MUNICIPAL SOLID WASTE INCINERATOR RESIDUES
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Studies in Environmental Science 67
MUNICIPAL SOLID WASTE INCINERATOR RESIDUES
The I N T E R N A T I O N A L ASH W O R K I N G G R O U P , compr ised of (in alphabetical order):
A. John Chandler A.J. Chandler and Associates Ltd., Willowdale, Ontario, Canada
T. Taylor Eighmy University of New Hampshire, Ourham, New Hampshire, U.S.A.
Jan Hartl6n Swedisch Geotechnical Institute, LinkEping, Sweden
Ole Hjelmar VKI Water Quality Institute, Hersholm, Denmark
David S. Kosson Rutgers, The State University of New Jersey, New Brunswick, New Jersey U.S.A.
Steven E. Sawell Compass Environmental, Burlington, Ontario, Canada
Hans A. van der Sleet Netherlands Energy Research Foundation, Petten, The Netherlands
JiJrgen Vehlow Forschungszentrum Karlsruhe GmbH, Institute of Technical Chemistry, Karlsruhe, Germany
1997 E L S E V I E R A m s t e r d a m - Lausanne - N e w Y o r k - Oxford - S h a n n o n - Tokyo
ELSEVIER SCIENCE B.V. Sara Burgerhartstraat 25 P.O. Box 211, 1000 AE Amsterdam, The Netherlands
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PREFACE
The International Ash Working Group (IAWG) was established in 1989 to conduct an in-depth review of the existing scientific data and develop a state-of-knowledge treatise on MSW incinerator residue characterisation, disposal, treatment and utilisation. The topics of operator and worker health and safety, and health risk assessment were beyond the scope of this project, and therefore have not been addressed.
Members of the IAWG had been involved in various research and development programs concerning MSW incineration residues for several years prior to establishing the IAWG. The IAWG has met regularly since its inception to discuss aspects of residue characterisation and management, as well as offering a forum for other researchers to provide their perspectives on the issues. The project soon grew beyond the original scope, due in part to the need to examine the ever increasing volume of published research data which became available in the early 1990's. In addition, the IAWG project was designated as an Activity under the International Energy Agency's (lEA) Bioenergy Agreement Task Xl - Conversion of MSW to Energy 1991 - 1994.
This final treatise and the Summary Report represent the culmination of the IAWG efforts over the period from February 1990 through July 1996. The input of information from colleagues, along with other information available from the literature and personal contacts, was used to formulate the conclusions and recommendations summarised in this document. The results of this effort have been presented in extended seminars, in conjunction with both the WASCON '94 Conference (June 1994) in Europe and with the Municipal Waste Combustion Conference (April 1995) in North America. In addition, the IAWG co-sponsored and participated in the "Seminar on Cycle and Stabilisation Technologies of MSW Incineration Residues" along with the Japan Waste Research Foundation (March 1996) in Japan. Currently, the IAWG continues to operate as a sub-group of Thermal Conversion Activity under the IEA's Bioenergy Agreement Task XlV - Energy Recovery from Municipal Solid Waste.
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AUTHORS
A. John Chandler A. J. Chandler and Associates, Ltd. Willowdale, Ontario Canada
T. Taylor Eighrny University of New Hampshire Durham, New Hampshire United States of America
Jan Hartldn Swedish Geotechnical Institute Linkoping Sweden
Ole Hjelmar Danish Water Quality Institute H~rsholm Denmark
David S. Kosson Rutgers, The State University of New Jersey New Brunswick, New Jersey United States of America
Steven E. Sawell Compass Environmental Burlington, Ontario Canada
Hans van der Sloot Netherlands Energy Research Foundation Petten The Netherlands
Jtirgen Vehlow Forschungszentrum Karlsruhe GmbH Institute of Technical Chemistry Germany
. . . V I I I
THE INTERNATIONAL ASH WORKING GROUP
A. John Chandler A. J. Chandler and Associates, Ltd. Willowdale, Ontario Canada
T. Taylor Eighmy University of New Hampshire Durham, New Hampshire United States of America
Jan Hartl6n Swedish Geotechnical Institute Linkoping Sweden
Ole Hjelmar Danish Water Quality Institute H~rsholm Denmark
David S. Kosson Rutgers, The State University of New Jersey New Brunswick, New Jersey United States of America
Shin-ichi Saki (Since 1994) Environment Preservation Centre Kyoto University Japan
Steven E. Sawell Compass Environmental Burlington, Ontario Canada
Hans van der Sloot Netherlands Energy Research Foundation Petten The Netherlands
JQrgen Vehlow Forschungszentrum Karlsruhe GmbH Institute of Technical Chemistry Germany
DISCLAIMER
This report was prepared by the International Ash Working Group (IAWG). The work was sponsored by the agencies listed herein, who are not necessarily in agreement with the opinions expressed by the IAWG. Neither the sponsoring agencies (including its members), nor the IAWG, nor any other person acting on their behalf makes any warranty, express or implied, or assumes any legal responsibility for the accuracy of any information or for the completeness or usefulness of any apparatus, product or process disclosed, or accept liability for the use, or damages resulting from the use, thereof. Neither do they represent that their use would not infringe upon privately owned rights. The IAWG also does not, and never intended to, discuss or make recommendations with regard to health and safety issues concerning facility operators or workers.
Furthermore, the sponsoring agencies and the IAWG hereby disclaim ANY AND ALL WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, WHETHER ARISING BY LAW, CUSTOM, OR CONDUCT WITH RESPECT TO ANY OF THE INFORMATION CONTAINED IN THIS REPORT. In no event shall the sponsoring agencies or the IAWG be liable for incidental or consequential damages because of the use of any information contained in this report.
Any reference in this report to any specific commercial product, process or service by tradename, trademark, manufacturer or otherwise does not necessarily constitute or imply its endorsement or recommendation by the IAWG and the sponsoring agencies or any of its members.
SPONSORING AGENCIES
The IAWG is grateful for the financial and technical contributions made to this project by the following agencies/organisations/companies:
Major Sponsors
Asea Brown Boveri (Switzerland) Danish Ministry of Energy Energy, Mines and Resources Canada Environment Canada European Commission Forschungszentrum Karlsruhe (Germany) International Energy Agency International Lead Zinc Research Organization Integrated Waste Services Association (USA) Japan Waste Research Foundation LAB (France) Management Office for Energy and the Environment (Netherlands) National Institute of Public Health and Environmental Protection (Netherlands) Swedish National Board for Industrial & Technical Development Takuma Co., Ltd. (Japan) United Kingdom Department of Environment United States Environmental Protection Agency Wheelabrator Environmental Systems (USA)
Minor Sponsors
TECHNICAL CONTRIBUTORS
The IAWG gratefully acknowledges the technical contributions made during the course of this project by:
T. Aalbers - RIVM, Netherlands M. Adams - VROM, Netherlands I. H. Anthonissen - RIVM, Netherlands J. A t w a t e r - University of British Columbia,Canada J. Barniske - Umweltbundesamt, Germany J. Ber ry- Wheelabrator Environmental Systems Ltd., USA S. B i n n e r - V~lund, Denmark R. B o e h m - PBI, Netherlands H. Borrmann - Forschungszentrum Karlsruhe, Germany J. P. Bo rn - VVAV, Netherlands R. Braam - PBI, Netherlands S. Burnley - Energy Technology Support Unit, United Kingdom D. Chambaz- BUWAL, Switzerland A. Chamberland - Tiru Inc. (formerly with Montenay Inc.), Canada W. Chesner- Chesner Engineering, P.C., USA B. Christensen - Environment Canada S. Cook- Bermuda Biological Station R. Comans- ECN, Netherlands S. Dalager- dk TEKNIK, Denmark A. Damborg - Danish Water Quality Institute C. Dent - AEA Technology, United Kingdom A. M. F~llman - Swedish Geotechnical Institute A. Finkelstein - Environment Canada J. Fraser - Wastewater Technology Centre, Canada M. Gal lo - Rutgers University, USA D. Goetz - University of Hamburg, Germany J. Gronow- United Kingdom Department of Environment T. Guest - Montenay Inc., Canada L. Gullbrand - Swedish National Board for Industrial and Technical Development G. Hansen - United States Environmental Protection Agency D. Hay - Environment Canada S. Hetherington - Compass Environmental Inc., Canada F. Hoffman - Rutgers University, USA G. Hoffmann - Umweltbundesamt, Germany R. Hui t r ic - LA County Dept. of Sanitation, USA L. Johansson - Swedish Geotechnical Institute B. Johnke- Umweltbundesamt, Germany T. Kimura - Kubota Corporation, Japan J. Kiser- Integrated Waste Services Association, USA R. Klicius - Environment Canada O. Knizik - Greater Vancouver Regional District, Canada M. Knoche- LAB, France K. Knox - Knox Associates, United Kingdom
T. Kosson - Rutgers University, USA H. K r u i j d e n b e r g - NOVEM, Netherlands P. Leenders- (formerly with VEABRIN - Netherlands) G. Luers- Corning Glass Ltd., USA T. Lundgren - Terratema AB, Sweden D. Mitchell - AEA Technology (formerly with Warren Spring Laboratory), United Kingdom K. Oberg- Swedish Environmental Protection Agency G. Owen - Environment Canada J. Pappain - Peel Resource Recovery Inc., Canada J. Pearson - AEA Technology, United Kingdom A. Petsonk- Swedish Environmental Protection Agency B. Putnam - International Lead Zinc Research Organization G. Rigo - Rigo & Rigo Associates, Inc., USA J. Robert- Energy, Mines & Resources, Canada F. Roethel - University of New York at Stoney Brook, USA H. Roffman - AWD Technologies, USA S. Sakai - Kyoto University, Japan M. Sheil - New Jersey Dept. of Environmental Protection & Energy, USA B. Simmons - California Board of Health, USA D. St~mpfli - formerly with EAWAG, Switzerland J. Stegemann - Wastewater Technology Centre, Canada
L. Stieglitz - Forschungszentrum Karlsruhe, Germany M. Stringer - Greater Vancouver Regional District, Canada H. Tej ima- Takuma Co., Ltd., Japan T. Theis - Clarkson University, USA B. T imm- Swedish Environmental Protection Agency J. Tsuji - formerly with Environmental Toxicology International Inc., USA
A. van Santen - Energy Technology Support Unit, United Kingdom
J. F. Vicard - LAB, France J. Vogel - Heidelberger Zement, Germany H. Vogg- Forschungszentrum Karlsruhe, Germany S. Waring - AEA Technology, United Kingdom C. Wiles - National Renewable Energy Laboratory, USA
M. Winka - New Jersey Dept. of Environmental Protection & Energy, USA J. W i t t w e r - Environment Canada D. Wexell -Corning, Inc., USA W. Wormgoor - TNO, Netherlands
The IAWG also wishes to thank all of the other people not mentioned here, who in their own way assisted us in this endeavour.
A special "thank you" to S t e p h e n H e t h e r i n g t o n for his patient efforts in revising and reformatting this document.
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T A B L E OF C O N T E N T S
PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
CHAPTER 1 - INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 A BRIEF HISTORICAL EXCURSUS . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 THE DEVELOPMENT OF WASTE INCINERATION . . . . . . . . . . . . . . . . 2 1.3 OBJECTIVE OF THIS TREATISE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
CHAPTER 2 - MUNICIPAL SOLID WASTE 2.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.1 DEFINITION OF MUNICIPAL SOLID WASTE . . . . . . . . . . . . . . . . . . . . 15 2.2 COMPOSITION OF MUNICIPAL SOLID WASTE . . . . . . . . . . . . . . . . . . 17 2.3 QUANTITY AND MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.3.1 Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2.3.2 Denmark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.3.3 France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 2.3.4 Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3.5 Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.3.6 The Netherlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2.3.7 Sweden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2.3.8 Switzerland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2.3.9 United Kingdom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2.3.10 United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.4 CHEMICAL CONSTITUENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
CHAPTER 3 - MUNICIPAL SOLID WASTE INCINERATION TECHNOLOGIES . . . . . . . . . 59 3.1 FUEL RECEIPT AND HANDLING 59 3.2 AVAILABLE COMBUSTION ALTERNATIVES . . . . . . . . . . . . . . . . . . . . 61
3.2.1 Mass Burning Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 European Type Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Grates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Furnace Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Operating Philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Modular Incineration Systems . . . . . . . . . . . . . . . . . . . . . . . . 76 Other Mass Burn Variants . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
3.2.2 Refuse Derived Fuel Systems . . . . . . . . . . . . . . . . . . . . . . . . 79 Semi-Suspension Burning Systems . . . . . . . . . . . . . . . . . . . . 82 Stoker Fired Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
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3.3 3.4
Fluidised Bed Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 HEAT RECOVERY SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 IN-PLANT RESIDUE MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . 89 3.4.1 Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 3.4.2 Grate Siftings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 3.4.3 Heat Transfer System Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
CHAPTER 4 - AIR EMISSION CONTROL STRATEGIES . . . . . . . . . . . . . . . . . . . . . . 97 4.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 4.1 COMBUSTION CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.1.1 Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Compensation for Fuel Variability . . . . . . . . . . . . . . . . . . . . . . 98 Factors Controlling the Chemical Reaction Rate . . . . . . . . . . . 98
4.2 POST-COMBUSTION CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 4.2.1 Unit Processes For Air Pollution Control . . . . . . . . . . . . . . . . 103
Particulate Matter Control Systems . . . . . . . . . . . . . . . . . . . . 103 Electrostatic Precipitators . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Fabric Filter (Baghouses) . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 Gaseous Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Wet Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Dry Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Metals Control in Dry Systems . . . . . . . . . . . . . . . . . . . . . . . 112 Mercury Control with Activated Carbon . . . . . . . . . . . . . . . . . 113 NOx Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
4.3 TYPICAL APC INSTALLATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 4.3.1 Hogdalen, Sweden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 4.3.2 Munich South, Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 4.3.3 Warren County, New Jersey, USA . . . . . . . . . . . . . . . . . . . . 122 4.3.4 Zirndorf, Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 4.3.5 Vestforbr~nding, Copenhagen . . . . . . . . . . . . . . . . . . . . . . . 125 4.3.6 Lausanne, Switzerland . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 4.3.7 Bremerhaven, Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 4.3.8 Stuttgart, Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
CHAPTER 5 - REGULATION OF MSW INCINERATORS . . . . . . . . . . . . . . . . . . . . . 135 5.1 EXISTING MSW INCINERATOR OPERATING GUIDELINES . . . . . . . . 137
5.1.1 Furnace Temperature and Residence Time . . . . . . . . . . . . . . 137 5.1.2 Combustion Efficiency and Carbon Monoxide . . . . . . . . . . . . 139 5.1.3 APC Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 5.1.4 Other Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
5.2 AIR EMISSION STANDARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 5.2.1 Chronological Changes in Emission Standards . . . . . . . . . . . 141 5.2.2 Emissions of Combustion Products and Acid Gases . . . . . . . 144
XV
5.2.3
Hydrogen Chlor ide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Part iculate Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sulphur Dioxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oxides of Nitrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Carbon Monoxide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Total Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrogen Fluoride . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trace Metals Emission Standards . . . . . . . . . . . . . . . . . . . .
144 144 144 145 145 145 145 145
5.2.4 Trace Organic Emission Standards . . . . . . . . . . . . . . . . . . . . 147 5.3 C U R R E N T ASH AND RESIDUE DISPOSAL PRACTICES . . . . . . . . . . 149
5.3.1 Disposal of Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 Denmark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Germany and Switzer land . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Nether lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 Sweden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 United Kingdom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
5.3.2 Disposal of Fly Ash and APC Residues . . . . . . . . . . . . . . . . 153 Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Denmark & the Netherlands . . . . . . . . . . . . . . . . . . . . . . . . . 153 France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 Nether lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 Sweden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
5.3.3 Util isation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 Denmark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 Nether lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Sweden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
CHAPTER 6 - ISSUES RELATED TO INCINERATOR ASH SAMPLING . . . . . . . . . . . . 167 6.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 6.1 THE C O N C E P T OF THE REPRESENTATIVE SAMPLE . . . . . . . . . . . 167
6.1.1 Waste Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 6.1.2 Type of Incinerator /APC System . . . . . . . . . . . . . . . . . . . . . 169 6.1.3 Residue Streams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
6.2 OBJECTIVES OF MATERIAL SAMPLING P R O G R A M S . . . . . . . . . . . 171
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AVAILABLE SAMPLING PROTOCOLS . . . . . . . . . . . . . . . . . . . . . . . . 174 SAMPLING CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 6.4.1 Increment Collection Classification . . . . . . . . . . . . . . . . . . . . 175 6.4.2 Bias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 6.4.3 Precision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
Number of Increments in Composite Sample . . . . . . . . . . . . . 178 6.4.4 Size of Increments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 6.4.5 Collection Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 6.4.6 Sampling Streams Other Than Bottom Ash . . . . . . . . . . . . . . 181
Grate Siftings and Heat Recovery Ash . . . . . . . . . . . . . . . . . 181 APC Residues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 Storage Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 Sampling from Trucks or Containers . . . . . . . . . . . . . . . . . . . 183
6.4.7 Sample Preparation Concerns . . . . . . . . . . . . . . . . . . . . . . . 183 Sample Size Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 Preservation of Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 Sample Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 Sample Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 Laboratory Sample Preparation . . . . . . . . . . . . . . . . . . . . . . 186 Laboratory Sample Subdivision . . . . . . . . . . . . . . . . . . . . . . 186 Drying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Size Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Balance of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
SAMPLE COLLECTION RECOMMENDATIONS . . . . . . . . . . . . . . . . . 188 6.5.1 Generic Bottom Ash Testing Protocol . . . . . . . . . . . . . . . . . . 188 6.5.2 Generic Boiler Ash Sampling Protocol . . . . . . . . . . . . . . . . . 191 6.5.3 Generic APC Residue Sampling Protocol . . . . . . . . . . . . . . . 192 6.5.4 Documentation of Sampling and Preparation Procedures . . . . 193 EXAMPLES OF SAMPLING STRATEGIES . . . . . . . . . . . . . . . . . . . . . . 194 6.6.1 Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Regulatory Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194 Research Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
6.6.2 Grate Siftings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 6.6.3 Boiler/Economiser Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Regulatory Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 Research Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
6.6.4 Air Pollution Control System Residues . . . . . . . . . . . . . . . . . 199 Regulatory Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 Research Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
7.1.1 Visual Observation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
7.2
7.3
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7.1.2
Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fly Ash and APC Residue . . . . . . . . . . . . . . . . . . . . . . . . . . Particle Size Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . Test Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dry Sieve Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fine Particle Analyses Methods . . . . . . . . . . . . . . . . . . . . . .
203 203 205 205 205 206 206
7.1.3 Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 Bulk Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 Specific Gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 Laboratory Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 Field Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
7.1.4 Absorption Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Test Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
7.1.5 Water Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Test Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
7.1.6 Proctor Compaction Test . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 Standard Proctor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 Modified Proctor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
7.1.7 Strength and Strength Development . . . . . . . . . . . . . . . . . . . 211 7.1.8 Bearing Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 7.1.9 Durability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
Soundness Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 LA Abrasion Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Freeze-Thaw Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
7.1.10 Permeabil ity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 Test Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
CHEMICAL COMPOSITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 7.2.1 Sample Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
Size Reduction Techniques . . . . . . . . . . . . . . . . . . . . . . . . . 221 7.2.2 Inorganic Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Digestion Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 Specialty Methods for Specific Elements . . . . . . . . . . . . . . . . 225
7.2.3 Analytical Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 Destructive Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 Non-Destructive Analytical Methods . . . . . . . . . . . . . . . . . . . 229
7.2.4 Loss on Ignition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 7.2.5 Total Carbon, Carbonate, Sulphur and Ammonia . . . . . . . . . . 234 7.2.6 Acid Neutralisation Capacity . . . . . . . . . . . . . . . . . . . . . . . . . 235 7.2.7 Organic Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
Sample Preservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236 Extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
CHEMICAL SPECIATION METHODS . . . . . . . . . . . . . . . . . . . . . . . . . 238 7.3.1 Separatory Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
xviii
Sample Drying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 Particle Size Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 Magnetic Separation Techniques . . . . . . . . . . . . . . . . . . . . . 241 Density Separation Techniques . . . . . . . . . . . . . . . . . . . . . . 242 Selective Phase Dissolution Methods . . . . . . . . . . . . . . . . . . 242
7.3.2 Impregnation, Thin-Sections, and Thin-Foil Methods . . . . . . . 243 7.3.3 Analytical Methods for Solid Phase Chemical Speciation . . . . 245
Transmitted Light Microscopy . . . . . . . . . . . . . . . . . . . . . . . 247 Scanning Electron Microscopy . . . . . . . . . . . . . . . . . . . . . . 247 Petrography (Morphology) . . . . . . . . . . . . . . . . . . . . . . . . . . 247 Scanning Tunnelling Microscopy . . . . . . . . . . . . . . . . . . . . . 249 X-Ray Powder Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . 249 Petrography (Mineralogy) . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 Scanning Electron Microscopy/X-Ray Microprobe Analysis . . 250 Scanning-Transmission Electron Microscopy/X-Ray
Microprobe Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 Auger Electron Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . 251 X-Ray Fluorescence Spectroscopy . . . . . . . . . . . . . . . . . . . 251 X-Ray Photoelectron Spectroscopy . . . . . . . . . . . . . . . . . . . 251 Secondary Ion Mass Spectroscopy . . . . . . . . . . . . . . . . . . . 252 Electron Energy Loss Spectroscopy . . . . . . . . . . . . . . . . . . . 252 X-Ray Adsorption Spectroscopy and Extended X-Ray
Adsorption Fine Structure . . . . . . . . . . . . . . . . . . . . . . . 253 Nuclear Magnetic Resonance . . . . . . . . . . . . . . . . . . . . . . . . 253 Infrared Spectroscopy and Raman Spectroscopy . . . . . . . . . 254
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
CHAPTER 8 - FATE OF ELEMENTS DURING INCINERATION . . . . . . . . . . . . . . . . . 263 8.1 MECHANISMS CONTROLLING THE FATE OF ELEMENTS . . . . . . . . 264
8.1.1 Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 8.1.2 Processes in the Combustion Chamber . . . . . . . . . . . . . . . . 265
Physical Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265 Chemical Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 Sintering and Related Processes . . . . . . . . . . . . . . . . . . . . . 272 Physicochemical Transformations . . . . . . . . . . . . . . . . . . . . . 277
8.1.3 Mechanisms in the Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 Condensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
8.1.4 Mechanisms in the Dust Removal System . . . . . . . . . . . . . . 284 8.1.5 Mechanisms in the Air Pollution Control System . . . . . . . . . . 285
8.2 MASS STREAMS IN A MUNICIPAL SOLID WASTE INCINERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
8.3 LITHOPHILIC ELEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 8.3.1 Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
xix
8.3.2 Alkal i Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288 8.3.3 Earth-Alkal i Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290 8.3.4 Heavy Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292 Chromium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 Nickel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
8.4 V O L A T I L E E L E M E N T S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296 8.4.1 Ha logens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
Chlor ine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297 Fluor ine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 Bromine and Iodine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 Su lphur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 Nitrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
8.4.2 Volat i le Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 Mercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304 Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 Zinc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308 Arsenic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310 An t imony . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 Other Volat i le E lements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
8.5 C A R B O N AND S E L E C T E D C A R B O N C O M P O U N D S . . . . . . . . . . . . . 312 8.5.1 Total Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312 8.5.2 Polychlor inated D ibenzo-p-Diox ins and -Furans . . . . . . . . . . . 314 8.5.3 Polychlor inated Biphenyls . . . . . . . . . . . . . . . . . . . . . . . . . . 320 8.5.4 Polychlor inated Benzenes . . . . . . . . . . . . . . . . . . . . . . . . . . 322 8.5.5 Polychlor inated Phenols . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 8.5.6 Brominated Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . 324 8.5.7 Polycycl ic Aromat ic Hydrocarbons . . . . . . . . . . . . . . . . . . . . 324
R E F E R E N C E S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
CHAPTER 9 - BOTTOM ASH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339 9.1 P H Y S I C A L C H A R A C T E R I S T I C S OF B O T T O M ASH . . . . . . . . . . . . . . 342
9.1.1 Gross Compos i t ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 Reject Fract ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342 Visual Classi f icat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343 Water Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345 Ferrous Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346 Loss on Ignit ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 Dissolvable Sol ids Content . . . . . . . . . . . . . . . . . . . . . . . . . . 351
9.1.2 Gravimetr ic Character is t ics . . . . . . . . . . . . . . . . . . . . . . . . . 351 Specif ic Gravi ty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353 Absorpt ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
XX
9.2
9.3
Soundness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 Abrasion Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
9.1.5 Geotechnical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362 Proctor Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362 Field Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 California Bearing Ratio (CBR) . . . . . . . . . . . . . . . . . . . . . . . 364 Permeability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 Influence of Combustor Type and Operation on Physical
Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 9.1.8 Influence of Aging on Bottom Ash Physical Characteristics . . 367 PARTICLE MORPHOLOGY, MINERALOGY, AND ALKALINITY OF BOTTOM ASH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368 9.2.1 Morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368 9.2.2 Mineralogy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370 9.2.3 Alkalinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372 9.2.4 Influence of Combustor Type and Operation on Bottom Ash
Surface Area, Mineralogy and Alkalinity . . . . . . . . . . . . . . 374 9.2.5 Influence of Aging on Bottom Ash Surface Area, Mineralogy
and Alkalinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374 INORGANIC CHARACTERISTICS OF BOTTOM ASH . . . . . . . . . . . . . 376 9.3.1 Elements Present in Bottom Ash . . . . . . . . . . . . . . . . . . . . . 377 9.3.2 Major Matrix Elements (> 10,000 mg/kg):
O,Si,Fe,Ca,AI,Na,K,C . . . . . . . . . . . . . . . . . . . . . . . . . . . 379 9.3.3 Minor Matrix Elements (1,000 to 10,000 mg/kg):
Mg, Ti, CI, Mn, Ba . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383 9.3.4 Other Minor Elements (1,000 to 10,000 mg/kg):
Zn, Cu, Pb, Cr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385 9.3.5 Other Trace Elements Including Oxyanionic Elements
(<1,000 mg/kg): Sb, V, Mo, As, Se . . . . . . . . . . . . . . . . . 388 9.3.6 Other Trace Elements (<1,000 mg/kg):
Sr, Ni, Co, Cd, Ag, Hg . . . . . . . . . . . . . . . . . . . . . . . . . . 391 9.3.7 Other Trace Elements Continued (<1,000 mg/kg):
B, Br, F, I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396 9.3.8 Elements Related to Biogeochemical Cycles:
C, S, N, P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397 9.3.9 Exotic Elements, Lanthanides, Actinides . . . . . . . . . . . . . . . 400 9.3.10 Isotopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 9.3.11 Role of Particle Size in Element Distribution . . . . . . . . . . . . . 400 9.3.12 Influence of Combustor Type and Operation on Bottom
Ash Inorganic Characteristics . . . . . . . . . . . . . . . . . . . . . 401 9.3.13 Influence of Aging on Bottom Ash Inorganic Characteristics . . 405
9.1.6 9.1.7
9.5 9.6
ORGANIC CHARACTERISTICS OF BOTTOM ASH . . . . . . . . . . . . . . 406 9.4.1 Organics Present in Bottom Ash . . . . . . . . . . . . . . . . . . . . . . 406 9.4.2 Dioxins and Furans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406 9.4.3 Chlorinated Benzenes and Chlorinated Phenols . . . . . . . . . . 408 9.4.4 Polyaromatic Hydrocarbons and Polychlorinated Biphenyls . . 408 CHARACTERISTICS OF GRATE SIFTINGS . . . . . . . . . . . . . . . . . . . . 408 CHARACTERISTICS OF COMBINED ASH AND SCRUBBER RESIDUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
CHAPTER 10 - CHARACTERISTICS OF HEAT RECOVERY SYSTEM ASH . . . . . . . . . 419 10.1 ASH DEPOSITION MECHANISMS . . . . . . . . . . . . . . . . . . . . . . . . . . . 419 10.2 PHYSICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
10.2.1 Particle Size Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . 422 10.2.2 Particle Morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
10.3 CHEMICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425 10.3.1 pH and Acid Neutralisation Capacity . . . . . . . . . . . . . . . . . . . 426 10.3.2 Solubility in Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426 10.3.3 Chemical Composit ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428 10.3.4 Heavy Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431 10.3.5 "Volatile" Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433 10.3.6 Organic Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
PCDD/PCDF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435 Other Chlorinated Organics . . . . . . . . . . . . . . . . . . . . . . . . . 437 Polycyclic Aromatic Hydrocarbons (PAH) . . . . . . . . . . . . . . . 437
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
CHAPTER 11 - CHARACTERISATION OF AIR POLLUTION CONTROL RESIDUES . . . . 441 11.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
11.1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441 Fly Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441 Dry System Residues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442 Semi-dry System Residues . . . . . . . . . . . . . . . . . . . . . . . . . 442 Wet Scrubber Sludge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
11.2 MAJOR FACTORS INFLUENCING THE CHARACTERISTICS OF APC RESIDUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
11.3 PHYSICAL CHARACTERISTICS OF APC RESIDUES . . . . . . . . . . . . . 444 11.3.1 General Appearance and Behaviour . . . . . . . . . . . . . . . . . . . 444 11.3.2 Particle Size Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . 444 11.3.3 Geotechnical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
11.4 PARTICLE MORPHOLOGY AND MINERALOGY . . . . . . . . . . . . . . . . 450 11.5 WATER SOLUBILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452 11.6 LOSS ON IGNITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
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11.7 CHEMICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454 11.7.1 pH and Acid Neutralisation Capacity . . . . . . . . . . . . . . . . . . . 457 11.7.2 Chemical Composition: Inorganic Constituents . . . . . . . . . . . 460
Ranges of Elemental Composition of APC System Residues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
Major Elements (>10,000 mg/kg): O, CI, Ca, Si, Mg, Fe, AI, K, Na, Zn, S, Pb . . . . . . . . . . . 464
Trace Elements (< 1,000 mg/kg): Hg, Cd, Sb, Cr, Sr, Ni, As, V, Ag, Co, Mo, Se . . . . . . . . . 470
11.7.3 Role of Particle Size in Element Distribution . . . . . . . . . . . . . 473 11.7.4 Chemical Composition: Organic Constituents . . . . . . . . . . . . 473
Organics Present in APC System Residues . . . . . . . . . . . . . 473 Chlorinated Benzenes and Phenols . . . . . . . . . . . . . . . . . . . 474 Polychlorinated Biphenyls . . . . . . . . . . . . . . . . . . . . . . . . . . 476 Polycyclic Aromatic Hydrocarbons . . . . . . . . . . . . . . . . . . . . 476 Dioxins and Furans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476 Phthalates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
11.8 COMPOSITION OF WASTEWATER FROM WET SCRUBBER APC SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
CHAPTER 1 2 - PHYSICAL ASPECTS OF LEACHING . . . . . . . . . . . . . . . . . . . . . . . 483 12.1 AN INTRODUCTION TO LEACHING . . . . . . . . . . . . . . . . . . . . . . . . . 483
12.1.1 Physical Aspects of Leaching . . . . . . . . . . . . . . . . . . . . . . . . 485 The Leaching System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485 Particle Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486 Fluid Flow Past Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . 486 The Local Equilibrium Assumption . . . . . . . . . . . . . . . . . . . . 487
12.1.2 Chemical Aspects of Leaching . . . . . . . . . . . . . . . . . . . . . . . 487 Equilibrium Versus Kinetic Systems . . . . . . . . . . . . . . . . . . . 488 Influence of pH on Dissolution . . . . . . . . . . . . . . . . . . . . . . . 488 Influence of Complexation on Dissolution . . . . . . . . . . . . . . . 488 Influence of Oxidation-Reduction Potential on Dissolution . . . 489 Influence of Sorption on Leaching . . . . . . . . . . . . . . . . . . . . 489
12.1.3 Leaching Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489 12.1.4 Leaching Modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490 12.1.5 Unified Approach to Leaching . . . . . . . . . . . . . . . . . . . . . . . 491
12.2 THE SOLID PHASE/LEACHANT/SOLUTE LEACHING SYSTEM . . . . . 491 12.2.1 The Leaching System Concept . . . . . . . . . . . . . . . . . . . . . . . 491 12.2.2 A Multiphase Heterogeneous System . . . . . . . . . . . . . . . . . . 491 12.2.3 Leaching Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
12.3 RESIDUE PARTICLES AS A SOLID PHASE . . . . . . . . . . . . . . . . . . . 495 12.3.1 Particle Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495 12.3.2 Particle Morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496
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12.4 FLUID FLOW, DIFFUSION AND MASS TRANSFER . . . . . . . . . . . . . . 498 12.4.1 Fluid Flow Through Residues . . . . . . . . . . . . . . . . . . . . . . . . 498 12.4.2 Fluid Flow Past Particles in Suspension . . . . . . . . . . . . . . . . 500 12.4.3 Diffusional Processes and Internal Mass Transfer
Considerations in Residues . . . . . . . . . . . . . . . . . . . . . . 501 12.4.4 External Mass Transfer Considerations in Residues . . . . . . . 503
12.5 THE LOCAL EQUILIBRIUM ASSUMPTION . . . . . . . . . . . . . . . . . . . . . 504 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505
CHAPTER 13 - CHEMICAL ASPECTS OF LEACHING . . . . . . . . . . . . . . . . . . . . . . 507 13.1 LEACHING CHEMISTRY FUNDAMENTALS . . . . . . . . . . . . . . . . . . . . 507
13.1.1 Thermodynamic Equilibrium Models Versus Kinetic Models . . 507 13.1.2 Ionic Strength, Ion Activity, Activity Coefficients . . . . . . . . . . . 511 13.1.3 Cation/Anion Balances . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517 13.1.4 A Note on General Equilibrium Constants . . . . . . . . . . . . . . . 520
13.2 SOLUTION COMPLEXATION AND SPECIATION . . . . . . . . . . . . . . . . 522 13.2.1 Solution Complexation Equilibria . . . . . . . . . . . . . . . . . . . . . 524 13.2.2 An Example of Lead Complexation in a Hypothetical
Leaching Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525 13.2.3 Leaching Solution Speciation . . . . . . . . . . . . . . . . . . . . . . . . 530
13.3 DISSOLUTION/PRECIPITATION REACTIONS . . . . . . . . . . . . . . . . . . 531 13.3.1 Heterogeneous Dissolution/Precipitation Equilibria . . . . . . . . . 532 13.3.2 Oversaturation/Undersaturation and the Ion Activity
Product . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534 13.3.3 Metastability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536 13.3.4 An Example of Lead Dissolution/Precipitation as PbSO4(s):
A Very Simple Leaching System . . . . . . . . . . . . . . . . . . . 538 13.3.5 An Example of Lead Dissolution/Precipitation as Pb(OH)2(s):
The Role of Solution Phase Complexation and Amphoterism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540
13.3.6 An Example of Lead Dissolution/Precipitation as PbCO3(s): The Role of CO2(g) in Controlling Metal Carbonate Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
13.3.7 Solubility Control and the Coexistence of Multiple Solid Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544
13.3.8 An Example of Lead Dissolution/Precipitation When Both Pb(OH)2(s ) and PbCO3(s ) are Present . . . . . . . . . . . . . . . 546
13.3.9 Solid Phase Stability in a Redox-Variable System . . . . . . . . . 548 13.4 CHEMICAL WEATHERING AND AGING . . . . . . . . . . . . . . . . . . . . . . 550
13.4.1 The Mineral Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551 13.4.2 Weathering Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551 13.4.3 Surface Reaction-Controlled Dissolution . . . . . . . . . . . . . . . . 553 13.4.4 Weathering Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555 13.4.5 Aging Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556
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13.5 SORPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558 13.5.1 Surface Functional Groups . . . . . . . . . . . . . . . . . . . . . . . . . 558 13.5.2 Activity-Based Sorption Models . . . . . . . . . . . . . . . . . . . . . . 561 13.5.3 Electrostatic Surface Complexation Models . . . . . . . . . . . . . . 564 13.5.4 Adsorption Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567
13.6 A UNIFIED APPROACH TO LEACHING . . . . . . . . . . . . . . . . . . . . . . . 567 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570
CHAPTER 1 4 - LEACHING TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579 14.1 PURPOSE OF LEACHING TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
14.1.1 Classification of Leaching Tests . . . . . . . . . . . . . . . . . . . . . . 579 Extraction Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580 Agitated Extraction Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . 581 Non-agitated Extraction Tests . . . . . . . . . . . . . . . . . . . . . . . 582 Sequential Chemical Extraction Tests . . . . . . . . . . . . . . . . . . 583 Concentration Buildup Tests . . . . . . . . . . . . . . . . . . . . . . . . 584 Dynamic Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584 Serial Batch Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585 Flow Around Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585 Flow Through Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586
14.1.2 Leaching Test Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . 588 Sample Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588 Leachant Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589 Method of Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 591 Liquid-to-Solid Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592 Contact Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594 Leachate Separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
14.1.3 Compilat ion of Leaching Tests . . . . . . . . . . . . . . . . . . . . . . . 595 14.2 A UNIFIED APPROACH TO LEACHING TESTS . . . . . . . . . . . . . . . . . 599 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606
CHAPTER 15 - LEACHING MODELLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607 15.1 EQUILIBRIUM MODELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 607
15.1.1 Thermodynamic Equilibrium Models . . . . . . . . . . . . . . . . . . . 608 15.1.2 Use of the Geochemical Thermodynamic Equilibrium
Model MINTEQA2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609 15.1.3 Verification of MINTEQA2 . . . . . . . . . . . . . . . . . . . . . . . . . . 611 15.1.4 Recommendations for Utilising MINTEQA2 to Model
Leaching Behaviour . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615 15.1.5 Modelling US, pH, and Redox Control of Leaching . . . . . . . . 617 15.1.6 Modelling US, pH, Redox and Complexation Control
of Leaching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 619
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15.1.7 Modell ing Sorption Reactions Influencing Leaching . . . . . . . . 621 15.1.8 Modell ing Solid Phase Control of Leaching in Conjunction
with Solid Phase Speciation Studies . . . . . . . . . . . . . . . . 621 15.1.9 Modelling Solid Phase Control of Leaching in Dynamic
Flow-Through Systems . . . . . . . . . . . . . . . . . . . . . . . . . . 626 15.1.10 Modelling Field Leaching Behaviour . . . . . . . . . . . . . . . . . . . 627
15.2 DYNAMIC MULTICOMPONENT MODELS . . . . . . . . . . . . . . . . . . . . . 628 15.2.1 Dynamic Mult icomponent Models . . . . . . . . . . . . . . . . . . . . . 628 15.2.2 Modelling Solid Phase Dissolution . . . . . . . . . . . . . . . . . . . . 632 15.2.3 Modelling Solid Phase Reprecipitation and Solubility
Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632 15.3 FUTURE DIRECTIONS IN MODELLING . . . . . . . . . . . . . . . . . . . . . . . 633 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634
CHAPTER 16- LEACHING DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637 16.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637
16.1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637 16.1.2 Data Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637 16.1.3 Data Transformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 638
16.2 TOTAL SOLUBLE FRACTION AND AVAILABILITY OF ELEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 638 16.2.1 Total Soluble Fraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 638 16.2.2 Total Availabil ity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639 16.2.3 Sequential Chemical Extractions . . . . . . . . . . . . . . . . . . . . . 641
16.3 SOLUBILITY AND RELEASE OF ELEMENTS . . . . . . . . . . . . . . . . . . . 642 16.3.1 Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646
Arsenic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 648 Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 Chromium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 Molybdenum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 Nickel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653 Zinc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653
16.3.2 APC Residues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653 Boron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653 Barium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657 Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657 Chromium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657 Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657 Mercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657 Molybdenum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657 Zinc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657
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16.4
16.5
16.6
GEOCHEMICAL MODELLING OF LEACHING EQUILIBRIA . . . . . . . . . 658 16.4.1 Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659
Calcium and Sulphate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659 Magnesium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659 Silicon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659 Aluminum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662 Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662 Manganese . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662 Sodium, Potassium, Bromide and Chloride . . . . . . . . . . . . . . 663 Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663 Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663 Molybdenum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666 Zinc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666
16.4.2 Modelling of APC Residue Leachability . . . . . . . . . . . . . . . . . 668 16.4.3 Application of Geochemical Modelling Results . . . . . . . . . . . . 668 RELEASE RATES OF ELEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 670 16.5.1 Release As A Function Of Liquid To Solid Ratio . . . . . . . . . . 671
Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 673 APC Residues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 679
16.5.2 Diffusion Controlled Release . . . . . . . . . . . . . . . . . . . . . . . . 682 RESIDUE LEACHING IN THE CONTEXT OF REGULATORY LEACHING TESTS AND WASTE FROM OTHER SOURCES . . . . . . . . 684 16.6.1 Regulatory Tests and pH Dependent Leaching . . . . . . . . . . . 684
German DIN 38414 (1984) and French AFNOR X-31-210 (1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 684
Japanese Leaching Test . . . . . . . . . . . . . . . . . . . . . . . . . . . 686 Swiss TVA (1988) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686 USA, California WET Test . . . . . . . . . . . . . . . . . . . . . . . . . . 686 US EP Toxicity Test (1980), the Toxicity Characteristic
Leaching Procedure (TCLP) (1990) and the Regulation 309 (now 347) Leach Procedure . . . . . . . . . . . . . . . . . . . 686
Alternative Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 687 16.6.2 Systematic Leaching Behaviour Among Different
Incinerator Residues Streams And Other Wastes . . . . . . . 687 LEACHING OF ORGANIC CONSTITUENTS . . . . . . . . . . . . . . . . . . . . 700 EFFECTS OF INCINERATOR OPERATION ON LEACHING . . . . . . . . 702 16.8.1 Combustion Efficiency (Burn out) and Facility Operation . . . . 702 16.8.2 Waste Feed Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . 702 16.8.3 Seasonal Variations In Leaching . . . . . . . . . . . . . . . . . . . . . 708
Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708 Molybdenum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711 Nickel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711 Zinc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711
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16.8.4 Quench Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711 16.9 EFFECTS OF RESIDUE PROCESSING AND
MANAGEMENT ON LEACHING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713 16.9.1 Size-Reduction And Size Fractionation . . . . . . . . . . . . . . . . 713 16.9.2 Storage And Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718 16.9.3 Comparison Of Laboratory Data To Field Measurements . . . 722
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 728
CHAPTER 17 - SEPARATION PROCESSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735 17.1 DEFINITION OF PROCESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735 17.2 PHYSICAL SEPARATION TECHNIQUES . . . . . . . . . . . . . . . . . . . . . . 736
17.2.1 On-site Separation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737 Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737 Fly Ash and APC Residues . . . . . . . . . . . . . . . . . . . . . . . . . 738
17.2.2 Metal Separation from Bottom Ashes . . . . . . . . . . . . . . . . . . 739 17.3 PHYSICO-CHEMICAL AND CHEMICAL SEPARATION
TECHNIQUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741 17.3.1 Washing Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741
Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741 Bottom Ashes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741 Air Pollution Control Residues . . . . . . . . . . . . . . . . . . . . . . . 743
17.3.2 Acid Leaching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745 Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745 Filter and Boiler Ashes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 746
17.3.3 Ion Exchange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 749 Principles and Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 749
17.3.4 Hg Recovery from Flue Gas Scrubbing Solutions . . . . . . . . . 751 17.3.5 C rystall isation/Evapo ration . . . . . . . . . . . . . . . . . . . . . . . . . . 751
Principles and Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 751 NaCI Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 751 CaCI 2 Production from Dry/Semidry APC System Residues . . 752 Gypsum Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 752
17.3.6 HCI Recovery by Distillation . . . . . . . . . . . . . . . . . . . . . . . . . 755 Principles and Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755 Proposed Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755
17.3.7 Electrochemical Processes . . . . . . . . . . . . . . . . . . . . . . . . . 755 Principles and Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755 Chlorine Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 758
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759
CHAPTER 1 8 - SOLIDIFICATION & STABILISATION . . . . . . . . . . . . . . . . . . . . . . . 763 18.1 DEFINITION OF PROCESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763 18.2 EFFECTS OF SOLIDIFICATION/STABILISATION . . . . . . . . . . . . . . . . 764
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18.2.1 Physical Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 764 18.2.2 Chemical Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766
18.3 EVALUATION OF SOLIDIFICATION/STABILISATION PROCESSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 767 18.3.1 Physical Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 771 18.3.2 Chemical and Leaching Tests . . . . . . . . . . . . . . . . . . . . . . . 773 18.3.3 Other Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775 REVIEW OF AVAILABLE PROCESSES . . . . . . . . . . . . . . . . . . . . . . . 776 18.4.1 Stabilisation Without Additives . . . . . . . . . . . . . . . . . . . . . . . 776 18.4.2 Solidification/Stabilisation with Binders . . . . . . . . . . . . . . . . . 777
Cement-Based Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 777 Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 780 Waste Pozzolanic Systems . . . . . . . . . . . . . . . . . . . . . . . . . 782 Chemical Stabilisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
18.4.3 Stabilisation With Organic Additives . . . . . . . . . . . . . . . . . . . 785 18.4.4 Macro-Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786 18.4.5 Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
19.1.1 Vitrification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791 19.1.2 Fusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792
19.2 GLASS COMPOSITION AND METALS RETENTION IN GLASS MATRICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793 19.2.1 Glass Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793 19.2.2 Constituent Retention Mechanisms . . . . . . . . . . . . . . . . . . . . 796 19.2.3 Chemical Attack and Leaching Mechanisms . . . . . . . . . . . . . 799 19.2.4 Factors Influencing Vitrified Ash Leaching . . . . . . . . . . . . . . . 801
Chemical Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801 Waste Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801 Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
19.3 PROCESSING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803 19.3.1 Processing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803 19.3.2 Energy Requirements and Costs . . . . . . . . . . . . . . . . . . . . . 803
19.4 THERMAL TREATMENT PROCESSES UNDER DEVELOPMENT . . . . 803 19.4.1 Overview of Reported Processes . . . . . . . . . . . . . . . . . . . . . 803
19.5 VITRIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805 19.5.1 Vitrification of APC Residues by Corning, Inc . . . . . . . . . . . . . 811
19.6 FUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 817 19.6.1 Fusion of Filter Ash by ABB Deglor Process . . . . . . . . . . . . . 819 19.6.2 Japanese Fusion Processes . . . . . . . . . . . . . . . . . . . . . . . . 822
19.7 SINTERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 830
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 836
CHAPTER 20 - LEACHING OF PRODUCTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 841 20.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 841 20.2 PHYSICAL AND CHEMICAL FACTORS WHICH EFFECT
CONSTITUENT RELEASE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 842 20.3 TEST METHODS FOR MONOLITHIC AND COMPACTED
GRANULAR PRODUCTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 843 20.3.1 ANS 16.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 844 20.3.2 NEN 7345 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 844 20.3.3 Compacted Granular Leach Test . . . . . . . . . . . . . . . . . . . . . 845
20.4 INTERPRETATION OF DIFFUSION CONTROLLED RELEASE . . . . . . 845 20.4.1 Characteristic Release Behaviours . . . . . . . . . . . . . . . . . . . . 845
Diffusion Controlled Release . . . . . . . . . . . . . . . . . . . . . . . . 845 Depletion of Leachable Species . . . . . . . . . . . . . . . . . . . . . . 845 Delayed Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 847 Surface Wash-Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 847 Wash-Out of Mobile Species (Dissolution) . . . . . . . . . . . . . . . 847 Change in Chemical Condit ions . . . . . . . . . . . . . . . . . . . . . . 847
20.4.2 Definition of Leaching Parameters . . . . . . . . . . . . . . . . . . . . 848 20.4.3 Calculation of Effective Diffusion Coefficients from
Cumulative Release Data . . . . . . . . . . . . . . . . . . . . . . . . 854 20.4.4 Alternative Release Models for Monolithic Materials . . . . . . . . 858
20.5. RELEASE FROM PRODUCTS CONTAINING INCINERATOR RESIDUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 860 20.5.1 Total Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 860 20.5.2 Effective Diffusion Coefficients, Physical Retention and
Chemical Retention . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861 Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861 Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 863 Zinc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 863 Sodium, Sulphate and Chloride . . . . . . . . . . . . . . . . . . . . . . 863
20.5.3 Solubility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 874 20.6 INTEGRATED INTERPRETATION OF pD e AND AVAILABILITY . . . . . . 878
Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 887 Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 887 Lead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 887 Zinc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 890 Sodium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 890 Chloride . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 890
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 893
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CHAPTER 21 - UTILISATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 895 21.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 895 21.2 CURRENT AND PLANNED PROJECTS . . . . . . . . . . . . . . . . . . . . . . 896
21.2.1 Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 896 21.2.2 Denmark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 896 21.2.3 Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 897 21.2.4 The Netherlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 897 21.2.5 Sweden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 898 21.2.6 United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 899
21.3 CURRENT REGULATORY FRAMEWORK . . . . . . . . . . . . . . . . . . . . . 901 21.3.1 Denmark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902 21.3.2 Germany . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905 21.3.3 The Netherlands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905 21.3.4 Sweden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 911 21.3 .5 United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 911
21.4 TECHNICAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 914 21.5 UTILISATION LIFE CYCLE AND ENVIRONMENTAL
CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916 21.5.1 Ash Type Selection and Elements of Concern . . . . . . . . . . . . 916 21.5.2 Ash Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 917 21.5 .3 Physical Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 918 21.5.4 Stockpiling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 918 21.5 .5 Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 919 21.5.6 Use Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 919
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 922 21.5.7 Reuse and Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 926 21.5.8 Economic Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 926
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 926
CHAPTER 22 - DISPOSAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 931 22.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 931 22.2 CHARACTERISTICS OF INCINERATOR RESIDUE LANDFILL
LEACHATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 932 22.2.1 Overview of Incinerator Residue Leachabil ity . . . . . . . . . . . . 932 22.2.2 Bottom Ash Leachate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 934 22.2.3 Fly Ash and Acid Gas Scrubbing Residue Leachate . . . . . . . 937 22.2.4 Combined Ash Leachate . . . . . . . . . . . . . . . . . . . . . . . . . . . 940
22.3 DISPOSAL STRATEGIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 940 22.3.1 General Philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 941
Lifetime of Active Systems . . . . . . . . . . . . . . . . . . . . . . . . . . 942 Waste Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 943 Adaptation of Landfill Design, Operation and Siting
to Strategy and Waste Types . . . . . . . . . . . . . . . . . . . . . 945 Ultimate Fate of the Leachate . . . . . . . . . . . . . . . . . . . . . . . 946
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22.3.2 General Disposal Strategies . . . . . . . . . . . . . . . . . . . . . . . . . 947 Total Containment or Entombment . . . . . . . . . . . . . . . . . . . . 948 Containment and Collection of Leachate . . . . . . . . . . . . . . . . 948 Controlled Contaminant Release . . . . . . . . . . . . . . . . . . . . . 950 Unrestricted Leaching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 950
22.4 DESIGN AND OPERATIONS ISSUES . . . . . . . . . . . . . . . . . . . . . . . . 950 22.4.1 Siting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 951 22.4.2 Liners and Leachate Collection Systems . . . . . . . . . . . . . . . . 951 22.4.3 Caps and Top Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 953 22.4.4 Geotechnical Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 953 22.4.5 Abatement of Noise, Odour and Fugitive Dust Problems . . . . 954 22.4.6 Monitoring of Leachate Quantity and Quality . . . . . . . . . . . . . 954 22.4.7 Monitoring of Groundwater and Surface Water Quality . . . . . . 955 22.4.8 Leachate Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 957 DISPOSAL PRACTICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 957 DISPOSAL RECOMMENDATIONS FOR INCINERATOR RESIDUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959 22.6.1 Bottom Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 960 22.6.2 APC Residues (Fly Ash and Acid Gas Scrubbing
Residues) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 961 22.6.3 Combined Ash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 962
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 962
CHAPTER 1 -INTRODUCTION
1.1 A BRIEF HISTORICAL EXCURSUS
Since the dawn of human existence, people have produced what could be described as waste. But the issue of managing these wastes did not appear until human culture evolved past the stage of nomadic hunter-gatherer into a settled agricultural-based existence. During these times, waste management was not a real cause for concern. The relatively small populations lived in vast areas, and there was no shortage of places to discard food-scraps and excrement. Food-scraps even provided a source of nourishment for livestock or were used as fertiliser to enrich the cultivated soil. Broken implements, pottery or other materials which were no longer useful were simply discarded on scrap piles in outlying areas without further thought.
Today, archaeologists are able to gather detailed information on the state of human cultural development and prosperity by excavating ancient dump sites. As human culture advanced, increasing population densities created a very real need to manage both the solid waste and excrement being generated. Evidence exists that the first culturally complex cities in Mesopotamia and Indus established means of disposing of excrement through underground sewage pipes and practised separate collection of solid waste. Even in the Bible, we find reference to a waste disposal site. In the time of King Solomon's successors Asa, Hisia and Josia, the waste from Jerusalem was brought to the Kidron Valley, where it was incinerated in open fires (Anonymous, First Book of Kings). The ashes from these fires were then brought to Bethel, or were scattered over the graves of the nearby Jerusalem cemetery (Anonymous, Second Book of Kings).
Even with all that had been achieved in some of these civilisations, waste management took a turn for the worst in the cities of medieval Europe. Excrement, food waste and other materials were merely cast into the streets to be dealt with by the rain, wind, sun and any unfortunate passerby. The situation became so serious that solutions had to be found. Examples of these, albeit simple solutions, began to appear during the latter half of the 13th century. There is evidence that streets constructed in Hamburg, Germany, were designed with inclines leading to a central gutter to allow the rains to wash away wastes more easily. During the 15th century, increasing population densities forced municipalities to introduce waste collection systems. In some areas, prisoners of war, slaves and criminals were often used to carry out these onerous tasks, whereas other municipalities hired people to do the job. These people were either paid directly by the authorities or special taxes were collected.
In 1473, there was a new twist in waste management. An enterprising commercial hauler actually paid the City of Amsterdam for the right to collect putrescible wastes from the City and then sold the material to farmers in the surrounding countryside as fertiliser (Erhard, 1964). Although this form of waste management soon caught on in
bigger cities, the eventual glut of material made it difficult to market the putrescibles to farmers, and municipalities were finally forced to pay for hauling of the waste. The commercial viability continued to decline until the 17th century, when individual towns began to takeover waste management operations themselves.
With the industrial revolution in the 19th century, came the generation of new types of waste materials in previously unheard of quantities. Although many of these new wastes were not biodegradable, they were considered a problem due to their noxious nature. In North America, the marketing of putrescible waste to farmers was a common and relatively successful practice, however to reduce the quantities of other waste materials requiring disposal, other potentially valuable materials were separated using a three level collection system. This involved installing three-bin collection systems in homes. One bin was used to collect only organic kitchen waste, such as food scraps, which was then used for food for livestock. In some instances, milkmen performed a double duty by collecting this waste as well as their normal delivery duties. In major cities like New York, Boston and Chicago, fat was collected and recycled in special facilities, some of which remained in operation into the early 1900's.
Another bin was used to collect potentially marketable materials such as textiles, footwear, glass, metals and wood. The remaining bin was used to store the ashes generated from fireplaces and stoves. This form of waste collection system was also in evidence in some parts of Europe in the latter part of the 19th century (de Fodor, 1911). However, most European cities managed their waste by transporting it out of the city and dumping the material in designated areas. Animals foraged in the piles for food and the less fortunate were allowed to pick through the waste for whatever was salvageable (see Figure 1.1 ). Despite the efforts of municipalities, waste management could not keep pace with the rapidly growing population and the resulting burgeoning quantities of waste. By the early 1900's, annual per capita waste generation rates were growing. For example, it was estimated that New York City's annual rate was 540 Kg/person, London's exceeded 300 Kg/person, whereas Budapest, Munich and Zurich all exceeded 230 Kg of waste/person/year (de Fodor, 1911 ).
1.2 THE DEVELOPMENT OF WASTE INCINERATION
Although the relationship between hygiene and human health was first recognised in England during the 19th century, it took the high profile efforts of physicians like Max von Pettenkofer, Louis Pasteur and Robert Koch to emphasise the fact that epidemics of disease, such as cholera and typhoid, were the result of bacteria spread by unsanitary conditions, and not acts of God. Based on this need to manage waste in a sanitary fashion and the growing need to quench industries' thirst for fuel, the first waste incinerators were developed in England.
Needless to say, the first attempts at the process were not very successful. In 1870, attempts were made to burn waste in a retrofitted coal-burning furnace in Paddington.
Figure 1.1 Women Sorting the Waste of Vienna at the end of the 19th Century
de Fodor, 1911
The incinerator was designed so that coal was burned on a grate to provide the major source of heat to initiate combustion of the waste on a separate grate located above the coal grate. Unfortunately, the wet nature of the waste and poor heat transfer in the system resulted in what could best be described as a smouldering effect. Only the persevering demands of physicians to "disinfect" waste kept this, and other small units operating against heavy public opposition.
But even in these early attempts, it was noted that high temperatures in the furnace not only reduced the odour of flue gases, but they also generated an ash which was suitable for reuse as a building material. The first fully functional municipal solid waste incinerator was constructed in Manchester, England in 1876. The unit design included an induced draft fan which helped to maintain higher burning temperatures on the hearth. The facility operated for 27 years and the generated ash was used as a building material.
The next major development was based on the need to further reduce the odours of the flue gases. In 1885, the incinerator in Egling was equipped with what was dubbed "a cremator." The "cremator" consisted of a coal-fired grate in which the flue gases from the waste furnace were passed before being released into the atmosphere. Soon after, the energy release from waste combustion came under the study of scientists like Lord Kelvin. It was found that 1 Kg of waste could generate 1.5 Kg of steam, which subsequently led to the design and construction of the world's first combined waste incinerator/electrical power generation facility, in the municipality of Shoreditch in London, in 1897.
Early waste incinerators were operated in a batch-wise mode. The units were usually fed by hand, as illustrated in Figure 1.2. Removing the slag and clinker was also done by hand, although proved to be a difficult task at times due to the extensive slagging on the grates. An example of this is illustrated in Figure 1.3. The Figure also illustrates the design of the facility. Note that the individual units were located in close proximity to one another, to facilitate better heat transfer and to help start-up new fuel beds after a unit was cleaned out.
Design efforts soon began to focus on mechanical feeding and cleaning of the incinerator grates. Sequential feeding and deslagging provided a more homogenous temperature profile and hence improved combustion (Figure 1.4). Even at this early stage, the basic principles of waste incineration were comparable with those of today. For example, it was not merely satisfactory to disinfect the waste, but it had to be done in a manner which prevented the emissions of malodorous flue gases. In addition, it was preferable to recover the energy released during the process and make use of the ash which remained. In 1910, 194 English towns made use of waste incinerators. The proliferation of the practice also led to further innovations, such as the practice of using the waste feed as a gas tight seal for the furnace, which is still used today (Figure 1.5).
One of the most successful incinerator designs of the day was the Horsefall cell-type incinerator, developed by the Horsefall Destructor Company of Leeds. This was further modified by Heenan & Froude Ltd. of Worcester. These systems were generally operated as the final stage in a separation and reclamation system which was equipped with drum screens, magnetic separator