Pre-Treatment of Municipal Solid Waste Incineration (MSWI) Bottom Ash for Utilisation in Road Construction
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2006:25 DOCTORAL T H E SI S Pre-Treatment of Municipal Solid Waste Incineration (MSWI) Bottom Ash for Utilisation in Road Construction Jelena Todorovic´ Luleå University of Technology Department of Civil and Environmental Engineering Division of Waste Science and Technology 2006:25|: 02-544|: - -- 06 ⁄25 -- Doctoral Thesis PRE-TREATMENT OF MUNICIPAL SOLID WASTE INCINERATION (MSWI) BOTTOM ASH FOR UTILISATION IN ROAD CONSTRUCTION Jelena Todoroviü Division of Waste Science and Technology Department of Civil and Environmental Engineering Luleå University of Technology SE-971 87 Luleå, Sweden 2006:25 1402-1544 LTU-DT--06/25--SE Utbildning Doctoral thesis Institution Upplaga Samhällsbyggnad Avdelning Datum Avfallsteknik 2006-05-12 Titel Pre-treatment of municipal solid waste incineration (MSWI) bottom ash for utilisation in road construction Författare Språk Jelena Todorovic ENG Sammanfattning Municipal solid waste incineration (MSWI) bottom ash has the potential for utilisation in construction, e.g. as a road base material. Such an utilisation would decrease the amount of bottom ash to be landfilled. However, leachates generated from bottom ash could be concentrated with respect to salts and metals, causing environmental problems. The use of carbonation of as a method to decrease the leaching of inorganic pollutants from MSWI bottom ash has been studied. Field investigations and laboratory leaching experiments enabled the identification of inorganic pollutants whose leaching might be critical during such an utilisation. Treatment methods by carbonation and water extraction were evaluated regarding the mobility of seven critical pollutants (Al, Cl, Cr, Cu, Mo, Sb and SO4). The stabilising effect of carbonation to a moderate alkaline level (~pH 8.3) was evaluated and compared to the mobilising effect of carbonation in excess (~pH 6.4). Carbonation to a moderate alkaline level demobilised four (Al, Cr, Cu and Sb) of seven critical components. Washing to remove easily soluble salts was recommended in addition to moderate carbonation. Carbonation in excess had the highest mobilising effect on Cr, Cu and Sb when interacted with other factors, mostly pH. Carbonation in excess was therefore proven to be a key factor enhancing the effectiveness of MSWI bottom ash treatment by wet extraction. Uppdragsgivare The Swedish Energy Agency, The Swedish Research Council for Environment, Agricultural Science, and Spatial Planning (Formas), Värmeforsk and the Board of Technical Faculty of Luleå University of Technology. Granskare/Handledare Anders Lagerkvist URL: http://epubl.luth.se/1402-1544/2006/25 III ACKNOWLEDGEMENTS Producing a PhD thesis would be impossible without the support from colleagues, friends and family. For helping me during the writing of this thesis, I would like to thank “from the bottom of my heart”: - Dr. Holger Ecke, my patient supervisor who shared his knowledge and experience, supported and encouraged me, and read and commented on hundreds of pages of my work; - Professor Anders Lagerkvist, who welcomed me to his team, supervised my work, shared his wisdom and gave me support; - Malin Svensson, Inga Herrmann and Solvita Ore for sharing their results and knowledge with me and for their fruitful cooperation on scientific publications; - Ulla-Britt Uvemo, Roger Lindfors, Kerstin Nordqvist and Thomas Forsberg, who patiently assisted me during my laboratory and field work; - Henrik Bristav (Umeå Energi AB), Maria Nyholm (Ragn-Sells Avfallsbehandling AB) and Maria Vamling (Sundsvall Energi AB), who provided information and material essential to this work; - Valerie Herbert who contributed with her senior design project to this work; - Lale Anderas and Christian Maurice for reading and commenting the manuscript; - Wayne Chan for language editing; - Herlander Sapage and Kjell Havnesköld for solving my computer related problems; - colleagues at the Division of Waste Science and Technology, Luleå University of Technology, for creating an inspiring environment for research work; - friends and colleagues at Alternative Academic Educational Network, Belgrade and Dräger Medical, Belgrade, for their help and support; - my dear friends in Sweden and Belgrade for all the joyful times that we shared; - mom, dad and Dragan for their unconditional love, support and encouragement, and; - my love Anders, who “coloured” my life with his friendship, humour and love. I would also like to gratefully acknowledge the financial support of the Swedish Energy Agency, The Swedish Research Council for Environment, Agricultural Science, and Spatial Planning (Formas), Värmeforsk and the Board of Technical Faculty of Luleå University of Technology. Eskilstuna, May 2006, Jelena Todoroviü. Jelena Todoroviü, Division of Waste Science and Technology, LTU, 2006 V TABLE OF CONTENTS List of papers .................................................................................................................VII Summary.........................................................................................................................IX Sammanfattning..............................................................................................................XI 1 Introduction............................................................................................................... 1 1.1 Objectives ......................................................................................................... 2 2 Material andmethods................................................................................................ 2 2.1 Material............................................................................................................. 2 2.2 Test road........................................................................................................... 2 2.3 Moderate carbonation of bottom ash ................................................................ 3 2.4 Excess carbonation of suspended bottom ash................................................... 3 2.5 Leaching tests................................................................................................... 3 Compliance leaching test.......................................................................................... 3 Availability test......................................................................................................... 4 Diffusion leaching test.............................................................................................. 4 pH-stat leaching test.................................................................................................. 4 Column test............................................................................................................... 4 2.6 Chemical analyses............................................................................................. 4 2.7 Statistical methods ............................................................................................ 5 Analysis of fractional factorial design...................................................................... 5 Multivariate data analysis (MVDA) ......................................................................... 5 3 Results anddiscussion .............................................................................................. 6 3.1 Critical components .......................................................................................... 6 Components exceeding regulatory leaching limits................................................... 6 Comparison with leaching from conventional construction material....................... 7 3.2 Testing approaches......................................................................................... 10 Leaching mechanisms............................................................................................. 10 Chemical aspects of self-binding of bottom ash..................................................... 11 Testing incineration residues using diffusion test................................................... 11 3.3 Evaluation of treatment methods .................................................................... 11 Moderate carbonation ............................................................................................. 12 Supplementary treatment to moderate carbonation ................................................ 16 Jelena Todoroviü, Division of Waste Science and Technology, LTU, 2006 VI Carbonation in excess .............................................................................................18 Prospects .................................................................................................................20 4 Conclusions .............................................................................................................21 5 Outlook....................................................................................................................22 6 List of abbreviations................................................................................................23 7 References ...............................................................................................................24 Appendices: Papers I – V Jelena Todoroviü, Division of Waste Science and Technology, LTU, 2006 VII LIST OF PAPERS The research presented is based on two projects, namely Bottom ash in road construction and Stabilisation of refuse-derived fuel (RDF) ashes by carbonation, resulting in the five appended scientific papers listed below. Todorovic, J. and Ecke,