulated wastes. This exclusion does not apply to
soils that fail the toxicity characteristic test for any of the v/aste codes D001
through DO 17. For example, petroleum-contaminated soil containing lead
from leaded gasoline could possibly fail the toxicity characteristic test for
lead (D008) and be classified as a RCRA hazardous waste.
RCRA Recycling Exemption. Some thermal desorption systems, such as
thermal screws, can treat petroleum-contaminated soils and recover the hy-
drocarbons via condensation. In some cases, the recovered hydrocarbons
may be eligible for a recycling exemption. Definitions of a recyclable mate-
rial are presented in 40 CFR 261.6(a)(3)(v-viii). Oil reclaimed from hazard-
ous wastes resulting from normal petroleum refining, production, and
B.20
-------
Appendix B
transportation practices is exempted from being a hazardous waste if the oil
is to be refined along with normal process streams at a petroleum refining
facility. Hazardous waste fuel produced from oil bearing hazardous wastes
is also subject to a recycling exemption if the resulting fuel meets the used
oil specification under 40 CFR Section 266.4(e). If the recovered petroleum
hydrocarbons are not handled in a manner that qualifies for the recycling
exemption, they must be handled as a hazardous waste.
State Regulations
Petroleum-contaminated wastes that are exempt from RCRA and TSCA
regulations must be managed subject to a variety of state and local regula-
tory requirements. Regulatory requirements vary widely from state to
state in terms of the degree of development of written regulations, per-
mitting requirements, soil pre-acceptance criteria, required cleanup stan-
dards, stack emission standards, performance testing requirements, con-
tinuous monitoring requirements, and required analytical methods.
Most states require thermal desorption systems to obtain a state air per-
mit and/or a solid waste permit.
The most common soil cleanup criteria are TPH and BTEX. Many states
establish cleanup criteria on a site-by-site basis, taking into account factors
such as the type and permeability of soil, type of petroleum contaminant,
depth to groundwater, groundwater usage, groundwater quality, ultimate use
of the treated soil, and risk-based analyses of potential human exposures to
contaminants. The most common numerical cleanup standard for TPH re-
siduals in soil after thermal desorption treatment is 100 mg/kg. However,
TPH cleanup criteria may vary from values as low as nondetectable to values
as high as 1,000 mg/kg on a site-by-site basis. The reported distribution of
TPH cleanup levels among the 50 states is as follows:
Site-by-site assessment 24 states;
100 mg/kg TPH 16 states;
50 mg/kg TPH 4 states;
10 mg/kg TPH ' 4 states;
Irng/kgTPH 1 state; and
Nondetectable or background TPH 1 state.
B.21
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
State standards for allowable soil BTEX residual levels also vary widely.
The most common cleanup criteria for individual BTEX compounds in soil
after thermal treatment are in the range of 1 to 10 mg/kg. Individual states
may have BTEX standards ranging from as low as 0.005 mg/kg for indi-
vidual BTEX compounds up to 200 mg/kg for individual BTEX compounds.
Specific analytical methodologies for testing petroleum-contaminated
soils vary widely from state to state. Common methods include determina-
tion of TCLP toxicity characteristics and analyses for BTEX and TPH. The
most common analytical methods are listed in Table B.2. Although chlori-
nated compounds are not normally present in petroleum-contaminated soils
at significant concentrations, many states require that soil pre-acceptance
tests include screening for PCBs or other chlorinated compounds.
Local Permits
A variety of local permits may be required for the implementation of
thermal desorption technologies. Types of permits include: (1) Air Quality
Districts, (2) Water Quality Management Districts, (3) Health Department,
(4) Fire Marshall, (5) Building Inspection, (6) Contractor's License, and
(7) Solid Waste.
Performance Results
Soil Decontamination
Table B.3 summarizes selected information provided by contractors on
contaminant removal performance for various thermal desorption systems.
The complete set of data indicates that concentrations of TPH in the feed
material range from 60 to as high as 67,000 mg/kg, with an average of ap-
proximately 5,000 mg/kg. Concentrations of TPH in the treated materials
range from non-detectable to as high as 5,500 mg/kg, with typical concentra-
tions of TPH in the treated soil in the range of 10 to 100 mg/kg. Contractor
data indicate that TPH removal efficiencies in the range of 95 to 99.9% are
readily attainable for a variety of types of petroleum products.
B.22
-------
Appendix B
Table B.2
Common Analytical Test Methods for Hydrocarbon Contaminated Soils
Parameter
Sample Preparation/Analytical Methods"
Total Petroleum Hydrocarbons (TPH)
Nonhalogenated Volatile Organics
Total Recoverable Petroleum Hydrocarbons (TRPH)
Total Volatile Organic Aromatics (BTEX)
. Volatile Organics
Semivolatile Organics
Halogenated Volatile Organicsb
Polychlorinated Biphenyls*
Organochlorine Pesticides*1
Herbicides'1
Toxicity Characteristic Leaching Procedure
Metals
Extraction Procedure
Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Selenium
Silver
EPA 418.1
EPA 8015 (Modified)
EPA 9073 (Draft)
EPA 5030/8020
EPA 3540/8240
EPA 3540/8270
EPA 5030/8010
EPA 3540/3620,8080
EPA 3540/3620,8081
EPA 8150
EPA 1311
EPA 3050
EPA 6010,7060, or 7061
EPA 6010 or 7080
EPA 6010,7130, or7131
EPA 6010,7190, or 7191
EPA 6010,7420, or 7421
EPA 7471
EPA 6010,7040, or 7041
EPA 6010 or 7760
•Test Methods for Evaluating Solid Wastes, Physical/Chemical Methods, US EPA, SW 846, Third Edition, November
1986.
""Parameter not normally found in petroleum-contaminated soil. Test may be required by pre-acceptance testing
requirements.
B.23
-------
03
System Type
Asphalt Aggregate
Dryer
Asphalt Aggregate
Dryer
Conveyor Furnace
Conveyor Furnace
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Thermal Desorption System
Soil Discharge
Temperature
(*F) Contaminants
Gasoline (leaded)
Gasoline (leaded)
Table
B.3
Soil Treatment Data
Initial
Contaminant
Concentration
Indicator
THC
THC
450 Diesel Fuel Diesel Fuel
298 Gasoline
Crude Oil
650 Crude Oil
Crude Oil
855 Crude Oil
Crude Oil
Crude Oil
Diesel Fuel
Diesel Fuel
Gasoline
TPH
TPH
TPH
TPH
TPH
TPH
TPH
TPH
(mg/kg)
. 393
370
5,000
5,000
2,000
3,403
6,000
5,100
6,000
2,000
3,400
2,450
Reported by
Final
Contaminant
Concentration
(mg/kg)
93
5.7
ND
ND,
<100
219 .
<300
69
<240
<70
<39
<76
Contractors
Contaminant
Removal
Efficiency
(%)
9738
98.46
> 95.00
9336
>95.00
98.65
> 96.00
> 96.50
> 98.85
> 96.90
Reference
Cudahy and Troxler 1990 '
x
California Department of
Health Services 1990b
Cudahy and Troxler 1990
Cudahy and Troxler 1990
Soil Remediation Company
1993b
Thennotech Systems Corp.
1993
Soil Remediation Company
1993b
Thermotech Systems Corp.
1993
Soil Remediation Company
1993a
Soil Remediation Company
1993a
Soil Remediation Company
. 1993a
Soil Remediation Company
1OO3o
-H
-------
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
P Rotary Dryer
fO *
Cn
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
775
650
500-700
580-615
700
500
640
612
550
625
750
580
500
500-700
Diesel Fuel
Diesel Fuel
Diesel Fuel
Diesel Fuel
Diesel Fuel
Diesel Fuel
Diesel Fuel
Diesel Fuel
Diesel Fuel
Fuel Oil
Fuel Oil (No. 2)
Fuel Oil (No. 2)
Fuel Oil (No. 2)
Fuel Oil (No. 6)
Gasoline
Gasoline
Gasoline, Diesel, JP-4
Diesel Fuel
TPH
TPH
Diesel Fuel ,
Diesel Fuel
TPH
TPH
Diesel Fuel
Diesel Fuel
TPH
TPH
TPH
TPH
TPH
TPH
TPH
TPH
1,875 < 1 '
1,758 78
3,000 < 10
67,000 < 1,000
5,200 <1
800 <45
5,400 ' <16
2,400 <1
1,085 < 1
2^00 7
1,708 < 1
34,300 <25
2,600 <2
8,500 <50
1300 6
600 <1 .
5,000 <10
> 99.95
95.56
> 99.67
> 98.51
> 99.98
> 94.38
> 99.70
> 99.96
> 99.91
99.68
> 99.94
> 99.93
> 99.92
> 99.41
9954
> 99.83
> 99.80
California Department of
Health Services 1990a
Thermotech Systems Corp.
1993
Williams Environmental
Services, Inc. 1993
California Department of
Health Services 1990a
California Department of
Health Services 1990a
Soil Remediation Company
1993a
Soil Remediation Company
1993a
California Department of
Health Services 1990a
California Department of
Health Services 1990a
Thermotech Systems Corp.
1993
Thermotech Systems Corp.
1993
ASTEC, Inc. 1990
Thermotech Systems Corp.
1993
ASTEC, Inc. 1990
.Thermotech Systems Corp.
1993
Thermotech Systems Corp.
1993
California Department of
Health Services 1990a
Q:
X
CD
-------
System Type
Rotary Dryer
Rotary Dryer
Rotary Dryer
CD
j^j Rotary Dryer
0
Rotary Dryer
Rotary Dryer
Rotary Dryer
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
Thermal
Soil Discharge
Temperature
OF)
530
600
725
550
580
400
400
400-550
400-550
400-550
Desorptlon System
Contaminants
Gasoline (unleaded)
Gasoline/Diesel
Gasoline/Diesel Fuel
Gas/Diesel
Motor Oil, No.6 Fuel
Oil
Petroleum
Hydrocarbons
Petroleum
Hydrocarbons
Fuel Oil (No. 2),
Gasoline
Fuel Oil (No. 2),
Gasoline
Crude Oil
Crude Oil
Crude Oil
Table
B.3 cont.
Soil Treatment Data
Indicator
TPH
TPH
TPH
TPH
TPH
TPH
TPH
PNAs
BTEX
TPH
TPH
TPH
Initial
Contaminant
Concentration
(mg/kg)
429
150
3,000
5,000
30,000
35,000
uoo
6
!55
15,000
17,000
43,000
Reported by
Final
Contaminant
Concentration
(mg/kg)
<1
22
<10
<100
<40
<10
<48
<0.3
<0.02
5^00
2,100
1,400
Contractors
Contaminant
Removal
Efficiency
(%)
> 99.77
85.33
> 99.67
> 98.00
> 99.87
> 99.97
> 96.31
> 95.00
> 99.99
63.33
87.65
96.74
Reference
Thermotech Systems Corp.
1993
Thermotech Systems Corp.
1993 v
Williams Environmental
Services, Inc. 1993
Williams Environmental
Services, Inc. 1993
ASTEC, Inc. 1990
ASTEC, Inc. 1990
Thermotech Systems Corp.
1993
Cudahy and Troxler 1990
Cudahy and Troxler 1990
Recovery Specialists, Inc.
1993
Recovery Specialists, Inc.
1993
Recovery Specialists, Inc.
1993
— 1
(D
Q
3
o
— *
0
—/
I
Lrf
61
CO
TO
CD
6
CD
c
6
o
-^
Q
q
—'
— *•
CD
CO
0.
CO
-------
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
P° Thermal Screw
fO
l\J
~~~i
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
Thermal Screw
400-550
400-550
400-550
400-550
400-550
400-550
400-550
400-550 '
400-550
400-550
400-550
400-550
400-550
400-550
400-550
Fuel Oil (No. 2)
Fuel Oil (No. 2)
Fuel Oil (No. 2)
Fuel Oil (No. 2)
Gasoline
Gasoline
Gasoline
Gasoline
Gasoline
Gasoline
Gasoline
Jet Fuel A
Kerosene
Stoddard Solvent
Stoddard Solvent
TPH
TPH
TPH
TPH
TPH
TPH
TPH
'TPH
TPH
TPH
TPH
TPH
TPH
TPH
TPH
390
2,100
13,000
50,000
60
210
560
550
350
1340
210
550
550
1,500
1,800
34
50
330
820
ND
ND
ND
20
ND
ND
ND
ND
ND
ND
ND
91.28 Recovery Specialists, Inc.
1993
97.62 Recovery Specialists, Inc.
1993
97.46 Recovery Specialists, Inc.
1993
98.36 Recoveiy Specialists, Inc.
1993 '?
Recovery Specialists, Inc.
1993
Recovery Specialists, Inc.
1993 >
Recoveiy Specialists, Inc. —
1993
96.36 Recovery Specialists, Inc.
1993
Recoveiy Specialists, Inc.
1993
Recovery Specialists, Inc.
1993
Recoveiy Specialists, Inc.
1993
Recovery Specialists, Inc.
1993
Recovery Specialists, Inc.
1993
Recovery Specialists, Inc.
1993
Recovery Specialists, Inc.
1993
ND Not detected
>
•0
U
(D
3
Q.
X"
CD
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
Air Emissions
Stack gas composition data reported by contractors is presented in Table
B.4. Since stack gas performance tests are regulated by individual states,
test parameters and protocols vary from site to site. The data indicate that
the most common test parameters, in order of reported test frequency, are as
follows: particulates (97%), VOCs (67%), carbon monoxide (53%), nitro-
gen oxides (30%), and lead (27%). Other test parameters that were reported
on a less frequent basis included sulfur dioxide (SO2), hydrogen chloride
(HC1), and opacity.
A summary of the contractor-supplied stack emissions data is presented in
Table B.5. The contractor data in Table B.5 indicates that significant perfor-
mance differences exist between those systems that use afterburners as a
control device (rotary dryers and conveyor furnace) and those system that do
not use afterburners (asphalt plant aggregate dryers). No data was reported
for thermal screws using condensation/carbon adsorption treatment as an
exhaust gas treatment system.
Thermal Desorption Costs
The applications manual provides detailed lists of project tasks and step-
by-step procedures for developing thermal desorption treatment cost esti-
mates. Treatment cost curves are presented in the report for treating petro-
leum-contaminated soils with two different sizes of mobile rotary dryer sys-
tems, a mobile thermal screw system, a stationary rotary dryer system, and a
stationary asphalt plant aggregate dryer. Ranges of cost factors for adjusting
estimated treatment costs for alternative conditions are presented. Spread-
sheets are provided for performing cost analyses for specific applications.
Treatment costs are highly application-specific and depend on the type
and size of the thermal desorption system, quantity of soil at the site, soil
transportation costs (stationary treatment systems only), soil type, soil mois-
ture content, type of petroleum product, concentration of hydrocarbon con-
tamination, and soil cleanup criteria. The example cost curves presented in
Figures B.7 through B.9 are based on the following assumptions:
B.28
-------
Appendix B
• soil moisture content is 20%;
• inorganic silty soil (USCS soil classification MH);
• contaminant is No. 2 fuel oil;
• contaminant concentration is 0.3%;
• afterburner exit gas temperature is 1,400°F for devices that use an
afterburner; and
• soil treatment criteria is 100 mg/kg TPH.
The costs presented in Figures B.7 through B .9 should be considered to be
±30% accuracy estimates.
Mobile Treatment Systems —
Costs for using mobile thermal desorption systems are very sensitive to the
site size as measured in tons of material. Fixed costs which are independent of
site size, such as planning and procurement, permitting, site preparation, equip-
ment mobilization, equipment erection, performance testing, and equipment
demobilization significantly impact the unit treatment costs ($/ton) at small
sites. Therefore, unit treatment costs decrease as the site size increases.
Cost curves relating estimated thermal desorption unit treatment costs in
dollars per ton for mobile systems to the quantity of soil treated at a site are
presented in Figures B.7 and B.8. The cost curves presented in Figures B.7
and B.8 are based on the projected costs of procuring "hopper-to-hopper"
treatment services from a remediation contractor. "Hopper-to-hopper" treat-
ment services include screening and/or size reduction of previously exca-
vated and stockpiled soils, thermal treatment services, and depositing treated
soils in a stockpile. The cost curves do not include any remedial investiga-
tion costs, excavation costs, or project management costs incurred by the site
owner. Cost curves are presented for the following types of systems:
• Large rotary dryer (7 ft diameter by 32 ft long with 40 MM Btu/
hr primary chamber burner and 40 MM Btu/hr afterburner). Sys-
tem includes cyclone, baghouse, afterburner, ID fan, and stack.
• Small rotary dryer (5 ft diameter by 18 ft long with 10 MM Btu/
hr primary chamber burner and 10 MM Btu/hr afterburner). Sys-
tem includes cyclone, baghouse, afterburner, ID fan, and stack.
B.29
-------
Table B.4
Thermal Desorption System Stack Emissions Data Reported by Contractors
Stack Emissions
Desorber Type
Rotary Dryer
P Rotary Dryer
8
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Thermal
Processor
Thermal
Processor
Rotary Dryer
Lead in
Feed
Contaminants (mg/kg)
Gasoline, -
Diesel Fuel
No. 2 Fuel Oil
Gasoline,
Diesel Fuel,
No. 2 Fuel Oil
_ _
Gasoline,
Crude Oil
Waste Oil
Hydraulic Oils,
Waste Oils
Gasoline
Stoddard
Solvent
Afterburner
Exit Gas
Temperature
CF)
1,400-1,600
1,600
1,400
1,500
1,600
1,600
1,400
1,400
1,650
Offgas
Treatment
System
Cyclone,
Baghouse,
Afterburner
Cyclone,
Baghouse,
Afterburner
Cyclone,
Baghouse,
Afterburner
Baghouse,
Afterburner
Baghouse,
Afterburner
Cyclone,
Baghouse,
Afterburner
Baghouse,
Afterburner
Baghouse,
Afterburner
Baghouse,
Afterburner
Volatile
Paniculate Organic
(gr/dscf @ Compounds
7%O2) (ppmvdry)
0.03
0.01
< 0.025 <82
<0.04
0.02 <20
0.03 <2
0.04
0.04
0.04 1"
Carbon Nitrogen Lead
Monoxide Oxides (g/ton of
(ppmv dry) (ppmv dry) feed)
_ _ _
10 - 0.001
_ _ _
_ _ _
<20 <50
2 - -
<5 <5
<5 <5
11.3 58
voc
Destruction
and .
Removal-
Efficiency
(%)
—
98
<95
98
>99
99.9
98
98
99.6
- Source
Troxleretal.
1993
Troxleretal.
1993
Troxleretal.
1993
Troxleretal.
1993
Troxleretal.
1993
Troxler et al.
1993
Troxleretal.
1993
Troxleretal.
1993
Troxleretal.
1993
(D
O
I
a
o
6
§
a
I
a
c?
-------
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
00
Gi
— ' Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Rotary Dryer
Gasoline,
Diesel Fuel
Diesel Fuel
Petroleum -
Hydrocarbons
JP-4
Diesel Fuel
Various -
Hydrocarbons
JP-4
Diesel Fuel
Diesel Fuel
Diesel Fuel
All Types
_ _
Fuels and -
Crude Oil
1,650
1,200
1,200
1,100
1,400
1,400-1,600
' 800-U50
1,500
1,600 .
1,400-1,800
1,500
1,600-2,192
1,600
Baghouse,
Afterburner
Catalytic
Afterburner,
Baghouse
Catalytic
Afterburner,
Baghouse
Baghouse,
Afterburner
Baghouse,
Afterburner
Cyclone
Baghouse,
Afterburner
Catalytic
Afterburner,
Baghouse
Baghouse,
Afterburner
Baghouse,
Afterburner
Cyclone
Baghouse,
Afterburner
Baghouse,
Afterburner
Baghouse,
Afterburner
Baghouse,
Wet
Scrubber
0.04 1" 11.3 58
0.026 14 2.1 120
0.023 351 2.1 120
0.04 <50 <10 <50
0.04 - - -
0.025 1.1
0.039 0.42 99.8
0.002_ 99.8
_ _
98.4
98.5
99.9
99.9
99.9
> 99.68
99.99
97
Troxler et al.
1993
Troxler etal.
1993
Troxler et al.
1993
Troxler etal.
1993
Troxler etal.
1993 v
Troxler etal. ""
1993
Troxler etal.
1993
Soil
Remediation
Company
1993a
Soil
Remediation
Company
1993a
Troxler etal.
1993
Troxler etal.
1993
Troxler etal.
1993
Troxler etal.
1993
TJ
T5
0>
Q.
X""™*
CD
-------
Table B.4 cont.
Thermal Desorption
Lead in
Feed
DesorberType Contamintnti (mg/kg)
Rotary Dryer Diesel Fuel
Asphalt Baseline1"
Aggregate
Dryer
Asphalt Gasoline 12
OD Aggregate
C*> Dryer
to
Asphalt Diesel 17
Aggregate
Dryer
Asphalt Diesel Fuel
Aggregate
Dryer
Asphalt Gasoline
Aggregate
Dryer
Conveyor Gasoline -
Furnace
Conveyor Diesel Fuel
Furnace
Afterburner
ExitGu
Temperature
CF)
1,400-1.600
NAC
NA
NA
NA
NA
1,825
1,825
Offgas
Treatment
System
Baghouse,
Afterburner'
Wet
Scrubber
Wet
Scrubber
Wet
Scrubber
Baghouse
Baghouse
Afterburner,
Wet
Scrubber
Afterburner,
Wet
Scrubber
System Stack Emissions Data Reported
Stack Emissions
Volatile
Paniculate Organic Carbon Nitrogen
(gr/dscf® Compounds Monoxide Oxide*
7%02) (ppmv dry) (ppmv dry) (ppmv dry)
0.012 <80
0.055 -
0.20
0.20 - - -
0.13 268d 1373
175-242'
0.008 23d 25
0.006 16* 1.8
by Contractors
Lead
(g/tonof
feed)
—
0.003
.
0.0028
0.0045
_
0.002
0.006
0.0023
VOC
Destruction
and
Removal
Efficiency
(%)
>99
61-65
_
-
89
47-64
-
-
Source
Troxleretal. 1993
Barr Engineering
Company 1990
Barr Engineering
Company 1990 *
Barr Engineering
Company 1990
Troxleretal. 1993
California DepL of
Health Services 1990a
California Dept of
Health Services 1990c
California Dept of
Health Services 1990c
•Volatile nonmethane organic expressed as carbon
a
3
CD
2-
a
o
D
s
Q
a
o
in
"D
CD
3.
®'
C
3
6
o
3
Q
__
Q
CD"
Q.
CO
o
5T
CNA * No afterburner
"Nonmethane VOC's, hydrocarbon basis not Identified
•Total hydrocarbons by flame lonization detector, hydrocarbon basis not identified
-------
Table B.5
Thermal Desorption System Stack Emissions Data Summary0
CD
CO
CO
Technology
Rotary Dryers, Conveyor Furnace
(Systems with Afterburners)
Asphalt Plant Aggregate Dryers
(No Afterburners)
Thermal Screws (Condensation/Carbon
Adsorption Offgas Treatment System)
Parameter
Particulates
Carbon Monoxide
Volatile Organic Compounds
Nitrogen Oxides
Lead
VOC Destruction and Removal Efficiency
Particulates
Carbon Monoxide
Volatile Organic Compounds
Nitrogen Oxides
Lead
VOC Destruction and Removal Efficiency
Particulates
Carbon Monoxide
Volatile Organic Compounds
Nitrogen Oxides
Lead
VOC Destruction and Removal Efficiency
Units
gr/dscf corrected to 7% O2
ppmv dry basis
ppmv dry basis
ppmv dry basis
g/ton of feed soil
%
gr/dscf corrected to 7% O2
ppmv dry basis
ppmv dry basis
ppmv dry basis
g/ton of feed soil
%
gr/dscf corrected to 7% O2
ppmv dry basis
ppmv dry basis
ppmv dry basis
g/ton of feed soil
%
# of Data
Points
25
15
17
9
4
21
4
1
3
NDR
4
5
NDR
NDR
NDR
NDR
NDR
NDR
Minimum
Value
0.002
1
0.42
5
0.0010
95
0.055
NDRb
175
NDR
0.0020
47
NDR
NDR
NDR
NDR
; NDR
NDR
Maximum
Value
0.040
20
351
120
0.0060
99.99
0.200
NDR
268
NDR
0.0045
89
NDR
NDR
NDR
NDR
NDR
NDR
Average
Value
0.025
6
45
58
0.0028
98.89
0.170
1,373
228
NDR
0.0031
65
NDR
NDR
NDR
NDR
NDR
NDR
•Data provided by contractors. No independent QA/QC provided by authors.
"NDR = No data reported
I
CO
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
Figure B.7
Large Mobile Rotary Dryer Treatment Costs
140
120
100
so
60
40
20
Large Mobile Rotary Dryer
40 MM Bhi/hr Primary Burner
40 MM Btu/hr Afterburner
30% Moisture Soil
20% Moisture Soil
10% Moisture Soil
Estimated Accuracy ±30%
I I I
I
468
Site Size (thousands of tons)
10
12
Stationary Treatment Systems
A key parameter influencing the economics of using stationary systems is
the cost of transporting soil from the excavation site to the thermal treatment
system. A series of cost curves relating estimated thermal desorption treat-
ment costs, including soil transportation costs, for a stationary system to soil
transportation distance is presented in Figure B.9. This figure is based on
using a 7 ft diameter by 32 ft long rotary dryer with a 40 MM Btu/hr primary
chamber burner and a 40 MM Btu/hr afterburner. The system includes a
cyclone, baghouse, afterburner, ID fan, and stack. The cost curves do not
include any remedial investigation and excavation cost factors and do not
include project management costs incurred by the site owner.
B.34
-------
Appendix B
Figure B.8
Small Mobile Rotary Dryer Treatment Costs
140
120
100 -
f,
6
s
80 -
60 -
40 -
20 -
Small Mobile Rotary Dryer
10 MM Btu/hr Primary Burner
10 MM Btu/hr Afterburner
30% Moisture Soil
20% Moisture Soil
10% Moisture Soil
Estimated Accuracy ±30%
468
Site Size (thousands of tons)
10
12
Conclusions
Technical and cost evaluations of thermal desorption systems for a spe-
cific remediation application should consider a number of key factors. These
factors include soil discharge temperature capabilities, equipment process
configuration, equipment size, site characteristics, type of petroleum con-
tamination, concentration of TPH, soil geotechnical properties, soil moisture
content, soil humic material content, regulatory requirements, quantity of
soil at a site, soil treatment criteria, and soil transportation considerations.
Thermal desorption is effective in treating petroleum-contaminated soils
to achieve residual TPH concentrations in the range of 10 to 100 mg/kg.
TPH removal efficiencies in the range of 95 to 99.9% are readily achievable
B.35
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
for a variety of types of petroleum products. Control efficiencies for air
emissions parameters (particulates, VOCs, carbon monoxide, nitrogen ox-
ides, and lead) vary widely depending on the type and operating conditions
of emissions control equipment used.
Hopper-to-hopper treatment costs for petroleum contaminated soils
are generally in the range of $30 to $125 per ton. The key factors influ-
encing treatment costs for mobile applications are the type and size of
the thermal treatment equipment and the quantity of soil at a site. Soil
transportation distance is a key factor affecting the cost of treatment at a
stationary facilities.
Figure B.9
Stationary Rotary Dryer Treatment Costs
140
120
100
« so
60
40
20
Stationary Rotary Dryer
40 MM Btu/hr Primary Burner
40 MM Btu/hr Afterburner
30% Moisture Soil
20% Moisture Soil
10% Moisture Soil
Estimated Accuracy ±30%
I
I
I
I
50 100 ISO 200
Transportation Distance (mil)
250
B.36
-------
Appendix 6
1. Troxler, W.L., J.J. Cudahy, R.P. Zink, J. J. Yezzi, and S.I.
Rosenthal. 1993. Guidance document for the application of
thermal desorption for treating petroleum contaminated soils.
Contract No. 68-C9-0033. Edison, NJ: US EPA.
2. Porras.AJ. 1990. Remedial alternatives for virgin petroleum
contaminated soils. Presented at the Air and Waste Management
Association 83rd Annual Meeting and Exhibition, Pittsburgh,
PA. Technical Paper No. 90-15.5. June.
3. Holtz, R.D. and W.D. Kovacs. 1981. An Introduction to
Geotechnical Engineering. Englewood Cliffs, NJ: Prentice-
Hall. 1981.
4. Lighty, J.S, and D.W. Pershing. 1988. Topical report on task II
results from utilization of natural gas for incineration process
research. Prepared for Gas Research Institute. October.
5. Helsel, R.W., R.D. Fox, and W.L. Troxler. 1987. Thermal pro-
cessing of soils to remove organic contaminants. Presented at
American Institute of Chemical Engineers 1987 Annual Meet-
ing, Session 181, New York, NY. pp 1-23.
6. Pederson, T.A., J.T. Curtis, and C.Y. Fan. 1991. Soil Vapor
Extraction Technology Reference Handbook. EPA/540/2-91/
003. February.
7. California Department of Health Services. 1990b. Soil
Detoxification Utilizing an Existing Aggregate Dryer. Re-
medial Technology Demonstration Report, Alternative Tech-
nology Division. March.
8. California Department of Health Services. 1990a. Soil
Cleanup System for a Diesel Contaminated Site in Kingvale,
California. Remedial Technology Demonstration Report, Alter-
native Technology Division. January.
9. Cudahy, J.J. and W.L. Troxler. 1990. Thermal remediation
industry contractor survey. Journal of the Air and Waste Man-
agement Association. 40(8): 1178-1182. August.
B.37
-------
Treatment of Nonhazardous Petroleum-Contaminated Soils
10. ASTEC, Inc. 1990. Product Literature. Chattanooga, TN.
September,
11. Soil Remediation Company. 1993. Processing Results from
Selected Projects. Denver, CO.
12. Soil Remediation Company. 1989. The SRC Remediator.
1(1): 1-4.
13. Thermotech Systems Corporation Product Literature. 1993.
Orlando, FL.
14. Williams Environmental Services, Inc. 1993a. Product Litera-
ture. Stone Mountain, GA.
15. Recovery Specialists Inc. 1993. Product Literature. Saline, MI.
16. California Department of Health Services. 1990c. Thermal
Treatment Process for Fuel Contaminated Soil. Remedial
Technology Demonstration Report, Alternative Technology
Division. March.
17. Barr Engineering Company. 1990. Petroleum Contaminated
Soil Treatment in Asphalt Plants. Report Prepared for Minne-
sota Pollution Control Agency Underground Storage Tank Pro-
gram. May.
B.38
-------
Append)
ACRONYMS AND ABBREVIATION
2,3,7,8 TCDD
2,3,7,8 TCDD TEQ
acfm
ARAR
ASTM
AWFCO
BTEX
Btu
°C
cal
CEM
CERCLA
CFR
DDD
DDE
DDT
DRE
dscf
dscm
microgram
2,3,7,8 tetrachlorodibenzo-para-dioxin
2,3,7,8 tetrachlorodibenzo-para-dioxin toxicity
equivalence
actual cubic feet per minute
Applicable or Relevant and Appropriate
Requirement
American Society for Testing and Materials
automatic waste feed cutoff
benzene, toluene, ethylbenzene, xylene
British thermal unit
Celsius
calorie
continuous emissions monitor
Comprehensive Environmental Response,
Compensation, and Liability Act
Code of Federal Regulations
dichlorodiphenyldichloroethane
dichlorodiphenyldichloroethylene
dichlorodiphenyltricholoroethane
destruction and removal efficiency
dry standard cubic feet
dry standard cubic meter
C.I
-------
Acronyms and Abbreviations
"F
ft
ft2
ft3
g
gr
HEPA
Hg
ID
in.
kg
km
Ib
L
LEL
LT3®
m2
m3
MACT
MBOCA
mg
MGP
mil
min
mm
NACEPT
NFPA
Fahrenheit
feet
square feet
cubic feet
gram
grain(s)
high efficiency particulate absolute
mercury
induced draft (fan)
inch
kilogram
kilometer(s)
pound
liter
lower explosive limit
Low Temperature Thermal Treatment System
square meter
cubic meter
Maximum Achievable Control Technology
4,4'-methylene bis(2)chloroaniline
milligram
manufactured gas plant
mile(s)
minute
millimeters
National Advisory Council on Environmental
Policy and Technology
National Fire Protection Association
C.2
-------
Append/* C
ng
NPDES
OCL
OSHA
PAH
PC
PCB
PCDD
PCDF
PICs
PLC
POHC
POTW
PPE
psig
QA
QC
RCRA
rpm
sec
svoc
TCLP
THC
TIO
tonne
nanogram
National Pollutant Discharge Elimination
System
organochlorine
Occupational Safety and Health Administration
polycyclic aromatic hydrocarbon
personal computer
polychlorinated biphenyl
polychlorinated dibenzo-para-dioxin
polychlorinated dibenzofuran
products of incomplete combustion
programmable logic controller
principal organic hazardous constituent
publicly owned treatment works
parts per billion by volume
personal protective equipment
parts per million by volume
pounds per square inch gauge
quality assurance
quality control
Resource Conservation and Recovery Act
revolutions per minute
second
semivolatile organic compound
toxicity characteristic leaching procedure
total hydrocarbons
Technology Innovation Office
metric ton (1,000 kg)
C.3
-------
Acronyms and Abbreviations
TPH total petroleum hydrocarbon
TRPH total recoverable petroleum hydrocarbon
TSCA Toxic Substances Control Act
UAO Unilateral Administrative Order
US EPA U.S. Environmental Protection Agency
VOC volatile organic compound
w.c. " water column
WBS work breakdown structure
yd3 cubic yard
C.4
-------
Appendix D
LIST OF REFERENCES
Alcamo, Tom. 1995. Personal communication, Tom Alcamo, RPM, to Jim Cummings, EPA/TIO.
February 14. ,
Anderson Development Company. 1992. NPL Public Assistance Database (NPL PAD) EPAID#
MID002931228. Adrian, MI. March.
ASTEC,Inc. 1990. Product Literature. Chattanooga, TN. September.
Ayen, Richard J., Paul Matz and Gregg S. Meyers. 1994. Thermal desorption of PCB-contaminated
soil at the Re-solve Superfund site. Presented at Superfund 1994. Washington, DC: Clemson
Technical Center Technical Report CTC-TR96-006.
Barr Engineering Company. 1990. Petroleum Contaminated Soil Treatment in Asphalt Plants.
Report Prepared for Minnesota Pollution Control Agency Underground Storage Tank Program. May.
BHA Inc. 1996. Data Sheet — Fiber Intrinsic Properties for Hot Gas Applications.
Burchsted, C.A and A.B. Fuller. 1970. Design, Construction, and Testing of High-Efficiency Air
Filtration Systems for Nuclear Applications. Report prepared for US Atomic Energy Commission
Report No. ORNL-NSIC-65.
California Department of Health Services. 1990a. Soil Cleanup System for a Diesel Contaminated
Site in Kingvale, California. Remedial Technology Demonstration Report, Alternative Technology
Division. January.
California Department of Health Services. 1990b. Soil Detoxification Utilizing an Existing Aggre-
gate Dryer. Remedial Technology Demonstration Report, Alternative Technology Division. March.
California Department of Health Services. 1990c. Thermal Treatment Process for Fuel Contami-
nated Soil. Remedial Technology Demonstration Report, Alternative Technology Division. March.
Camp Dresser & McKee, Inc. et al. 1986. Performance of Remedial Response Activities at
Uncontrolled Hazardous Waste Sites (REMII), U.S. EPA Contract No. 68-01-6939, Final
Remedial Investigation Report, Pristine, Inc. Site, Reading, OH. REM II Document No 115-
RIL-RT-CMKQ-1. July.
Canonic Environmental Services Corp. 1990. Treatability Study Report and Remedial Contracting
Services Proposal. September.
Canonie Environmental Services Corp. 1993-1994. Treated Soil Analytical Results. Letters from
Canonic Environmental Services Corp. to Conestoga-Rovers & Associates Limited. December 1993
through March 1994.
Canonie Environmental Services Corp. 1993a. Health and Safety Plan, Pristine, Inc., Reading, OH
92-171-03. August.
Canonie Environmental Services Corp. 1993b. Soil Excavation and Handling Plan, Pristine Inc
Reading, OH. 92-171-03. August.
D.I
-------
List of References
Canonic Environmental Services Corp. 1993c. Treated Soil Handling, Sampling, and Analysis Plan,
Pristine, Inc., Reading, OH. 92-171-03. September.
Canonic Environmental Services Corp. 1994. SoilTechATP System Proof of Process, Pristine, Inc.
Site, Reading, OH. 92-171-03. February.
Chemical Engineering. 1996. Chemical engineering plant cost index (preliminary value for June,
1996). Chemical Engineering. 103(9): 196.
Cleary, John P. 1994. Data sets provided by John P. Cleary, P.E. from THAI'}. November 22.
Conestoga-Rovers & Associates. 1993. Final Design Report, Thermal Treatment of Soil and Sedi-
ment (100% Design) Pristine, Inc. Site, Pristine, OH. Ref. No. 3250 (25). July.
Cudahy, J J. and W.L. Troxler. 1990. Thermal remediation industry contractor survey. Journal of
the Air and Waste Management Association. 40(8): 1178-1182. August
Cudahy, J.J. and W.L. Troxler. 1991. 1991 Thermal treatment remediation industry contractor
survey. Journal of the Air and Waste Management Association. 42(6): 844-849. (unpublished
update, 1996).
Ecology and Environment, Inc. 1986. Remedial Investigation Followup Work Plan for Pristine, Inc.,
Reading, OH. TDD ROS-8607-01. September.
ETC Environmental, Inc. 1995. Project Summary — Marketing Literature.
ETS Inc. 1995. Air Emissions Test Report for McLaren Hart PCX Superfund Site. April.
Federal Remediation Technologies Roundtable. 1995a. Guide to Documenting Cost and Perfor-
mance for Remediation Projects. EPA-542-B-95-002. March.
Federal Remediation Technologies Roundtable. 1995b. Remediation Case Studies: Thermal Desorp-
tion, Soil Washing, and In Situ Vitrification. EPA-542-R-95-005. March.
Focus Environmental, Inc. 1993a. Interim Performance Test Report THAN Facility, Albany, GA.
Prepared for THAN. August
Focus Environmental, Inc. 1993b. Presentation Materials for the THAN Site, Public Meeting,
Albany, GA. February.
Focus Environmental, Inc. 1994. Appendix I, Removal Action Report — Thermal Desorption, TH
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Goh, S.K, W.L Troxler, and J.P. Cleary. 1995. Thermal desorption of pesticide-contaminated soils at
a Superfund site. Presented at The 88th Annual Meeting of Air and Waste Management Association,
San Antonio, TX. June 18-23.
Goh, Steve. 1995. Data provided by Steve Goh, Focus Environmental, Inc. January 17.
Hahnenburg, Jim. 1995. Comments on 30 November 1994 Draft Report from Jim Hahnenburg,
RPM. Received January 18,1995.
Hastings, Mark. 1992a. Memorandum from Mark Hastings, Anderson Development Company, to
James J. Hahnenburg, US EPA, regarding off-site disposal of Composite Soil Pile B. December 3.
Hastings, Mark. 1992b. Memorandum from Mark Hastings, Anderson Development Company, to
•James J. Hahnenburg, US EPA, regarding off-site disposal of Composite Soil Pile B, additional
semivolatile analytical data. December 14.
Hastings, Mark. 1992c. Memorandum from Mark Hastings, Anderson Development Company, to
James J. Hahnenburg, US EPA, regarding off-site disposal of Composite Soil Pile C. December 22.
D.2
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Appendix D
Hastings, Mark. 1993a. Memorandum from Mark Hastings, Anderson Development Company, to
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Hastings, Mark. 1993b. Memorandum from Mark Hastings, Anderson Development Company, to
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Hastings, Mark. 1993c. Memorandum from Mark Hastings, Anderson Development Company, to
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Hastings, Mark. 1993d. Memorandum from Mark Hastings, Anderson Development Company, to
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D.3
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List of References
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D.4
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Appencffx D
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D.5
-------
List of References
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D.6
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THE WASTECH® MONOGRAPH SERIES (PHASE ii) ON
INNOVATIVE SITE REMEDIATION TECHNOLOGY:
DESIGN AND APPLICATION
This seven-book series focusing on the design and application of innovative site remediation
technologies follows an earlier series (Phase 1,1994-1995) which cover the process descriptions,
evaluations, and limitations of these same technologies. The success of that series of publications
suggested that this Phase II series be developed for practitioners in need of design information
and applications, including case studies.
WASTECH* is a multiorganization effort which joins in partnership the Air and Waste Manage-
ment Association, the American Institute of Chemical Engineers, the American Society of Civil
Engineers, the American Society of Mechanical Engineers, the Hazardous Waste Action
Coalition, the Society for Industrial Microbiology, the Soil Science Society of America, and
the Water Environment Federation, together with the American Academy of Environmental
Engineers, the U.S. Environmental Protection Agency, the U.S. Department of Defense, and the
U.S. Department of Energy.
A Steering Committee composed of highly respected members of each participating organization
with expertise in remediation technology formulated and guided both phases, with project
management and support provided by the Academy. Each monograph was prepared by a Task
Group of recognized experts. The manuscripts were subjected to extensive peer reviews prior to
publication. This Design and Application Series includes:
Vol 1 - Bioremedicrtion
Principal authors: R. -Ryan Dupont, Ph.D., Chair,
Utah State University; Clifford J. Bruell, Ph.D.,
University of Massachusetts; Douglas C. Downey,
Parsons Engineering Science; Scott G. Huling,
USEPA; Michael C. Marley, Ph.D., Environgen, Inc.;
Robert D. Norris, Ph.D., Eckenfelder, Inc.; Bruce
Pivetz, USEPA.
Vol 2 - Chemical Treatment
Principal authors: Leo Weitzman, Ph.D., LVW
Associates. Chair, Irvin A. Jefcoat, Ph.D., University
of Alabama; Byung R. Kim, Ph.D., Ford Research
Laboratory.
Vol 3 - Liquid Extraction Technologies:
Soil Washing/Soil Flushing/Solvent Chemical
Principal authors: Michael J. Mann, P.E., DEE,
Alternative Remedial Technologies, Inc., Chair,
Richard J. Ayen, Ph.D., Waste Management Inc.;
Lome G. Everett, Ph.D., Geraghty & Miller, Inc.;
Dirk Gombert II, P.E.. LIFCO; Mark Meckes,
USEPA; Chester R. McKee, Ph.D., In-Situ, Inc.;
Richard P. Traver, P.E., Bergmann USA; Phillip D.
Walling, Jr., P.E., E. I. DuPont Co. Inc.; Shao-Chih
Way, PhJ)., In-Situ, Inc.
Vol 4 - Stabilization/Solidification
Principal authors: Paul D. Kalb, Brookhaven National
Laboratory, Chair, Jesse R. Conner, Conner Technolo-
gies, Inc.; John L. Mayberry, PJS., SAIC; Bhavesh R.
Patel, U.S. Department of Energy, Joseph M. Perez, Jr.,
Battelle Pacific Northwest; Russell L. Treat, MACTEC
Vol 5 - Thermal Desorption
Principal authors: William L. Troxler, P.E., Focus
Environmental Inc., Chair, Edward S. Alperin, IT
Corporation; Paul R. de Percin, USEPA; Joseph H.
Button, P.E., Canonie Environmental Services, Inc.;
JoAnn S. Lighty, Ph.D., University of Utah; Carl R.
Palmer, P.E., Rust Remedial Services, Inc.
Vol 6 - Thermal Destruction
Principal authors: Francis W. Holm, Ph.D., SAIC, Chair,
Carl R. Cooley, Department of Energy; James J.
Cudahy, P.E., Focus Environmental Inc.; Clyde R.
Dempsey, P.E., USEPA; John P. LongweU, Sc.D.,
Massachusetts Institute of Technology; Richard S.
Magee, ScJ>., P.E^ DEE, New Jersey Institute of
Technology; Walter G. May, ScJX, University of Illinois.
Vol 7 - Vapor Extraction and Air Sparging
Principal authors: Timothy B. Holbrook, P.E., Camp
Dresser & McKee, Chair, David H. Bass, Sc.D.,
Groundwater Technology, Inc.; Paul M. Boersma,
CH2M Hill; Dominic C. DiGuilio, University of
Arizona; John J. Eisenbeis, Ph.D., Camp Dresser &
McKee; Neil J. Hutzler, Ph.D., Michigan Technologi-
cal University; Eric P. Roberts, P.E., ICF Kaiser
Engineers, Inc.
The monographs for both the Phase I and Phase II
series may be purchased from the American Academy
of Environmental Engineers*, 130 Holiday Court, Suite
100, Annapolis, MD, 21401; Phone: 410-266-3390,
Fax: 410-266-7653, E-mail: aaee@ea.net
•&U.S. GOVERNMENT PRINTING OFFICE: 1997 -521-9J8/90317
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