EPA542-B-97-009
May 1998
INNOVATIVE SITE
REMEDIATION
TECHNOLOGY
Thermal
Destruction
jiffliHii! ilil^ilK
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Prepared by the American
Academy of Environmental
Engineers under a .
cooperative agreement with
the U.S. Environmental
Protection Agency
EPA542-B-97-009
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INNOVATIVE SITE
REMEDIATION TECHNOLOGY:
' DESIGN AND APPLICATION
THERMAL DESTRUCTION
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
American Society of
Civil Engineers
345 East 47th Street
New York, NY 10017
American Academy of
Environmental Engineers®
130 Holiday Court, Suite 100
Annapolis, MD 21401
American Society of
* Mechanical Engineers
345 East 47th Street
New York, NY 10017
Hazardous Waste Action
Coalition
1015 15th Street, N.W., Suite 802
Washington, DC 20005
Monograph Principal Authors:
Francis W. Holm, PhJX, Chair Clyde It. Dempsey, P.E.
CarlR. Cooley John P., Longwell, Sc.D.
James J. Cudahy, P.E. Richard S. Magee, Sc.D., P.E., DEE
Walter G. May, Sc.D.
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.
"Principal authors: Leo Weitzman, Irvin A. Jefcoat, Byung R. Kim"~V.2, p. Hi.
"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 Atly) III. 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 1998 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
Francis W. Holm, Ph.D., Task Group Chair
Private Consultant
Carl R. Cooley
Department of Energy
James J. Cudahy, P.E.
Focus Environmental Inc.
Clyde R. Dempsey, P.E.
USEPA
John P. Longwell, Sc.D.
Massachusetts Institute of Technology
Richard S. Magee, Sc.D,, P.E., DEE
New Jersey Institute of Technology
Walter G. May, Sc.D.
University of Illinois
REVIEWERS
The panel that reviewed the monograph under the auspices of the Project
Steering Committee was composed of:
Charles O. Velzy, P.E., DEE, Chair
Lyndonville, VT
Charles M. Barnes
Lockheed Martin Idaho Technologies
Peter B. Lederman, Ph.D., P.E.,
DEE, P.P.
New Jersey Institute of Technology
Walter Niessen
Camp Dresser & McKee Inc.
Carl R. Peterson, Ph.D.
Massachusetts Institute of Technology
David Wilson
Dow Chemical Company
Hi
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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
1
George Pierce, Ph.D.
Manager, Bioremediation Technology Dev.
American Cyanamid Company
Representing the Society of Industrial
Microbiology
Peter W. funnicliffe, P.E., DEE
Senior Vice President
Camp Dresser & McKee, Incorporated
Representing Hazardous Waste Action
Coalition
i .
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:
Mike Durham
ADA Technologies
Englewood, CA
Tim Holbrook, P.E., DEE
Camp Dresser & McKee
Denver, CO
Sandy Lopez
Gradient Corporation
Ann Arbor, MI
Bill Schofield
Focus Environmental
LaPorte,
American Society of
Civil Engineers
The American Society of Civil
Engineers, established in 1852, is the
premier civil engineering association in
the world with over 124,000 members.
Qualified reviewers were recruited from
its Environmental Engineering division.
These individuals reviewed the
monograph and have determined that it
is acceptable for publication.,
The reviewer was:
Richard Reis, P.E.
EMCON
Bothell,WA
American Society of
Mechanical Engineers
Founded in 1880, the American
Society of Mechanical Engineers
(ASME) 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.
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This document was reviewed by
volunteer members of the Monograph
Review Committee of the Solid Waste
Processing Division, the Hazardous
Waste Committee of the Environmental
Engineering Division, and the Research
Committee on Industrial and Municipal
Waste, each with technical expertise
and interest in the field covered by this
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.
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
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 Tiemeus
Editor
Catherine L. Schultz
Yolanda Y. Moulden
Project Staff Production
J. Sammi Olmo
I. Patricia Violette
Project Staff Assistants
vii
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TABLE OF CONTENTS
Contributors »i
Acknowledgments vll
List of Tables xvii
List of Figures xvlli
1.0 INTRODUCTION 1.1
1.1 Thermal Destruction 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 I-4
1.4 Objectives .1.4
1.5 Scope 1-5
1.6 Limitations 1-5
1.7 Organization 1-6
2.0 APPLICATION CONCEPTS 2.1
2.1 Wet Air Oxidation 2.1
2.1.1 Scientific Principles 2.1
2.1.1.1 Carboxylic Acids 2.6
2.1.1.2 Phenol and Substituted Phenols 2.6
2.1.1.3 Cyanides and Nitriles 2.7
2.1.2 Potential Applications 2.8
2.1.3 Treatment Trains 2.12
2.2 Texaco Gasification Process 2.12
2.2.1 Scientific Principles 2.12
2.2.2 Potential Applications 2.13
2.2.3 Treatment Trains 2.15
ix
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Table of Contents
2.3 Flameless Thermal Oxidation 2.15
2.3.1 Scientific Principles 2.15
2.3.2 Potential Applications 2.19
2.3.3 Treatment Trains 2.19
2.3.3.1 Pretreatment for GWS '2.2Q
2.3.3.2 Pretreatment for SVE 2.20
2.3.3.3 Posttreatment for GWS and SVE 2.20
2.4 Plasma Furnaces £.21
2.4.1 Scientific Principles 2.21
2.4.2 Potential Applications 2.22
2.4.3 Treatment Trains 2.22
3.0 DESIGN DEVELOPMENT 3.1
3.1 Wet Air Oxidation 3.1
3.1.1 Remediation Goals 3.1
3.1.2 Design Basis 3.3
1 I !"
3.1.3 Design and Equipment Selection 3.7
3.1.4 Process Modifications 3.7
3.1.5 Pretreatment Processes 3.9
3.1.6 Posttreatment Processes 3.9
3.1.7 Process Instrumentation and Controls 3.9
3.1.8 Safety Requirements 3.10
3.1.9 Specification Development 3.10
3.1.10 Cost Data 3.11
3.1.11 Design Validation 3.14
3.1.12 Permitting Requirements 3.14
3.1.13 Performance Measures 3,14
3.1.14 Design Checklist 3.15
3.2 Texaco Gasification Process 3.16
3.2.1 Remediation Goals 3.16
3.2.2 Design Basis 3.16
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Table of Contents
3.2.3 Design and Equipment Selection 3.18
3.2.4 Process Modifications 3.18
3.2.5 Pretreatment Processes 3.18
3.2.6 Posttreatment Processes 3.19
3.2.6.1 Solids Residuals 3.19
3.2.6.2 Gas Stream 3.19
3.2.6.3 Process Wastewater 3.20
3.2.7 Process Instrumentation and Controls 3.20
3.2.8 Safety Requirements 3.20
3.2.9 Specification Development 3.21
3.2.10 Cost Data 3.21
3.2.10.1 Issues and Assumptions 3.22
3.2.10.2 Site Preparation Costs 3.22
3.2.10.3 Permitting and Regulatory Requirements 3.23
3.2.10.4 Capital Equipment i 3.23
3.2.10.5 Labor 3.24
3.2.10.6 Consumables and Supplies 3.24
3.2.10.7 Utilities 3.25
3.2.10.8 Effluent Treatment and Disposal 3.25
3.2.10.9 Residuals and Waste Shipping and Handling 3.25
3.2.10.10 Analytical Services 3.26
3.2.10.11 Maintenance and Modifications 3.26
3.2.10.12 Demobilization 3.26
3.2.11 Design Validation 3.26
3.2.12 Permitting Requirements 3.26
3.2.13 Performance Measures 3.27
3.2.14 Design Checklist 3.27
3.3 Flameless Thermal Oxidation 3.30
3.3.1 Remediation Goals 3.30
3.3.1.1 Performance 3.30
xi
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Table of Contents
3.3.1.2 Regulatory and Public Acceptance
3.3.1.3 Reliability
3.3.2 Design Basis
3.3.2.1 Volumetric Flowrate
3.3.2.2 Organic Concentrations
3.3.2.3 Types of Organic
3.3.2.4 GWS or SVE Offgas Composition
3.3.2.5 Utility Requirements
3.3.2.6 Regulatory Basis
3.3.2.7 Pilot Test Data
3.3.3 Design and Equipment Selection
3.3.4 Process Modifications
3.3.5 Pretreatment Processes
3.3.6 Posttreatment Processes
3.3.7 Process Instrumentation and Controls
3.3.8 Safety Requirements
3.3.9 Specification Development
3.3.10 Cost Data
3.3.11 Design Validation
3.3.12 Permitting Requirements
3.3.13 Performance Measures
3.3.14 Design Checklist
3.4 Plasma Furnaces
3.4.1 Remediation Goals
3.4.2 Design Basis
3.4.2.1 Post Combustion Ratios
3.4.2.2 Theoretical Fuming Rate
3.4.3 Design and Equipment Selection
3.4.4 Process Modifications
3.4.5 Pretreatment Processes
3.32
332
333
333
3.33
3l34
336
3.36
3.36
3.37
3.37
3.37
3.^9
3.40
3.40
3.40
3.41
3^1
3.42
3.42
3.44
3.45
3.46
3.46
3.47
3.47
3.48
3.49
3.51
3.51
xii
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Table of Contents
3.4.6 Posttreatment Processes 3.52
3.4.7 Process Instrumentation and Controls 3.54
3.4.8 Safety Requirements 3.54
3.4.9 Specification Development 3.55
3.4.10 Cost Data 3.56
3.4.11 Design Validation 3.60
3.4.12 Permitting Requirements 3.60
3.4.13 Performance Measures 3.60
3.4.14 Design Checklist 3.61
4.0 IMPLEMENTATION AND OPERATION 4.1
4.1 Wet Air Oxidation 4.1
4.1.1 Implementation ! 4.1
4.1.2 Start-up Procedures 4.1
4.1.3 Operations Practices 4.2
4.1.4 Operations Monitoring 4.2
4.1.5 Quality Assurance/Quality Control 4.3
4.2 Texaco Gasification Process 4.3
4.2.1 Implementation 4.4
4.2.2 Start-up Procedures 4.4
4.2.3 Operations Practices 4.4
4.2.4 Operations Monitoring 4.4
4.2.5 Quality Assurance/Quality Control 4.4
4.3 Hameless Thermal Oxidation 4.4
4.3.1 Implementation 4.4
4.3.2 Start-up Procedures 4.5
4.3.3 Operations Practices 4.6
4.3.4 Operations Monitoring 4.6
4.3.5 Quality Assurance/Quality Control , 4.7
4.4 Plasma Furnaces 4.8
4.4.1 Implementation 4.8
xiii
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Table of Contents
4.4.2 Start-up Procedures 4.8
4.4.3 Operations Practices 4.9
4.4.4 Operations Monitoring 4.9
4.4.5 Quality Assurance/Quality Control 4.10
4.4.5.1 Construction Quality Control . 4.10
4.4.5.2 Chemical Quality Control 4.12
5.0 CASE HISTORIES 5.1
5.1 Wet Air Oxidation 5.1
• . j
5.2 Texaco Gasification Process 54
5.2.1 Equipment and Process Description 5.5
11 !
5.2.1.1 Solids Grinding and Slurry Preparation Unit 5.7
; , j . .
5.2.1.2 High Pressure Solids Gasification Unit II 5.7
5.2.1.3 Acid Gas Removal/Sulfur Removal 5.8
5.2.2 Performance Data 5.8
5.2.2.1 DRE 5^10
5.2.2.2 Slag and Solid Residuals Leachability 5.10
5.2.3 SITE Demonstration Results 5.13
5.2.4 Synthesis Gas Product Composition 5.15
5.2.5 Products of Incomplete Reaction 5.15
5.2.6 Particulate Emissions 5.16
5.2.7 Acid Gas Removal 5.16
5.2.8 Metals Partitioning 5.17
5.2.9 Process Wastewater 5.17
5.2.10 Overall Unit Cost ' 5.18
5.2.11 Overall Unit Reliability 5.19
5.3 Flameless Thermal Oxidation 5.19.
I
5.3.1 U.S. Department of Energy Savannah River Site S VE
Demonstration Test 5.19
5.3.2 Full-Scale Treatment of Wastewater Stripper Offgas 5.21
5.4 Plasma Furnaces 5,22
xiv
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Table of Contents
5.4.1 Brown's Battery Site Pilot-Scale Testing 5.22
5.4.2 Treatability-Scale Tests 5.24
Appendices
A. Other Promising Technologies A.I
B. List of References B.I
C. Points of Contact C.I
XV
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LIST OF TABLES
Table Title Page
2.1 Recent WAO Installations 2.2
2.2 Removal of Carboxylic Acids by WAO 2.7
2.3 Electrically Powered Furnaces Containing Molten Slag or Metal 2.23
2.4 US EPA Assessments of Field Tests Smelting Lead and
Destroying Battery Cases 2.24
3.1 Database of Wastes That Have Been Treated by WAO 3.2
3.2 Technical Basis for Data Extrapolation 3.3
3.3 Sarin Wet Air Oxidation Products 3.4
3.4 Capital Cost of the 90 tonne/day (100 ton/day) Texaco :
Gasification Process Unit 3.24
3.5 Evaluation Criteria for the Texaco Gasification Process
Technology ,3.28
3.6 Compounds Processed by Thermatrix FTO 3.35
3.7 Process Cost Estimate of a FTO Treating SVE Offgas 3.43
3.8 Annual Processing Rates and Power Requirements 3.57
3.9 Operating Cost per Ton of Material Processed 3.57
3.10 Capital Cost Estimates 3.58
3.11 Summary of Total Operating and Capital Costs 3.59
5.1 Characterization of Feed and Oxidation Products from the
Oxidation of Glyphosate 5.3
5.2 Composition of Demonstration Slurry Feed 5.9
5.3 Destruction and Removal Efficiencies (DREs) for Principal
Organic Hazardous Constituent (POHC)— Chlorobenzene 5.11
5.4 TCLP and WET-STLC Results —Lead and Barium 5.12
5.5 Comparison of the Composition of Raw and Treated Synthesis Gas 5.14
xvii
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LIST OF FIGURES
Figure Xitk Page
2.1 Solvation Properties of Pure Water (at 25 MPa) 2.3
2.2 Oxygen Solubility in Water 2.4
2.3 WAO Flow Diagram 2.10
2.4 Projected Costs of Advanced Oxidation Processes for
Destruction of Organic Contaminants in Water 2.11
2.5 Block-Flow Diagram of the Texaco Gasification Process 2.16
2.6 Thermatrix FTO ("Top Down" Preheat) 2.18
2.7 Plasma Furnace and Auxiliary Equipment Train 2.25
3.1 Hazardous Waste Wet Oxidation Installed Capital Costs vs.
Wet Oxidation Unit Capacity 3.12
3.2 Operating and Maintenance Costs for WAO Units 3.13
3.3 Thermatrix FTO Treatment System — Wastewater Stripper
Offgas 3.38
3.4 Process-Row Diagram of Thermatrix FTO Treating
SVE Offgas 3.39
' • • ' i
3.5 Plasma Furnace Cross-Section 3.50
3.6 Solids Preprocessing and Feed System 3.52
3.7 Offgas Cleanup System with Energy Recovery 3.53
5.1 Structures of the Pesticides Tested 5.2
5.2 Schematic-Flow Diagram of the Texaco Gasification Process
Used in the SITE Demonstration 5.6
5.3 DOE Westinghouse Savannah River Site, South Carolina 5.20
xviii
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Chapter 1
INTRODUCTION
This monograph covering the design, applications, and implementation of
selected Thermal Destruction technologies, 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 descrip-
tion, 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; stabilization/solidification;
thermal desorption; and vapor extraction and air sparging.
I, I Thermal Destruction
Thermal destruction, as considered in this monograph, is an ex-situ pro-
cess that thermally destroys organic contaminants. Often, thermal destruc-
tion is considered a mature technology employing a variety of reaction
chambers. Rotary kilns are most common. Innovation in this area has oc-
curred primarily in the form of modifications and improvements to 'existing
systems, process reactions, and by-products.
Information on the more established thermal destruction technologies
used in site remediation can be found in the companion monograph,
Innovative Site Remediation Technology — Thermal Destruction
(Magee et al. 1994). Thermal destruction technologies discussed in that
monograph include: catalytic oxidation, rotary cascading bed incinera-
tion, the ECO LOGIC thermo-chemical reduction reactor, and the HRD
flame reactor process.
1.1
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Introduction
This monograph on design and application focuses on wet air oxidation,
the Texaco gasification process, flameless thermal oxidation, and plasma
furnaces. Two of these processes, wet air oxidation and flameless thermal
oxidation, are useful adjuncts to treating by-products from other remediation
technologies.
7.2 Development of the Monograph
i " , ' ' , i , • , i , ' •, . ' i
'! ' '
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 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.
i
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.
1.2
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Chapter 1
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 American Insti-
tute 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 Acad-
emy, 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 experts to write a
manuscript for each monograph. The task groups were appointed with a
view to balancing the interests of the groups principally concerned with the
application of innovative site and waste remediation technologies — indus-
try, 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.
1.3
-------
Introduction
i
To develop broad, consensus-based monographs, the Steering Committee
prescribed a twofold peer review of the first drafts. One review was conducted
by the Steering Committee itself, employing panels consisting of two members
of the Committee supplemented by 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 repre-
sented in the Project reviewed those monographs addressing technologies in
which it has 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 innovative thermal
destruction site remediation and waste processing technologies, that is, tech-
nologies not commonly applied; where their use can provide better, more
cost-effective performance than conventional methods. To this end, the
monograph documents the current state of thermal destruction technology.
7,4 Objectives
The monograph's principal objective is to furnish guidance for experi-
enced, practicing professionals and users' project managers. This mono-
graph, and its companion monograph, are intended, therefore, not to be pre-
scriptive, but supportive. It is intended to aid experienced professionals in
applying their judgment in deciding whether and how to apply the technolo-
gies 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 processes it ad-
dresses are potentially applicable.
1.4
-------
Chapter 1
7.5 Scope
The monograph addresses innovative thermal destruction technologies
that have been sufficiently developed so that they can be used in full-jscale
applications. It addresses all aspects of the technologies for which sufficient
data were available to the Thermal Destruction Task Group to briefly review
the technologies and discuss their design and applications.
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 technology is site-
specific and involves consideration of a number of matters besides alterna-
tive technologies. Among them are the following that are addressed only to
the extent that they are essential to understand the applications; and limita-
tions of the technologies described:
• site investigations and assessments;
• planning, management, and procurement;
• regulatory requirements; and
• community acceptance of the technology.
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.
1.5
-------
I
Introduction
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.
i
Chapter 2, Application Concepts, summarizes the process, its scientific
basis, the potential applications, and key requirements for thermal destruc-
tion technologies. Design Development, Chapter 3, provides essential infor-
mation for those contemplating use of the technologies discussed. Chapter
4, Implementation and Operation, focuses on the procedures commonly used
to implement thermal destruction technologies and key facets of their opera-
tion. Finally, Chapter 5 presents example case histories.
1.6
-------
Chapter 2
APPLICATION CONCEPTS
Thermal destruction, as considered in this monograph, is an ex-situ
process that destroys or removes organic compounds or metals from
contaminated matrices. The reader is referred to the companion mono-
graph, Innovative Site Remediation Technology — Thermal Destruction
(Magee et al. 1994) for information on other more established technolo-
gies, specifically, catalytic oxidation, rotary cascading bed incineration,
the ECO LOGIC thermo-chemical reduction reactor, and the HRD flame
reactor process. This monograph on design and application focuses on
wet air oxidation, the Texaco Gasification Process, flameless thermal
oxidation, and plasma furnaces. Two of these processes, wet air oxida-
tion and flameless thermal oxidation, are useful adjuncts to treating by-
products from other remediation technologies.
2.1 Wet Air Oxidation
2.1.1 Scientific Principles
Wet Air Oxidation (WAO) is a process for oxidizing materials in a dilute
aqueous matrix. The process has been applied industrially to detoxify or-
ganic and, to a lesser extent, oxidizable inorganic materials in dilute solution
or suspension. High destruction efficiencies (99+%) have been reported for
a wide range of materials. The process substantially reduces chemical oxy-
gen demand (COD); the COD of the product is usually 25% or less than that
of the original waste stream. Typically, biological treatment is used as a
final polishing step.
The major WAO system suppliers are U.S. Filter-Zimpro, Kenox Corpora-
tion, and Nippon Petrochemical. Table 2.1, a listing of recent WAO
2.1
-------
Application Concepts
1 ' • ' 1 [
Recent
Installation
Yukong Ltd
Ulsan, S. Korea
CPC-Kaphsiung Refinery
Quantum Chemical
Deer Park, TX
Finaneste
Antwerp, Belgium
Westlake Polymer
Lake Charles, LA
CPC-Talin Refinery
Formosa Plastics
Point Comfort, TX
Sterling Organics
Dudley, UK
Table 2.1
WAO Installations
Application # of Units
Spent Caustic
Spent Caustic
Spent Caustic
Spent Caustic
Spent Caustic
Spent Caustic
Spent Caustic
Pharmaceutical
Yorkshire Water
Leeds, UK Commercial Treatment
Phillips Petroleum
Sweeny, TX
CPC-Lin Yuan Refinery
ELEME Petrochemicals Co.
Port Harcourt, Nigeria
Refinaria de Petroleos de Manguinhos
Rio de Janeiro
UC Under construction
Source: Moment, Copa, arid Randall 1995
Spent Caustic
Spent Caustic
Spent Caustic
Spent Caustic
1
3
1
1
1
3
1
1
1
1
2
1
1
Capacity
(gal/min)
145
25
21
25
H) '
53
21
30
10
65
17
35
25
"''! :,
Start-up
Date
1
1 " .
1989
1990
1991
1991
1991
1994
1994
1992
1993
1993
1994
UC
UC
\ :
installations (Moment, Copa, and Randall 1995), shows a large number of
applications for treating spent caustic wastes.
To maintain a liquid phase in the usual operating temperature range of
150 to 320°C (300 to 600°F), pressure must be in the range from 0.5 to 11.5
MPa (75 to 1,700 lb/in.2). The high pressure necessary for the process is
2.2
-------
Chbpter 2
usually generated by pumping and compressing. An interesting alternative is
to drill a deep hole and pump water and reactants down (and back up) via
concentric piping; the column of liquid provides the high pressure required
at the bottom of the hole. However, this discussion of WAO is devoted to the
more usual, aboveground technology, although the chemistry and scientific
principles apply to both methods. Mishra, Vijaykumer, and Joshi (1995)
have extensively reviewed research work on the WAO process.
The properties of water change as temperature (and pressure) increase. At
room temperature water is a highly polar fluid; nonpolar materials (e.g.,
hydrocarbons) are almost insoluble, while most salts have high solubilities.
Under usual WAO conditions, the fluid properties (solubility characteristics
in particular), still resemble those of ordinary water, as shown in Figure 21.
Figure 2.1
Solvation Properties of Pure Water (at 25 MPa)
"I
•I
I
Q
100
200
300 400 500
Temperature (°C)
600
800
Source: Copa 1995
2.3
-------
Application Concepts
, . ,;, , IN] ; , . ,1 :„„
The solubility of oxygen is also important to the process (Figure 2.2).
Under normal conditions for WAO, the solubility remains well below that
required for most applications; oxygen must continue to be transferred from
the gas to the liquid phase to complete the oxidation. It is worth noting that
supercritical water oxidation is covered under Chemical Treatment in this
series of monographs.
Figure 2.2
Oxygen Solubility in Water
so
100
150 200 250
Temperature (°C)
300
400
O 10PSIAP(02)
• 25 PSIA
X 50 PSIA
• 100 PSIA
A 250 PSIA
Source: Copa 1995
2.4
-------
Chapter 2
Water at high temperature and pressure, approaching critical conditions,
will react with most organic materials even in the absence of oxygen. The
hydrolysis of carbon tetrachloride at elevated temperature and pressure is
known to produce hydrochloric acid and carbon dioxide:
CC14 + 2H2O -> 4HC1 + CO2
Other halogenated organic compounds hydrolyze to alcohols and carbo-
nyl compounds (Copa 1995).
Most, if not all, organic compounds are attacked under WAO conditions.
Typical products, in addition to carbon dioxide and water, are a small
amount of carbon monoxide, soluble carbonate and bicarbonate, and acetic
acid, acetone, butanone, and other low molecular weight oxygenated materi-
als. Elements, such as halogens, nitrogen, phosphorous, sulfur, are usually
released as halides, ammonia, or other nitrogen gases, phosphate, and sul-
fate; these elements are separated almost completely from the residual or-
ganics (Moment, Copa, and Randall 1995).
Many different materials, including Cu2+, Fe2+, CuO/ZnO, Cu3+, and Ce4*
will catalyze the oxidation reactions. Homogeneous and heterogeneous
catalyses have been used experimentally. The presence of catalyst in the
liquid discharge complicates the final disposition, particularly for a soluble
homogeneous catalyst. Catalysis does not appear to have been used in in-
dustrial systems.
Wet air oxidation has been studied in considerable detail for a few types
of chemicals using small-scale, batch reactors. Carboxylic acids have been
studied because of their importance as intermediates in the oxidation pro-
cess. Phenols and some nitrogen compounds (cyanides and nitriles) have
also been studied because of their prevalence and hazardous properties. In
addition, many and varied materials have been tested for completeness of
reaction, etc. Such work has been done in both batch and flow-through type
reactors, much of it to provide information for plant design.
The oxidation reactions usually progress in a series of steps involving
free radicals (Sadana and Katzer 1974). As a result, the detailed kinetics
are complicated with a variety of reaction orders being reported for dif-
ferent materials.
2.5
-------
Application Concepts
2.1.1.1 Carboxylic Acids
Long chain molecules are broken down quickly to intermediates which
then react more slowly. The effluent products can be divided into three
groups: remaining unstable (initial) intermediates, refractory intermediates
such as acetic acid, and endproducts, such as carbon dioxide or carbonates.
The results of most of the studies have been summarized by Mishra,
Vijaykumer, and Joshi (1995). Linear monocarboxylic acids (formic, acetic.,
propionic, butyric, valeric, and caproic), and dicarboxylic acids (oxalic, adipic,
succinic, and glutaric) were studied. In summary, reaction rates were found to
be on the order of 1.0 to 1.5 with respect to the substrate concentrations; the
order with respect to oxygen pressure was generally in the range 0.31 to 0.46
(although one reference reported an order close to zero). Activation energies
were reported in the range 75 to 142 kJ/mole. The reaction rate generally in-
creased with size of the molecule (formic acid is an exception; it is easily oxi-
dized), and dibasic acids were more readily oxidized than monobasic acids.
The extent of reaction for most of the materials studied was low to moderate,
illustrating the fact that low molecular weight acids are refractory and tend to
show up in the effluent products. Lnamura, Kinunaka, and Kawabata (1982)
illustrate this with the data shown in Table 2.2 from a catalyzed system. Experi-
ence also indicates the same trends in uncatalyzed systems.
2.1.1.2 Phenol and Substituted Phenols
A particularly interesting observation is that WAO of most phenols exhib-
its a pronounced induction period, the length of which depends on the sever-
ity of the oxidation conditions (i.e., temperature and pressure), as well as the
particular phenol. The induction period is presumably related to establishing
a reactive concentration of an important chain carrier. This has been exam-
ined in some detail by Sadana and Katzer (1974).
The oxidation process for phenols occurs at variable rates due to the pres-
ence of side chains; alkyl side chains oxidize much more readily than the
ring, resulting in rapid formation of radicals. Therefore, the oxidation shows
a rapid initial rate as the alkyl groups are oxidized, followed by a slower
reaction as the ring is broken down.
Studies done at relatively low temperature (25 to 80°C [77 to 176°F]),
have identified some very reactive intermediates in the oxidation process,
e.g., pyrocatechol and hydroquinone, as well as carboxylic acids. Some
2.6
-------
Chapter 2
Table 2.2
Removal of Carboxylic Acids by WAO
Substrate
Formic Acid
Acetic
Propionic
Butyric
Valeric
Hexanoic
Oxalic
Adipic
Succinic
Glutamic
WAOatP0z = 1MPa
Time = 20min
Temperature . Total Organic Carbon
fC) (% Removal)
112
248
248
248
248
248
160
248
248
248
Note: Total system pressure is much higher than the oxygen partial pressure of 1
Source: Imamura, Kinunaka, and Kawabata
1982
173
83
6.9 '•
115
83
12,4
90.0
273
58.6
725
MPa^Slb/in.2).
polymeric material, tars, might also form, although these are not observed at
normal (higher temperature) conditions.
The reaction orders for phenol oxidation are similar to those for carboxy-
lic acid — first order for the substrate and low (approaching zero) for oxy-
gen. The activation energies reported are lower, 5.44 to 54.01 kJ/mol
(Mishra, Vijaykumer, and Joshi 1995).
2.1.1.3 Cyanides and Nitriles
Nitrogen-containing compounds can react to yield various products: N2,
NH3, CN~ (Mishra, Vijaykumer, and Joshi 1995). Hydrolysis appears to be
an important first step in the WAO of both cyanides and nitriles. Thus, acry-
lonitrile is reported to undergo hydrolysis to acrylamide and then to acrylic
2.7
-------
Application Concepts
acid (liberating NH3), followed by oxidation of the acid. The oxidation of
the acid is the slow step.
Cyanide can be hydrolyzed, depending on temperature:
NaCN + 2H,O—;=-> HCOONa + NH3 at high temperatures; and
2 K !
I
NaCN + H2O—^->NaOH + HCN at temperatures below 50°C (120°F).
NaCN can also be oxidized directly, first to give cyanate and then nitro-
gen. Thus, oxidation of cyanides can yield both N2 and NH3 (the latter being
resistant to further oxidation).
A range of reaction orders and activation energies for nitrogen-com-
pounds have been reported; see Mishra, Vijaykumer, and Joshi (1995)
for details.
2.1.2 Potential Applications
Patents for WAO technology date back to 1911 — however, industrial
application has occurred mainly in the past 25 years. The extension of the
concept to supercritical conditions has spurred interest.
Wet air oxidation is a versatile process which might have advantages over
competing technologies where the following conditions prevail:
• the feed material to be oxidized is in the form of a fairly dilute,
aqueous solution or suspension — usually in the range of 1 to 5%
solids;
• biological treatment of the feed material is either ineffective or
inconvenient because of limited space or other considerations; and
t\
• the moderate to high pressure requirement for WAO treatment is
not viewed as a serious safety hazard.
More than 200 WAO plants have been built worldwide. The applications
fall into two principal categories:
• Roughly half of the applications have been used to treat sewage
sludges, consisting of low concentrations of sewage in water,
typically less than 2%. The process conditions are mild so that
only a modest amount of oxidation occurs, e.g., 15% reduction in
COD. The products are (1) a liquid effluent containing partially
2.8 !
-------
Chapter 2
oxidized organic matter and most of the original sulfur content
present as sulfate; and (2) a solid residue that is easily dewatered
and either incinerated or, in some cases, landfilled when suffi-
ciently stable and detoxified.
• The other applications have been to a wide variety of waste solu-
tions at low concentrations — less than 2% — from the chemi-
cal, petroleum, pharmaceutical, and metallurgy industries. In
most cases, the materials were not suitable for direct biological
treatment and their high water content made them difficult to
detoxify by other methods, such as direct incineration.
A flow plan for a continuous WAO process is shown in Figure 2.3. The
oxidation process generates heat so that the temperature rises in the reactor
to the final desired temperature. The flow diagram shown applies to a very
dilute feed which would release too little heat to achieve the desired tem-
perature. Therefore, additional heat is added. With higher concentration
feeds, the reverse may be true; heat must be removed by cooling or by gener-
ating high pressure steam. Typically, the process can operate with no!addi-
tional energy if the oxygen uptake is greater than 15 g/L. Air is the oxidiz-
ing gas normally used, though enrichment with oxygen has been used and
has reduced costs in some cases. Plants have been designed for pure oxy-
gen, but none are in operation. The process resembles combustion in that it
is generally applicable to combustible organics. The high pressure is an
obvious disadvantage, particularly with very toxic materials, where any acci-
dental release could be harmful; some preliminary chemical detoxification
could be considered for such cases.
Most applications have been to organic materials; the process is also ap-
plicable to oxidizable inorganic materials, although there have been only a
few applications to date.
The WAO process is capable of a high degree of conversion of toxic or-
ganics, e.g., 99+% conversion. Most materials, however, are not oxidized
completely to final oxidation states, CO2, H2O, etc. Instead, the reaction
proceeds through a series of intermediate compounds and some of these are
slow to oxidize further. For example, some carboxylic acids — acetic acid
in particular — remain in solution and can represent 25% of the original
weight of organic. The usual WAO process is followed by biological treat-
ment of the liquid.
2.9
-------
Application Concepts
Figure 2.3
WAO Flow Diagram
High
Pressure
Pump
Separator
Air Compressor
Oxidized Liquor
Source: Copa and Lehmann 1992
As indicated previously, the process conditions call for a rather low
concentration of oxidizable material in water. Unit treatment costs (i.e.,
the cost to oxidize a pound of organics) generally increase with greater
dilution (see Figure 2.4).
Consequently, WAO would appear to be particularly suitable for highly
dilute wastes. The process could find application to toxic materials in highly
concentrated or energetic form; in this case, dilution is necessary and addi-
tional costs are incurred.
The material to be oxidized does not need to be completely miscible with
water. Partly miscible liquids and solids can be treated. However, they must
be finely dispersed so that they do not settle out in the reactor.
2.10
-------
Figure 2.4
Projected Costs of Advanced Oxidation Processes for Destruction of Organic Contaminants in Water
1,000
0.01
0.1
Source: Glaze 1991
Concentration of Organics in Water (ppm or mg/L)
1 10 102 103
104
UV/Peroxide
Incineration
Modar
Modar/Oxidyne SCWO
H 10-3 10-2 j0., j
Concentration of Organics in Water (% by weight)
O
D
t
K>
-------
Application Concepts
Products of the oxidation process have (at least to date) been soluble
under the reactor conditions; no problems have been encountered with
insoluble salts or other products settling out in the reactor or in the ex-
pansion valves.
2.1.3 Treatment Trains
Posttreatment of the products from WAO is generally required and pre-
treatment is sometimes desirable. Feed materials containing species such as
chlorine, can yield very acidic conditions upon oxidation. Caustic addition
to the feed might be necessary for corrosion control. The vent gas shown in
Figure 2.3, consisting primarily of depleted air and carbon dioxide, can con-
tain part per million levels of carbon monoxide and low molecular weight
organics which might require a catalytic oxidation step before release.
.The oxidized liquor shown in Figure 2.3 generally is treated in a biologi-
cal processing plant where the low molecular weight organics in solution are
readily converted. Inorganic salts in the process liquor might require recov-
ery (by evaporation) and land filling if concentrations are high.
2.2 Texaco Gasification Process
2.2.1 Scientific Principles
This process reacts organic compounds with steam and oxygen to form a
mixture of carbon monoxide, carbon dioxide, and hydrogen. Depending on
feed composition, there may also be products of reaction of chlorine, nitro-
gen, sulfur, and other elements that form volatile compounds in a hydrogen-
rich atmosphere under high temperature conditions. Low volatility inorganic
components of the feed are converted to molten slag and some fines that
leave the reactor with the gas stream.
The major reactions for carbon are:
C + O2 -> CO and CO2 (2.1)
C + H20-*COandH2 (2.2)
2.12
-------
Chapter 2
The first of these reactions is exothermic and provides the major source of
heat needed to run the process. This heat is used to bring the feed to reaction
temperature and to supply heat for the second reaction which is highly en-
dothermic. Low heating value feedstocks (the waste materials) must be
supplemented with coal or another high heating value feedstock to, achieve
the required operating temperature in the reactor.
2.2.2 Potential Applications
The Texaco Gasification Process (TGP) is used in the petroleum and
chemical industries to produce hydrogen and synthesis gas — also known as
syngas, a mixture of H2, CO, and CO2 — from tars and coal. Virtually any
carbonaceous, hazardous, or nonhazardous waste stream can be processed in
the TGP as long as adequate facilities are provided for pretreatmerit and
storage. The TGP has operated commercially for nearly 45 years on feeds
such as natural gas and coal, and nonhazardous wastes, such as liquid petro-
leum fractions and petroleum coke (US EPA 1995). .
Depending upon the physical and chemical composition of the waste
stream, it can either be used as the primary feed to the gasifier, or it can be
co-gasified with a high-Btu fuel, such as coal, petroleum, coke, or oil. The
combined feed must be slurried successfully, high enough in heating value to
maintain gasifier temperatures, and composed of an ash matrix with a fusion
temperature that falls within operational limits (US EPA 1995).
In general, the ratio of waste feed to fuel can be adjusted over a wide
range. Although a waste stream can serve as the sole feed to the gas-
ifier, blending the waste with another feed can ensure continuity and
stability of operation. The TGP can treat wastes that fall into three cat-
egories (US EPA 1995):
• solid or liquid wastes that contain sufficient energy to sustain
gasifier operation as the sole feed without adding another
higher-heating-value fuel;
• solid wastes with heating values too low to sustain gasifier opera-
tion that can be supplemented with a higher-heating-value fuel,
such as coal; and
• liquid waste with insufficient heating values that can be com-
bined with a higher-heating-value fuel. In this case, the liquid
waste can be used as the fluid phase of the primary feed slurry.
2.13 :
-------
Application Concepts
i :
Texaco's gasification process is currently licensed in the U.S. and abroad.
The syngas is used for the production of electric power and numerous
chemical products, such as ammonia, methanol, and high-purity hydrogen.
As an innovative process gasifying less traditional and hazardous wastes,
Texaco reports that the TOP has processed various waste matrices containing
a broad range of hydrocarbon compounds, including coal liquefaction resi-
dues, California hazardous waste material from an oil production field (pe-
troleum production tank bottoms), municipal sewage sludge, waste oil, used
automobile tires, waste plastics, and low-Btu soil. Texaco licensees in Eu-
rope have had long-term success in gasifying small quantities of hazardous
waste as supplemental feedstock, including PCBs, chlorinated hydrocarbons,
styrene distillation bottoms, and waste motor oil (US EPA 1995).
1 i i ,. . i '
It was also used in California to demonstrate production of electric power
from coal for the Cool Water Program (Electric Power Research Institute
1993). Here, the medium-Btu fuel gas produced was cleaned and burned in
a gas-fired power plant. The low price and ready availability of natural gas
made use of coal uneconomical, and the gasifier has since been used to pro-
duce synthetic natural gas and electricity from a sewage sludge/coal mixture.
Texaco expects to design TOP facilities with flexible and comprehensive
storage and pretreatment systems capable of processing a wide range of
waste matrices slurried with coal or oil, water, and additives (US EPA
1995). Although commercial gasification units are much larger than typical
waste disposal units, a transportable, 91 tonne/day (100 ton/day) unit has
been proposed for use at large waste sites. Texaco has also announced plans
to build a $75 million gasification facility at their El Dorado, Kansas, facility
which will process about 150 tonne/day (170 ton/day) of noncommercial
petroleum coke and refinery wastes into fuel gas for internal use. The
syngas, combined with natural gas, will power a gas turbine to produce ap-
proximately 40 MW (54,000 hp) of electrical power — enough to meet the
full needs of the refinery. The exhaust heat from the turbine will produce
82,000 kg/hr (180,000 Ib/hr) of steam — approximately 40% of the refiner-
ies' requirements. Startup is projected for the second quarter of 1996.
The TOP can process all waste stream matrices based on the availability
of adequate materials — handling, pretreatment, arid slurrying equipment.
The unit's complexity and costs, and the economic benefit of a tie-in to its
syngas product, mandate that on-site remediations be limited to relatively
large sites with a minimum of approximately 45,000 tonne (50,000 ton) of
2.14
-------
Chapter 2
waste feed and about two years of operation (US EPA 1995). Alternatively,
smaller amounts of waste could be transported to an industrial facility.
2.2.3 Treatment Trains
Figure 2.5 presents a schematic diagram of the process. Liquid and gas-
eous feeds can be injected directly into the reactor. Solid feeds, which might
first require grinding and sieving, are mixed v/ith water to form a pumpable
slurry that is injected along with oxygen into the top of the reaction chamber
where the temperature is typically 1,480°C (2,700°F) and the pressure 4 MPa
(600 lb/in.2). This mixture ignites and flows downward through the reactor
with a residence time of a few seconds. The molten slag is cooled and so-
lidified by water injection and, in some cases, radiant cooling.
Approximately two-thirds of this solidified slag is classified as coarse and
can then be used for fill, aggregate, or sent to a landfill disposal site. The fine
particles are combined with fines from the gas cleanup system and either re-
cycled to the reactor or disposed directly. The gaseous stream is then cooled
and treated to remove particulates and other impurities (DOE 1987).
2.3 Flameless Thermal Oxidation
2.3.1 Scientific Principles
Flameless thermal oxidation is a patented technology being developed
and marketed by Thermatrix, Incorporated. The basic process consists of
thoroughly mixing and then heating a gas which contains organic contami-
nants to temperatures at which oxidation occurs under very uniform, stable
conditions. These stable conditions are obtained by passing the contami-
nated gas stream through a packed bed of hot, chemically inert, ceramic
materials that thoroughly mix and heat the incoming gases to reaction tem-
peratures and absorb a portion of the heat released during oxidation (Binder
and Martin 1993). The oxidation of the organlcs is flameless and occurs at
concentrations below the lower explosive limit (LEL). The highly visible,
high temperature flame front that normally exists during the combustion of
flammable gases in a burner is not present in the Thermatrix unit. There are
2.15
-------
Application Concepts
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2.16
-------
Chapter 2
two major equipment related differences between the Thermatrix design and
a conventional flame burner-based, fume incinerator: (1) the Thermatrix
flameless thermal oxidizer (FTO) uses a reaction chamber containing ce-
ramic packing instead of an empty chamber, and (2) it does not use a burner
flame for heat transfer to the vent gas.
One configuration for the FTO is shown in Figure 2.6. In this design, the
contaminated gas enters the distribution plenum through the inlet port, flows
upward into the mixing zone, which is at ambient temperature, and then goes
to the reaction zone, which is maintained at high temperatures — typically in
the 870 to 1,010°C (1,600 to 1,850°F) range (Wilbourn, Allen, and Baldwin
1995). The mixing and reaction zones are packed with different types of
ceramic media. After mixing, the contaminated gas enters the reaction zone.
As the contaminated gas flows through the reaction zone, it is heated by the
hot ceramic packing to the oxidation temperature. At some point in the reac-
tion zone, a relatively uniform and stationary reaction wave is formed per-
pendicular to the axis of gas flow throughout a cross-section of the reaction
zone. The oxidation taking place in the reaction wave between the organics
and oxygen releases energy back to the ceramic matrix, replacing some or all
of the energy used to heat the gas to the oxidation temperature (Binder and
Martin 1993).
The amount of air used can be automatically adjusted based on organic
concentration. If the waste stream has a low organic concentration, which is
unable to support oxidation and maintain the matrix at operating tempera-
ture, thermal energy can be introduced by using an electric heating element
or an internal heat recuperation system, or by adding natural gas or propane
to the contaminated gas in the distribution plenum (Wilbourn, Allen, and
Baldwin 1995).
The ceramic packing in both the mixing and reaction zones ensures mix-
ing of oxygen and the contaminated gas and a very even axial temperature
distribution in the bed. Because the reaction wave covers the entire flow
cross-section of the reactor, all organic constituents present in the contami-
nated gas pass through this reactive region. The reaction wave contains
active radicals that cause the oxidation reaction in the reaction wave to occur
at higher rates than would occur in the post-flame region of a conventional
flame-fired fume incinerator (Binder and Martin 1993). Residence times of
0.2 sec are sufficient to achieve high destruction efficiencies (DeCiccp
1996). The relatively uniform temperature in this reaction wave results in an
average reaction temperature that is very close to the maximum reaction
2.17
-------
Application Concepts
temperature in the unit. Because the maximum temperatures in the FTO unit
are typically below 1,100°C (2,000°F), thermal NOx is generated at very low
levels relative to a conventional flame-fired fume incinerator in which maxi-
mum flame temperatures reach 1,650 to 1,925°C (3,000 to 3,500°F)(Binder
and Martin 1993). Guarantees by Thermatrix of 2 ppmv of NOx are standard
when no organically-bound nitrogen is present in the fumes being treated
(DeCicco 1996).
Figure 2.6
Thermafrix FTO ("Top Down" Preheat)
r*+***>'~*-s~>si
Outlet Port
Preheat Burner Port
Porous Inert Media
(loose packed ceramic)
:...:...:..j...:.
:.!.:.l.:.i.:.!.3!.:.!.( } Reaction Front
»'i '• 'J^ '' \ I
Fume Tie Point
Reproduced courtesy of Thermatrix, Inc.
2.18
-------
Chapter 2
2.3.2 Potential Applications
Soil and groundwater contamination from spills, inadequately designed
landfills and surface impoundments, poorly-operated waste management
facilities, and leaking underground storage tanks have occurred throughout
the United States. Two common technologies for remediating these con-
taminated sites are air stripping for groundwater cleanup and soil vapor ex-
traction (SVE). Each of these technologies generates an offgas that gener-
ally needs some kind of treatment before it can be discharged to the atmo-
sphere. The FTO technology has the potential to be used as an offgas treat-
ment process for both of these technologies.
2.3.3 Treatment Trains
Groundwater stripping (GWS) is a very common cleanup technology used
to separate volatile organics from contaminated groundwater at remediation
sites. In this process, the contaminated groundwater is pumped to a packed
bed and contacted with air, which is blown through the packing. In most
systems, the groundwater flow is downward through the packing. The air
flow can be either up through the packing in. a countercurrent mode, or
cross-flow through the packing in a horizontal cross-flow scrubber (Wood et
al. 1990). As the groundwater cascades through the packing, it is sheared
into fine droplets by the packing and the air. Volatile organics present in
these droplets of groundwater are volatilized and transferred to the air flow-
ing through the packing, primarily by a mass transfer mechanism (Anony-
mous 1994).
In the SVE process, an array of vertical vents is placed in a contaminated
soil. A manifold connects the vents to a vacuum pump, which is used to
create a negative pressure in the vents. The negative pressure draws air
through the soil and volatilizes organic contaminants in the soil, transferring
them to the air. The contaminated air is drawn into the vents, through the
manifold, and into the vacuum pump, which discharges it either to the atmo-
sphere or to a treatment system. The decisions on whether to treat and the
type of treatment depend on the concentration and type of contaminants
present in the air (Johnson et al. 1994).
The use of the FTO as an offgas treatment process in GWS and SVE sys-
tems requires additional equipment for both pretreatment and posttreatment
of the offgas. A discussion of pre-and posttireatment follows.
2.19
-------
Application Concepts
2.3.3,1 Pretreatment for GWS
In GWS systems in which entrainment of liquid water droplets might
occur, the offgas from the groundwater stripper should pass through a
knock-out pot followed by a flame arrester and a mist eliminator. This
offgas pretreatment minimizes impingement of droplets of entrained and
condensed liquid water on to the hot packing in the reaction zone. The
flame arrester is a safeguard against flashback to potentially explosive
mixtures in the knock-out pot head space. A full-scale FTO, which is
treating 170 standard mVhr (100 scfm) of an offgas from a chemical
company wastewater stripper, uses this pretreatment system (Binder,
Martin, and Smythe 1994).
2.3.3.2 Pretreatment for SVE
In SVE systems, the offgas should also pass through a knock-out pot
followed by a flame arrestor. The flame arrestor is a safeguard against flash-
back to potentially explosive mixtures in the knock-out pot head space. This
offgas pretreatment minimizes impingement of droplets of liquid water and
organic condensate on the hot packing in the reaction zone. A pilot-scale
FTO, which has treated 8.5 standard m3/hr (5 scfm) of offgas from an SVE
system at the Department of Energy's (DOE) Savannah River Laboratory
site, used this pretreatment system (Wilbourn, Allen, and Baldwin 1995).
i, j
2.3.3.3 Posttreatment for GWS and SVE
If the organic contaminants in the offgas that is being treated by an FTO
are composed of only carbon, hydrogen, and oxygen, then it is likely that the
exhaust gas can be released directly to the atmosphere without any posttreat-
ment. If, however, the organic contaminants contain other elements, such as
halogens or sulfur, then a posttreatment system, such as a packed bed alka-
line wet scrubber, might be required for removing acid gases, such as HCt,
other hydrogen halides, or SO2. The need for a posttreatment wet scrubber
depends on the concentration of the acid gases in the FTO offgas, and US
EPA and/or state regulatory performance or emission standards that are part
of the specific remediation agreements for the site. Additional treatment or
permitting might be required for the scrubber wastewater, which may con-
tain chloride and/or sulfite and sulfate salts. The degree and type of scrubber
wastewater permitting and/or treatment depends on site-specific
2.20
-------
Chapter 2
considerations and US EPA and/or state regulatory effluent and treatment
standards that are part of the specific remediation agreements for the, site.
A full-scale FTO, which is treating 170 standard m3/hr (100 scfm) of an
offgas containing ethyl and butyl chlorides from a chemical company waste-
water stripper, uses a wet scrubber as a posttreatment system to remove 99%
of the HC1 from the exhaust gas. The scrubber wastewater is discharged to
the chemical plant's wastewater treatment system (Wilbourn 1995).!
2.4 Plasma Furnaces
2.4.1 Scientific Principles
A plasma furnace has two high temperature reaction zones. One is the
general furnace atmosphere or freeboard zone of the furnace, which is at a
temperature on the order of 1,760'C (3,200°F). The second is the plasma
zone in which temperatures exceed 5,500°C (10,000°F) and can approach
14,000 to 17,000°C (25,000 to 30,000°F). Chemically, the furnace atmo-
sphere can be controlled to be oxidizing, reducing, or neutral. It operates at
a higher temperature than most combustion-based incinerators; however, it
does not depend upon exothermic combustion reactions to maintain its oper-
ating temperature. The volume of gases in the furnace atmosphere is not
dominated by burner combustion products and the associated high volumet-
ric flow rates of reactants is also important.
The reactor's main driving potential is the plasma zone, technically re-
ferred to as a high temperature thermal plasma. It is characterized by high
viscosity, extremely high heat transfer rates, and molecular species that are
predominantly ionized. The plasma is electrically neutral with, an equal
number of positive and negatively charged ions present. It is highly electri-
cally conductive and, once formed, stable. Large molecules are broken
down into small fragments and ionized, and the plasma incorporates simple
monatomic and diatomic ions (one or two atom species). Typical reaction
products from the furnace are: N2, CO, HCl, HF, H2, P2O5,02, and CO2.
Depending on the conditions present in the furnace atmosphere, oxides of
nitrogen can also form.
2.21
-------
Application Concepts
Briefly, ionized gas, reaching temperatures of 12,OQO°C (21,600°F), can
be shaped to form a torch or an arc in a carbon electrode furnace. Waste
streams can be either pyrolyzed or oxidized as they are heated by the plasma.
Bulk temperature gradients in the reactor are controlled to protect refractory
linings; however, operating temperatures impact fuel gas production, effi-
cient reduction of organic waste, and production and control of vitrified slag,
and metals recovered for reuse. Reactor bulk temperatures are 1,400 to
1,750°C (2,550 to 3,180°F).
2.4.2 Potential Applications
Plasma furnaces operated in commercial settings frequently maintain a
molten pool of metal covered by a molten layer of slag (primarily non-metal)
and can process, within limits, organic material introduced with the feed-
stock. Several commercial vendors are promoting technologies using elec-
trical power to reach high temperature operating conditions. Their primary
goal is processing waste materials in a manner that encourages recycling of
the process effluents. Some of these vendors and their furnace applications
are listed in Table 2.3.
The Exide corporation, the largest lead-acid battery manufacturer with
secondary lead smelting facilities, designed and tested plasma furnace tech-
nology for treating contaminated soil at a former battery recycling plant.
The site had a mixture of broken-rubber (battery cases) in soil that was also
contaminated with lead and lead compounds. The results of field tests on
smelting lead and destroying battery casings were summarized by the US
EPA (1994a) and are reproduced in Table 2.4.
2.4.3 Treatment Trains
A simplified equipment train for a typical plasma furnace is illustrated in.
Figure 2.7. The basic process steps used in plasma technologies are:
• preprocessing and introduction of waste materials into the
reactor;
• preparing the neutralizing chemicals, or other additives;
• chemical reaction in the plasma reactor for effective destruction;
" i .
• separating, post-process handling, and monitoring of a low Btu
synthesis gas or furnace offgas if operated in an oxidizing mode;
2.22
-------
Table 2.3
Electrically Powered Furnaces Containing Molten Slag or Metal
Company
Power Delivery
Waste Application
Reference
ro
o
ABB
Chem Nuclear
Elkem Technologies
Electro-Pyrolysis
Exide
M4 Environmental
M4 Environmental
Molten Metal Technology
PEAT
PERC
Retech
Retech
SAIC
Startech
Tetronics
Tetronics
U.S. Bureau of Mines
Westinghouse
Westinghouse
Resistance (Ceramic Domes)
Resistance
Carbon Electrode
Hollow Carbon Electrode
Hollow Carbon Electrode
Induction
Induction
Induction
Plasma Torch
Plasma Torch
Plasma Torch
Plasma Torch
Plasma Torch
Plasma Torch
Plasma Torch
Plasma Torch
Carbon Electrode
Plasma Torch
Carbon Electrode
Incinerator Fly Ash
Mixed Radioactive Waste
Electric Arc Furnace Dust
PCB Capacitors
Contaminated Soil
Mixed Radioactive Waste
Chemical Warfare Agents
Industrial Waste
Medical Waste
Munitions And Agents
Contaminated Soil
Chemical Warfare Agents
Mixed Radioactive Waste
Chemical Warfare Agents
Spent Automobile Catalyst
Electric Arc Furnace Dust
Incinerator Ash
Hazardous Waste
Incinerator Ash
Plumley and Boley 1990
Aune 1992; National Research Council 1993
Lee 1989; Titus 1992; National Research Council 1993
US Army 1996
Nagel 1994
Chanenchuk 1994
Mather 1995; National Research Council 1993
US Army 1996
Persoon 1996
Geimer 1991
Eshenbach 1991; National Research Council 1993
Geimer 1993
Hendricks 1996
Anniston, AL
Florida Steel
US Army 1996 -
Freeman 1985; National Research Council 1993
American Society of Mechanical Engineers and US Bureau of Mines 1994
I
to
-------
Application Concepts
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2.24
-------
Chapter 2
tapping molten slag and molten metal;
reducing offgas temperature; and
separating and post-process handling and monitoring of solid and
liquid effluents.
Figure 2.7
Plasma Furnace and Auxiliary Equipment Train
Chemical
Additives
Electric Power
Waste Feed
Solid Feed
Plasma Reactor
Gas Tempering
Caustic
Offgas
Treatment/Recovery
Separation/Recovery
Sweep
Gas
->• Solid Effluent
->• Gas Effluent
-> Liquid Effluent
2.25
-------
-------
Chapter 3
DESIGN DEVELOPMENT
3.7 Wet Air Oxidation
3.1.1 Remediation Goals
A large number of waste materials and streams have been tested for pos-
sible treatment using wet air oxidation (WAO). Table 3.1 lists the range of
materials that have been tested in the laboratory. Table 3.2 provides the
chemical structures of some pesticides that can be destroyed by WAO; the
table also includes "sulfides" as another class of compound that can be de-
stroyed. Destruction of the toxic materials at levels of 99+% is almost al-
ways possible. Therefore, the severity of the oxidation conditions — tem-
perature, pressure to maintain liquid phase, and residence time in the reactor
— is determined by the prescribed amount of COD allowable in the process
effluent. Any new feed should be tested in a batch reactor to provide design
data (conversion levels and COD remaining vs. temperature and time). The
usual batch reactor is a shaking bomb in an autoclave. In addition, if it is
suspected that corrosion will be particularly severe, test coupons of possible
materials of construction should be tested at design conditions.
The acceptability of the process to regulators and to the public de-
pends on the toxicity of the material to be oxidized and the proximity of
the plant to residential areas. It should be noted that many industrial
processes operate at pressures exceeding WAO conditions. The. corro-
sive nature of some systems under WAO conditions, however, requires
special attention and proof of reliability.
3.1
-------
Design Development
Table 3.1
Database of Wastes That Have Been Treated by WAO
Spent Caustics
Ethylene Scrubbing Liquors
Refinery
Coke Oven Scrubbing Liquors
Sludges
Municipal Wastewater Treatment
Industrial Wastewater Treatment
Tanning Industry
Cattle, Hog, Chicken Manures
Chemical Production Wastewaters
AcrylortStrile
Caprolactam
Synthetic Rubber
Pesticides
Pharmaceuticals
Food Processing
Styrene/Butadiene
Phenol/Acetone
Refinery (Oily) Residuals
Photographic
Plastics/Polymers
Textile/Dye
Pulp & Paper
Spent Pulping Liquors
. Paper Filler Recovery
Sludge Conditioning
Deinking Sludges
Commercial Waste Treatment
Phenolics
Cyanides
Sulfidic
Pesticides
Solvent and Solvent Still Bottoms
General Organics
Drum Washings
Military Wastes
Propellants
Red Water
Miscellaneous Applications
Metallurgical Extractions
Powder Carbon Regeneration
Coal Oxidation and Desulfurization
Vanillin Production
Peat Dewatering
Oxygen Pulping
Source: Copa and Lehmann 1992
3.2
-------
Chapter 3
Table 3.2
Technical Basis for Data Extrapolation
Wet Air Oxidation: Chemical Structures Destroyed
Glyphosate (Roundup)
Diazinon
Dursban
Parathion
Phosphono
O
O-
-P
o-
Phosphorothio—
S
Betasan
Dimethoate
Disufoton
Dyfonate
Imidan
Malathion
Phorate
Spent Caustic
Phosphorodithio—
S
Sulfides (Organic and Inorganic)
Mercaptans
3.1.2 Design Basis
A sample mass balance is presented below to illustrate flow rates, prod-
ucts expected, reactor dimensions, etc. Sarin is a nerve agent with a struc-
ture resembling some of the pesticides chosen for study. The WAO of this
material, with NaOH added to the mixture for pH control, approximately
follows Equation 3.1; note that substantial residual organic material remains
in the product solution; this is shown in Equitation 3.1 as sodium acetate, but
other low molecular weight oxygenated species will also be present.
F
I
JLC-P = O + 5.7 O, + 4.4 NaOH
3 1 *>
O-CH(CH3)2
(Sarin)
-> NaF + Na3PO4 + 3.2 CO2
+0.4 CH3COONa + 6.6 H2O
(3.1)
3.3
-------
Design Development
Equation 3.1 does not show nitrogen supplied with the air, nor does it
show low levels of other materials present in the gas phase. The products
withdrawn from WAO of Sarin, based on data with pesticides, are anticipated
to have the characteristics shown in Table 3.3.
Table 3.3
Sarin Wet Air Oxidation Products
Products
Concentration Range
Oxygen
Nitrogen (mainly from air)
Carbon Dioxide
Carbon Monoxide
Organics
Liquid
Biochemical Oxygen Demand (BOD)
Chemical Oxygen Demand (COD)
Solids
3-6% (by volume)
78-82% (by volume)
8-12% (by volume)
10-1,000 ppm
100-1,000 ppm
5,000-10,000 mg/L
10,000-20,000 mg/L
Salts, such as NaF, Na3PO4, excess NaOH, etc. Other materials could lead to other salts, such as
NaCl, depending on feed composition.
Source: Copa and Lehmann 1992
Both the offgas and the liquid require further treatment. The gas is sub-
jected to either thermal or catalytic oxidation. The liquid is diverted to a
biological wastewater treatment plant for complete detoxification of the
remaining organics. Solids are recovered from the liquid by vaporization
and sent to a landfill.
; . - j
Corrosion can be a problem under WAO conditions, particularly for mate-
rials containing species such as chlorine, fluorine, and sulfur, which yield
strong acids upon oxidation. Control of pH will be required in such cases; in
3.4
-------
Chapter 3
the example of Equation 3.1, sodium hydroxide was added. The addi-
tion of a caustic might also influence the amount of solid product. The
pH is normally maintained below 8 to prevent the caustic from reacting
with CO2 to form carbonate. Materials with a large content of chlorine,
fluorine, etc., might require a pH up to 11 for corrosion control. Most
of the carbon dioxide will be reacted to carbonate as a result, with a
consequent large increase in the process solid residue. This has not been
shown in Equation 3.1; a rough estimate for it has been included in the
following material balance.
An approximate material balance has been calculated with estimates for
the size of equipment and the product streams (National Research Council
1993). The oxidizing gas in this case was oxygen-enriched air.
The mass balances are based on the following:
• feed: 1,000 kg of Sarin;
• oxygen: 25% excess over theoretical;
• enriched air: Oj/N2= 1/1;
• NaOH added to produce a 3 molar solution after reaction (this is
a large excess of NaOH and is included for corrosion control;
testing would be needed to better judge what is required);
• 20% of C-H in the feed is left as sodium acetate; and
• the CO2 content of the gas is an estimate and is not based on
equilibrium with liquid.
Feed (Input):
• Sarin: 1,000 kg (7.14 kg mol)
• Water: 19,000 kg (1,056 kg mol)
• NaOH: 4,770 kg (119 kg mol)
•. O2: 50.7 kg mol
• N2: 50.7 kg mol
Gas Phase (Output):
• O2: 16.0% by volume (dry basis)
• N2: 81.7% by volume
3.5
-------
Design Development
• CO2: 2.3% by volume
• CO: 500 ppm
• Hydrocarbons: 500 ppm
• Volume (dry basis): 62.1 kg mol = 1.52 • 103 rn3 @
Pressure = 1 atm (1 bar) and Temperature = 25°C (77°F)
• H2O in gas phase at reactor conditions « 62 kg mol
Liquid Phase (Output):
« H20: 19,118kg
• NaF: 300kg
• Na3P04: 1,171kg
• Na2CO3: 2,271kg
• CH3COONa: 234kg
• NaOH: 1,799kg
Total 24,893 kg (54,765 Ib)
• Reactor volume (assuming feed = 1,000 kg of Sarin/day (0.5
volume of feed per hour per volume of reactor) 2.6 m3 (92 ft3)
• Length = 7 m (23 ft); Diameter = 0.68 m (2.2 ft)
The calculations demonstrate that the volumes of material to be handled
and the inorganic residue are many times greater than the volume of original
toxic material to be destroyed. They also demonstrate that it would be quite
practical to operate WAO as a closed system with material released from the
process only after analysis. For example, based on processing 1,000 kg
Sarin/day, the resulting volume of by-products would be:
• liquid holdup for 8 hours retention time = 8,300 kg (18,260
lb)(approximately 8 m3 [280 ft3]); and
• gas holdup for 8 hours' retention, at 25°C (77°F) and 60 atm (60
bars) = 8.4 m3 (300 ft3) on a dry basis.
The volumes of both liquid and gas for 8-hour retention time are modest.
The compositions shown above change under upset conditions. A low
inlet temperature will quench the reaction, leading to little oxygen consump-
tion and little organic destruction, whereas a high inlet temperature will yield
3.6
-------
Chapter 3
more complete oxidation to CO2 and H2O and possibly an undesirable tem-
perature excursion. Both conditions will lead to a shutdown. In the first
case, the unreacted material is recycled to a feed tank.
3.1.3 Design and Equipment Selection
Design and equipment selection will depend on the nature of the feed: its
concentration in water, its chemical composition, and toxic hazard.
If the feed is highly diluted, e.g., less than 1%, heat exchange must be
provided to increase the temperature close to final design temperature. If the
feed is relatively concentrated, e.g., more than 5% in water, heait exchange
(cooling) will probably have to be provided to control the final temperature.
A complete energy balance will be needed to finalize the design.
The extent of oxidation required will vary with the feed and nature of the
product. For example, sewage to be treated to improve its de-watering will
be treated at low temperature (and relatively low pressure); a chemical pesti-
cide which needs complete destruction will require higher temperature and
longer residence time. Specific details can best be determined on the basis
of previous experience, or by tests in a pilot plant (shaking autoclave).
A feed with a composition that will yield a strongly acidic product
will require special treatment, e.g., a chlorine-containing material such
as PCB which will produce hydrochloric acid. Corrosion control in this
case will probably require addition of a caustic to the feed to control pH.
The extent of corrosion problems may also be determined by prelimi-
nary pilot plant tests.
3.1.4 Process Modifications
Corrosion has been emphasized as a serious problem. Stainless steel
(304L, 316L) has provided adequate resistance to corrosion for most com-
mercial applications; 316L is now preferred. Materials with high concentra-
tion of chlorine and fluorine, etc., pose more severe corrosion problems
because of their strong acid formation. Other potential materials of con-
struction are Incoloy 800, 825; Inconel 600, 625; Hastelloy C-276, G-3,
C-22; Carpenter 20 CB-3; or various grades of titanium. Corrosion test
work on possible materials with simulated product solutions, under WAO
temperature and pressure conditions, should be done before any plant con-
struction. Corrosion test work applicable to supercritical water oxidation of
3.7
-------
Design Development
some materials has been carried out, but it is not clear that this test work is
directly applicable to WAO conditions.
Commercial WAO units have operated on very dilute feeds (less than
2%), because of their advantage over other technologies for low concentra-
tions. At higher concentrations, there could be large temperature excursions,
raising the possibility of unstable operation.
The system has some built-in safeguards. Increased heat release
causes only modest temperature rise because (1) the large heat capacity
of the water present moderates temperature increases; and (2) increased
vaporization of water automatically occurs. Finally, temperature can be
controlled by modulating the air flow. There is no gas-cap maintained in
the reactor, and oxygen solubility is limited. Cutting off the air flow
shuts down the reaction quickly.
Testing is usually done in batch reactors, whereas commercial units are
operated continuously. Some design features help in adapting the test data to
flow conditions:
• The flow systems are usually baffled, so that the reactors do not
behave as completely stirred tank reactors (CSTRs); instead, they
are constructed with some of the characteristics of plug flow
reactors and resemble batch reactors in their kinetics. In some
cases, two or more reactors have been run in series, again ap-
proximating plug flow kinetics.
• Occurrence of an induction period could be a special complica-
tion, with a major effect on a batch reactor. The commercial
designs have their first baffle approximately halfway up; thus, the
bottom half of the reactor comes close to CSTR operation and
provides a continuous source of the reactive intermediates re-
quired to end any induction period.
1 ' .' ' i •
Batch laboratory data are useful, but testing under continuous flow (plant)
conditions is alway desirable for a new application. Portable, sled-mounted
units have been used for this purpose (National Research Council 1993).
3.8
-------
Chapters
3.1.5 Pretreatment Processes ;
The process can handle a wide variety of feed materials with no pretreat-
ment required. However, the concentration of pollutant(s) and the physical
characteristics of the water, may require some pretreatment.
Water may be added to feedstocks that are too concentrated. For feed-
stocks which are too dilute, extra heat must be provided; this has sometimes
been done by adding some extra material (fuel) to the aqueous feed, to pro-
vide added heat of combustion in the reactor.
A feedstock that will produce a strongly acidic solution may call for pre-
treatment with caustic to control pH in the reactor.
Insoluble feedstocks can be handled by breaking up and dispersing in
water. Alternatively, a pretreatment to solubilize the material may be help-
ful, e.g., hydrolysis of a nitrocellulose propellant. i
3.1.6 Posttreatment Processes
The example cited in Section 3.1.2 produced a liquid effluent with a COD
of 10,00,0 to 20,000 mg/L. This would need to be reduced, probably by a
biological wastewater treatment plant, before discharge to the environment.
The usual products — such as low molecular weight carboxylic acids —
respond well to biological posttreatment.
The carbon monoxide and hydrocarbons In the effluent gas may be exces-
sive require oxidation before release.
3.1.7 Process Instrumentation and Controls
Reactor flow and pressure control are standard. Temperature control is criti-
cal; too low a final reactor temperature will affect the conversion level and too
high a temperature could drive up the pressure and force a shut-down. Most
instrument response times are not very demanding, as suggested by the typical
feed residence times in the reactor of one-half hour or more.
The gas residence time is much shorter; it is measured in seconds. There-
fore, offgas is monitored continuously with on-line analyzers. Parameters to
be monitored are: oxygen, nitrogen, carbon dioxide, carbon monoxide, and
at least one product characteristic of the oxidation products, e.g., an interme-
diate in the oxidation process. The product gas may require treatment before
3.9
-------
Design Development
release (e.g., catalytic oxidation), and would require monitoring both before
treatment and upon release.
i
3.1.8 Safety Requirements
The operating temperature and pressure of a WAO unit may be high,
e.g., up to 316°C (600°F) and 11.7 MPa (1,700 psi), though lower for
most units. These are not unusual conditions, and are well within
state-of-the-art-technology. All equipment must be built to meet appro-
priate code requirements.
Typical of industrial equipment, hazards result from off-specification
operation — in this case, too high a temperature and pressure. The
time-constant for transient temperature change is long, certainly many min-
utes, due to the relatively large volume of water in the reactor and the small
concentration of feed material. In addition, any temperature increase is lim-
ited by the pressure; the water will boil when it reaches its boiling point.
The response to a temperature rise above the preset operating window is
to shut off the feed. Any further temperature rise is then limited by the small
concentration of oxidizable feed remaining in the water.
3.1.9 Specification Development
Process and equipment specification and materials of construction are
determined by the nature of the feed and the product requirements. Key
operating variables and process results requiring specification are:
• anticipated range of feedstock composition, concentration in
water in particular;
• reactor operating conditions: temperature, residence time, pres-
sure, and air flow rate;
• liquid effluent composition, particularly the level of destruction
of the feed material required; and
• offgas composition, particularly the level of some prescribed
product of the oxidation process.
In cases where the feedstock is a new material that has not been tested or
processed previously, some preliminary (pilot-plant) experimental work will
probably be required to set operating specifications.
3.10
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Chapters
3.1.10 Cost Data
A range of capital costs, as well as operation and maintenance costs, has
been presented by U.S. Filter-Zimpro (Copa and Lehmann 1992) and de-
picted in Figures 3.1 and 3.2. These do not reflect any costs for environmen-
tal impact assessments, permitting, testing/research/development required
before design, special materials of construction required for particularly
severe corrosion problems, the cost of additional chemicals required, or any
costs for posttreatment.
The capital cost (Figure 3.1) increases with the flow rate of total liquid.
The total overhead and maintenance (O & M) cost also increases with the
flow rate. It is clear that costs increase with dilution. As mentioned, most
applications of WAO have been to toxic materials which are already highly
diluted. Where some additional dilution is required, it is desirable to mini-
mize its extent, consistent with a stable process operation.
The costs depicted Figures 3.1 and 3.2 have been applied to develop the
following crude cost estimates for a plant capable of destroying 1.8 tonne/
day (2 ton/day) of the nerve agent Sarin (Equation 3.1). It was assumed for
these estimates that the plant life was 5 years,, its availability was 90%, the
cost of money was 10%, and there was zero salvage value.
O&Mcost $675/ton/day
Capital Cost ($6M) $3,170/ton/day
Total $2,845/ton/day
This cost translates to $3.13/kg of Sarin destroyed, or about $500/barrel.
Realistically, costs for destruction of Sarin will be much higher (many-fold
higher). The costs for destroying toxic materials are frequently driven by
factors other than the engineering and direct operating costs given in the
example above. These include costs for design reviews required by regula-
tory agencies, tests on surrogates to demonstrate performance, start-up de-
lays due to public concern for safety, quantitative risk assessments and
health risk assessments that may be required before startup, etc. These addi-
tional costs depend on the site (proximity to population centers), and on the
toxic material being destroyed. For reference, the cost of destroying the very
toxic agent Sarin by incineration has proven to be many-fold larger than the
'normal' direct engineering and operating costs; the same will probably be
true for other disposal processes.
3.11
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Design Development
Figure 3.1
Hazardous Waste Wet Oxidation
Installed Capital Costs vs. Wet Oxidation Unit Capacity
10.0
5.0 ~
4.0 -
3.0 -
2.0 -
0 10
20 30 40 50
Unit Capacity (gal/min)
60
Source: Copa and Lehmann 1992
3.12
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Chapter 3
Figure 3.2
Operating and Maintenance Costs for WAO Units
8.0
7.0
6.0
4.0
3.0
2.0
1.0
- Total O&M
Labor and Utility Rates
Labor and Benefits $18.75/hr
Power $0.05/kWhr
Power,.
Maintenance
I
'*'—a;.... __
J_
I
10 20 30 40
Unit Capacity (gal/min)
50
60
70
Source: Copa and Lehmann 1992
3.13
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Design Development
3.1.11 Design Validation
The engineering design will probably experience more than one review
before construction as part of design development and permitting. These
reviews should ensure that local conditions and limitations have been prop-
erly considered.
The design package will usually contain some guarantee of performance.
Therefore, validation of the design will be based on a performance test car-
ried out under conditions defined in the performance guarantee.
3.1.12 Permitting Requirements
The permitting process will depend on the nature of the waste. The
state regulatory agency should be notified as early as possible of the
problem to be addressed, and the general plan. In turn, they will define
their requirements for information to be submitted and the emission
standards to be satisfied.
j
It is helpful if the regulatory personnel have had experience with WAO. If
not, the process will have to be explained and performance data from other
WAO units will need to be presented. Ultimately, very complete process-flow
diagrams, with piping and instrumentation, will probably be required.
''' " j? • ^
Wet Air Oxidation is not a new, untried technology. In view of its
history, it should be possible to obtain construction and operating per-
mits. It must be recognized, however, that permitting requirements are
usually site-specific.
3.1.13 Performance Measures
Offgas from WAO is monitored by on-line analyzers for oxygen, nitrogen,
carbon dioxide, carbon monoxide, and total hydrocarbon. Ammonia can
also be determined by gas scrubbing and liquid analysis, if necessary. The
gas product of the WAO unit should be monitored as part of the operating
control, e.g., analysis for excess oxygen. In addition, the gaseous effluent
from any posttreatment unit, such as catalytic oxidation, will need analysis.
Gas released to the atmosphere will need to be tested for residual feed mate-
rial, with provision for immediate plant shut-down if any is detected.
The wastewater is usually analyzed for conventional wastewater param-
eters: COD, BOD, solids, ash, pH, total Kjeldahl nitrogen, NH3, etc. Gas
: |
j
3.14
-------
Chapter 3
chromatography, liquid chromatography, and gas chromatography/mass
spectroscopy (GC/MS) have been used for specific organic constituents
and are the methods of choice for analyzing the effluent liquid for re-
sidual toxic feed material. The solid salts produced should be classified
as nonhazardous, but will require detailed analysis before disposal.
Solid products from any biological posttreatment of the liquid must be
tested for toxicity before disposal. :
The oxidation process is exothermic, with large activation energies in
some cases. The process must be controlled to avoid unstable operation with
large temperature excursions. A high level of dilution (1% solution) will
limit this type of problem. At higher concentrations (5%), it is necessary to
set an operating window, with plant shut-down triggered by any departure
from the design limit.
3.1.14 Design Checklist
The key information to be compiled and/or developed during design
includes:
• plot plan, with any limitation set by adjoining constraints;
• utility supply — by the owner, by outside supplier;
• process requirements set by the owner, for example permit re-
quirements;
• possible interference with adjoining operations during tie-in to
utilities etc.;
• public sensitivities, e.g., proximity to housing, schools, etc., and
impact on such things as acceptable noise-level (e.g., compressor
noise) etc.;
• materials of construction of various parts of the plant, and
test work required to show that materials specifications have
been met;
• major component checklist;
• piping and instrumentation diagrams; and
• control room layout.
3.15
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Design Development
3.2 Texaco Gasification Process
i
3.2.1 Remediation Goals
The Texaco Gasification Process (TOP) is widely used for producing
hydrogen and synthesis gas in the refining and petrochemical industries
from low heat value feedstocks, such as petroleum residuals and coal.
These raw materials sometimes contain significant concentrations of metals
plus sulfur, chlorine, and nitrogen compounds. The industry has developed
processes to remove such impurities which are available for licensing for
specific applications and are also applicable to waste treatment. Generally,
these processes can remove impurities from the product gas stream to levels
below those required by current US EPA regulations.
The gas treating system produces fused slag, inorganic fines, and a waste
gas stream consisting mainly of CO2 and N2, as well as smaller amounts of
methane, volatile metals, and any residual sulfur, chlorine, and nitrogen
compounds that escape the gas treating system. The low volumes of process
waste gas and wastewater allow these waste streams to be economically
stored and analyzed prior to release. This way, plant personnel can verify
that the waste streams meet regulatory requirements.
The high temperature and elevated pressure and the use of coal with an
accompanying increase in solid waste could generate some concern by regu-
lators and the public. These concerns tend to be very site-specific and less
concern is expected near existing industrial sites where comparable opera-
tions are underway. Greater concerns might be encountered at sites sur-
rounded by residential communities.
3.2.2 Design Basis
The TGP support considerations include site conditions (surface, subsur-
face, clearance, area, topography, climate, and geography), utilities, facili-
ties, and equipment.
For a 90 tonne/day (100 ton/day) transportable waste processing unit,
surface requirements include a level, graded area capable of supporting the
3.16
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Chapter 3
equipment and the structures housing it. The complexity and mechanical
structure of a high-temperature, high-pressure TOP unit mandate a level and
stable location. The unit cannot be deployed in areas where fragile geologic
formations could be disturbed by heavy loads or vibrational stress. Founda-
tions must support the weight of the gasifier system, which is estimated at 45
tonne (50 ton), as well as other TGP support facilities and equipment. The
transportable TGP unit weighs approximately 270 tonne (300 ton) and con-
sists of multiple, skid-mounted trailers requiring stable access roads that can
accommodate oversized and heavy equipment.
The transportable 90 tonne/day (100 ton/day) TGP unit requires an area
of approximately 3,700 m2 (40,000 ft2), 83 mi by 46 m (275 ft by 150 ft),
with height clearances of up to 21 m (70 ft). This area should accommodate
all TGP process operations, although additional space could be needed for
special feed preparation and waste residuals storage facilities.
The transportable TGP unit can be used in a broad range of different cli-
mates. Although prolonged periods of freezing temperatures might interfere
with soil excavation and handling, coal handling, slurry preparation, and
water-related operations, they would not affect a TGP design that incorpo-
rates adequate heating, insulating, and heat-tracing capabilities at critical
locations.
The transportable 90 tonne/day (100 ton/day) TGP unit requires the fol-
lowing supplies: 83 tonne/day (91 ton/day) of oxygen, 35 tonne/day (39 ton/
day) of coal, 4.5 tonne/day (5 ton/day) of lime, 431 MJ/hr (410 kW/hr) of
electrical power, 2.5 L/sec (40 gal/min) of makeup water, and less than 900
kg/day (1 ton/day) of nitrogen.
The support facilities required include staging areas for contaminated soil
and coal prior to pretreatment, materials-handling, and slurry preparation.
Syngas product can be routed by pipeline directly off-site without any sup-
port facilities for storage or transport. Solid products would be stored in
roll-off bins. Wastewater would be collected in an appropriate size storage
tank. All support facilities must be designed to control runoff and fugitive
emissions. Support equipment required includes excavation/transport equip-
ment, such as backhoes, front-end loaders, dump trucks, roll-off bins, and
storage tanks.
3.17
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Design Development
3.2.3 Design and Equipment Selection
The major information needs for applying this technology at a specific
site are:
• range of composition and properties of the wastes to be treated;
• amount and rate of delivery of the waste material to the gasifica-
tion system;
• tests in pilot facilities of representative samples of the wastes to
be treated. These would include tests in the existing gasification
pilot facilities to establish optimal conditions and also to provide
samples for studies leading to specification of posttreatment
processes;
• regulatory requirements and costs of disposing of the process
waste streams; and
• site area available for the process. An area of approximately
3,700 m2 (40,000 ft2) plus land for storage of feed material and
waste streams is needed.
i j
3.2.4 Process Modifications
It is anticipated that the feed system and the gas cleanup system will
be matched to the specific wastes to be treated and to meet the environ-
mental requirements for disposal of the gas, liquid, and solid waste
streams produced.
3.2.5 Pretreatment Processes
i
The TOP requires a steady supply of the material to be treated in a physi-
cal form that is suitable for the process. While liquid and gaseous feeds can
be injected directly into the reactor, solids are mixed with water to form a
pumpable slurry that is sufficiently stable to allow averaging of composition
and physical properties by storage in the feed system.
The particle size must be small enough to form a pumpable slurry.
Coarser materials require grinding and/or sieving to meet the size require-
ment. Additives can be used to adjust slurry properties or control slag char-
acteristics, such as viscosity. If the waste exhibits unusual physical or
chemical characteristics that would affect the ability of the pretreatment
3.18
-------
Chapter 3
module to slurry the feed, additional pretreatment equipment can supplement
the existing design (US EPA 1995). A typical feed slurry contains 60 to 70%
solids by weight. Recycled fine solids from the slag separator and the gas
cleanup system can also be added to the feed system.
3.2.6 Posttreatment Processes
3.2.6.1 Solids Residuals
Solid TOP by-products, such as course slag, fine slag, and clarifier solids,
are stored and characterized to allow proper disposal based upon their haz-
ardous or nonhazardous characteristics (US EPA 1995).
Most of the inorganic compounds of the waste form a molten slag
which, on cooling, is expected to have sufficiently low solubility to pass
US EPA leaching tests. If solubility is a problem, additives might be
required in the feed to reduce the solubility. This material can then be
disposed in a waste landfill or it can, in some cases, be used as aggregate
or for paving.
Some inorganic fines leave with the gas produced and are captured by
filtration in the gas treatment system. If these particles do not contain vola-
tile components, the fines can be recycled to the gasifier and then disposed
along with the rest of the slag. If volatile metals, such as lead, exist, they
concentrate in the fines and then the fines must be disposed as a separate
toxic waste stream.
3.2.6.2 Gas Stream ; . .
The gas leaving the gasifier quench section contains fine particulates and
a variety of gaseous Impurities (CO2, HC1, H2S, NH3, etc.). The traditional
petrochemical uses for synthesis gas in production of ammonia, methanol,
and other products require partial removal of CO2 and nearly complete re-
moval of hydrogen sulfide and other acid gases. The cleanup requirements
for use of the gaseous product as fuel can be easily met by existing processes
suitable for production of gas for use in sensitive catalytic processes
(Astrita, Savage, and Bisio 1983). If very volatile components, such as
mercury, are present, a separate treatment step, such as activated carbon
adsorption, might be required.
3.19
-------
Design Development
3.2.6.3 Process Wastewater
Although the chemical reactions that drive the gasification process
(Equations 2.1 and 2.2) indicate net water consumption for a dry feed, the
feed slurry generally contains surplus water. This water, if combined with
water from cooling and scrubbing, can produce a wastewater stream that
might require treatment before disposal. For the Superfund Innovative
Technology Evaluation (SITE) project discussed in Chapter 5, a wastewater
stream was produced that would probably need treatment. The impurities in
the water are specific to the waste and fuel compositions. Appropriate wa-
ter treatment processes are available and their selection would be part of a
site-specific design.
•
I
3.2.7 Process Instrumentation and Controls
It is anticipated that process instrumentation and controls for the reactor
would be essentially the same as those used in current operating plants. For
the feed preparation and injection systems, it may be necessary to adapt the
instrumentation and controls to the specific feeds being treated; however,
Texaco's systems for handling both solid and liquid feedstocks will not re-
quire major modification.
i
The gas stream monitors and controls used in commercial synthesis gas
production with its stringent purity requirements should be more than ad-
equate for waste treatment. The possible exception to the foregoing is if
chlorine compounds are present.
The liquid and solid wastes produced must also meet increasingly
stringent purity requirements which may call for some requirements for
instrumentation and control beyond those currently used in industrial
installations. It is believed that equipment and technology are available
to meet these requirements.
I .
3.2.8 Safety Requirements
1 I
Apart from the conventional safety requirements for the feed handling sys-
tem and the gas cleaning system, the reactor operation at high temperature and
moderately high pressure introduces additional considerations. Leaks of flam-
mable gas must be dealt with by adequate dilution by surrounding air under all
operating conditions. The remote possibility of catastrophic reactor failure
might require special containment for heavily-populated areas.
3,20
-------
; Chapter 3
3.2.9 Specification Development
It will be necessary to develop performance specifications to ensure that
the wastes will be converted into satisfactory product streams at the required
rates. Since the technologies and treating requirements can be expected to
differ somewhat at each site, these performance specifications will require
some development for each installation and would logically be part of the
licensing process.
3.2.10 Cost Data
Estimates of the cost to treat contaminated soils and sludges with TCP
were prepared by Texaco based on the performance data from the demon-
stration at Montebello Research Laboratory (MRL) which is discussed in
Chapter 5. The demonstration was conducted in a pilot facility of a size that
would be impractical for an on-site cleanup or for a commercial facility.
Texaco has designed a transportable gasifier that would be suitable as a
minimum size for site cleanup contracts. The small gasifier falls within the
size range of commercial plants and is less than one-tenth the size of the
largest operating TGR The pilot facility at Montebello is used to optimize
operating conditions for the design of commercial units.
Results from this demonstration were applied to a probable commercial
configuration. Soil with approximately the same composition of that used in
the SITE Demonstration was used as a basis for the commercial design and
economic analysis. This soil would be slurried with 5% lime and 34.65
tonne/day (38.19 ton/day) of coal in water to produce a feedstock of 62.5%
solids and fed to the unit at the rate of 90 tonne/day (100 ton/day). This
feedstock with coal would have a gross heating value of 5,555 Btu/lb dry
which compares to the average gross heating value of 6,133 Btu/lb during
the demonstration. More oxygen would be required per pound of feed to
offset this difference in heating value. Since the TOP is being used for site
remediation, the soil throughput has been maximized.
The costs have been placed into twelve cost categories applicable to typi-
cal cleanup activities at Superfund and RCRA corrective action sites and are
discussed in turn in the following subsections.
3.21
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Design Development
3.2.10.1 Issues and Assumptions
This analysis is based on operating the TGP with the demonstration
soil with a minimum of coal and oxygen. The demonstration soil has
about 20% combustibles that partly offset the amount of auxiliary fuel
required to maintain the gasification reaction. Other soils might not
have as much heating value.
Even with low-Btu feedstocks, the TCP convents waste to useful syngas.
Any proposed cleanup activity should take into consideration practical uses
for the syngas. The simplest uses for syngas are as a gaseous fuel for steam
production or power generation. These uses are not included in this eco-
nomic analysis. Because the capital equipment and its installation represent
a high percentage of the total project cost, TGP should be considered for
larger cleanup activities.
• i : •!
A transportable system can be designed to be used at several sites over its
usable service life; fifteen years is assumed for this analysis. Because relo-
cation can be expensive, the more practical investment might be at a central
location for the entire life of the equipment — perhaps thirty years. Both
alternatives are presented for comparison.
The transportable TGP system is rated at 90 tonne/day (100 ton/day) of
soil and is assumed to be set up at three sites and operated for about four
years at each during its fifteen-year life. The central TGP system is rated at
180 tonne/day (200 ton/day) of soil and is assumed to be operated at a fixed
location for fifteen years. Both systems are assumed to operate 24 hours per
day, seven days per week. Capacity utilization factors of 70% and 80% are
included to allow for both scheduled and unplanned outages. The costs for
the transportable unit are based on three sites with 90,000 tonne (100,000
ton) of soil each. That is a rate of 90 tonne/day (100 ton/day) at 80% utiliza-
tion for 3.42 years. The cleanup of the same site at 70% utilization would
require 3.91 years and would result in higher labor and maintenance costs.
3.2.10.2 Site Preparation Costs
The costs for excavation and on-site transportation of a contaminated soil
vary widely. No estimates of the cost of waste handling nor of the tempo-
rary roads and facilities that might be required are included because they are
site-specific. The costs for foundations, utilities, and equipment erection for
the TGP systems can be estimated and are included in the Capital Equipment
subsection, 3.2.10.4.
i
3.22
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Chapter 3
3.2.10.3 Permitting and Regulatory Requirements
The costs for permitting are not included. These include federal, state,
and local permits and will vary with each project and are generally the obli-
gation of the site owner or responsible party. Depending on the site, these
costs could be significant in terms of time and money. The monitoring and
analytical protocols that would be required on an ongoing basis during op-
eration have been estimated and are included under subsection 3.2.10.10,
Analytical Services.
3.2.10.4 Capital Equipment
The capital costs are based in part on a firm quotation in 1993 received by
Texaco for a modular gasifier for soil remediation. This quotation included
about two-thirds of the equipment included in this estimate. The balance of
the installed equipment, including that required for feed preparation, gas
cleaning, and wastewater treatment, was estimated by Texaco. The costs of
the 180 tonne/day (200 ton/day) central plant were extrapolated from the
costs developed for the 90 tonne/day (100 ton/day) transportable plant. For
the transportable unit option, it is assumed that the same unit would operate
at three sites over its fifteen-year life. The capital costs are based on amorti-
zation over fifteen years at 8% interest with no tax considerations and no
salvage value. The annual capital recovery (amortization) factor is 0.11683,
and the total was allocated evenly between the three sites or 58.4% of the
capital cost for each. Table 3.4 lists the capital cost for the 90 tonne/day
(100 ton/day) TOP unit.
The implementation costs are for the la.bor and contracts for site prepara-
tion, equipment installation, utility service connections, and equipment
check-out. The transportable system occupies approximately one-half acre
and requires 16 weeks for installation. The major contracts are for founda-
tions and slabs, equipment and structural erection, electrical., and controls
and instrumentation. The total is estimated at $2,500,000.
Most of the components for the transportable TOP unit are shipped in
factory-built, structural modules. The largest of these will be 12.8 m by 4.3
m by 4.3 m (42 ft by 14 ft by 14 ft). Transportation was estimated on the
basis of relocation from Texas to California or Illinois.
The implementation costs for the central plant are one-time costs and are
included with the capital equipment estimate.
3.23
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Design Development
Table 3.4
Capital Cost for the 90 tonne/day (TOO ton/day)
Texaco Gasification Process Unit
Capital Cost (Thousands of $)
a
h
c.
d
a
f
g
h
L
j-
k
Feed Receiving and Storage
Grinding and Slurry Preparation
Gasification
Lockhopper
Syngas Cleaning
SulFerox*
Slag and Solids Handling
Wastewater Treatment
Control System
Utilities and Support Facilities
Engineering
Total Cost
$1,000
700
1,600
; . 1,,
800
600
1,900
400
300
700
1,000
i ' 1 ',
2,000
$11,000
' ' 1
•Proprietary hydrogen suifids treatment module
3.2.10.5 Labor
Labor costs are based on 24 employees working 40-hour weeks for 50
weeks per year. Each employee has an average all-inclusive (salary and
fringe benefits) cost per hour of $32.00, or $64,000 per year per employee.
The total labor cost of $1,536,000 per year is the same for either option and
is independent of utilization.
i i
3.2.10.6 Consumables and Supplies
The major costs are for oxygen and coal. The rates per ton of soil are less
than those used during the SITE Demonstration because the ratio of soil to
coal can be increased during a longer run. Oxygen can be delivered at $66
tonne ($60.00/ton) and is expected to be consumed at the rate of 0.83 tonne
per tonne of soil. Coal is estimated at $44/tonne ($40/ton) and consumed at
a rate of 0.353 tonne per tonne of soil. Lime addition at a rate of 0.045
3.24
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Chapter 3
tonne per tonne of soil is estimated to cost $44/tonne ($40/ton). SulFerox
hydrogen sulfide treatment solvents are estimated to cost $220 per tonne
($200 per ton) of sulfur removed or $5,50/tonne of soil ($5.00/ton of soil).
3.2.10.7 Utilities
The charge for electric power is estimated at a flat rate of $0.06/kWhr for
447 operating kW (600 operating hp). The water cost is based on $0.407
1,000 L ($1.50/1,000 gal) and a consumption rate of 2.5 L/sec (40 gal/min).
The cost of utilities for the transportable and control unit were assumed to be
equal per ton of soil processed.
3.2.10.8 Effluent Treatment and Disposal
This category includes disposal costs for wastewater and the hazardous clari-
fier bottoms and fine slag — but not syngas or coarse slag whose treatment
costs are included in other categories as part of the process. The one-time dis-
posal cost for clarifier bottoms and slag fines was $25Q/tonne ($230/ton) in the
SITE Demonstration. The rate for continuing operations should be less. For
soil with a dry solids content of 87.7%, of which 62.5% is nonhiazardous coarse
slag, the disposal of the 30 tonne/day (32 ton/day) hazardous portion at $2207
tonne ($200/ton) is $72.40/tonne of soil ($65.80/ton of soil).
3.2.10.9 Residuals and Waste Shipping and Handling
The TOP produces useful by-products. Slag can be sold for the cost of trans-
portation or at no value from a central plant and returned to the site hi the trans-
portable unit case. Nonetheless, to be conservative, a cost of $5.50/tonne ($5/
ton) or $3.0 I/tonne of soil ($2.74/ton of soil) for the coarse slag handling and
transport is included for the 62.5% of the solids that is nonhazardous.
The syngas can be valued on a par with natural gas for the transportable
unit case and at a higher value for the central plant based on its hydrogen
and carbon monoxide content. Syngas is expected to be sold at $3.30/1,000
kWhr ($1.00/MM Btu) on-site and at $6.60/1,000 kWhr ($2.00/MM Btu) at
a central plant. The process equipment to use the syngas is not included in
these estimates. The potential uses are as a process fuel or as a feedstock to
produce ammonia, methane, or hydrogen.
3.25
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Design Development
3.2.10.10 Analytical Services
This category is for sampling and TCLP testing by an independent labora-
tory on a periodic basis. Tests for lead and several other species, two to four
times per day, could be expected to be contracted at a rate of $60 to $75 per
sample and total $5.50/tonne ($5/ton) of waste processed.
3.2.10.11 Maintenance and Modifications
I ]
The necessary maintenance can be figured at 3% of the capital cost per
year. In previous studies for the Cool Water Coal Gasification Program, the
DOE estimated maintenance for the TOP and combined-cycle power plant at
1.5% of capital. The cost at Montebello, including modifications for differ-
ent configurations, was budgeted at 5% per year.
3.2.10.12 Demobilization
, i
Site demobilization is assumed to cost $500,000. This is intended to
! ' I
cover all labor and contracts to close and leave a cleanup site. There is no
cost assumed for demobilization at the central plant.
i
; j
3.2.11 Design Validation
Each new installation will require a start-up and testing phase which,
when performance specifications are met, will validate the design for
that unit.
i j
3.2.12 Permitting Requirements
i , i
The applicable or relevant and appropriate regulations (ARARs) that
might apply to the TOP were outlined by US EPA (1995) in its SITE Dem-
onstration Report and include the following:
• RCRA treatment, storage, and land disposal federal regulations
(of hazardous waste);
• location-specific ARARs might exist governing construction and
operation of the transportable treatment unit and excavation of
soils to be treated;
• air quality standards will apply if volatile compounds and par-
ticulate emissions occur during excavation, handling, and treat-
ment prior to slurrying;
i
3.26
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Chapter 3
• Clean Water Act regulations govern wastewater discharge to
treatment facilities or surface water bodies;
• CERCLA defines drinking water standards established under
the Safe Drinking Water Act that apply to remediation of
Superfund sites;
• Toxic Substances Control Act prescribes regulations governing
the treatment and disposal of wastes containing polychlorinated
biphenyls; and
• Occupational Safety and Health Administration requirements apply
to CERCLA remedial actions and RCRA corrective actions.
3.2.13 Performance Measures
Table 3.5 summarizes the performance of the TOP process based on infor-
mation reported by US EPA (1995).
3.2.14 Design Checklist
Items that must be considered in designing and applying TGP follow:
1. Design Basis
• Volumetric flowrate
• Types of organic contamination in the offgas
• Offgas composition — organics, oxygen, nitrogen, moisture,
particulate, and other vapors
• Flowrate and compositional variation
• Chlorine, other halogen, sulfur, and nitrogen contents of any organics
• Organo-phosphorous and metallo-organic concentrations
2. Utility Requirements
• Auxiliary fuel usage
• Electrical usage
• Process water
• Compressed air
• Caustic for neutralizing HC1, other hydrogen halides, and SO2
3,27
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Design Development
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3.28
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• Fine slag and clarifier solids may require further treatment, particularly when volatile heavy metals
are present.
Wastewaters require further treatment to effect long-term stability of contaminants and reuse of water.
Reduction of Toxicity, Mobility, or Volume Through • Effectively destroys toxic organic contaminants and demonstrates a potential to immobilize inorganic
treatment heavy metals into the primary solid product, a non-leaching glassy coarse slag.
• Reduction of soil to glassy slag reduces overall volume of material.
Short-Term Effectiveness • Emissions and noise controls are required to eliminate potential short-term risks to workers and
community from noise exposure and exposure to contaminants and paniculate emissions released to
air during excavation, handling, and treatment prior to slurrying.
Implementability . Treatability testing required for wastes containing heavy metals.
• Large process area required.
• Large-scale transportable 100-tpn/day unit on multiple transportable skids requires large-scale
remediation with on-site commitment of more than 50,000 tons of soil and 2 years of operation.
• Initial transportable unit can be constructed and may be available in 24 months.
* Large size of unit and ex-situ thermal destruction basis for unit may cause delays in approvals and
permits.
(-ost ' Large-scale, complex, high-temperature, high-pressure, transportable thermal destruction "nit =>t
approximately $340/tonne ($300/ton) of waste soil.
Community Acceptance • Large-scale, ex situ, high-temperature, high-pressure, thermal destruction unit may require significant
effort to gain community acceptance.
State Acceptance • • If remediation is conducted as part of RCRA corrective actions, state regulatory agencies may require
operating permits, such as a permit to operate the treatment system, an air emissions permit, and a
permit to store contaminated soil for greater than 90 days.
'Actual cost of a remediation technology is highly site-specific and dependent on material characteristics.
Source: US EPA 1995
g
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CO
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Design Development
3. Regulatory Requirements
• Air permits
• Wastewater permits
4. Site-Specific Considerations
• Fuel gas (natural gas or liquid propane) availability
• Electrical service
• Wastewater treatment availability
• Wastewater discharge
• Meteorological conditions (wind, lowest temperature)
• Seismic zone
• Distance to the nearest homes, schools, and/or businesses
3.3 Flameless Thermal Oxidation
3.3.1 Remediation Goals
i |
Flameless Thermal Oxidation (FTO) is an innovative technology for
the treatment of offgases from Groundwater Air Stripping (GWS) and
Solvent Vapor Extraction (SVE) remediation processes. Generally, the
offgas from these processes will need treatment to satisfy air quality
standards. These air standards vary from state to state and are discussed
in more detail in Section 3.3.6.
j
! i
3.3.1.1 Performance
In one pilot-scale test program, an FTO supplied by Thermatrix, Inc., San
Jose, California, treated a SVE offgas and achieved DEs greater than 99.99%
(DOE 1995). A case history for this FTO is presented in Chapter 5. This
test involved three full-scale, modular, skid-mounted FTOs with internal heat
recovery which were installed in January, 1996, at the Idaho National Engi-
neering Laboratory to treat SVE offgas containing chlorinated volatile or-
ganic compounds (CVOCs) from a mixed-waste site. Two of the units are
3.30
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Chapter 3
designed for 680 standard m3/hr (400 scfm), and the other is designed for
340 standard mVhr (200 scfm)(DeCicco 1996).
While no data are available for the treatment of the offgas from'a GWS
system, Thermatrix does have data for the treatment of the offgas from a
full-scale industrial wastewater air stripping system. These data show that
FTO can achieve DEs of greater than 99.99% (Binder, Woods, and Schofield
1994). Comparable performance when an FTO is applied to pilot- and full-
scale groundwater air stripping systems is expected. A case history of the
use of FTO in a full-scale industrial wastewater air stripping system is pro-
vided in Chapter 5.
As of October, 1995, Thermatrix had installed over 30 FTO units ranging
from 1.7 to 11,050 standard m3/hr (1 to 6,500 scfm). The 1.7 standard mVft
(1 scfm) units are installed on pump seals for fugitive emission control at a
petroleum refinery (Martin, Smythe, and Schofield 1993). The 11,050 stan-
dard m3/hr (6,500 scfm) unit is installed on an automotive paint finishing
booth. Thermatrix has fabricated and delivered a 39,950 standard m3/hr
(23,500 scfm) unit which had not been placed in service when this mono-
graph was prepared. This unit incorporates three recuperative FTO modules
that will be used to treat the offgas from a thermal desorber handling 73
tonne/hr (80 ton/hr) of petroleum contaminated soils. The unit is designed to
recover about 60% of the energy in the treated offgas (Wilbourn, Newbura,
and Schofield 1994).
Performance data from sources other than SVE or GWS indicate that
the FTO is a very efficient emission control device. A 2,125 standard
rnVhr (1,250 scfm) FTO unit installed as a control device on two Ameri-
can Petroleum Institute (API) separators at a petroleum refinery had a
total hydrocarbon (THC) DE of >99.9% and CO concentrations of <10
parts per million by volume (ppmv). A 6,800 standard m3/hr (4,000
scfm) FTO unit installed as a control device on a mobile waste oil recov-
ery system had a THC DE of >99.99% and CO concentrations of <10
ppmv. A 5,100 standard m3/hr (3,000 scfm) FTO unit installed as a con-
trol device for the treatment of non-condensable gases at a pulp mill had
a DE of >99.99% for total reduced sulfur compounds and H2S concen-
trations of <5 ppmv. A 2,550 standard m3/hr (1,500 scfm), skid-
mounted FTO unit installed as a control device at a pesticide production
plant had a DE of >99.99% for methylene chloride and other chlorinated
hydrocarbon emissions (Wilbourn, Allen, and Baldwin 1995).
3.31
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Design Development
The FTO process also produces very low NOx emissions. This occurs
because FTO is flameless, and the gases being treated experience a
maximum reaction temperature that is near the average temperature. An
FTO operating at an average temperature of 870°C (1,600°F) has a maxi-
mum temperature close to 870°C (1,600°F), not the peak flame tempera-
tures of 1,650 to 1,925°C (3,000 to 3,500°F) typically encountered in a
conventional thermal oxidizer. This results in typical NOx emissions
from FTO of less than 2 ppmv (Binder, Martin, and Smythe 1994). The
treatment of nitrogen-containing organics in FTO results in higher NOx
concentrations in the stack gas.
i • •.. • ,. ]
,|; ]
3.3.1.2 Regulatory and Public Acceptance
•;' : j -
Acceptance of FTO by regulatory agencies typically depends on the abil-
ity of the technology to meet or exceed air quality standards required at the
remediation site. Acceptance of FTO by the public also depends on the abil-
ity of the technology to meet or exceed applicable air quality standards, but
in some cases will likely involve other issues. These issues, which are some-
times raised when thermal treatment is involved at a remediation site, in-
clude questions about the potential for FTO to cause fires, explosions, odors,
excessive noise, or emissions such as chlorinated dioxins and furans, which
are perceived by the public to be harmful. The FTO process has successfully
been permitted in a number of states.
'
3.3.1.3 Reliability
Because FTO is an innovative technology, the technology does not have a
long operational history regarding reliability. An analysis of FTO indicates
that it has no internal moving parts, has high temperature-resistant and
corrosion-resistant ceramic packing, and that the reaction vessel can be con-
structed of corrosion-resistant alloys (Binder, Woods, and Schofield
1994). These factors and operational data on full-scale FTO units being
used for VOC vent control indicate that the technology should be able to
operate with reliability factors of 90% or higher. An 8.5 standard m3/hr
(5 scfm) FTO unit operated for a U.S. Department of Energy (DOE)
demonstration test, required no maintenance or repairs during a
six-week test program (DOE 1995).
3.32
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Chapters
3.3.2 Design Basis
The overall design basis of GWS or S VE systems provides the data nec-
essary to evaluate different offgas treatment technologies, such as carbon
absorption, conventional thermal oxidation, catalytic oxidation, and FTO.
This comparative evaluation is used to select the most appropriate offgas
treatment technology based on performance, economics, and site-specific
considerations. The key factors needed to evaluate FTO as a gas treatment
technology are described in the following subsections.
3.3.2.1 Volumetric Rewrote
The volumetric flowrate of the offgas from the GWS or the S VE system
should be estimated. The minimum and maximum flowrates and the
flowrate variability during normal operation and over the project's life are
also necessary.
3.3.2.2 Organic Concentrations
The organic concentration in the offgas from the GWS or the SVE system
should be estimated. The minimum and maximum organic concentrations
and the organic concentration variability during normal operation and over
the project's life should also be estimated, If the offgas contains more than
267 kcal/m3 (30 Btu/ft3), the oxidation reaction is self-sustaining, and no
auxiliary fuel or recuperative heat exchange would be necessary in the FTO
design (Binder and Martin 1993). For offgas with a lower organic concen-
tration, internal heat recovery can be built into the reactor (Wilbourn, Allen,
and Baldwin 1995), thereby producing a self-sustaining reaction down to
less than 89 kcal/m3 (10 Btu/ft3)(Martin, Woods, and Schofield 1994). At
very low concentrations, even with recuperative air preheat, auxiliary fuel
usage might be high enough to consider using an organic concentration tech-
nology as an offgas pretreatment. Organic concentration devices have been
developed, using carbon or zeolites, that can increase organic concentrations
and reduce volumetric flowrates by a factor of ten or more (Anonymous
1992). The incorporation of an organic concentrator in the design must be
carefully evaluated, however, relative to the increased potential for explo-
sions, since the concentrated organic could be above its Lower Explosive
Limit (LEL).
3.33
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Design Development
An important design consideration with SVE systems is that the concen-
tration of organic in the air will decrease over time as the organic is volatil-
ized from the soil (Johnson et al. 1994). This will impact auxiliary fuel us-
age and the possible need for recuperative heat exchange; these needs must
be reflected in the FTO design.
3.3.2.3 Types of Organic
The FTO process can treat most types of organics that occur as contami-
nants at remediation sites. Table 3.6 lists some of the compounds that have
been treated by FTO.
i i -'
If chlorinated, halogenated, or sulfur-containing organics are present in
the GWS or SVE offgas, wet scrubber pretreatment of the reactor offgas may
be required by US EPA or state regulatory agencies. Chlorinated or
sulfur-containing compounds in a wet or very humid offgas feed to an FTO
could also result in the need for special alloys for the construction of the
reactor vessel. For example, a 170 standard m3/hr (100 scfm) full-scale
FTO, which is treating the offgas from a wastewater air stripper containing
chlorinated organics, is constructed of a chromium-nickel-aluminum alloy
(Binder, Woods, and Schofield 1994). Carbon steel lined with protective
resins can also be used when corrosive gases are being treated. The FTOs
being used at the Idaho National Engineering Laboratory are constructed of
carbon steel lined with Siloxirane (DeCicco 1996).
The presence of organo-phosphorous and metallo-organic compounds in
the SVE or GWS offgas would also need to be considered in design develop-
ment. Oxidation of these compounds in an FTO might generate a solid inor-
ganic paniculate that could condense into a solid residue and plug the ce-
ramic packing (Martin, Woods, and Schofield 1994). Metallo-organics con-
taining high vapor pressure inorganics, such as mercury and certain forms of
arsenic, would have low plugging potential at reaction temperatures and
could probably be treated in the unit if a suitable air pollution control system
were incorporated into the system design. If there are uncertainties about the
plugging potential of a particular metallo-organic compound in an FTO,
pilot testing should be used to assess the suitability of the technology.
3.34
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Co
CO
Ol
Table 3.6
Compounds Processed by Thermatrix RO
Petroleum Fuel
Hydrocarbons Sulfonated
Methane Hydrogen Sulfide
Propane Methyl Mercaptan
Hexane Dimethyl Sulfide
Heptane Dimethyl Disulflde
Octane
Naphtha
JP-5 Jet Fuel
Aromatics/Cyclics Nitrogenated Halogenated
Benzene Ammonia Methyl Chloride
Toluene Monomethylamine Dichloromethane
Xylene Dibutylamine Chloroethane
Pinene Trichloroethane
Polychlorinated Biphenyls Trichloroethylene
Perchloroethylene
Chloroform
Carbon Tetrachloride
Freon
Others
Isopropanol
Methanol
Acetone
Methv! Eth«! Ketone
Acrylic Acid
Formaldehyde
Methyl Tert-Butyl Ether
Dichloromethyl Ether
Hexamethyldisilazane
Reproduced courtesy of Theimatrix, Inc.
9
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Design Development
3.3.2.4 GWS or SVE Offgas Composition
The paniculate concentration of the offgas from the GWS or SVE system
should be estimated, as well as the minimum and maximum paniculate con-
centration variability during normal operation and over the project's life.
The paniculate concentrations in the GWS or SVE offgas stream need to be
very low to minimize plugging of the reactor bed. If necessary, this can be
accomplished by prefiltering the GWS or SVE offgas.
The moisture content of the offgas from the GWS or the SVE system
should be estimated. The variability of the moisture content during normal
operation and over the project's life should also be gauged. The offgas from
most GWS and from some SVE systems is saturated with moisture. Con-
densation of this moisture in the ductwork leading to the FTO needs to be
considered in the design.
3.3.2.5 Utility Requirements
Process utility requirements — auxiliary fuel, electricity, water, and com-
pressed air — should be estimated as part of the design. The auxiliary fuel
requirements of the FTO can be estimated using a mass-energy balance.
Other utility requirements are available from Theirmatrix since they may be
technology-specific and difficult to estimate.
* . i ,
3.3.2.6 Regulatory Basis
The US EPA and/or state regulatory requirements for the offgas treatment
system are a very important part of the design. These air quality standards
vary from state to state and can involve some or all of the following:
• minimum DE, based on a stack test, of specific organic contami-
nants in the SVE or GWS offgas;
• maximum concentration, based on a stack test, of specific or-
ganic contaminants in the treated exhaust gas;
j .
• maximum organic mass emission rate, based on a stack test, of
specific organic contaminants in the treated exhaust gas;
• maximum nitric oxide (NOxj concentration in the treated exhaust
gas, generally based on testing; and
3.36
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Chapter 3
• maximum participate, HC1, and/or SO2 concentrations in the
treated exhaust gas from the posttreatment wet scrubber, gener-
ally based on testing.
While it is common to require CO and/or THC continuous emissions
monitors (CEMs) on the exhaust gas of a conventional thermal oxidizer
during an S VE or GWS related remediation., CEMs have never been required
by a state regulatory agency for any FTO air permits. The most common
FTO operating permit condition is an automatic low temperature waste gas
cutoff (DeCicco 1996).
3.3.2.7 Pilot Test Data
Bench-scale or pilot-scale data can serve as inputs to design to confirm
that the FTO can meet the regulatory requirements for organic destruction,
organic emissions, THC, CO, and NOx. Thermatrix has a 1.7 standard m3/hr
(1 scfm) bench-scale unit and an 8.5 standard mVhr (5 scfm), skid-mounted
pilot unit available for field testing on slip-streams of offgas from GWS or
SVE projects.
3.3.3 Design and Equipment Selection
The design basis information is used to develop a duty specification that
would be used to solicit a bid on the supply of the equipment to treat the
SVE or GWS offgas. A typical equipment layout for FTO treating GWS
offgas is shown in Figure 3.3. A typical process-flow diagram for FTO treat-
ing SVE offgas is shown in Figure 3.4.
3.3.4 Process Modifications
During design development, consideration should be given to the impact
of variable or changing site conditions. For an SVE process, contaminant
concentrations in the soil can vary significantly from one area to another. In
addition, during operation, the contaminant present in the offgas will gradu-
ally decline as the contaminant is vaporized from the soil. Variable soil con-
taminant concentrations should be addressed during the soil investigation
and accounted for in FTO design by using a realistic upper limit for the con-
taminant concentration. A reasonable balance must be reached however,
between capital cost and equipment flexibility. Declining contaminant con-
centrations in the SVE offgas can also be accommodated by having
3.37
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Design Development
Figure 3.3
Thermatrix FTO Treatment System — Wastewater Stripper Offgas
Process In
Air Stripping
Air
Stripping
Blower
Scrubber Recirculation Pump
"o Chemical Sewer
Gravity Drajn to
Process Sewer
Reproduced courtesy of Thermatrix, Inc.
3.38
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Chapter 3
Figure 3.4
Process-Flow Diagram of Thermatrix FO Treating SVE Offgds
Air Bleed
Pressure
I Vac Relief
IdOinHg)
Temperature
Sensor r
o-
Flow
Meter
Flame
Arrester
Pressure
Gauge ^ Hi-Vac Switch
Knockout
Pot
^ Drain
Flameless
Thermatrix
Oxidizer
Silencer
Reaction
Zone
Electric
Heater
Quench
Zone
Rotary Lobe Blower
Reproduced courtesy of Thermatrix, Inc.
sufficient auxiliary fuel capability to ensure complete destruction. Spikes of
high concentration volatile organic compounds (VOCs), while not common
in SVE applications, can be handled by the FTO design (DeCicco 1996).
Since the FTO can be skid- or trailer-mounted, the process can be easily
modified by adding equipment.
3.3.5 Pretreatment Processes
In GWS and SVE systems in which entrainment of liquid water droplets
can occur, the offgas should pass through a knock-out pot followed by a
flame arrester and a mist eliminator. Such offgas pretreatment .minimizes
impingement of droplets of entrained and condensed liquid water on the hot
packing in the reaction zone. The flame arrester is a safeguard against
flash-back to potentially explosive mixtures in the knock-out pot headspace.
3.39
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Design Development
3.3.6 Posttreatment Processes
;
If the organic contaminants in the offgas from a GWS or S VE system con-
tain only carbon, hydrogen, and oxygen, then it is likely that the FTO exhaust
gas can go directly to the atmosphere without any posttreatment. However, if
the organic contaminants contain other elements, such as halogens or sulfur,
then a posttreatment system, such as a packed-bed alkaline wet scrubber, might
be required to remove acid gases, such as HC1, other hydrogen halides, or SO2.
The need for a posttreatment wet scrubber depends on the concentration of the
acid gases in the FTO offgas, and any US EPA and/or state regulatory perfor-
mance or emission standards that are part of the site-specific remediation agree-
ments at the site. Additional treatment or permitting can be required for the
scrubber wastewater that contains salts. The degree and type of scrubber waste-
water permitting and/or treatment depends on site-specific considerations and
US EPA and/or state regulatory effluent and treatment standards that are part of
the site-specific remediation agreements.
i
3.3.7 Process Instrumentation and Controls
! ;
For either an SVE system or a GWJ> system, the key instruments are the
blower flow meter and the FTO temperature indicator. While LEL meters
and stack CEMS are generally not required (DeCicco 1996), some state
regulatory agencies require them.
i
3.3.8 Safety Requirements
It is common practice to use an LEL meter on any offgas entering a ther-
mal control device if the offgas contains organics at concentrations which
can potentially exceed the LEL. Extensive testing by Fenwall Safety Sys-
tems Co. showed that the heat capacity and geometry of the ceramic packing
matrix provides an inherent flame arresting capability (Woods, Binder, and
Schofield 1994). A 1.7 standard nVVhr (1 scfm) FTO unit was tested at an
engineering safety laboratory at organic concentrations from 5% of the LEL
up to 170% of the upper explosive limit (UEL). Under all test condi-
tions, there was no evidence of flashback, detonation, or any uncon-
trolled combustion (Martin, Smythe, an3 Schofield 1993). However, a
Hazardous Operation (HAZOP) analysis should be considered to deter-
mine whether an LEL meter and flame arresters need to be incorporated
into the design and operation of an FTO.
3.40
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: Chapter 3
3.3.9 Specification Development
Because the discussions in this section are only considered to be guid-
ance, it is important to discuss with the SVE or GWS equipment suppliers
whether there are any site-specific or other factors that must also be consid-
ered during the development of the procurement specification.
The procurement specification should incorporate the considerations dis-
cussed in the Design Basis, Section 3.3.2. The key procurement specifica-
tions for either an SVE or GWS treatment system include the following:
• volumetric flowrate;
• types of organic contamination in the offgas;
• offgas composition:
• organics,
• oxygen,
• nitrogen,
• moisture,
• particulate,
• other vapors;
• flowrate and compositional variation;
• chlorine, other halogens, sulfur, and nitrogen contents of any
organics; and
• organo-phosphorous and metallo-organic concentrations.
A performance test is often developed and included with the procurement
specification. Acceptance of the final system can be contingent on the sys-
tem passing the performance test.
3.3.10 Cost Data
A demonstration test was conducted at the DOE's Savannah River Inte-
grated Demonstration site using the FTO to treat the offgas from an SVE
system (DOE 1995b). In its summary repont, the DOE provided a cost esti-
mate for a 680 standard m3/hr (400 scfm), gas-fired FTO treating SVE
offgas. A cost estimate for an FTO system of the same size to treat an SVE
offgas containing an average of 400 ppmv of chlorinated volatile organic
3.41
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Design Development
compound (CVOC) or 1.7 kg (3.7 Ib) of CVOC per hour was prepared using
information from the DOE report, discussions with Thermatrix, and the au-
thors' experience. That cost estimate is summarized in Table 3.7 and in-
cludes the following assumptions:
• FTO has an operating factor of 95% or 8,322 hr/yr (DeCicco 1996);
.i,'.: -. I
• installed capital cost of a 680 standard m3/hr (400 scfm),
skid-mounted recuperative style FTO unit is $160,000;
• capital recovery at 10% for seven years (capital recovery factor
of 0.2089)(authors'experience);
• one operator per shift for four shifts at $40,000 per year with
20% of each operator's time dedicated to the FTO unit (DeCicco
1996 and authors' experience);
• one supervisor at $60,000 per year and 20% of the
supervisor's time dedicated to the FTO unit (DeCicco 1996
and authors' experience);
• maintenance costs based on 3% of installed capital per year (au-
thors' experience);
• auxiliary gas cost of $6,920 per year for 315,000 Btu/hr; and
; • I
• power costs of $530 per year.
The estimate does not include the capital and operating costs for a wet
scrubber. If a wet scrubber for the removal of acid gases such as HC1 is
required, the costs for this operation would need to be added.
•
3.3.11 Design Validation
!
Validation of the process can be accomplished by including a perfor-
mance test with the procurement specification. In this instance, acceptance
of the final system is contingent upon the system passing the performance
test. A peer review during the procurement and design process is another
commonly used design validation method that could be applied to FTO.
I i
!
3.3.12 Permitting Requirements
*
Prior to the procurement of equipment, the US EPA and/or state regulatory
agencies need technical and performance information on FTO pertaining to the
offgas treatment system's ability to comply with air quality requirements. This
3.42
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Chapter 3
Table 3.7
Process Cost Estimate of a FTO Treating SVE Offgas
Process Operating Costs
Labor
Auxiliary Fuel
Power
Maintenance @ 3% of Capital
Operating Costs-Sub Total
Capital Recovery
Total Process Costs
Cost ($/yr)
$44,000
$6,920
$530
$4,800
$56,250
$33,420
$89,670
$/kg CVOC
$3.14
$0.49
$0.04
$0.34
$4.02
$2.39
$6.41
$/lb CVOC
$1.43
$0.22
$0.02
$0.16
$1.83
$1.09
$2.91
Capital Cost (1995) = $160,000
Source: DOE 1995b
technical information typically involves a description of the FTO process, a
conceptual design showing the preh'minary process, and performance data from
similar installations. After approval of FTO for the application, the state and
US EPA will probably want to review more detailed information, such as
process-flow diagrams (PFDs) and piping and instrument diagrams (P&IDs)
during the procurement and installation phase. If relevant bench-scale or
pilot-scale data are available, the state and US EPA will also want to examine
these data to confirm that FTO can meet state and/or US EPA requirements.
The air quality standards vary from state to state and can involve some or
all of the following:
• minimum DE, based on a stack test, of specific organic contami-
nants in the SVE or GWS offgas;
• maximum concentration, based on a stack test, of specific or-
ganic contaminants in the treated exhaust gas;
• maximum organic mass emission rate, based on a stack test, of
specific organic contaminants in the treated exhaust gas;
• maximum nitric oxide (NOX ) concentration in the treated ex-
haust gas, generally based on testing; and
3.43
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Design Development
• maximum paniculate, HC1, and/or SO2 concentrations in the
treated exhaust gas from the posttreatment wet scrubber, gener-
ally based on testing. !
While it is common to require CO and/or THC GEMS on the exhaust gas
of a conventional thermal oxidizer during an S VE or GWS related
remediation, CEMS have never been required by a state regulatory agency
for any FTO air permits. The most common FTO operating permit condition
is an automatic low temperature, waste gas cutoff (DeCicco 1996). Other
permitting areas not listed above, such as metal emissions, could be required.
Special requirements, such as radionuclide emission regulations, could also
be required for DOE sites.
3.3.13 Performance Measures
1
Performance measurements that are required for FTO by states and US
EPA vary from state to state. For projects involving SVE or GWS offgas
treatment, performance measurements generally incorporate the state air
permit requirements for an organic emission control device. Some of the
possible performance measurements are:
• Destruction efficiencies for either total hydrocarbons or specific
constituents, such as dichloroethane, may be required. The DE
requirements could range from 95% to 99.99% depending on the
state and the specific constituents in the offgas. Many states have
maximum ground level concentration standards that require dis-
persion calculations based on stack concentrations of specific
organic constituents;
• Hydrogen chloride removai efficiencies of 99% or emissions of
less than 4 Ib/hr out the stack could be required; and
• Depending on the state, SO2 and/or NOx emissions might be
regulated.
It has been Thermatrix's experience that CEMS for CO, THC, HC1, NOx
and SO2 have never been required by regulatory agencies for air permits
(DeCicco 1996). Other performance measures, not listed above, such as
metal emissions, could be required. Special requirements, such as radionu-
clide emissions could also be required for DOE sites.
i i .
3.44
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Chapter 3
3.3.14 Design Checklist
The key factors that must be considered when procuring and installing
FTO are summarized in the following checklist:
1. Design Basis
• Volumetric flowrate
• Types of organic contamination in the offgas
• Offgas composition — organics, oxygen, nitrogen, moisture,
particulate, and other vapors
• Flowrate and compositional variation
• Chlorine, other halogens, sulfur, and nitrogen contents of any
organics
• Organo-phosphorous and metallo-organic concentrations
2. Utility Requirements
• Auxiliary fuel usage
• Electrical usage
• Process water
• Compressed air
• Caustic for neutralizing HC1, other hydrogen halides, and SO2
3. Regulatory Requirements
• Air permits
• Wastewater permits
4. Site-Specific Considerations
• Fuel gas (natural gas or liquid propane) availability
• Electrical service
• Wastewater treatment availability
• Wastewater discharge
• Meteorological conditions (wind, lowest temperature)
3.45
-------
Design Development
• Seismic conditions
• Distance to the nearest homes, schools, and/or businesses.
i „ i
Special requirements, such as radionuclide emissions, could also be re-
quired for DOE sites.
3.4 Plasma Furnaces
i
The process developed by the Exide Corporation and commercially-avail-
able through Asea Brown Boveri (ABB). There are many types of plasma
furnaces and many types of designs that differ significantly in chamber con-
figuration (fixed/table), electrode configuration, iarc type, cooling system,
electrode type, power (AC/DC), and other design elements. The process was
chosen to illustrate the application of plasma furnaces
The Exide Corporation process uses plasma arc technology originally
developed by ABB. Commercial systems supplied by ABB are operat-
ing in Europe and South Africa (since the mid 1980s), using controlled
atmosphere and hollow electrode feed systems. In the early 1990s,
South Carolina Research Authority operated a. research unit in Charles-
ton with the ABB technology.
' '
1
3.4.1 Remediation Goals
i ,
In July 1992, the US EPA issued a Record of Decision (ROD) for reme-
dial action at a former used battery recycling site. The US EPA's strategy for
cleaning up the site included innovative thermal treatment technology to
treat soil contaminated with battery casings and lead.
To meet US EPA's goals, the Exide Corporation conducted a two-phase
pilot program to evaluate the feasibility of using their plasma furnace tech-
nology. This technology was specifically developed to treat soils associated
with secondary battery smelting operations that contain broken battery cases
and separator plates containing a variety of organic and chlorinated organic
compounds, as well as lead, lead sulfate, and associated metal compounds.
It is a high temperature process which introduces the liquid, solids
smaller than 1.6 cm (5/8 in.), and gaseous wastes directly into the
plasma zone of the furnace by means of a hollow electrode. Larger
,
i . • • i
3.46
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Chapter 3
solids, not introduced through the electrode, can be added through
air-locks in the roof of the furnace.
The goals for the plasma furnace process are to produce clean, combus-
tible synthesis gas, a molten ceramic slag that passes US EPA's Toxic Leach-
ing Characteristic Procedure (TCLP), and metal for recycle. Since the fur-
nace uses electrical power to drive the reactions, the process creates mini-
mum quantities of effluents (solid, liquid, or gas).
3.4.2 Design Basis
The primary objective of the plasma furnace process is to remove the
maximum amount of lead from the feed and to render the trace amount of
lead that is not removed into an insoluble form, as measured by TCLP. A
secondary objective is to optimize the use of chemical energy from the bat-
tery case materials so as to minimize the cost of operation.
3.4.2.1 Post Combustion Ratios
The effectiveness of heat transfer from the plasma and the chemical reac-
tions to the feed materials depends on the geometry and the temperature
differential between the plasma and the material being heated. Since more
energy is generated by converting carbon to CO2 than by converting carbon
to CO, sufficient oxygen is needed for conversion to CO2to maximize the
use of chemical energy in the furnace. It should be noted the a graphite
electrode is also susceptible to oxidation reactions. This becomes less criti-
cal if a reducing offgas with a high CO content can serve as an energy source
for another process.
The degree to which combustion reactions have proceeded to completion
(CO2 and H2O) is typically measured as the post combustion ratio (PCR).
There are two ways to express the PCR using volumetric gas composition
measurements:
PCR -
L
=
(C02+C0) >
(C02+H2Q)
(C02 + H20 + COH-H2) (3.3)
3.47
-------
Design Development
As Equation 3.2 requires only CO2 and CO volumetric concentration
measurements, it is somewhat simpler to measure and lends itself to continu-
I :.
ous monitoring.
3.4.2.2 Theoretical Fuming Rate
A production system is designed to operate at temperatures exceeding
1,649°C (3,000°F) to maximize the vaporization of lead. Lead sulfate in
soils fed to the furnace decomposes to lead oxide according to the equation:
2PbSO4-»2PbO
Lead metal entering the furnace can be oxidized to lead oxide according to:
2Pb + O2->2PbO (3.5)
i i 'inii;1
and, if reducing conditions are maintained, lead oxide can be reduced ac-
cording to the reverse of Equation 3.5. The vapor pressure of lead
(Brimacombe 1989; Jacob andfoguri 1975; Holi 1989; Willis 1980; Toop
1994), as a function of temperature, is:
log P = - 10'13° + 8.28-0.985 log T (3.6)
, | , •.'. . , | ,. .
and for lead oxide, as a function of temperature, is:
+ 6.012
i • • • ••
Lead in the furnace converts to liquid phase and vaporizes at a rate that is
dependent on both temperature and gas flow conditions (Kellogg 1967;
Richards and Brimacombe 1985). Lead that volatilizes is carried out of the
furnace with the offgas, condensing to liquid and solid phases. The lead that
leaves the furnace with the offgases is referred to as fume. As the fume
cools, it can collect as deposits on furnace ductwork or be captured by the
offgas particulate collection system. The lead-bearing capacity of the offgas
limits the fuming rate of the furnace. For optimal lead removal, the theoreti-
cal fuming rate must exceed the lead introduction rate. A theoretical fuming
rate can be calculated as follows:
3.48
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Chapter 3
p _ (MPb) ,-
Pb (Mpb+Moffgos)
where: P^ = vapor pressure of lead at temperature T;
Mpb = moles of lead fumed per hour; and
M = moles of offgas generated per hour.
Using 207 as the molecular weight for lead, and solving Equation 3.8, the
theoretical fuming rate (TFR) is:
M P
= 207Mpb= °^gas Pb (3.9)
3.4.3 Design and Equipment Selection
The plasma furnace used by the Exide Corporation is a direct current arc
furnace with a refractory-lined chamber; a side elevation of the furnace is
shown in Figure 3.5. It has an air-cooled bottom, with an electrical connec-
tion and a copper plate to distribute the current evenly over the bottom. Re-
fractories in the bottom of the furnace are electrically conductive.
The graphite electrode can be moved up and down to compensate for
changes in the bath depth as materials build up in the slag or metal phases or
as the slag or metal are tapped from the furnace. The movement also com-
pensates for any electrode consumption. The electrode position determines
the arc length and, thus, the operating voltage. The hollow electrode is
proven technology. Commercial graphite electrodes are available from sev-
eral companies in sizes up to 91.44 cm (36 in.) in diameter. Electrodes cost
approximately $1 to $2 per pound, depending on the custom machining
requested, and are available in many lengths and diameters. They usually
have tapered threaded ends to join sections together; however, the furnace
must be de-energized to add an electrode section.
The roof of the furnace is water cooled and helps to guard the furnace
from electrical short circuits formed through the layer of frozen metal. Not
shown in Figure 3.5 is an auxiliary opening in the roof that can be used to
charge larger pieces into the furnace.
An induction coil circling the furnace helps to stir the bath arid confine
the plasma zone, in addition to the natural arc pressure. The plasma zone of
3.49
-------
Design Development
Figure 3.5
Plasma Furnace Cross-Section
Plasma Gas/Feed Material Through Electrode
Metal Vapors CO, CO2;
To Recovery System
Water Cooled Roof
Induction Coil
\
Copper Plate
Cooling Air on Bottom
Reproduced courtesy of Exide Corp.
3.50
-------
Chapter 3
the furnace is below the electrode, and the freeboard area, or furnace atmo-
sphere, is above the bath.
Plasma support gas is added to the furnace through the hollow electrode
and ends up as part of the furnace atmosphere. Any of several gases can be
used. In the laboratory, argon or helium is frequently used. Reducing gases,
such as H2 or CO work as plasma support gases. When the substances being
treated contain significant amounts of organic chemicals, the furnace free-
board is soon dominated by H2 and CO. The freeboard volume of the fur-
nace is relatively large, and the exhaust gas volumes are small, so residence
time in the furnace is long and the space velocities are low. Particulates are
less easily entrained and swept from the furnace. The furnace atmosphere is
maintained at a slightly negative pressure. Plasma arc furnaces for hazard-
ous waste management are procured as a unit; they are not designed per se.
Other suppliers of plasma arc furnaces have designs similar to ABB.
3.4.4 Process Modifications
Depending on site-specific considerations, energy recovery from plasma
arc furnaces can be modified to provide methanol conversion, hydrogen
conversion, or cogeneration. Also refer to the Section 3.4.6, Posttreatment
Processes.
3.4.5 Pretreatment Processes
Solids are mixed and blended to obtain uniform composition prior to their
introduction into the furnace. During pilot tests, the feed material was sized
to minus 0.9525 cm (0.375 in.), so that it could pass unobstructed down the
5.08 cm (2 in.) diameter hollow electrode. With a larger electrode, handling
pieces up to 2.54 cm (1 in.) should be possible. Figure 3.6 shows the solids
feed system used in the 1994 battery site cleanup tests. A vibrating screw
feeder with a variable speed drive is mounted on a load cell to meter the rate
of solids delivered to the furnace. A feed pipe with a rotary feeder and isola-
tion valve conveys solids into the hollow electrode. The excavated contami-
nated soil is bedded or blended for compositional uniformity and is usually
dried ahead of the furnace.
3.51
-------
Design Development
Figure 3.6
Solids Preprocessing and Feed System
Heat from
Offgas
Slag, 100%
Casings
Soil, Some
Casings, and
Drosses
Computer Monitor
Power, Offgas
Temperature
3.4.6 Posttreatment Processes
i ' • -
Plasma furnaces use conventional wet and/or dry air pollution control
systems. The volume of offgas produced by plasma furnaces is minimal,
since they use electric power to establish the high temperature environment
which drives thermal destruction.
3.52
-------
Chapter 3
Exide's recommended offgas tempering and cleaning system (assuming
5% or less carbon content in the feed materials) is shown in Figure 3.7. Syn-
thesis gas from the furnace enters an optional afterburner where the addition
of oxygen (or air) liberates heat for recovery. Gases from the afterburner are
cooled prior to entering a fabric filter. The fabric filter removes particulates.
Depending on the material being treated, acid gases can be removed in a wet
Figure 3.7
Offgas Cleanup System with Energy Recovery
Hot Oil to Soil Dryer •*
Chilled Water
*• [Option: Co-generation
»• [Option: Methanol Conversion
•>- [Option: Hydrogen Conversion |
3.53
-------
Design Development
reflux, or other type of scrubbing system. Feed containing greater than 5%
carbon can produce a high Btu synthesis gas that has potential for further
chemical conversion or cogeneration.
Metals, such as iron or copper, are reduced and recovered as liquid metal.
This type of furnace has been used to metallurgically process
ferro-chromium, ferro-nickel, ferro-silicon, and other metal alloys. They
enter the furnace as oxides or natural ores and are recovered as metals. Con-
"
laminated soils, as are natural ores, are melted to form slag. Slag, withdrawn
from the furnace at approximately 1,760°C (3,200*?), when solidified, has a
density greater than 3,200 kg/m3 (200 lb/ft3).
i !
' . |
3.4.7 Process Instrumentation and Controls
i . • • , i !
1
The plasma furnace instrumentation and controls consist of DC power
supply controls and a means of tapping the furnace periodically to remove
and recover accumulated metal and slag. Power supply technology for high
amperage rectification is commercially available. The graphite electrode can
be moved up and down to compensate for changes in pool depth as materials
build up in the slag and metal phases or as slag and metal are tapped from
the furnace.
i
Since the plasma furnace operates in a reducing atmosphere and produces
a combustible gas, common practice is to use instrumentation to detect the
LEL in the furnace offgas.
3.4.8 Safety Requirements
An operational hazards evaluation should be conducted on a site-by-site
basis to identify potential hazards associated with the plasma furnace 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.
A number of standard safety precautions are required and should be
observed. All systems must comply with Occupational Safety and
Health Act (OSHA) requirements. These include, but are not limited to,
confined space entry procedures, fire protection, and spill protection.
Precautions relating to hot operating equipment, such as warning signs,
barriers, and safety shields, must be implemented. Conveyors and other
3.54
-------
Chapter 3
mechanical and electrical equipment must have adequate lock-out/
tag-out safety mechanisms to prevent inadvertent operation during main-
tenance. Special attention to high voltage electrical safety precautions are
required. Special precautions must also be observed to contain the with-
drawn slag so as to avoid fires and personnel injury.
In addition to the safety of personnel and equipment, environmental
safety is also a key consideration. Monitoring of the LEL in the offgas and
the proper fracturing of system controls ensures the protection of the sur-
rounding environment.
3.4.9 Specification Development
A specification package couples the characteristics of the contaminated
materials requiring treatment with the design specifications available for
plasma furnaces. As an example, some procurement specifications might be:
• size reduction requirements for the contaminated soil entering the
furnace;
• moisture content or drying requirements for the contaminated soil;
• organics concentrations in the contaminated material;
• metals concentrations in the contaminated soil;
• capacity of plasma furnace to treat contaminated soil;
• volumetric flow rates into and out of the furnace;
• offgas composition, including organics, metals, oxygen, mois-
ture, particulate, nitrogen, and other vapors;
• frequency for tapping metal and slag from the furnace;
• offgas cleaning requirements;
• process control requirements;
• electricity costs; and
• desired offgas utilization — cogeneration, methanol, hydrogen, etc.
To verify that the final facility meets the specification package, an accep-
tance test should be included. Ownership of the facility should be made
contingent on the facility's ability to pass the acceptance tests.
3.55
-------
Design Development
3.4.10 CostData
; , i , , „ I i ... .,
Costs are site-specific; however, an example of a system to process soil
contaminated with ebonite battery cases, lead, arsenic, cadmium, and anti-
mony was chosen to estimate costs. The estimate is based on the following:
I " • ' I
• 10 MW furnace system;
• soil contaminated with approximately 20% casings and 3% lead;
• feed at maximum 30% moisture, dried to 3% or less in preparation;
• operation modes — 5-min oxidation cycle; 15-min oxidation
cycle;
• operational (productive) time per year is 6,650 hr;
• j
• total feed per cycle is 22 tonne (24 ton);
11 ' I '
• carbon content per cycle — 15% of total feed in 20% casings;
• electrical cost per kWhr — $0.04 ($40.00/MWhr);
• labor, direct — 4 persons per crew, 4 crews @ $16/hr;
• management not included;
• burden on labor — 60%;
• no credits taken for value of metals recovered;
i
• no credits taken for value of slag;
• no credits taken for the value of energy recovered;
• no credits taken for processing charges to customer;
i : . i , i •. ; .'•...
• contractor finances capital costs; and
• miscellaneous electrical load by support equipment — 3 MW.
i , , „. ;
, ,„ i „ • • , • i ,
The basis for calculating operating costs is presented in Table 3.8 and is
normalized to cost per ton in Table 3.9.
Capital costs are site dependent. They are also Impacted by the amount of
equipment leased compared with the equipment that must be purchased.
The estimates of capital cost presented in Table 3.1.0 are for equipment only
and do not include site, site preparation, security, site closure, or the cost of
bringing electrical power or gas utilities to the site. The cost of functional
buildings needed for the process are relatively minimal.
3.56
-------
Chapter 3
Table 3.IJ
Annual Processing Rates and Power Requirements
Requirements 5 min Residence 15 min Residence
Tons of Feed Processed per year 87,192 80,000
MWHr (Electrical) per year 70,396 72,910
Reproduced courtesy of Exide Corp.
Table 3.9
Operating Cost per Ton of Material Processed
Operating Cost per Ton
Electrical
Labor, Direct
Labor, Indirect
Maintenance
Electrodes
Gases
TCLP
Refractories
Flux
Miscellaneous
Total
5 min Residence
($)
32.23
9.40
3.45
735
3.10
2.10
525
3.45
2.10
230
$70.80
15 min Residence
($),
36.46
10.24
3.76
8.00
330
235
52*
3.75
225
250
$77.76
Reproduced courtesy of Exide Corp.
Using the information in Table 3.10, leasing and depreciation costs can be
estimated on the basis of cost per ton of material processed for a facility with
a total capital cost of $26,400,000 of which $18,238,000 is for leased
3.57
-------
Design Development
Table 3.10
Capital Cost Estimates
Item
Buildings
Electrical 15.5 MW
Furnace 10 MW
Equipment Maintenance, Spares
Equipment, Mobile
Equipment, Wheel Wash
Furnace Ventilation
Personnel Facilities
Slag Casting
Bridge Crane
Engineering
Material Preparation
Material Feed System
Water Cooling System
Offgas System, Monitoring
Subtotal
10% Contingency
Total
Leased
(Thousands of $)
i.
1,500
8,300
550
1
210
' 115
215
i
1,780
450 ''
,|
1,100
600
590
1,170
|
16,580
1,658
|
18,238
Not Leased
(Thousands of $)
2,200
500
2,200
95
90
300
230
150
635
300
175
220
325
7,420
t
742
IJ.162
i
Total
" i
2,200
2,000
10,500
550
210
210
|
305
300
2,010
600
1
635
1,400
775
810
1,495
24,000
2,400
26,400
• 1
Reproduced courtesy of Exide Corp.
'." : • •. ,.:
equipment, $2,200,000 is for buildings, and $5,962,000 is for equipment
which must be purchased.
The annual cost for the major components either leased or amortized is:
I .< i • i
Leased Equipment $18,238,000 @ 17.5%/yr for 8 yr =
$3,192,000/yr
Buildings $5,962,000 @ 7 yr = $851 JOO/yr
1
Purchased Equipment $2,200,000 @ 10 yr = $22Q,000/yr
3.58
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Chapter 3
The total capital cost of each major component is:
Leased Equipment 8 yr @ $3,192,000/yr = $25,533,000
Buildings 7 yr @ $851,700/yr = $5,962,000
Purchased Equipment 10 yr @ $ 220.000/yr = S2.200.000
Total Capital and Finance Costs $33,695,000
During the first seven years of operation, the capital cost totals
$4,263,000/yr. Therefore, the cost for 15 min residence time is $53.29/ton
($4,263,000 per 80,000 ton/yr) or for 5 min residence time it is $48.90/ton
($4,263,000 per 87,192 ton/yr).
A summary of the capital and operating costs normalized to one ton of
material processed is presented in Table 3.11.
Table 3.Ill
Summary of Total Operating and Capital Costs"
Item
Total Capital Costs
Ton/yr at 6,650 hr/yr
MWhr of Electrical Power/yr
Electrical Demand Max. at 13.8 kV
5 min Residence
$26,400,000
87,192
70,400
15.5 MW
15 min Residence
$26,400,000
80,000
72,910
15.5 MW
Cost per ton of feed
Operational
Financing
Total
$70.80
$48.90
$119.70
$77.76
$53.29
$131.05
•Burden rate is 60% and no profit is included.
Reproduced courtesy of Exide Corp.
3.59
-------
Design Development
3.4.11 Design Validation
I ,:, , !
Design validation procedures are usually based on acceptance tests that
are best defined in the design specification package (see Section 3.4.9). It is
also common practice to engage an independent peer reviewer during the
procurement, design, and fabrication of the system to assess the information
submitted.
3.4.12 Permitting Requirements
' •••;.... • . I . . „ I ,' ... , ', I .. ,„
Regulatory compliance issues often drive remedial actions. The com-
plexities of the Resource Conservation and Recovery Act (RCRA) and other
regulatory requirements for conducting remedial actions at contaminated
sites not only include the processes involved, but the need to identify regula-
tory constraints and cleanup goals in the early stages of a project to collect
the appropriate data and provide the relevant remedy. Throughout the vari-
ous phases of a project, the contractor should assist the regulatory agencies
with the issues that affect a project, such as cleanup criteria, applicability of
Land Disposal Restrictions (LDRs), and establishment of specifications to
meet Applicable or Relevant and Appropriate Regulations (ARAR) or other
regulatory requirements.
j
3.4.13 Performance Measures
Performance of a plasma furnace facility can be evaluated based on the
degree of treatment and the amount of residual emissions of hazardous com-
pounds. These measures are intended to protect human health and the envi-
ronment during and after the treatment process.
I • • . : ' , I •.!
Measures of the degree of treatment are:
•
• removal or reduced concentrations of toxic organics from con-
taminated soil; and
• removal or reduction of toxic metals from contaminated soil.
Measures of residual emissions of hazardous compounds are:
• trace organic waste constituents in the stack gas;
• products of incomplete reactions;
• acid gas emissions;
3.60
:, :; J;.,:..,'..;:;.,. ::v/.; 1:1,:..;;.,,;...:..: ,j
^:/.'••; * ^'
-------
Chapter 3
• toxic metal emissions;
• teachable toxic compounds from slag or metal residuals; and
• trace contaminants in control device fluids.
The techniques used to collect and analyze the samples that provide data
on performance and emission levels are of critical importance. Essentially
all feed streams and effluent streams must be sampled and then analyzed for
a wide variety of constituents and physical or chemical properties.
3.4.14 Design Checklist
The key factors discussed in Section 3.4.2 (Design Basis) that a designer
would need to consider when procuring and installing a plasma furnace are
summarized in the following checklist.
1. Design Basis Information
• Feed system
• Flow rates
• Offgas composition
• Slag and metal
• Controls
2. Utility Requirements
• Auxiliary Fuel
• Electrical usage
• Process water
• Nitrogen/Oxygen
• Caustic
3. Regulatory Requirements
• Air permits
• Water permits
• Construction permits
• Operating permits
• Public involvement
3.61
-------
Design Development
4. Site-Specific Considerations
• Water discharge
• Meteorological conditions
• Seismic conditions
• Distance to nearest homes, businesses, schools
3.62
-------
Chapter 4
IMPLEMENTATION AND OPERATION
4.7 Wet Air Oxidation
4.1.1 Implementation
The principal supplier of Wet Air Oxidation (WAO) has been U.S.
Filter-Zimpro (formerly Zimpro-Passavant Knc.). The company has designed
and built most of the operating units, including construction of the major
process vessels. It has provided preliminary test work on the actual materi-
als to be oxidized, as well as start-up help plants after construction.
Some preliminary test work will be needed on any new material to set the
operating conditions needed to meet the required product specifications.
Temperature (with corresponding pressure) and residence time in the reactor
are the variables that need to be defined in preliminary work. In general, the
operating temperature is set for the most oxidation resistant component.
As pointed out previously, oxidation is never complete in WAO; some
intermediate products remain. Preliminary work will define the analytical
work needed to monitor the process; specific compounds will be chosen for
monitoring the process to assure adequate reaction.
4.1.2 Start-up Procedures
Startup of a new WAO unit will have many of the same requirements of
other chemical processes:
• operators must be trained, particularly in the use of the control
program chosen;
4.1
-------
Implementation and Operation
• individual plant items need to be tested, e.g., air compressor, feed
(water) pumps, control valves, heat-transfer equipment, etc.; and
• a surrogate may be tested before the actual feed, particularly if
there is concern over the feed toxicity.
4.1.3 Operations Practices
. , . | . . i
Some scale formation can occur on heat transfer equipment and in the
reactor. Commercial practice is to remove it periodically with an acid wash.
Some pollution control equipment is usually required with WAO.
Liquid from the process will always contain incompletely oxidized mate-
rial. In the usual case, the liquid will go to a biological wastewater treatment
plant for complete detoxification of the effluent.
• 'j ;;'" • i i . '.. : / • .•
Offgas is usually suitable for direct exhaust to the atmosphere. In some
cases, there is enough volatile organic in the gas or high enough CO content
that further oxidation is needed. This may be either thermal (a small auxil-
iary burner) or catalytic.
4.1.4 Operations Monitoring
Temperatures, pressures, and flow are monitored. Reactor temperature
and pressure must be kept within a pre-set operating window — too high a
temperature suggests an unsafe condition that needs correction; too low a
temperature will lead to inadequate conversion. Action must be taken, either
to correct the situation or to shut down.
Offgas is monitored online for a number of constituents: oxygen, nitro-
gen, carbon dioxide, carbon monoxide, and total hydrocarbon. In addition, a
constituent that is a characteristic partial oxidation product of the particular
feed may also be monitored to ensure suitably complete oxidation.
The effluent is analyzed by laboratory procedures for typical wastewater
parameters (COD, BOD, solids, ash, pH, TKN, NH3, etc.).
The process area may be monitored for specific functional groups, de-
pending on feed characteristics, particularly toxicity. Various analytical
techniques have been applied for this purpose:
4.2
-------
Chapter 4
• Infrared
• Electron capture
• Conductivity
• Flame lonization
• Flame Photometric
• GC
Personal monitoring and protective equipment must meet OSHA standards.
4.1.5 Quality Assurance/Quality Control
Quality assurance starts with the individual plant components and plant
construction. Most components, such as compressors, pumps, valves, pipe
and fittings, are standard and reliance is placed on the manufacturer. For
special-purpose items, e.g., the reactor, suitable documentation and reference
material, weld inspection, etc., must be provided.
Quality assurance in the complete plant is the responsibility of the con-
struction contractor, with, presumably, oversight from the ov/ner's engineer.
Depending on the toxicity of the feedstock and other considerations, a de-
tailed Quality Assurance plan may have to be provided to state or federal
regulators. Responsibility for contact with regulators must be firmly fixed;
compliance with environmental and safety requirements, keeping permits
up-to-date, and maintaining contact with regulatory agencies, are essential
elements of a Quality Assurance program.
A Quality Assurance plan for the plant operation after it has been turned
over to the owner is mandatory, particularly so for toxic feeds. Records will
have to be kept of effluents leaving the plant, and assurance will need to be
given that effluents will be within agreed-upon limits.
4.2 Texaco Gasification Process
Texaco normally provides design and licensing services for licensee own-
ers, but is also open to the possibility of taking an equity position.
4.3
-------
Implementation and Operation
4.2.1 Implementation
In a turnkey procurement, Texaco could bid the project on a turnkey basis
and then subcontract the various components of the procurement.
4.2.2 Start-up Procedures
Startup would be similar to the procedures followed in the chemical and
oil refining industries where a start-up team from the major contractors is
responsible for the initial tests and for working with the site operator to de-
velop operations and maintenance manuals for the facility.
4.2.3 Operations Practices
Operations would generally be carried out by the contractor responsible
for the site remediation. This would generally include maintenance and
calibration of the instalments, acquisition of measurements and samples for
establishing the level of performance, and for reporting on unit throughput
and performance.
4.2.4 Operations Monitoring
The remediation contractor will monitor operations to ensure that require-
ments are met. In addition, the agencies responsible for the environmental
effects of the cleanup would use the operations data and samples produced to
determine that their requirements are met.
i i
4.2.5 Quality Assurance/Quality Control
ii'",.1 '. '•;• jv. ' ':,jl!'',iri:, " .'''• I, '•'....,
The instruments usecl for monitoring water stream composition will re-
quire periodic validation by an independent laboratory.
4.3 Flameless Thermal Oxidation
4.3.1 Implementation
The method of implementation of Flameless Thermal Oxidation
(FTO) for an SVE or GWS project depends on the needs of the
4.4
-------
Chapter 4
organization responsible for remediating the site. A private company would
probably bid the project using the turnkey procurement process which in-
cludes all of the tasks necessary for successful remediation of the site. In a
turnkey procurement, the PRPs responsible for the remediation would send a
procurement specification to several architectural/engineering (A/E) firms.
The procurement specification would define a scope of services to remediate
the site with payment for the services to be a lump sum. The A/E firm se-
lected would be responsible for the entire project. One of the tasks would be
to develop a basis of design for the S VE or GWS offgas treatment as dis-
cussed in Section 3.3.2. This design basis would be incorporated into a pro-
curement specification for FTO. The A/E firm would then work with
Thermatrix on the detailed design, installation, startup, testing, and operation
of the FTO.
A governmental organization, such as DOE or the Department of Defense
(DoD), might choose to bid the project on a cost-plus fixed-fee basis. The
DOE and DoD typically have large contractors operating their facilities or
bases who would be asked to implement a remediation. The government
contractor would then be responsible for developing the procurement specifi-
cation and interfacing with Thermatrix and other equipment suppliers on the
detailed design, installation, startup, testing,, and operation of the system.
4.3.2 Start-up Procedures
After installation of the SVE or GWS equipment and the FTO equipment,
the total system is ready for the start-up phase of the project. Startup typi-
cally includes the following tasks:
• operator and supervisor training;
• mechanical and electrical testing of the equipment;
• operation of the SVE or GWS with clean air or water while feed-
ing the offgas into the FTO to ascertain if the FTO can achieve
the design temperature at the design flowrate; .
• preoperational testing on contaminated SVE or GWS offgas;
• performance testing (optional); and
• regulatory pretest and test prognun.
The preoperational testing optimizes system performance and establishes
preliminary operating conditions that are used for the performance and
4.5
-------
Implementation and Operation
I , ]
regulatory pre-testing and regulatory testing. The performance test can be
used as a basis for acceptance of the final system. .The regulatory testing can
also be used as the basis for acceptance of the system. The regulatory
pre-test is a practice test to make sure that the equipment can achieve the
required test conditions and performance, and that the operators and the
sampling and analytical contractors all understand what their responsibilities
will be during the formal regulatory tests.
I , , ' |"
!,„,. '-,..: , • ,", • i ,
4.3.3 Operations Practices
• i • - i , , '" • :• . |.:..
A good design and a comprehensive operator training program are the
best ways to assure satisfactory operation of the S VE or GWS and FTO.
Most process upsets are handled by an automatic waste feed cutoff
(AWFCO) system which is typically tied into a set of operational permitting
conditions and initiated by a computer control system. Process upsets, such
as low oxidizer temperature, instantaneously activate the AWFCO system
and initiate corrective actions, such as higher levels of auxiliary fuel. The
S VE or GWS computer control system also typically incorporates safety
features into the design that also initiate AWFCOs or corrective actions to
make sure the equipment and operators are protected and that the permit
conditions are met.
• • i •
Maintenance requirements for routine and non-routine maintenance are
typically specified in one or more plans, such as a Health and Safety Plan,
which are generally required by states and the US EPA for the remediation
of contaminated sites. Except for routine maintenance, FTO is designed to
operate with minimal operator attention.
4.3.4 Operations Monitoring
. , i . . . ., . , • •• i""
During operation of S VE or GWS with FTO, various process parameters
must be monitored to ensure that the system is safely operated with minimal
upsets and in compliance with the regulatory standards. Examples of regula-
tory and process parameters that might be monitored are:
• S VE.or GWS offgas flowrate;
• S VE or GWS offgas temperature;
1' , i , f ' '" I i'
• negative pressure of the SiVE system;
4.6
"' ''f'l f' T" ". i-1' "i : "t1 '"1'^L.._......'!.'__.;'.'"'-_-..L ' '" 'i'"'"' '"
-------
Chapter 4
• the temperature of the FTO;
• wet scrubber process parameters, such as pH;
• the temperature in the stack;
• blower and pump on/off status; and
• fugitive emissions (usually by an equipment walk-through
inspection).
4.3.5 Quality Assurance/Quality Control
Quality Assurance/Quality Control (QA/QC) for S VE or GWS with FTO
is generally handled by preparing a Quality Assurance Project Plan (QAPP)
for the site. The'QAPP presents the organization, objectives, functional
activities, and specific QA and QC activities for the compliance testing and
continuous emissions monitoring of the FTO. The QAPP also describes the
specific protocols to be followed for sampling, sample handling and storage,
chain-of-custody, and laboratory analyses during the test program. The con-
tents of a typical QAPP include, but are not limited to, the following:
• project organization and responsibility;
• QA objectives (accuracy, precision, completeness);
• sampling procedures;
• sample custody;
• calibration procedures;
• analytical procedures;
• data reduction, validation, and reporting;
• internal quality control checks;
• performance and system audits;
• preventive maintenance;
• procedures for assessing data accuracy and precision;
• corrective action;
• QA reports; and
• analytical data packages.
4.7
-------
Implementation and Operation
4.4 Plasma Furnaces
4.4.1 Implementation
Preliminary assessments and site characterization are needed to develop a
successful implementation plan. The preliminary assessment is often a
quick analysis based on readily-available information, such as site manage-
ment practices, information from generators, photographs, literature, and
personal interviews. One goal of the preliminary assessment is to determine
the urgency of the situation and to identify commercial, state, or federal
parties ready, willing, and able to authorize the proper response.
Most frequently, companies that are responsible for site remediation
ask for turnkey solutions for the project. In a turnkey solution, a single
vendor will assume responsibility for all tasks necessary for a successful
remediation and will prepare the overall project implementation plan.
The overall plan encompasses detailed design, mobilization, startup,
testing, and operating procedures for that particular system.
4.4.2 Start-up Procedures
Several factors are essential for starting a remedial operation using a
! i
plasma furnace:
• development of Standard Operating Procedures (SOPs) and Lim-
iting Conditions of Operations (LCOs);
••:•" i • '. ' .• i| :;, • ' i , • • .. , •• '• h* .
• defining the Quality Assurance/Quality Control (QA/QC) measures;
• providing for safety concerns and emergency medical support;
! . I
• providing for laboratory testing and monitoring activities;
• defining, reporting, and process control protocols; and
• providing procedures for handling process upsets to ensure envi-
ronmental compliance.
1 • ,' ". , • ' i: \ ... ' \ ' •'•'". ',:•'. ,; .."
The contractor must demonstrate a thorough understanding of the overall
process and how all the pieces fit together. A proactive approach to identify-
ing potential problems is also desirable.
4.8
-------
Chapter 4
4.4.3 Operations Practices
A site remediation operator conducts daily activities that must be accom-
plished in strict accord with detailed SOPs and within exact operating pa-
rameters. Regulation requirements for the receipt, testing, treatment, trans-
portation, and disposal of toxic and hazardous waste dictates strong controls
for operational procedures and the use of control mechanisms to alarm and
shut down systems before unsafe conditions occur. Operations personnel
must review, update, and correct all SOPs and LCOs so they reflect current
operating procedures and conditions at the remediation site.
All SOPs and LCOs should be thoroughly tested during pre-operational
surveys to establish procedure/conditions validity, identify any potential
problems, and verify personnel ability to execute. Testing should be per-
formed with inert/simulated contaminated soil. The SOPs and LCOs should
be used in the training program for site personnel. Those procedures and
conditions specific to individual operations areas or tasks (e.g., lab analysis
procedures, materials handling, control room operator responses to upsets,
etc.) should also be used to certify that personnel know how to properly
perform and respond according to procedure. The QA personnel should
continuously ensure all operations adhere strictly to the SOPs and LCOs.
The SOPs and LCOs need to be incorporated into checkoff lists for the shift
Safety and QA/QC personnel to verify compliance.
4.4.4 Operations Monitoring
The remediation operator must provide accurate, continuous monitoring
of the emissions and waste effluents for toxic or hazardous substances to
ensure safe operation of the facility.
The operator needs to coordinate all matters related to environmental
permits. Activities should be focused on keeping all permits up-to-date,
monitoring/auditing to ensure compliance with all requirements, interacting
with regulatory agencies via reports, and fulfilling all state and local regula-
tory requirements. The environmental monitoring program could include:
• establishment of background levels prior to operations;
• continuous review of permits;
4.9
-------
Implementation and Operation
permit modification and update;
I ,
the establishment of an Audit Program;
training of the workforce;
hazardous waste management;
v • • '• ' ' •"[' ,:: ; :l '•• ' ••
monitoring for compliance;
preparation of Environmental Compliance Plans;
monitoring of trial performance tests;
post sampling/monitoring; and
closure certification.
4.4.5 Quality Assurance/Quality Control
. . , , , •' ; , | • •
QA/QC encompasses and integrates the various tasks of a project
(geotechnical, sampling, analytical, processing, and assessment) by requiring
data to be representative, precise, and accurate within defined limits. Docu-
mentation, prepared and maintained according to the QA/QC plan, provides
the defensible evidence of unbroken custody, traceability, and adherence to
;. , "I, "" ' ' ' :' , ' j i"1' 'i''1' • ''''' • '" ' '" ' ' |! "r ' * • '' " "' • ' *''1' l||1:i1'' '''"'""""'' l"''""l|li
prescribed protocols and planned operations.
1 ' • ]. , ,, | •_ ;;. | ;.: ' . ' ,| :, :', ' ',;;•, '. ];'! ? 'V
In addition, a Quality Assurance Project Plan (QAPP) specific to each
project and each site should be prepared. Each QAPP is based on a QA/
QC program. The QA/QC program and the QAPP define control activi-
ties, testing, and administration of trie facility. The QAPP needs to in-
clude provisions for construction quality management and chemical
i • i
quality management.
4.4.5.1 Construction Quality Control
A comprehensive Construction Quality Control Plan (CQCP) should
be developed for all projects that involve excavation and removal of
contaminated soil. This CQCP needs to be tailored to conform to the
requirements of each site's scope of work. The plan encompasses the
following main elements:
• ', :: • • : :; ::[ ; : • , •• • . ]
• construction quality assurance objectives;
• inspection activities;
4.10
-------
Chapter 4
• chemical quality control;
• corrective actions;
• documentation; and
• reporting.
Activities under the construction QA/QC plan include:
• perform preparatory, initial, periodic, and completion inspections
for each segment of work, and maintain inspection records hi a
site file;
• maintain the project record doctaments;
• develop procedures, forms, and documents required to control
procurement of equipment and materials required by the project;
• develop procedures, forms, and documents for the required sub-
mittal from all subcontractors;
• coordinate all activities with the Health and Safety Officer to
ensure that the health and safety plan is being followed during all
. phases of work. Provide QA/QC oversight for the air monitoring
program outlined in the Health and Safety Plan;
• ensure that construction of storrnwater control structures are
sufficient;
• implement VOC and dust controls, as necessary, during construc-
tion and remediation phases of the project; and
• during excavation and backfilling, activities will be scheduled
and implemented to prevent cross-contamination of clean areas
and to minimize the open cut areas.
QA/QC responsibilities include verification of areas for excavation,
checking calculations of area and volumes for excavation, testing for pos-
sible VOC emission sources, validation or invalidation of verification sam-
pling and testing, confirmation of suitability of backfill materials through
sampling, development of control procedures for transport of contaminated
materials, flood control procedures during excavation, and overseeing the
placement, compaction, and contouring of backfill where applicable.
4.11
-------
Implementation and Operation
4.4.5.2 Chemical Quality Control
On-site fixation/stabilization projects typically involve testing of soils
before and after treatment, groundwater)surface water testing, and some
detailed record keeping.
Chemical quality assurance and control must be provided By the analyti-
cal testing laboratory tasked with the project. Any laboratory used should
meet US EPA Contract Laboratory Program (CLP) requirements, as well as
requirements or certifications of appropriate state regulatory agencies (e.g.,
the site/project state's environmental protection or health department). A
specific Quality Assurance Plan for chemical parameters must be established
that identifies:
• QA/QC objectives of the analytical laboratory;
• precision, accuracy, completeness, representativeness, and com-
parability of measurement data;
'' i
• sample holding times and turn-around times;
• a list of tests and the frequencies at which they will be performed;
•i .. t
• sampling procedures for each test;
• maintenance of a field log book;
| : '•
• sample custody procedures and documentation;
• calibration procedures and schedules;
• analytical procedures;
• data reduction, validation, and reporting;
• internal quality control cheeks;
• performance and system audits;
• preventive maintenance procedures;
:]: ; * , •' "1 ; ,.J, i" . ; „. • ' ,. :• I '!?:
• corrective action for work which fails to meet QA/QC require-
i • , ,'•',",' •• ' • ' .", 11 .'.'.' • : - '. • , ' = I::
ments; and
.:•: ': .. • 'I ;• , i.- , • h
• quality assurance reports to management.
All field sampling, sample handling, and analysis must be performed in
accordance with the QAPP and CQCP within the Construction Quality Man-
agement Program (CQMP), and all chemical analysis data will be examined
according to US EPA Analytical Laboratory QA procedures to assure accuracy.
4.12
-------
Chapter 5
CASE HISTORIES
5.1 Wet Air Oxidation
Detailed test work on a number of pesticides has been reported (Moment,
Copa, and Randall 1995). The pesticides studied were:
Fungicide: Captan
Herbicides: Atrazine
Bromacil
Glyphosate
Terbacil
Insecticides: Methoxychlor
Carbaryl
Their structures are shown on Figure 5.1. Test work has also been done on
other pesticides but with less-detailed reporting.
Complete test results reported for one of the pesticides, Glyphosate (com-
mercial name — Roundup), are shown in Table 5.1. Similar detailed results
have been reported for the other pesticides shown on Figure 5.1 (Moment,
Copa, and Randall 1995). The data of Table 5.1 were obtained in a shaking
autoclave, batch reactor.
The initial Glyphosate concentration was 14,600 mg/L, or 1.46%, a "typi-
cal" concentration for WAO operation. Extensive change of the carbon-
phosphorus and carbon-nitrogen bonds occurred even at the lowest tempera-
ture conditions, 200°C (390°F); practically all of the phosphorus was con-
verted to phosphate, and 99.5% of the Glyphosate was destroyed. However,
large COD remained (52% of the original) representing organic
5.1
-------
Case Histories
0) O-
5
-------
pi
CO
Table 5.1
Characterization of Feed and Oxidation Products from the Oxidation of Glyphosate
Analyses
COD, mg/L
COD Destruction, %
1NPOC,mg/L
pH
Total Solids, mg/L
Total Ash, mg/L
Total Kjeldahl Nitrogen, mg/L
Ammonia-N, mg/L
Nitrate-N, mg/L
Ortho-P, mg/L
Glyphosate, mg/L
Glyphosate Destruction, %
2DIC, mg/L
Total Carbon in Offgas, mg/L
Total Nitrogen in Offgas, mg/L
Autoclave Feed
27,500
7,500
4.89
24,000
6,000
2,320
1,157
<0.5
2,»yo
M
14,600
<10
-
-
200'C (390°F) for 60 min
14,400
47.6
5,800
5.85
15,500
5,200
2,440
1,871
1
2,463
2,277
73
800
1,900
<200
240°C(460"F)for60min
9,300
662
3,900
5.49
10,800
4,550
2,190
1,739
9
2,264
2.120
65
99.5
300
4,100
870
280"C (540T) for 60 min
6,900
749
2,300
449
10,000
5,700
1 320
1,463
87
2 353
2226
33
99.8
5,700
850
onc Ca
"DIG is Dissolved Inorganic Carbon. This is carbon as C02 and carbonate. A sample is acidified and the CO, is measured.
Source: Moment, Copa, and Randall 1995
« ** °^c <*«- - — *,' —a, is
9
Q
-------
Case Histories
decomposition products remaining in solution. Higher conversions were
obtained at 280°C (540°F) — over 75% of the organic carbon was con-
verted to CO2; organic nitrogen was converted mainly to ammonia (over
60%) and nitrogen (36%).
Methoxychlor (a material with 31 % chlorine by weight) was tested on a
batch basis (shaking autoclave) and in a continuous flow unit. The feed
concentration in the batch test was 4,400 mg/L. The feed to the continuous
flow reactor was a process wasteWater of much lower concentration, 8.84
mg/L. Destruction of 99.9% or higher was observed at a temperature of
275°C (527°F), with a 1-hour residence time in the batch reactor. The COD
was reduced to 17% under these conditions. Essentially all of the chlorine in
the original was converted to chloride ion in solution.
The continuous flow reactor produced results similar to that obtained
by batch processing — over 99.9% destruction. The comparison is
prejudiced somewhat by the extremely low concentration of methoxy-
chlor in the feed. Oxygen mass transfer required from the gas phase was
minimal as a consequence.
5.2 Texaco Gasification Process
1 ! ! ''
A pilot-scale demonstration of the Texaco Gasification Process (TOP)
was carried out at their Montebello, California facility as part of the US EPA
SITE program. This facility had a nominal throughput of 23 tonne/day (25
ton/day) of coal (compared to 91 tonne/day [100 ton/day] for the proposed
transportable facility). The material in this section was abstracted from the
resulting SITE report (US EPA 1995).
' ; '.:., , . ! , | ,•,.' ' , ' " I ":
The TOP produced a syngas suitable for feed for chemical synthesis fa-
cilities or for a clean fuel for the production of electrical power when com-
busted in a gas turbine. The average composition of the dry synthesis gas
product consisted of 37% H2, 39% CO, and '21%' CO2. No organic contami-
nants, other than methane (55 ppm), exceeded 0.1 ppm. The average heating
value of the gas, a readily combustible fuel, was 239 Btu per dry standard ft3.
The destruction and removal efficiency (ORE) for chlorobenzene, the desig-
nated principal organic hazardous constituent (POHC) exceeded the 99.99%
remediation goal.
5.4
-------
Chapter 5
The average TCLP measurement for the coarse slag was lower than
the regulatory levels for lead (5 mg/L) and barium (100 rng/L). The
average California Waste Extraction Test-Soluble Threshold Limit Con-
centration (WET-STLC) measurement for the coarse slag was lower than
regulatory value for barium (100 mg/L) and higher than the regulatory
value for lead (5 mg/L).
Volatile heavy metals, such as lead, tend to partition and concentrate in
the secondary TOP solid products — fine slag and clarifier solids. The aver-
age TCLP and WET-STLC measurements for these secondary TOP solid
products were higher than the regulatory limits for lead, but lower than the
regulatory limits for barium.
Texaco estimates an overall treatment cost of $339/tonne ($308/ton) of
soil for a proposed transportable unit designed to process 90 tonne/day (100
ton/day) of soil with characteristics similar to that from the Purity Oil Sales
Superfund Site, based on a value of $3.30/1,000 kWhr ($1.00/MM Btu) for
the syngas product. Texaco estimates an overall treatment cost of $248/
tonne ($225/ton) of soil for a proposed stationary unit designed to process at
a central site, 180 tonne/day (200 ton/day) of soil with characteristics similar
to that from the Purity Oil Sales Superfund Site, based on a value of $6.60/
1,000 kWhr ($2.00/MM Btu) for the syngas product.
In continuous operations, proposed commercial units are expected to
operate at on-stream availability of 70% to 80% to allow for scheduled
maintenance and intermittent, unscheduled process interruptions.
The TOP technology evaluation applied the US EPA's standard nine crite-
ria from the Superfund feasibility study process and the results are summa-
rized in the following sections.
5.2.1 Equipment and Process Description
Texaco maintains three pilot-scale gasification units, ancillary units, and
miscellaneous equipment at the Montebello Research Laboratory (MRL),
where the SITE demonstration was conducted. Each gasification unit can
process a nominal throughput of 23 tonne/day (25 ton/day) of coal. The
SITE Demonstration used one of the three pilot-scale gasification units, the
High Pressure Solids Gasification Unit II (HPSGUII), and support units as
shown on the Figure 5.2 block-flow diagram. The diagram identifies the key
MRL process units that are part of the overall facility.
5.5
-------
Figure 5.2
Schematic-Flow Diagram of the Texaco Gasification Process Used in the SITE Demonstration
Oxygen
Organic Spike
Water
CoaVSoil
Inorganic Spike
> Solids Grinding and
^ Slurry Preparation
Slurry
1 1 <
r
'
Scrubbed Raw Syngas
Gasifier
Tank(s)
Gas Cooling and
Acid Gas Removal
*-Clarifier Solids
I
8
-------
Chapter 5
5.2.1.1 Solids Grinding and Slurry Preparation Unit
The slurry feed used in the demonstration was a blend of the Purity Oil
soil slurry and a clean soil slurry. Coal and clean soil were precrushed in a
hammer mill. For each slurry, the precrushed product (coal and clean soil,
site-screened Purity Oil waste soil and coal) was combined with water, an
ash fluxing agent, and a slurry viscosity reducing agent in a rod mill, where
the mixture was ground and slurried. The mill product was screened to re-
move oversized material and transferred to the HPSGU H slurry storage
tanks where the inorganic spikes (lead and barium) were added.
5.2.1.2 High Pressure Solids Gasification Unit II
The slurry was gasified in MRL's HPSGU II. This unit includes equip-
ment for slurry feeding, gasification, gas scrubbing, slag removal, clarifier
solids removal, and process water handling. Figure 5.2 is a schematic-flow
diagram of the process equipment and flows within the HPSGU II used in
this demonstration. Figure 5.2 also defines the interaction of the HPSGU II
process streams with other MRL TOP process streams and units.
During the demonstration, the slurry was spiked with chlorobenzene as it
was pumped into the gasifier. The gasifier is a two-compartment vessel,
consisting of an upper, refractory-lined reaction chamber and a lower quench
chamber. Oxygen and slurry feeds were charged through an injector nozzle
into the reaction chamber .where they reacted under highly reducing condi-
tions to produce raw syngas and molten slag. The oxygen-to-slurry ratio was
controlled so as to maintain an operating temperature sufficient to convert
the soil and coal ash into a molten slag. The average pressure was 3.5 MPa
(SOOpsig).
From the reaction chamber, the raw syngas and molten slag flowed into
the quench chamber, where water cooled and partially scrubbed the raw
syngas. The raw syngas leaving the gasifier quench chamber was then fur-
ther scrubbed of hydrogen chloride and particulates with additional water,
cooled to near-ambient temperature, and routed to MRL's Acid Gas Removal
Unit. More than 99% of the chlorides in the syngas were transferred to the
circulating water in these steps.
The water quench transformed the molten ash into glass-like slag par-
ticles, which then passed down through the quench chamber/lockhopper
system. The lockhopper system discharged the slag solids to a shaker
5.7
-------
Case Histories
screen, which separated the slag into a coarse fraction (coarse slag) and
a fine fraction (fine slag). The fine slag was recovered using a vacuum
belt filter. The filtrate from the vacuum belt filter was recycled to the
lockhopper system.
Water from the quenching and scrubbing steps was combined and cooled.
Solids in the combined stream were removed using a clarifier, which pro-
duced an underflow stream of concentrated' solids and water, called clarifier
bottoms, and an overflow stream of clarified water. Periodically, the clarifier
bottoms were drawn off and filtered to produce clarifier solids cake and
filtrate. The clarifier effluent flowed to the flash tank where it combined
with the condensate from the cooling of the raw syngas. In the flash tank,
dissolved gases were removed from the water at low pressure (flash gas).
Except for a small wastewater blowdown stream, the flash tank water was
recycled to the gasifier quench chamber and raw gas scrubber.
The wastewater blowdown and clarifier bottoms filtrate were routed to
temporary storage for testing prior to treatment and disposal.
1 i . ,
5.2.1.3 Acid Gas Removal/Sulfur Removal
During the demonstration, MRL used a regenerate solvent process to
separate hydrogen sulfide and carbonyl sulfide from the raw syngas.
The raw syngas was contacted with the solvent, which removed the hy-
drogen sulfide, carbonyl sulfide, and some carbon dioxide (acid gases)
producing a combustible fuel gas of low sulfur content. The fuel gas
was then flared. The acid gases that were stripped from the solvent and
combined with the gasification system flash gas were fed to the sulfur
removal unit where the sulfides were absorbed by a caustic solution.
The dissolved sulfides were oxidized with air and steam, producing a
solution of sodium thiosulfate that was neutralized and routed to waste-
water treatment. As with the fuel gas stream, the sulfur removal unit
absorber and oxidizer offgas streams were flared.
5.2.2 Performance Data
To assess the TOP operation and its ability to process a RCRA-designated
hazardous waste feed" that does not comply with TCLP and WET-STLC
regulatory limits, non RCRA hazardous soil from the Purity Oil Sales
Superfund Site in Fresno, California, was spiked with lead nitrate and
5.8
-------
Chapter 5
barium nitrate during slurry preparation to create a surrogate RCRA-hazard-
ous waste feed. For the extended SITE demonstration, additional slurry was
required and prepared using a mixture of clean soil and oil spiked with
barium nitrate since further supplies of Purity Oil soil could not be obtained.
To ensure a sufficient concentration of the designated Principle Organic
Hazardous Constituent (POHC) for Destruction and Removail Efficiency
(DRE) determination, chlorobenzene was added to the Purity Oil/clean soil
mixed-test slurry at the slurry feed line to the gasifier. Table 5.2 shows the
overall composition of the mixed, spiked-test slurry processed during the
TOP SITE Demonstration.
Three runs were conducted over a 2-day period, treating approximately 36
tonne (40 ton) of slurry. The total amount of slurry treated during the entire
demonstration (scoping runs, initial shakedown, system startup, a pretest
run, the three replicate runs, and post-demonstration processing of the slurry
Table 5.2
Composition of Demonstration Slurry Feed
Pittsburgh #8 Coal
Havoline SAE 30 Oil
L.A. County Soil
Fresno County Soil
Purity Oil Soil
Water
Gypsum
Surfactant
Barium Nitrate
Lead Nitrate
Total
Purity of Soil
10,511
-
-
-
5,264
10,529
-
21
330
145
26,800
Slurry/lb
Clean Soil
56,280
2,050
11,000
11,080
-
54,000
2,500
130
1,000
-
138,040
Total Mixed*
66,791
2,050
11,000
11,080
5,264
64,529
2,500
151
1,330
145
164,840
*The total slurry feed does not include the chlorobenzene organic spike (L-5) that was added (at approximately 3,150
mg/kg based on slurry flow) to the total mixed slurry flow to the gasifier at 6.20,6.30 and 6.75 Ib/hr for Runs 1,2 and 3,
respectively.
5.9
-------
Case Histories
inventory) was approximately 90 tonne (100 ton). Critical process param-
eters included slurry feed rate; raw syngas, flash gas, and fuel gas flow rates;
make-up and effluent water flow rates (except neutralized wastewater);
weight of coarse slag, fine slag, and ciarifier solids; and the organic spike
flow rate. Critical chemical/analytical parameters included volatile organic
compounds (VOCs), polychlorinated dibenzodioxins (PCDDs), polychlori-
nated dibenzofurans (PCDFs), and metals in all feed and discharge streams
(except neutralized wastewater); TCLP and WET-StLC analyses on waste
feed, slurry feed, coarse slag, fine slag, and ciarifier solids; and composition
of process gas streams.
5.2.2.1 DRE
DRE is the measure of organic destruction. This parameter is deierminect
by analyzing the concentration of the POHC in the feed slurry and the efflu-
ent gas stream(s). For a given POHC, DRE is defined:
DRE =
_w
W
OUT • 100%
IN
where: Wm = Mass feed rate of the POHC of interest in the waste
(5.1)
W.
OUT
stream feed; and
= Mass emission rate of the same POHC present in the
effluent gas streams prior to release to the flare.
For these TOP SITE tests, DREs were calculated in two ways. For the
gasification process, the effluent gas streams included the raw syngas and
flash gas. For the overall TOP operation, the effluent gas streams included
the fuel gas, the absorber offgas, and oxidizer offgas. The POHC identified
for the demonstration was chlorobenzene. This compound was selected as a
representative stable compound for the purpose of evaluating the TGP's
ability to destroy organic compounds. As shown in Table 5.3, all calculated
DREs were greater than 99.99% for chlorobenzene.
5.2.2.2 Slag and Solid Residuals teachability
Test Slimy Leaching Characteristics. The test slurry was spiked with
lead nitrate and barium nitrate to create a surrogate RCRA-hazardous waste
feed and to evaluate the TGP's ability to produce a nonhazardous solid re-
sidual in which heavy metals are bound in an inert slag resulting in TCLP
5.10
- i
-------
Chapter 5
Table 5.3
Destruction and Removal Efficiencies (DREs) for Principal
Organic Hazardous Constituent (POHC) — Chlorobenzene
DRE for Gasification Process
Run
1
2
3
Average
W*
(Ib/hr)
6.20
6.30
6.75
6.42
Raw Syngas
(Ib/hr)
0.00016
0.00019
0.00023
0.00019
Flash Gas
(Ib/hr)
0.000013
0.000010
0.000014
0.000012
Total W"
(Ib/hr)
0.000173
0.000200
0.000244.
0.000210
DRE'**
(%)
99.9972
99.9966
99.9964
99.9967
DRE for Overall Texaco MRL Operation
Run
1
2
3
Average
*W
"W
*"DRE
W*
(Ib/hr)
6.20
6.30
6.75
6.42
Fuel Gas
(Ib/hr)
0.0000033
0.0000620
0.0000130
0.0000250
Abs. Offgas
(Ib/hr)
0.00010
0.00038
0.00023
0.00024
Oxid. Offgas
(Ib/hr)
< 0.000019
0.000018
0.000011
< 0.000016
Total W*
(Ib/hr)
< 0.000122
0.000460
0.000254
< 0.000281
. DRE"*
(%)
> 99.9980
99.9926
99.9962
> 99.9956
= Mass feed rate of Chlorobenzene (POHC) In the waste stream feed.
= Mass emission rate of Chlorobenzene (POHC) in gas effluent streams.
= The measure of organic destruction during the demonstration test. For a given POHC, DRE is defined
= [(WIN-WOUT)/W1N]«100% .where: W1(l = mass feed rate of the POHC of interest in the waste
stream feed and WOUT = mass emission rate of the same POHC present in the effluent gas streams prior
'OUT
to release to the flare.
and WET-STLC measurements that are lower than their respective regula-
tory limits. Table 5.4 shows that the test slurry feed measurements were
higher than the TCLP and WET-STLC regulatory limits for lead, but lower
than the regulatory limits for barium.
Normalized TCLP and WET-STLC Values for Lead in Test Slurry. The
test soil composed of approximately 20% by weight Purity Oil soil (lead
TCLP of Purity Oil soil: 223 mg/L) and 80% by weight clean soil (lead
TCLP of clean soil: <0.03 mg/L) could be expected to have a normalized or
corrected TCLP value for lead of approximately 40 mg/L. The test slurry
composed of approximately 20% by weight total soil (normalized TCLP
5.11
-------
Case Histories
..'•.''"•• •?
TCLP
Table i
and WET-STLC Result
TCLP Lead (mg/L)
u
s — Lead and Barium
WET-STLC Lead (mg/L)
Range Average Range Average
Regulatory Value
Purity Oil Soil
Clean Soil (S-lJ*
Slurry (SL-1)*"
Coarse Slag (S-3)
Fine Slag (S-4)
Clarifier Solids (S-5)
5.0
223
<0.03
8.1-S.4 83
3.3-5.8 4.5
11-18.3 14.9
691-1.330 953
TCLP Barium (mg/L)
5.0
<0.5
1 54-61 '"' ' '' ' 36
6.7-11.1 9.8
22.8-52.9 43.0
903-1,490 1,167
WET-STLC Barium (mg/L)
Range Average . Range Average
Regulatory Value
Purity Oil Soil
Clean Soil (S-lJ*
Slurry (SL-1)"'
Coarse Slag (S-3)
Fine Slag (S-4)
Clarifier Solids (S-5)
" 1' ""P:,1!:, ,.'i . I " '"' ,i
100
329
0.3
0.1-0.2 0.1
0.5-0.8 0.6
1.2-ZO 1.75
i.2-3.8 2.7
100
<5.0
< 5.0-5.5 <5.5
<5.0 <5.0
5.6-10.4 9.3
' 14-51.4 38.4
•Lead TCLP of purity oil soil (waste feed to produce purity oil slurry) with 15,000 mg/kg (as elemental lead) lead nitrate
spike and barium TCLP of purity oil solid with 30,000 mg/kg (as elemental barium) barium nitrate spike-measured in
pretest spike study.
"Clean soil is soil matrix used to produce clean soil slurry.
***The SITE Demonstration slurry (SL-1) is a mixture of lead nitrate and barium nitrate-spiked slurries produced using
purity oil soil and clean soil. SL-1 is composed of 26,800 Ib of purity oil slurry mixed with 138,040 Ib of clean soil slurry
(See Table 5.2).
value for lead: 40 mg/L) diluted by the remaining slurry solution of 80% by
weight coal, gypsum, and water (no lead TCLP value) could be expected to
have a calculated TCLP value for lead of around 8 mg/L, which closely ap-
,' ' • , ' ' , '!; " , , ,'":',, i:'"".p" i I:,,1 ''" , ': ' , ' ,,,l' , ,' II: , ,„,' ' ' I " ' ' • , ""'',, I: ' s ,
proximates the average TCLP measurement of 8.3 mg/L lead for the test
slurry. Similarly, an expected normalized WET-STLC value of 280 mg/L
lead, based on spiked soil blending, would be consistent with the average
5.12
a ,,' t: ;:,».,., • „ i i mis • iiiki:, "a t, • n..., J „ „! j, i :\j.'.;;'.., j „
-------
Chapter 5
WET-STLC measurement of 56 mg/L lead for the test slurry, due to the
dilution of the coal, gypsum, and water.
Fate of Barium in Test Slurry. The fate of the barium contaminant indi-
cates that significant changes occurred in the barium chemistry during slurry
formulation. A pretest TCLP value of 329 mg/L was measured in a leachate
produced from the spiked Purity Oil soil. This contrasts with the much
lower 0.1 mg/L measured in the TCLP leachate from the test slurry matrix,
which included coal, gypsum, and water. The introduction of
sulfur-containing gypsum and coal could have provided an environment in
the slurry that changed the original soluble barium nitrate spike material to
insoluble barium sulfate. The relative solubilities of barium nitrate and
barium sulfate differ by ten-thousand fold. Since barium sulfate is relatively
insoluble, it remains with the solids and does not transfer to the leachate
during the TCLP test. The one thousand limes reduction in the test slurry
TCLP result for barium from the pretest level in the Purity Oil soil would be
consistent with a partial speciation change to barium sulfate.
5.2.3 SITE Demonstration Results
The SITE demonstration showed that the mobility of the lead in the main
residual solid product — the coarse slag — was lower than the mobility of
the lead in the contaminated/spiked soil. The mobility of the barium essen-
tially remained unchanged. The average TCLP and WET-STLC measure-
ments for coarse slag, which comprised 62.5% by weight of the total solid
residuals, were lower than the TCLP regulatory levels for lead and barium
and the WET-STLC regulatory value for barium. The average TCLP and
WET-STLC measurements for fine slag, which constituted 35.9% by weight
of the total solid residuals, and clarifier solids, which amounted to 1.6% by
weight, were higher than the TCLP and WET-STLC regulatory limits for
lead but lower than the tests' regulatory limit for barium. The leach test
results indicated mixed success, in meeting the test objectives. Analysis of
the effects of dilution by the non-contributing slurry components — coal,
water, gypsum — on the TCLP and WET-STLC test results showed that the
TOP can potentially produce a coarse slag product as its major solid residual
with TCLP and WET-STLC measurements below regulatory limits. The
TOP effectively treated a soil matrix exhibiting a normalized TCLP value of
40 mg/L lead and produced a coarse slag with an average TCLP value of 4.5
mg/L lead and a fine slag with an average TCLP value of 14.9 mg/L lead.
5.13
-------
pi
'
Table 5.5
Comparison of the Composition of Raw and Treated
H
Run (vol%)
1 34.6
2 265
3 35.4
Average 323
Run (vol%)
1 37.6
2 383
3 34.7
Average 365
CO CO2
33.0 255
313 265
39.6 262
34.6 263
«£» (£*)
39.1 21.0
35.0 205
413 212
385 21.0
Synthesis Gas
Raw Syngas Composition and Heating Value
(ppmv)
87
51
42
60
(ppmv)
7i
49
44
55
N2
65
5.1
5.7
5.8
Fuel Gas Composition
N2
5.8
45
5:6
5.4
A
«>!%)
03
0.0
0.05
0.1
and Heating
A
02
0.05
0.1
0.1
COS
(ppmv)
120
170
130
140
Value
ens
(ppmv)
33
44
50
42
H2S
(ppmv)
1,180
3,050
1,980
2,070
(ppmv)
490
580
68
380
THC
(ppmv)
49
17
14
27
THC
(ppmv)
32
16
15
21
Heating Value
(Btu/dscfy
219
210
228
219
Heating Value
(Btu/dscfy
239
239
239
239
*diy standard ft3
o
Q
en
(D
(D
-------
Chapter 5
The average WET-STLC measurements for all solid residual streams
were higher than the WET-STLC regulatory values for lead. However, the
TOP demonstrated significant improvement in reducing lead mobility as
measured by WET-STLC results. The process treated a soil matrix exhibit-
ing a normalized WET-STLC value of 280 mg/L lead and produced a coarse
slag with an average WET-STLC value of 9.8 mg/L lead and a fine slag with
an average WET-STLC of 43 mg/L lead.
5.2.4 Synthesis Gas Product Composition
The syngas product from the TOP is composed primarily of hydrogen,
carbon monoxide, and carbon dioxide. For a commercial unit, the raw
syngas would need further treatment to remove hydrogen sulfide, typically,
using an acid gas treatment system. This would produce a combustible fuel
gas that could be burned directly in a gas-turbine/electrical-generation facil-
ity or could be synthesized into other chemicals.
The raw gas from the gasifier was sampled and analyzed to evaluate
the TCP's ability to gasify a slurry containing a RCRA-hazardous waste
material and produce a synthesis gas product. This gas stream was then
treated in the MRL Acid Gas Removal System; the resulting fuel gas
product was flared. Table 5.5 shows the composition of the raw syngas
and the fuel gas products.
5.2.5 Products of Incomplete Reaction (PIRs)
The TOP is a gasification process which converts organic materials into
syngas by reacting the feed with a limited amount of oxygen (partial oxida-
tion). In addition to the syngas mixture of hydrogen and carbon monoxide,
other organic compounds appear as products of the incomplete partial oxida-
tion reaction. The term "PIR" describes the organic compounds detected in
the gas product streams as a result of the incomplete reaction process.
All gas streams, including the raw gas, flash gas from the gasification
section, fuel gas, absorber offgas, and oxidizer offgas, contained trace
amounts of volatile and semivolatile PIRs,, Carbon disulfide, benzene, tolu-
ene, naphthalene, naphthalene derivatives, and acenaphthene concentrations
were measured in the gas streams at parts per billion (ppb) levels. The
POHC, chlorobenzene, was also detected. Small amounts of methylene
chloride and phthalates were also detected, but probably were sampling and
5.15
-------
Case Histories
analytical contaminants. Measured concentrations of PCDDs and PCDFs in
the gas streams were comparable to the blanks, indicating that these species,
if present, were at concentrations less than or equal to the method detection
limits (parts per quadrillion). Other compounds, such as xylenes, chlo-
romethane, bromomethane, dibenzofuran, fluorene, and phenanthrene (ex-
pected from trie thermal treatment of coal and cnlorobenzene), were detected
at lower concentrations in the flash gas and offgais.
5.2.6 Particulate Emissions
' •'•!•. .' ,• • . ;| . «/" • r •, ,,:!•.• r: !•;
During the SITE demonstration, particulate emissions were measured
for the raw syngas and fuel gas streams. These averaged 6.1 mg/m3 in
the raw syngas and 1.3 mg/m3 in the fuel gas. By comparison, the par-
ticulate emission standards for boilers and industrial furnaces processing
hazardous waste (40 CFR Part 266 Subpart H) and industrial, commer-
cial, and institutional steam generators processing coal and other fuels
(40 CFR Part 60 Subpart D(b)) are higher than the average measured
values for these gas streams. Since the fuel gas product would not be
vented or flared in a commercial unit, but would be burned directly in a
gas-turbine/electrical-generation facility or synthesized into other
chemicals, it is expected that the vent gas from any of these downstream
facilities will be treated to meet applicable particulate emissions stan-
dards. This must be assessed on a case-by-case basis.
5.2.7 Acid Gas Removal
Measured hydrogen chloride gaseous emission rates ranged from
0.0046 to 0.0117 Ib/hr. The chlorine concentration in the feed slurry,
based on a chlorobenzene spike addition equivalent to 3,150 mg/kg in
the slurry and the chloride concentration in the slurry, ranged from 4.3
to 4.7 Ib/hr. Using these figures, the TGP's hydrogen chloride removal
efficiency exceeded 99%.
Measured sulfur-containing gas emission rates ranged from 2.2 to 2.7 lb/
hr. The sulfur concentration in the slurry, based on the ultimate analysis for
sulfur, ranged from 0.97 to 1.20% by weight. Using these figures, the TCP's
sulfur removal efficiency averaged 90%.
According to Texaco, the MRL systems for acid gas removal are designed
to process a wide variation (flow and composition) of gas streams based on
5.16
-------
Chapter 5
the developmental nature of the research activities to which they are applied.
It is expected that systems designed to meet the specific requirements of
proposed commercial TOP units will provide higher removal efficiencies.
5.2.8 Metals Partitioning
The fate of the spike metals in the slurry (lead and barium) appeared to
depend on their relative volatilities under TOP operating conditions. Lead
— a volatile metal — concentrated in the clarifier solids, which were
scrubbed from the raw syngas. Lead probably evaporated in the ;hot regions
of the gasifier and condensed on the fine particles in the cooler areas of the
process. The more refractory barium did not concentrate in any particular
solid residue. It partitioned throughout the solid residual streams roughly in
proportion to the mass of each residual stream.
The average lead concentrations were 880 mg/kg, 329 mg/kg, 491 mg/kg,
and 55,000 mg/kg in the demonstration slurry, coarse slag, fine slag, and
clarifier solids, respectively. Although the clarifier solids comprised only
1.6% by weight of the solid residuals, they contained 71.1% by weight of the
measured lead in all the solid residuals. The remaining 28.9% by weight of
the lead partitioned to the coarse and fine slags.
Average barium concentrations were 2,700 mg/kg, 11,500 mg/kg, 15,300
mg/kg, and 21,000 mg/kg in the demonstration slurry, coarse slag, fine slag,
and clarified solids, respectively. The barium partitioned to the solid re-
sidual streams in approximate proportion to the mass flow of each stream.
The coarse slag, which comprised 62.5% by weight of the solid residuals,
contained 55% by weight of the measured barium in the solid residuals. The
remaining 45% by weight of the barium partitioned to the fine slag and clari-
fier solids in approximate proportion to their mass flows.
5.2.9 Process Wastewater
The demonstration produced three process wastewater streams: process
wastewater (flash tank blowdown and quench/scrubber and lockhopper water
inventory on shutdown); gasification vacuum filtrate (produced from the
vacuum filtration of the clarifier bottoms); and neutralized wastewater from
the sulfur removal unit. Samples from each of these streams were collected
and analyzed for VOCs, semivolatile organic compounds (SVOCs), PCDD/
PCDF, metals, pH, and organic and inorganic halogens. Samples of the inlet
5.17
-------
Case Histories
water stream were also analyzed to determine if the water supply was intro-
ducing any contaminants of concern.
Lead concentrations in the process wastewater and vacuum filtrate ranged
from 12.4 to 38.9 mg/L and from 3.98 to 18.4 mg/L, respectively. Although
the majority of the lead was found in the clarifier solids, small amounts of
lead or lead compounds remained suspended in the clarifier effluent and
traveled to the process wastewater as the flash tank blowdown. Similarly,
small amounts of lead remained suspended in the vacuum filtrate and did not
settle in the clarifier sqlids.
Trace concentrations of VOC and SVOC PIRs, such as benzene, acetone,
carbon disulfide, methylene chloride, naphthalene and naphthalene deriva-
tives, and fluorene were found in the wastewater streams. No concentrations
of PCDDs or PCDFs were found at or above the method detection limit of
lOng/L.
Inorganic chloride concentrations in the wastewater streams ranged from
380 mg/L to 6,800 mg/L. These values were, in general, an order of magni-
tude higher than the concentrations found in the inlet water; they indicated
the presence of additional chlorides in the feed. Ammonia was also detected
in the process wastewater and vacuum filtrate streams; the pH values of
these streams were fairly neutral. The inorganic chloride concentrations
indicated the presence of chloride, but the neutral pH values indicated that
the chloride species is not acidic. These results show that the HC1 produced
in the gasification process was removed in the quench and scrubber, neutral-
ized by the ammonia, and discharged in the process wastewater/vacuum
filtrate effluents.
Concentrations of organic chloride in the inlet water, ranging from 680
mg/kg (Run 3) to 2,500 mg/kg (pretest), were carried through the system to
the wastewater streams. Similar concentrations appeared in the process
wastewater, vacuum filtrate, and neutralized wastewater streams.
For proposed commercial units, the wastewater streams would be treated
oh-site for recycling or for disposal as nonhazardous water.
5.2.10 Overall Unit Cost
j,1 i,, u •• •'' l,: . i ji . ,,„ ^ . ,|,,, „ '"';h ' " ' ' '
Information available to date on capital and operating costs is preliminary.
According to Texaco, an overall treatment cost of f 339/tonne ($308/ton) of
soil is estimated for a transportable unit designed to process 91 tonne/day
5.18
-------
Chapter 5
(100 ton/day) of soil with characteristics similar to that from the Purity Oil
Sales Superfund Site, based on the production of a marketable syngas prod-
uct valued at $3.30/1,000 kWhr ($1.00/MM Btu). Texaco estimates an over-
all treatment cost of $248/tonne ($225/ton) of soil for a stationary unit de-
signed to process 180 tonne/day (200 ton/day) of soil at a central site, with
characteristics similar to that from the Purity Oil Sales Superfund site, based
on a value of $6.60/1,000 kWhr ($2.00/MM Btu) for the syngas product.
These costs include amortized capital costs and all operating costs. They
exclude waste soil handling, waste site-specific roads and facilities, and
permitting and regulatory costs, which can be extremely variable and are the
obligation of the site owner or responsible party at the waste site. Actual
costs will vary depending on the site and the soil matrix being treated.
5.2.11 Overall Unit Reliability
The SITE demonstration experienced three operational incidents that
were identified and resolved prior to startup or during operations; they did
not require the shutdown and disruption of the demonstration operations. A
major earthquake also occurred one day prior to the scheduled demonstra-
tion test. Based on the minimal disruptions caused by these incidents and
the continuous post-demonstration processing of the remaining slurry inven-
tory, the reliability and efficiency of the proposed commercial TOP units
should be consistently high, and they are expected to operate at on-stream
efficiencies of 70% to 80%. The downtime allows for scheduled mainte-
nance and intermittent unscheduled shutdowns, such as those caused by
materials-handling equipment problems due to variations in, and the abrasive
nature of, soil and coal matrices.
5.3 Flameless Thermal Oxidation
5.3.1 U.S. Department of Energy Savannah River Site SVE
Demonstration Test
A demonstration test was conducted at the DOE Savannah River Inte-
grated Demonstration site using FTO to treat the offgas from an SVE system
(DOE 1995). The DOE's Savannah River Integrated Demonstration site is
5.19
-------
Case Histories
located at the M-Area operations site where solvents were sent to an unlined
basin with subsequent release to the groundwater beneath the basin. At the
M-Area site, an 8.5 standard mVhr (5 scfm) FT6 unit was used to treat the
offgas from an SVE system located within the one' square mile VOC ground-
water plume. The contaminants of concern at the site in the groundwater
and the SVE offgas were 1,1,2-trichloroethylene (TCE), tetrachloroethylene
(PCE), and 1,1,1-trichloroethane (TCA). A photograph of the FTO at the
Savannah River Integrated Demonstration site is shown in Figure 5.3.
i *
Figure 5.3
DOE Westinghouse Savannah River Site, South Carolina
300 sofh from soil vapor extraction demonstration
Chlorinated VOCs (TCE, PCE) -99.999% ORE
Installed early 1995
Reproduced courtesy of Thermatrix, Inc.
5.20
-------
Chapter 5
During the demonstration test, the FTC) unit operated continuously at
870°C (1,600°F) for 22 days with an SVE flowrate of 8.5 standard mVhr
(5 scfm) and produced the following results:
• 11.17 kg (24.6 Ib) of total chlorinated VOCs (CVOCs) were de-
stroyed.
• The DE for PCE was >99.995%. No PCE was found above the
detection limit during testing.
• TheDEforTCEwas>99.95%. No TCE was found above the
detection limit during testing.
• The total CVOC DE was >99.95%.
• No products of incomplete oxidation were detected in FTO
offgas during the continuous testing phase.
• Minimal operator attention was required; and no maintenance
was required for the 22-day test period and for a total period of 6
weeks during the demonstration.
The DOE estimated that FTO would be more cost-effective than conven-
tional thermal oxidation and catalytic oxidation (DOE 1995).
5.3.2 Full-Scale Treatment of Wastewater Stripper Offgas
While Trier-matrix has not supplied any units for GWS offgas treatment,
they have supplied an FTO to a chemical company for the treatment of the
offgas from an air stripper handling 189 L/min (50 gal/min) of industrial
wastewater. The FTO is a 170 standard m3/hr (100 scfm) unit followed by a
wet scrubber because the oxidation offgas contains HC1. The FTO oxidizer
is constructed of a corrosion-resistant, chrornium-nickel-aluminum alloy
(Binder, Martin, and Smythe 1994). Performance testing of the unit resulted
in 99.97% to 99.99% DE for THC and 3 to 9 ppmv of CO on a dry gas basis,
corrected to 7% oxygen.
5.21
-------
Case Histories
5.4 Plasma Furnaces
5.4.1 Brown's Battery Site Pilot-Scale Testing
To evaluate the feasibility of using a plasma furnace to remediate soils
from the Brown's Battery site, the Exide Corporation performed pilot tests
using materials that would simulate the chemicaiand physical characteristics
of the materials found at the site. Prior to completion of the pilot tests, sub-
strate material was collected from a shale quarry containing soil of composi-
tion similar to that at the Brown's Battery site. Lead sulfate, fluxes, and
ground battery case materials were added to the soil in proportions similar to
those likely to be encountered during full-scale remediation of the site. The
specific objectives of the pilot tests were:
• to prove the technology on a smaller scale than the proposed
production-sized furnace for the Brown's Battery site using
lead-contaminated soil and battery cases that were representative
of the site;
; "• i; : :,.-., ,••:; *• •••'! " • :i •[•. ! "••• r .«'"'• ••' •,.'•;V1 ••''•}':k\M
• to test a DC transferred arc furnace equipped with a hollow elec-
trode with the contaminated soil entering the furnace through the
1 ' ::', ' ' i ! ,1 ;':,;: L '. ,! -j, , ,r ; i i
hollow electrode;
• to test the process under conditions (temperature, gas environ-
ments, and energy input) that would simulate the full-scale op-
erational conditions; and
> . ],-,,- .. .,; i .. .... ,
• to collect data on material and energy balances, material compo-
sition, and off gas properties.
;" ' •• '•' -' r .'•''• -i ~ " ; I ••• • •• •- • , •.•••' !•••; •
The data from material and energy balances were used to validate process
capabilities for lead removal and to provide information on the relative con-
•*• „ , |lln « , i . . , " ,: in , | ,. in, «i i| , ,ii , • • IIM, IF
tribution of electrical energy and carbon combustion to furnace energy de-
mands,. The data from the testing of material composition and offgas proper-
ties were required for final engineering and permitting of the process.
Pilot testing was conducted in March, 1994, arid June, 1994, at the
Ontario Hydro Technologies (OHT) Lakeview Generating Station in Canada.
Prior to the tests, a furnace and an offgas handling system were constructed
using an existing power supply and scrubber. Mobile stack testing equip-
ment was brought to the site for pilot tests. Samples of feed materials, slags,
offgas dusts, scrubber solids, and other materials were collected during the
., ,. ... „ , ,i „, , . ., - „ i, .;.
„ ' , „ ' ': :,!„'' ' , , ' , '•'••" i' : '
'• " ' " 5.22
-------
Chapter 5
tests for analysis and calculating mass balances. Highlights of the test re-
sults follow:
• Lead removal rates for 1,118 kg (2,459 Ib) of material processed
in the furnace varied from 99.56% to 99.97%.
• Residual slags with total lead concentrations of less than 100 mg/
kg were consistently produced under furnace operating condi-
tions. Leachable lead concentrations, based on TCLP tests, were
consistently below 0.6 mg/L.
• With proper attention to feed material processing, the;electrode
feed system can operate trouble-free.
• With the furnace operating under oxidizing conditions, the slag
caused excessive deterioration of the furnace refractory and liq-
uid iron heel. The rate of refractory attack was less pronounced
when the furnace was operated under reducing conditions. A
better refractory choice than castable MgO, taking into account
the acidic nature of slag produced from the Brown's Battery site
materials, should be considered for commercial operations.
• Under reducing conditions, iron oxides in the Brown's Battery
site shale were reduced to iron metal and mixed with the iron
heel for later recovery and use after separation from the slag.
• Offgas solids contained from 3% to more than 29% lead by
weight — higher lead concentrations than offgas solids from
commercial fuming operations. Higher lead concentrations in
the offgas solids are desirable from the standpoint of reclamation
of the solids.
• The calculated lead fuming capacity of the system greatly ex-
ceeded the furnace feed rate, suggesting that the process can treat
materials with higher lead concentrations than those found at the
Brown's Battery site.
• Slag from the process was tested and found to contain extremely
low concentrations of antimony, arsenic, and cobalt, suggesting a
potential for treating soils contaminated with these elements.
• With the final furnace design, air inlet rates ranged from approxi-
mately 85 to 170 m3/hr (50 to 100 fWmin). Offgas flow rates
ranged from 252 to 546 actual mVhr (148 to 321 acfm) at
5.23
-------
Case Histories
temperatures ranging from 388 to 588°C (730 to 1,090°F). A com-
mercial process would be able to better control these characteristics.
• i: ',. - : : ., ,;: > , ~. ' |,: . • ,. ,;
• Under oxidizing conditions, O2 levels in the offgas were typically
in the 12 to 13% by volume range. Under reducing conditions, in
excess of 40% CO by volume could be attained in the offgas with
less than 1 % O2 by volume. The reducing offgas also contained
significant levels of H2.
'•"'•'. The system exhibited a characteristic carbon consumption rate
that could exceed the feed rate of carbon to the furnace and cause
electrode consumption. This electrode consumption was sup-
pressed at higher battery case feed rates.
• Under strongly reducing conditions, oxygen was removed from
the bath, indicating that the process can be used for smelting.
: • • • • 'I • •• .... i
' . ' •• ! .. '• , • J • ..." |
-------
Chapters
Tests conducted in 1993 and 1994 used a TCLP test with lead detection
levels of 0.1 mg/L lead. After HTMR published TCLP levels, Exide used a
detection limit of 0.04 mg/L lead. Old samples were tested and found to
have lead levels that were below the detection limit of 0.04 mg/L.
5.25
-------
t i"
-------
Appendix A
OTHER PROMISING TECHNOLOGIES
This Appendix provides information on ex-situ treatment processes under
development that thermally destroy organics. They are presented in the
context of thermal destruction technologies as defined in Section 1.1.
Appendix C provides a list of "Points of Contacts" for each technology
discussed in this Appendix. The reader is encouraged to contact the listed
persons or their organizations for the most current information.
For some technologies, as noted in the descriptions, metals are partitioned
during the organic destruction process. This side effect of thermal destruc-
tion will, for the most part, facilitate subsequent metal recycle or stabiliza-
tion for disposal.
All technologies must be considered as part of a total treatment system if
they are to be compared for a particular application. Such a system must
account for (a) all treatment functions, not just thermal destruction, (b) tech-
nology interfaces within the system, (c) material balances within the system,
and (d) the different waste types (liquids, sludges, debris, etc.) and hazard-
ous contaminants that are to be treated.
Organic Destruction Using Solar Energy
Solar technology has been proposed for the destruction of toxic organics
(Schwinkendorf et al. 1995). Applications to date are directed at the destruc-
tion of gaseous or liquified organic contaminants that are thermally desorbed
from contaminated soils. Solar technology is also applicable to liquid,
semi-volatile and volatile wastes generated by other processes. Solar de-
struction technologies often rely on both conventional and solar radiation
destruction to maximize organic destruction efficiencies. In some cases,
solar destruction occurs in a separate stage where the remaining high
A.I
-------
Other Promising Technologies
molecular weight products of incomplete combustion from the conventional
stage (e.g., dioxins, furans and PCBs) are destroyed. Concentrated solar
fluxes between 100 W/cm2 (645 W/in.2) and 230 W/cm2 (1,484 W/in.2) are
used to destroy organic contaminants (Glatzmaier et al. 1990; Ball et al.
1992). Organic destruction efficiencies are between 99% and 99.999%,
depending on the organic contaminant, the type of solar reactor, and the
reactor operating conditions.
The DOE, through its National Renewable Energy Laboratory (NREL) in
Golden, Colorado, has been studying solar destruction since 1986. Labora-
tory and field testing has shown that photons in the ultraviolet portion of the
solar spectrum significantly decrease the products of incomplete combustion
in the offgas. For fiscal years 1990 through 1992, the US EPA budget in-
cluded a line item for cooperative work with DOE in investigating the use of
this technology to treat various kinds of waste. In fiscal year 1991, the DoD
budget included a tine item providing $5 million to research, develop, test,
and evaluate a fully functional solar unit. In 1991, a tri-agency agreement
(involving US EPA, DOE and DoD) was formed to develop solar technology
for destruction of hazardous organic wastes. Solar organic destruction tech-
nology is still in the test and evaluation phase and has not yet been commer-
cialized. Nonetheless, this technology is being considered for soil decon-
tamination applications at various military sites.
Two specific systems were developed through the tri-agency agreement,
one by Midwest Research Institute (MRI), Kansas City, Missouri, and the
other by Science Applications International Corporation (SAIC), Golden,
Colorado.
•. -|' ••• : | • . • - • ! •
US EPA and DOE have sponsored the evaluation of the two-stage solar
destruction technology by MRI through the US EPA National Risk Manage-
ment Research Laboratory (NRMRL), Cincinnati, Ohio. Liquid and
semi-volatile organics, or thermally-desorbed volatilized organics are in-
jected into the first stage, mixed with air, and combusted. Combustion prod-
ucts are then transferred, at temperatures up to 966°C (1,760°F) into the
second stage where solar radiation is used to desstroy residual Principle Or-
ganic Hazardous Constituents (POHCs) and Products of Incomplete Com-
bustion (PIC) in the combustion" products"." Based on fundamental studies
and tests conducted at the DOE High-Flux Solar Furnace (HFSF) at
NRMRL, MRI has developed and tested the Minipilot Solar System (MSS)
for thermal treatment of liquid organic waste and solar destruction of
A[2
••I •.
-------
Appendix A
combustion products. After a nonsolar operational performance demonstra-
tion, the MSB underwent full solar testing (up to 8 kW solar power) at the
HFSF at NRMRL. Typical MSS full solar operating temperatures were in
the range of 818 to 826°C (1,504 to 1,519'F). At these conditions, it was
found that organic destruction was high, 99.999% or greater, but that solar
irradiation did not provide significant emissions reductions relative to
non-solar operations. On the other hand, irradiation with artificial ultraviolet
light did reduce the emission of volatile PICs. The NRMRL solar demon-
stration provided unexpected yet critical data needed for future study of
emissions phenomena and design information for a larger pilot or full-scale
systems (US EPA 1994b; Gorman et al. 1996).
SAIC has completed the design phase of a DoD, U.S. Army Environmental
Center (AEC), contract for demonstration of a full-scale system .(U.S. Army
Environmental Center 1993) installation of a solar demonstration facility at the
Sierra Army Depot in Herlong, California (Glatzmaier et al. 1993). Energy and
Environmental Research Corporation (EERC) and International Technologies
(IT) are supporting SAIC in the integral combustion/solar destruction reactor
and soil vapor extraction system designs, respectively. The SAIC solar system
features a faceted, stretched-membrane dish solar concentrator and an inte-
grated, single-stage, high-temperature combustion and solar detoxification reac-
tor. Operating temperatures within the reactor are approximately 1,000°C
(1,8QO°F) and residence tunes are 1 to 2 sec. Simulated soil vapors will be
condensed and transferred to the reactor as liquid waste at flow rates up to 12.3
kg/hr (27.3 Ib/hr). Offgases are treated and scrubbed before they are released.
The effort will culminate in the full-scale demonstration, scheduled to begin in
late 1996 (Davenport et al. 1995).
Thermal Catalytic Oxidation
Thermal Catalytic Oxidation (TCO) is used to destroy VOCs and CVOCs
in moderately contaminated gaseous waste streams (DOE 1995a). Original
catalysts for destruction of CVOCs were subject to irreversible chlorine
poisoning of the active metals. However, new catalysts developed in the
early 1990's are much more resilient to metal chloride formation and TCO
has emerged today as a reliable baseline treatment method.
A.3
-------
Other Promising Technologies
• . , , • , .;.. , " ; , , .. .. .;;... ;?:.* , • • .i;,,1,1 ;•,; .',:„; •.\.w,\., ": ;';,,;, ;, i* • : .;•
Current applications of TCO employ monolith catalyst blocks constructed
of a ceramic base with a wash coat of metal or metal oxide impregnated
alumina"' TCO systems can be designed to handle flow rates from 0.3 to 300
mVrnin (10 to 10,000 scfm), and as such, are applicable for typical soil vapor
extraction and air stripping offgas treatment operations. Operating tempera-
tures range from 250 to 600°C (480 to 1,100°F). At these temperatures,
energy needs, electrical or natural gas, range from 15 to 20 kW, per each 2.8
mVmin (100 scfm) of humid air flow, this energy is about half that required
for incineration. TCO systems require caustic scrubbers for CVOC opera-
tions. TCO is subject to fouling, active metal poisoning, an3 metal particle
sintering, as are all catalytic operations. As a result, catalyst replacement
times are on the order of three years.
1 1 " ' '! ' ' '" ' : ' "
Several different catalysts have been tested and used in offgas treat-
ment operations at DOE's Savannah kiver Site in South Carolina. An
early 0.3 m3/min (10 scfm) pilot-scale test using a Johnson Matthey
monolith catalyst was conducted in 1992. This test was conducted as
part of the DOE's Office of Technology Development, VOCs in
Non-Arid Soil and Groundwater Integrated Demonstration. Results
show that organic destruction efficiencies equal to or greater than 99%
could be achieved at temperatures above 500°C (930°F) for each com-
pound in a waste stream containing perchloroethylene (PCE), trichlor-
ethylene (TCE), and 1,1,1 -trichioroethane (TdA)(Jarosch et al. 1994).
Current full-scale soil vapor extraction units, 6 to 23 mVmin (200 to 800
scfm), are in operation. These units use either a newer, lower operating
temperature Johnson Matthey catalyst that is less susceptible to poisoning, or
an Allied Signal catalyst. Both catalysts operate at temperatures ranging
from 400 to 450°C (750 to 840°F) and can achieve organic destruction effi-
ciencies greater than 98% for a broad range of toxic organics.
Fluidized Bed Cyclonic Agglomerating
Combustoif (AGGCOM)
AGGCOM is a two-stage organic destruction and ash agglomeration (vit-
rification) process for remediating soils ancl sludges contaminated with both
organic and inorganic compounds. AGGCOM combines two environmental
'/tt
-------
Appendix A
remediation technologies developed by the Institute of Gas Technology
(IGT)(US EPA 1991; Mensinger et al. 1991). The first stage is based on a
sloping grid, fluidized-bed (SGFB) technology originally developed for coal
gasification applications. Both organic destruction and ash agglomeration
are accomplished hi the SGFB stage. The bulk of the fluidized bed operates
at temperatures between 820°C (1,500°F) and 1,100°C (2,OOG°F). The cen-
tral spout in the bed operates at a sufficiently higher temperature to partially
fuse and agglomerate the ash and immobilize inorganic contaminants, such
as metals, in the glassy, agglomerated ash matrix. Additional destruction of
gaseous organics and products of incomplete combustion leaving the first
stage is achieved in a high intensity, second stage, cyclonic combustor where
inorganic fuzing and agglomeration is completed. Overall organic destruc-
tion efficiencies range up to 99.99%.
The two-stage AGGCOM process has been under development at IGT for
several years. Bench-scale [15 cm (6 in.) diameter, 9 kg/hr (20 lb/hr)] SGFB
test results were used to establish operating conditions for acceptable soil
agglomeration in the pilot-scale AGGCOM unit. Leaching characteristics
of the soil agglomerates were determined. A 0.9 m (3 ft) diameter SGFB
unit was tested with coal (over 10,000 hr of operation) and demonstrated that
agglomerated ash can be readily produced. Agglomerated ash samples
passed the Extraction Procedure (EP) Toxicity Test.
The bench-scale unit was also tested with spent blast abrasive and spent
foundry sand at feed rates between 450 kg/hr (1,000 lb/hr) and 900 kg/hr
(2,000 lb/hr). Both wastes were contaminated with 1% to 2% organics. In
the spent blast abrasive tests, it was determined that organic destruction ex-
ceeded 99.99% for the tributyl tin oxide contaminant, and the reclaimed
blast abrasive was suitable for reuse under U.S. Navy specifications. The
spent foundry sand test yielded similar results. I
In separate testing, the cyclonic combustor has been evaluated in a 0.84
Gj/hr (0.8 MM Btu/hr) unit at a feed rate of 14 kg/hr (30 lb/hr) to 27 kg/hr
(60 lb/hr) of surrogate wastes. Carbon tetra.chloride (CC14) destruction effi-
ciencies exceeding 99.9999% were achieved under less than optimum condi-
tions (Rehmat et al. 1995).
More recently, a series of soil agglomeration tests was conducted with
raw and spiked samples of soil in the bench-scale unit. Agglomerated or
vitrified soil samples were produced in four of eight tests that were con-
ducted. Operating conditions to achieve soil agglomeration were confirmed,
. A.5
-------
, , • . ,• , , ,... :•,.•:;;. ;» . t ,., ;•., >;. ,,. • i :
Other Promising Technologies
sanjples passed the foxicity Characteristic Leaching Procedure (TCLP)
tests, and results indicate that higher contaminant levels can be processed by
theAdbcblVI process.' " "' ' ""
This technology was accepted into the Superfund Innovative Technol-
ogy Evaluation (SITE) Emerging Technologies Program in July, 1990.
A 5.4 tonne/day (6 ton/day) two-stage, pilot plant has been constructed
and tested, producing additional agglomerated soil samples under vari-
ous operating conditions (Mensinger et aE1991). Future testing of the
AGGCOM process will focus on the sustained and continuous operation
of the pilot plant with soil admixed with both organic and inorganic
surrogate compounds. Plans are to test other feedstocks, such as indus-
trial waste, auto shredder fluff, and medical wastes.
Hybrid Fluidized Bed System
• ..............
, .•..• • :,;. . • •- • .( , .••. : . ;.; . -. ,!.;.., : --, \,-, -• ' ••••• , • ; -
The Hybrid Fluidized Bed System is a three-stage system designed to
treat soils and sludges contaminated with toxic org'anics and volatile
inorganics (US EPA 1991). The first stage consists of a spouted bed that
operates at an inlet velocity of 46 m/sec (150 ft/sec) and a temperature be-
tween 820°C (1,500°F) and 930°C (1,7000F). Large particles are retained in
this stage until they are reduced in size through abrasion and grinding. Sys-
tem advantages based on calculations and limited experimental work include
better heat transfer for large clumps of dirt as compared to conventional
rotary kilns, and less pressure drop as compared to a conventional fluidized
bed. Fine particles, volatile metals, and organic compounds pass to the sec-
ond stage, the fluidized bed afterburner, where the organic compounds are
further destroyed. Upon testing, materials that absorb metal vapors (i.e.,
silica sand, alumina balls, and steel shot), capture fine particles and promote
the formation of less mobile metal compounds. Processed soil is removed in
the third, hot cyclone stage. Offgases are quenched and treated in a conven-
tional baghouse for paniculate and metal control. Organic destruction effi-
ciencies range up to 99 9% and metal removal efficiencies range up to 95%.
....... •- •:•>• i : •' : .'..":•'" *j •.. ........ '•• .: ...... " :!":"" ...... • '! ' • .' " '• • I ,:
Bench-scale tests were conducted in 1989 to determine the ability of
the fluidized bed materials to capture metals (Energy and Environmental
Research Corporation 1992). Capture rates for volatile metals of 85% to
A.6
-------
Appendix A
95% were achieved. A 30 cm (12 in.) diameter pilot-scale unit was con-
structed and tested in 1991 under a Small Business Innovative Research
(SBIR) grant. This system was operated in a short-term batch mode at a
feed of 2.3 kg/5 min (1 Ib/min), with a soil feed spiked with organics
and metals. Greater than 99.9% removal of contaminants was achieved.
This technology was accepted into the SITE Emerging Technologies Pro-
gram in July, 1990. A Process Development Unit (61 cm diameter, continu-
ous feed at 227 kg/hr [24 in. diameter, continuous feed at 500 lb/hr]) was
built and mechanically tested with soil feed (Mensinger et al. 1994). The
system was then modified to convert the spouted bed from an oxidation to a
gasification system and to add an afterburner after the fabric filter. It was
then tested with an auto shredder residue feed. A modified pilot-scale unit
with a processing capacity between 450 kg/hi' (1,000 lb/hr) and 680 kg/hr
(1,500 lb/hr) has been constructed and operated (US EPA 1993).
Metallurgical-Based Treatment Processes
Metallurgical-based treatment processes employ a molten metallurgical
bath to destroy organics, capture inorganic contaminants, such as metals in
the bath, and produce a leach-resistant waste form (Schwinkendorf et. al.
1995). The processes accept a wide variety of waste after size reduction.
Waste is introduced into the molten bath, e.g., iron or an alumina matrix,
within a refractory-lined vessel. Methods of forming the molten bath in-
clude electrical induction coil and combustion heating. In the bath, waste
constituents separate into metallic and oxide slag layers, and offgas products.
Separation of metals from the slag depends on properties of the constituents,
process additives, and the operating environment. The metals and slag can
be recovered from the melt. The metals can either be recovered and re-
cycled, or stabilized for disposal. The oxide slag, after any required stabili-
zation, is usually disposed. Offgases can be treated to recover or recycle
reusable constituents or processed through an air pollution control system
before being released. Toxic organics are destroyed in the intense heat of the
bath, up to 1,800°C (3,300°F), at destruction efficiencies exceeding
99.9999% for some organics.
A.7
-------
It' 'J i
Other Promising Technologies
si,;;
...si; Ei .....
"ill ..... • -Hi .....
...Ifi-, .;;;- i
Metal melting and refining technology is an established decontamination
method in which contaminated steel, copper, or other contaminated wastes
are melted within a molten bath. Generally, these processes have been
adapted to treat hazardous wastes and can be applied in some cases to treat
mixed radioactive and hazardous wastes. Research and development re-
quirements continue to be addressed including (a) pretreatnient system dem-
onstrations, (b) bulk solid feed methods, (c) component operability, perfor-
mance and lifetime, (d) DOE mixed waste treatment demonstrations, (e)
heating methods for high nonnietal waste feeds, and (f) organic content ef-
fects on radionuclide partitioning and particulate generation.
Ausmelt, Asniand^and M4 Environmental IIP. (M4) are actively promot-
ing metallurgical-based technologies for waste treatment applications.
Ausmelt Technology Corporation oif Denver, Colorado, has demonstrated
its system, including the use of a patented lance that is submerged in the
molten metal (Lightfoot et al. 1992). A total of 10 Ausmelt facilities are now
in operation. A 90,000 tonne/yr (99,000 ton/yr) facility to process lead slag
started operation in 1992 and a 120,000 tonne/yr (132,000 ton/yr) plant to
treat zinc leach residues is under construction, both in South Korea. Data on
processing a variety of wastes, approximately 30 different materials, have
been generated in pilot plants in Australia, France, and Colorado. Each pilot
plant has a capacity of 200 kg/hr (440 Ib/hr).
Ashland Petroleum's Hymelt® (Ashland 1995) is another metallurgi-
cal process that has been operating for over a year at the pilot-plant
stage! The reactor has two chambers, one yields hydrogen and the other
yields carbon oxides. Demonstrated waste feeds include trash, garbage,
bacteriological hazardous waste, chemical agents, and other, principally
high hydrocarbon, wastes.
M4, a Molten Metals Technology (MMT) and Lockheed Martin Corpora-
tion partnership, was established in 1994 to demonstrate and apply the Cata-
lytic Extraction Process (CEP) to waste streams at DoD, DOE, and other
government and private facilities. MMT developed CEP under DOE spon-
sorship (Sheridan 1993). A related technology, Quantum CEP™, has been
developed for processing radioactive and mixed radioactive and hazardous
wastes. CEP uses an inductively-heated molten metal bath. Potentially
marketable metals can be recycle!. CEl* destruction efficiencies are re-
ported to exceed 99.9999% for dioxins, furans, and other hazardous organ-
ics, including chemical warfare agents. CEP was recently designated by US
•* .;,•
A.8
-------
Appendix A
EPA as the Best Demonstrated Available Technology (BDAT) for all waste
for which incineration had been the only approved processing method. Ad-
ditionally, several states have approved CEP as a recycling technology, con-
firming it to be distinct from incineration.
A multiple unit Quantum-CEP™ facility is operating at M4's Technology
Genter in Oak Ridge, Tennessee. The center is being used for research and
development, and full-scale processing of mixed waste from government,
commercial, and university sources (M4 Environmental L.P. 1996).
Molten Salt Oxidation
Molten Salt Oxidation (MSO) is a flameless, high temperature molten
salt pool process that (a) destroys toxic organics, (b) separates and re-
tains toxic metals, radionuclides, and products of incomplete combus-
tion in the molten salt residue, and (c) treats acidic gas by-products
(Adamson et al. 1995; Schwinkendorf et al. 1995). MSO operating tem-
peratures are between 700°C (1,300°F) and 950°C (1,740'F), tempera-
tures at which salt viscosity is similar to that of water. External electric
or natural gas heaters are used to heat the salt to operating temperature
and in most cases the pool is kept at these temperatures by the heat of
oxidation of the organics. The salt is generally sodium carbonate or an
eutectic of alkali carbonates. Test results indicate that Inconel 600 is an
acceptable material for the pool vessel. Results also indicate that the
vessel may require a ceramic liner for some applications.
Candidate waste streams for MSO treatment are high heating-value mate-
rials, such as spent solvents, oils, and other organic liquids; crucible graph-
ite; plutonium-contaminated leaded gloves; ion exchange resins; granulated
solids; and energetic materials such as explosives, propellants, and pyrotech-
nics. Both waste and oxidant air are injected into the bottom of the molten
salt pool. Organic destruction efficiencies have exceeded 99.9999% in some
cases. Metal and radionuclide molten pool retention fractions are 99% or
better, depending on the metal/radionuclide and operating conditions (Gay
1991; Stelman et al. 1992). Tests indicate that potential offgas emissions can
be maintained at relatively low levels, but a suitable offgas system may be
required for some applications (Watkins et al. 1994).
A.9
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Other Promising Technologies
n ', i. in ,1,1 , i i ,i ,, , i ii ,i .1. , , i«i
MSO advantages include catalytic acceleration of oxidation rates, en-
hanced organic destruction efficiencies due to high mass and heat transfer
rates within the liquid salt, resistance to thermal surges, and stability with
respect to variations in waste feed. Disadvantages include limitations on
types of treatable wastes, the potential of molten salt freeze-up in process
equipment, and added requirements for molten salt recycle. The latter pro-
vides for continuous-mode operations and the removal of entrapped metals
and radionuclides to avoid performance degradations.
MSO was developed by Rockwell International and the U.S. Navy in the
1970's for disposal of explosives and propellants (Darnell et al. 1974) and
later for coal gasification and the processing of radioactive waste (Cudahy et
al 1993). Waste treatment applications were recognized and laboratory-
scale, bench-scale and pilot-scale MSO units were operated at the Energy
Technology Evaluation Center, Rockwell International, and Lawrence
Livermore National Laboratory (LLNL), all in California, and Oak Ridge
National Laboratory in Tennessee (DOfi 1993). A DOE peer review
(Cudahy et aL 1993) identified a number of unresolved MSO issues, e.g., the
pretreatment of solids, materials of construction, melt freeze-up, monitoring
of residues in the melt, and molten salt recycle. MSO test units continue to
be operated to address these and other development issues. An example of
an operating MSO unit is the LLNL 2 kg/hr Engineering Development Unit.
This unit is currently being operated to resolve engineering design and de-
ii i .•
velopment issues.
LLNL, the Naval Surface Warfare Center (NSWC), other government labo-
ratoriesrand MSO equipment suppliers are now cooperating in a combined
effort to bring laboratory and commercial expertise together to resolve MSO
design implementation issues. Current efforts are focused on design and devel-
opment of a 5 kg/hr (11 Ib/hr) pilot-scale unit for planned implementation at
LLNL (Hersey 1994) and a pilot-scale unit for implementation at NSWC.
Steam Reforming
Steam reforming is a mature industrial process that is used to make hy-
drogen gas from methane (Schwinkendorf et al. 1995). This process is being
applied to treat hazardous and radioactive wastes,, Two steam reforming
A.10
-------
Appendix A
systems, one by the Scientific Ecology Group (SEG) and the other by
ThermoChem, Inc., are described. In both systems, steam reforming (a) is
performed at atmospheric pressure, (b) significantly reduces waste volume,
and (c) takes place in a low oxygen, reducing environment to avoid produc-
tion of dioxins and furans.
Now owned by SEG, Thermolytica and Synthetica Technologies, Inc. pio-
neered and patented steam reforming systems for treating hazardous and radio-
active wastes using a two-stage operation (Galloway 1987; Galloway 1989). In
the first stage, organics are vaporized and decomposed by superheated steam at
temperatures between 320°C (600°F) and 600°C (1,100°F>. In the second stage,
the first-stage offgas is mixed with superheated steam at a nominal temperature
of 1,100°C (2,000°F) to complete organic decomposition and the formation of
syngas and other useful gaseous products. For organic solvents found in mixed
wastes, destruction efficiencies between 99.99% and 99.9999% can be achieved
by varying the second-stage temperature from 1,000°C (1,800°F) to 1,200°C
(2,200°F). Also, radioactive treatment applications have been addressed (Gallo-
way et al. 1994). For nitrate-mixed waste destruction, Resources Conservation
and Recovery Act (RCRA) organic destruction requirements are met, plus over
92% destruction efficiencies of the nitrates have been demonstrated (Galloway
et al. 1993). Metals and other inorganic residues in the waste feeds are parti-
tioned and isolated in the first stage for direct: disposal, solidification, or reuse.
In 1995, SEG, a wholly-owned subsidiary of Westinghouse Electric Cor-
poration, acquired Synthetica Technologies, Inc., including the early work of
Thermolytica. SEG now holds the entire patent portfolio for
steam-reforming waste processing and manufacturing of Synthetica steam
reforming units for commercial activities. The US EPA classifies SEG tech-
nology as a non-incineration technology. The SEG technology is available
as fixed or mobile units.
SEG has provided demonstrations for DOE-sponsored tests with Sandia
National Laboratories (Miller et al. 1995). It recently completed an
eight-month waste treatment contract for about 230 m3 (300 yd3) of nuclear
power plant radioactive waste containing heavy metals. SEG now operates a
dual feed (drum or shredder/ heated screw) commercialized unit for treat-
ment of a variety of radioactive, mixed radioactive and hazardous, and halo-
genated wastes, including bio-pharmaceutical and research laboratory radio-
active wastes. These wastes have elevated levels of chlorine and fluorine
that are being handled by a proprietary SEG process that produces inert salt
A.11
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Other Promising Technologies
I'"
disposal products. Other treatment contracts exist with the Trojan Nuclear
Power Plant, and with DOE's Rocky Flats Plant in Colorado and the Idaho
T* ' ", !' • | | | m T 1 , I
National Engineering Laboratory in Idaho.
The ThermoChem system (DOE 199^) consists mainly of a solidTliquid
continuous feed system, a first and a second stage steam reformer, and a
flameless thermal oxidizer. The first stage steam reformer is an indirectly
heated fluidized bed in a refractory-lined reactor vessel. The fluidized bed
temperature (480 to 650°C [900 to 1,200°F]) is closely controlled to ensure
complete volatilization and partial steam reforming of all organic com-
pounds. The temperature is also kept sufficiently low to ensure retention of
radionuclides in the bed material and retention of Inorganic materials in the
first stage. Radionuclides and inorganic materials are continuously removed
from the first stage for final disposal. Product gases from the first stage are
routed to the second stage where greater destruction efficiencies can be
achieved, if required. Otherwise, the second stage can be bypassed.
" .• ' ..• .* .! , ;.. . •• •• , I ...... .. . .1 J.._ ; „ . ...;..; .: ,."[""•?
Product gases, either from the first or second stage, are routed to a
flameless thermal oxidizer where hydrocarbon vapors are converted to car-
bon dioxide, water, hydrogen chloride, and sulfur dioxide. Outputs from the
oxidizer are routed through a hot gas scrubber and filtration system and then
released. Laboratory testing indicates that 99.9999% organic destruction
efficiencies can be achieved with the ThermoChem system. This testing has
included naphthalene, dichlorobenzene, toluene, phenol*, tetrachloroethylene,
vinyl chloride, trichloroethylene, and ethylene glycol. Additional tests have
been conducted using feed sludge from paper mill waste containing dioxins
(AghaMohammadi 1995).
ThermoChem is under contract to design, build, and operate a nominal 45
kg/hr (100 Ib/hr) Process Development tlnlt (PDtr). The PDU will be tested
Using six surrogate feedstocks that are representative of DOE mixed low
level waste. Preliminary screening tests were conducted at Saridia National
Laboratories with a single-stage (fluidized bed) unit operating at 900°C
(l,650°F)(AgnaNloharnmadi 1995). Destruction efficiencies In this test
ranged from greater than 99.99% for tetrachloroethylene to an average of
98.48% for 1,2-Dichlorobenzene. Plans are to conduct additional testing
with a two-stage, 1.1 tonne/day (1.2 ton/day) unit.
A.12
-------
Appendix A
Plasma Torch and Electric Arc Technologies
Plasma torch and electric arc technologies are alternating or direct current
electrical heating processes (Schwinkendorf et al. 1995; DoD 1995). They
are adaptations of foundry technologies and rely on high energy electrical
discharges to convert a gas into a high-temperature plasma. The plasma
torch functions in a flowing gas medium while the electric arc functions in a
static gas medium. Although centerline plasma temperatures may reach
12,000°C (22,000°F) or more, plasma surface and surrounding gas tempera-
tures vary between 1,500°C (2,700°F) and 5,300°C (9,600°F). Heat transfer
to the waste material in the primary reactor hearth is primarily by radiation
with some contribution by convection from the surrounding gas. In addition,
joule heating occurs when the waste material is used as one of the elec-
trodes. Generally, these systems can accept a variety of input wastes materi-
als, even "as received" in their original containers.
The plasma torch and electric arc systems volatize and decompose organic
materials and melt inorganic materials into a glassy slag, and in some cases,
into a separate molten metal phase. Offgas processing systems are provided to
ensure complete combustion of combustible gases and volatized organics.
When withdrawn, the slag forms a leach-resistant vitrified (glassy) waste form
that is suitable for disposal. The molten metal phase, if formed, can be with-
drawn separately and recycled for alternate uses of the recovered metal.
Plasma torch and electric arc technologies are similar. Laboratory, pilot,
and demonstration units are being developed by several companies; alone
and in conjunction with DOE and DOE national laboratories. Some compa-
nies have commercialized and are applying these technologies for the treat-
ment of hazardous wastes. Preparations for mixed radioactive and hazardous
waste testing are underway.
DOE has sponsored development, test, arid evaluation of the Plasma
Hearth Process(PHP), a non-radioactive, fixed hearth, plasma torch system,
at both the laboratory- and pilot-scale (DOE 1994a; DOE 1994c). In addi-
tion, Science Applications International Corporation (SAIC) operates a 200
KW nonradioactive fixed hearth plasma process at its Science and Technol-
ogy Applications Research (STAR) Center in Idaho. A pilot-scale,
A.13
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Other Promising Technologies
non-radioactive PHP system will be constructed at Retech, Inc. in Ukiah,
California. A bench-scale radioactive PHP system is being installed in the
Argonne National Laboratory West (ANL-W) Transient Reactor Test
(TREAT) facility in Idaho (DOE 1995b).
Retech, Inc. has also developed the plasma Arc Centrifugal Treatment
(PACT) system, a rotating-tub (hearth), plasma torch system. Several sizes,
ranging from 46 cm (1.5 ft) to 244 cm (8 ft) in diameter have been tested. A
183 cm (6 ft), 136 kg/hr (300 Ib/hr) design has been used in DOE-sponsored
tests at the Component Development and Integration Facility (CDIF) in
Butte, Montana, to demonstrate its application in the treatment of mixed
wastes at the Idaho National Engineering Laboratory ONEL).Two systems
are operating in Switzerland and one in France. Retech also built the
bench-scale PHP unit for the ANL-W radioactive waste demonstration
project. Two PACT systems for treatability studies are located at Retech's
Ukiah facility and a third one is under construction (Eschenback et al. 1993).
In early 1996, Retech, Inc. was acquired by M4 Environmental L.P., Oak
Ridge, Tennessee.
Plasma Energy Applied technology (PEAT), Iric., Huntsville, Alabama,
has developed a single stage, plasma torch Thermal Destruction and Recov-
ery (TDR) patented system for treating mixed hazardous and radioactive
wastes. Steam, oxygen, or air is injected into the reactor vessel to enhance
organic destruction efficiencies. Temperatures within the reaction vessel are
often over 1,650°C (3,000°F). Inorganics are either recovered or immobi-
lized for disposal. Gaseous products are similar to other plasma torch pro-
cesses, are relatively free of dioxins and furans, and are scrubbed before they
are released. An "Authority to Construct" has been issued by the San Diego
County Air Pollution Control District to install a TDR system for processing
medical waste at the Kaiser Permanente Medical Center in San Diego, Cali-
fornia. However, its implementation has been delayed pending results of
additional cost benefit analyses. A contract is in place with Allied Technol-
ogy Group (ATG), Richland, Washington, to provide a TDR system for treat-
big mixed, low-level waste from DOE's Hanford facility.
Other plasma torch systems are under various stages of development include:
i i 1
• Plasma Technology, Inc., Santa Fe, New Mexico, has developed
and is marketing a Plasma Energy Recycle and Conversion
(PERC™) process that uses electrodeless Induction Coupled
Plasma (ICP) torches that provide a wide range of plasma gases.
A.14
-------
Appendix A
A commercial PERC™ system has been installed for Alliant
Techsystems in Elk River, Minnesota, to treat energetic materials
and chemical warfare agents. Initial operations were completed
in September, 1995 (Blutke et al. 1995).
• INEL has developed a hybrid steam plasma technology that has
two plasma sources operated in tandem. Bench-scale demonstra-
tions have been completed on liquid organics and black liquor
waste from the wood pulping process (DOE 1994b).
• Westinghouse Electric Corporation under Electric Power Re-
search Institute (EPRI) sponsorship has developed a plasma cu-
pola technology that is now being marketed by Westinghouse
(Dighe et al. 1991).
Two electric arc systems have been tested and demonstrated. One is the
graphite electrode direct current arc system, demonstrated in both the Mark
1,0.3 MW furnace (Surma et al. 1993) and the larger Mark II, 1 MW furnace
(DOE 1994a). A Mark I unit is currently being used at the Clemson Vitrifi-
cation Research Laboratory, Clemson, South Carolina (Erich and Overcamp
1996). These furnaces, based on Electro-Pyrolysis technology, were jointly
developed and demonstrated by Pacific Northwest Laboratoiy (PNL), Mas-
sachusetts Institute of Technology (MIT), and Electro-Pyrolysis Inc. with
funding support from DOE. These systems are now being marketed by
Svedala Industries, Pyro Systems Division, Waukesha, Wisconsin, a unit of
Sweden's Svedala Industries, Inc. (Trescot et al 1995).
The second electric arc system is the alternating current graphite electrode
arc melter. Development of this system has been supported by DOE and is
an extension of a U.S. Bureau of Mines (USBM) and American Society of
Mechanical Engineers (ASME) demonstration of the vitrification of munici-
pal waste combustor residues (DOE 1994a; American Society of Mechanical
Engineers 1994). The furnace, developed in cooperation with Lectromelt, a
subdivision of the Salem Furnace Company, is a sealed, 800 kVA (0.8 MW)
arc furnace. It is generally operated between 350 and 550 kW in power.
This unit has recently been used to treat simulated transuranic (TRU) con-
taminated waste and soils, and high sodium, low-level radioactive liquid tank
waste by encapsulating the TRU contaminants in a glass/ceramic waste form
(O'Connor et al. 1996; O'Connor et al. 1995; Soelberg et al. 1994).
A.15
-------
' ! ! -I'ti'1
I
Other Promising Technologies
Horseheqd Resource development
Company iame Reactor
The Flame Reactor is a Mgh-temperature metaf recovery process that
destroys organics, extracts metals, and vitrifies contaminants. It consists of a
burner stage (fuel combustion) and a reactor stage (oxide reduction). It can
be used to treat sludges, slags, and soils and recover metals in these wastes
for recycling. Three large-scale tests have been conducted and show that
organic destruction efficiency exceeds 99.99% for CC14, metal recovery
efficiencies range up to 92%, and the solidified slag consistently passes
.,'•'. 'I ,i ''. •!•.,,, ,:'|| , "'..,i! ", • • lut ,„"' '„ mi , ,' if j ,, ;,„ , „••; „", , , ,,. | \M !|| ;i
TCLP testing.
Electric Arc Furnace (EAF) steelmakers in the United States generate
approximately 545,450 tonne (600,000 ton) of hazardous EAF flue dusts
annually. Most of the dust is processed at large regional facilities to recover
marketable metal products (e.g., lead, cadmium, zinc, copper, and nickel) for
recycling. A smaller gas-fired Flame Reactor has been developed under
sponsorship of the Gas Research Institute (GRI). This unit is intended for
on-site applications at new "mini-mills" and existing facilities remote from a
regional facility (Natural Gas Applications in Industry 1994).
Pilot plant tests for small-scale Flame Reactor have been completed on
more than 3,600 tonne (4,000 ton) of various wastes. A commercial, 27,300
tonne/yr (30,000 ton/yr) facility has been permitted and started operations in
Beaumont, Texas, in 1993. Other facilities are under consideration. With
GRI support, Horsehead is investigating alternative waste applications for
the gas-fired Flame Reactor. Included are electroplating wastes,
lead-contaminated soils, hazardous waste incinerator ash, and secondary
copper and brass foundry wastes (Clark et al. 1994).
Systems Engineering Analysis
DOE has taken an overall systems view in applying technologies for treat-
ment of mixed waste. A study was conducted of thermal treatment systems
in which nineteen system options using varied technologies were considered.
System options were compared for costs, effluents, and amounts of final
residue for disposal. The thermal study results emphasized the importance
A.16
-------
Appendix A
of reducing characterization and pretreatrnent, operating and maintenance,
and disposal costs. All types of wastes were processed within the same facil-
ity. Where only 20% of the total waste mass was combustible, the overall
costs were rather insensitive to the type of thermal treatment (Feizollahi et
al. 1995; Cudahy et al. 1995).
A similar study of nonthermal (operating temperatures less than 350°C
[660°F]) treatment systems was also conducted in which five system options
using varied nonthermal technologies weire considered (Biagi et al. 1996).
Major conclusions are that:
• gas emissions from nonthermal systems are significantly less
than those from thermal systems;
• waste form volumes for disposal are generally greater for
nonthermal systems; '.
• technology maturity levels are generally less than for nonthermal
technologies; and
• nonthermal systems tend to be more expensive than thermal sys-
tems (Schwinkendorf 1996).
A.17
-------
j, ; :
-------
i Appendix B
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B.4
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Appendix B
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O'Connor, W.K., L.L. Oden, and P.C. Turner. 1995. U.S. Bureau of Mines Pilot-Scale Demonstra-
tion of Electric Arc Furnace Melting of Multiple-Source Simulated Low-Level Radioactive Wastes.
American Chemical Society I&C Special Symposium. Atlanta, GA. September 17-20.
O'Connor, W.K., P.C. Turner, R.R. Soelberg, and G.L. Anderson. 1996. Evaluation of the
graphite electrode arc melter for processing heterogeneous mixed wastes. 1996 International
Conference on Incineration and Thermal Treatment Technologies Proceedings. Savannah,
GA. May 6-10. pp 559-569.
Persoon, J.R. 1994. Letter from Alliant TechSystems. September 28.
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B.5
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List of References
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Stelman, D., A.E. Stewart, S.J. Yosim, and R.L. Gay. 11992. Treatment of mixed waste by the molten
salt oxidation process. Proceedings of the 1992 Incineration Conference. Albuquerque, NM. May
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Surma, JX'D.R. Cohn, D.L Smatlak, R Thomas, P.P. Woskov, C.H^Titus, J.K. Wittie, and RX
Hamilton. 1993. Graphite electrode DC arc technology development for treatment of buried wastes.
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Tester, J.W., FJ. Holgate, P.A. Armeilinin, W.R. Webley, GT. Hong Kiliilea, and HJE. Barrier. 1991.
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Thermatix, Inc. 1992. Destruction of Organic Compounds in the fhermatrix Flameless Thermal
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• • , - :; •;• . • " • / ••. "| < "";; ::• • I"';111' •;• ' ' "'. •;' • ".'" I
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• • '• • !! •) -| ' •• • • ;- 'i"
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-------
Appendix B
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B.7
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1, Hill ' ' ,.' I, I ,11'
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Appendix C
POINTS OF CONTACT
Organic Destruction Using Solar Energy
C.C. Lee, Project Manager
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7520
Mark Bohn, Tri-Agency Project Technical Coordinator
U.S. Department of Energy
National Renewable Energy Laboratory
1617 Cole Boulevard
Golden, CO 80401-3393
(303) 384-7405 i
Ronald Jackson, Project Manager
Attn: SHM-AEC-ETD
U. S. Army Environmental Center
Aberdeen Proving Ground, MD 21010-5401
(410) 612-6849
Paul Gorman
Midwest Research Institute
425 Volker Boulevard
Kansas City, MO 64110
(816) 753-7600
C.I
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Points of Contact
t I U" I1
Kelly Beninga, Manager
Energy Products Division
Science Applications international Corporation
15000 West 6th Avenue, Suite 202 '
Golden, CO 80401-5047
(303)279-5677
Thermal
G. (Skip) A. Chamberlain, Program Manager
U.S. Department of Energy
Office of Science and Technology
Clpverleaf Building
19901 Gemantown Road
Germantown, MD 20874-1290
(301) 903-7248
John L'. Steele, Technical Program Manager
Westinghouse Savannah River Company
P.O. Box 616
Aiken,SC 29802 T
(803)725-1830
T. (Tim) R. Jarosch
Westinghouse Savannah River Company
Building 773-42A
Aiken,SC 29808
(803)725-5189
' ' . " ' ' |
Wilson dhu '' '"" " '"' """'
Johnson Matthey
Environmental Products Division
460 East Swedesford Road
Wayne, PA 19087-1880
(610)971-3105
C.2
,. k •-
iii:! ,;,
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Appendix C
Fluidized Bed Cyclonic Agglomerating
Combustor (AGGCOM)
Teri Richardson, Project Manager
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7949
Michael Mensinger
Institute of Gas Technology
1700 S. Mt. Prospect Road
Des Plaines, IL 60018-1804
(708) 768-0602
Hybrid Fluidized Bed System
Teri Richardson, Project Manager
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7949
Wyman Clark
Energy and Environmental Research Corporation
18 Mason Street
Irvine, CA 92718
(714) 859-8851
C.3
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Points of Contact
Metallurgical-Based Treatment Processes
Jo-Ann Bassi, Program Manager
U.S. Department of Energy
Office of Science and Technology
Cloverleaf Building
19901 Germantown Road
Germantown, MD 20874-1290
(301)903-7659
• ;•;; --;'.•• = ...i .' .';. ,' .".:;.. ' I •••
Steve Webster, Technical Program Officer
U.S, Department of Energy
Chicago Operations Office
9800 South.Cass Avenue
Argonne, IL 60439-4837
(708) 252-2822
• . . , . , <,M> „ , < I. • „ .1 „•!, I
I
Don Malone, Group Leader
Ashland Petroleum Company
P.O. Box 391
Ashland, KY 41114
(606)921-6526
J. Alan Smith, General Manager
Ausmelt Technology Corporation
1331 17th Street, Suite M103
Denver, CO 80202
(303) 295-2216
VicGatto
Molten Metal Technologies
950 Winter Street
Walthham, MA 02154
(617)487-7642
C.4
-------
Appendix C
Robert M. Sameski, Manager
M4 Environmental Management, Incorporated
Business Development
151 Lafayette Drive
Suite 210, Corporate Center
Oak Ridge, TN 37830
(423) 220-5017
Molten Salt Oxidation (MSO) Process
Martyn Adamson, Project Manager
Waste Processing Development Program
Lawrence Livermore National Laboratory
P. O. Box 808, L-276
Livermore, C A 94551
(510)423-2024
William Brummond, Lead Engineer, MSO
Lawrence Livermore National Laboratory
P. O. Box 808, L-276
Livermore, CA 94551
(510)423-6866
John P. Consaga
Naval Surface Warfare Center
Indian Head Division
101 Strauss Avenue
Indian Head, MD 20640-5035
(301) 743-6123
C.5
-------
J. Kenneth Wittle
Elecfrq-Pyrolysis, Inc.
996 Old Eagle School Road
Wayne, PA 19087
(610) 687-9070
William (Bill) K. O'Connor
U.Sl Bureau of Mines
Albany Research Center
1450 Queen Avenue SW
Albany, OR 97321
(541)967-5834
Appendix C
'!» ;?; ',. I
Horsehead Resource Development
Company Flame Reactor
Marta Richards
U.S, Environmental Protection Agency
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7692
Regis J. Zagrocki, Senior Engineer
Horsehead Resource Development Company, Inc
401 Delaware Avenue
Palmerton, PA 18071
(610)826-8818
C.9
-------
Points of Contact
Carla Dwight, Principle Investigator
Argonne National Laboratory-West
P.O. Box 2528
Idaho Falls, ID 83403-2528
(208)533-7651
Leroy Leland, Sales Manager
ReTech Division
P.O Box 997
100 Henry Station Road
Ukiah, CA 95482
(707) 467-1724
Andreas Blutke, Director
Engineering and Operations
Plasma Technology Incorporated
1800 Old Pecos Trail, Suite O
Santa Fe,NM 87501
(505) 988-4943
Peter C. Kong, IRC MS-2210
Idaho National Engineering Laboratory
Lockheed-Martin Idaho Technologies
Idaho Falls, ID 83415-2210
(208) 526-7579
Marlin Springer, Vice President
Plasma Energy Applied Technology, Inc.
4914 Moores Mill Road
Huntsville,AL 35811
(205) 859-3006
Dr. Shyam V. Dighe, Manager
Plasma Technology
Westinghouse Electric Corporation
Science and Technology Center
1310BeulahRoad
Pittsburgh, PA 15235
(412) 256-2235
C.8
-------
'•1
Appendix C
Terry. R. Galloway, Manager
Technology
SEG California
, 6801 Sherwick Drive
Berkley, 'CK 94705-1744.
(510)849-0100
Gary Voelker, Chief Operating Officer
ThermpChem, Incorporated
:: "::'*;;;"' ;i0220-H''bldiCoiurnWa'Road " '
Columbia, MD 21046
(410) 3li-6300
Plasma Torch and Electric Arc Technologies
Jq-Ann Bassi, Program Manager
UlS. Department of Energy
Office of Science and Technology
Cloyerleaf Building
10901 Germantown Road
Germantown, MD 20874-1290
(301)903-7659
,' , . '..,. ,:. .j:..::..;;.;.. [ .. '•
Gary Leatherman
Science and Technology Applications Research (STAR) Center
Science Applications International Corporation
545 Shoup Avenue
Idaho Falls, ID 83402-3575
(208)528-2179
Ray Geimer or Robert Gillins, Principle Investigators
Science Applications International Corporation
545 Shoup Avenue
Idaho Falls, ID 83402-3575
(208) 528-2144 or (208) 528-2114
C.7
<;. • f
-------
Pofote of Contact
Richard L. Gay, Manager
[Rockwell International and Energy Technology Evaluation Center]
Process Development, Advanced Programs
Rocketdyne Division
Rockwell International Corporation
6633 Canoga Avenue
P.O. Box 7922
Canoga Park, CA 91309-7922
(818) 586-6110
Steam Reforming
Jo-Ann Bassi, Program Manager
U.S. Department of Energy
Office of Science and Technology
Cloverleaf Building
19901 Germantown Road
Germantown, MD 20874-1290
(301) 903-7659
John Beller, Program Coordinator
Idaho National Engineering Laboratory
P. O. Box 1625
Idaho Falls, ID 83415-3970
(208) 526-1205
Maher Tadros
Sandia National Laboratories
P. O. Box 5800, MS 0734
Albuquerque, NM 87185-0734
(505) 845-8930
C.6
-------
Appendix C
Robert M. Sameski, Manager
M4 Environmental Management, Incorporateji
Business Development
151 Lafayette Drive •
Suite 210, Corporate Center
Oak Ridge, TN 37830
(423)220-5017
- -i
• ti" f
Molten Salt dxidation (MSO) Process
Martyn Adamson, Project Manager
Waste Processing Development Program
Lawrence Livermore National Laboratory
P. O. Box 808, L-276 j
Livermore, C A 94551
(510)423-2024
I ' • j '•' ' •' •• '
William Brummond, Lead Engineer, MSO
Lawrence Livermore National Laboratory
P. O. Box 808, L-276
Livermore, CA 94551
(510) 423-6866
John P. Consaga
Naval Surface Warfare Center
Indian Head Division
101 Strauss Avenue
Indian Head, MD 20640-5035
(301)743-6123
C.5
-------
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 I, 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 Ah- 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 - Bioremediation
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, Ph.D., 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, P.E., 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.
Derapsey, P.E., USEPA; Johia P. Longwell, Sc.D.,
Massachusetts Institute of Technology; Richard S.
Magee, Sc.D., P.E., DEE, New Jersey Institute of
Technology; Walter G. May, Sc.D., 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. GOVEHNMEOT PRINHKO OFFICE: 1998-621-075X93279
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