Environmental Impacts of Multi-Storey Buildings Using Different ...

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- 100 -Gasification of waste wood involves the extraction of gaseous fuel from wood by heating inan oxygen-free environment. The gas from the wood (which can include hydrogen andmethane) is then mixed with oxygen and used for energy production, for example in gasturbines. This method can be an effective way of recovering energy from waste wood. Theproblem with using gasification for waste treated timber is the same as with incineration.Gasification usually occurs at above 800 °C, and at this temperature volatilisation of arsenicwill occur. Again the waste gas stream would have to be cleaned before it could be released tothe atmosphere. Currently there are no commercial projects that use gasification to processtreated waste wood.Pyrolysis is a similar process to gasification, except the decomposition of the wood happensat much lower temperatures (
- 101 -example, removal of CCA treatment from treated wood has been demonstrated using oxalicacid and copper-tolerant bacteria. (Clausen, 2004) This process reported removal rates as highas 83 % for Cu, 86 % for Cr, and 95 % for As. The downside to this technology is the timeand expense needed to complete this extraction. The method involves an 18-hour extractionusing oxalic acid to remove the chromium and arsenic, followed by a 7 to 9 day bioleachingprocess to remove the copper. Some brown-rot fungi have displayed copper tolerance, andhave been successfully used for the purpose of treatment extraction. (Taylor, 2005).Electro-dialytic remediation is a method developed and patented at the Technical Universityof Denmark (DTU). It uses an electric current to mobilise the metal ions in solution, and anion exchange membrane to then separate the electrolytes out. Prior to electro-dialytictreatment, wood is soaked in solutions of oxalic acid or a combination of phosphoric acid andoxalic acid. In experiments, this type of electro-dialytic treatment removed up to 87% of theCu, 81% of the Cr and >95% of the As in wood. (Christensen, 2004).All of the remediation techniques mentioned above have a major drawback; that is, the woodmust be chipped or ground into small particles to achieve a high extraction rate. This is anenergy-intensive process. Also, high volumes of wood would be difficult to process due to thelengthy time these processes take. A 10-day treatment time, plus drying time and thepossibility of altered wood properties (important if the wood is to be recycled intoparticleboard etc.) renders these processes impractical at this current time. One very importantpoint is that the literature articles describe how the processes result in virtually non-toxicwood, yet most of these articles neglect to mention what happens to the extraction liquid,which will have become saturated with heavy metals. The disposal or processing of this liquidcould be of serious environmental concern.An ideal solution for end-of-life treated timber would be a recycling or disposal process thatcan deal with treated and untreated wood, without the need for additional processing (see alsosection 8.6.5).8.6.3 RecyclingA few different options for creating recycled products have been tested with treated timber.Many of these are mentioned in the 2005 UK-based report on treated wood waste (WRAP,2005). Products such as particleboard, chipboard and oriented strand board (OSB) cantheoretically be made with treated timber; however there are drawbacks to this.Firstly, in Europe and the UK, contamination standards are set for the production ofparticleboard (and similar products). These standards would mean that the percentage ofCCA-treated timber that could be used in particleboard production would be less than 1 %.Also, CCA-treated timber that had been subjected to oxalic acid chemical extraction andbacterial remediation displayed a reduction in integrity and strength (but an increase inelasticity) once processed into particleboard.Standard CCA-treated wood waste used in particleboard resulted in similar physicalproperties, yet leaching of arsenic was relatively high. (Clausen, 2000 and 2001). Wetprocessedfibreboard using CCA-treated timber can be made with very similar properties asnormal untreated fibreboard, however the product is processed in water, and the cleanup ofthis water could pose problems due to the leaching of arsenic. In New Zealand, the Auckland
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Environmental Impacts ofMulti-Store
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ContentsGlossary...................
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6.3.4.3 Maintenance related embodie
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- 9 -GlossaryCO 2 stored - refers t
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- 11 -Chapter 7Chapter 8Chapter 9Ch
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- 13 -An alternative end-of-life sc
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- 15 -designers and a shortage of b
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- 17 -• Ministry for the Environm
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- 19 -which it can be fashioned to
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- 21 -For fire safety, the New Zeal
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- 23 -buildings for low seismic are
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- 25 -4 The Buildings4.1 Constructi
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- 27 -the building. The basement le
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- 29 -4.3.2 Common Design Principle
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- 31 -Figure 4.5: South-west façad
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- 33 -the three longitudinal frames
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- 35 -4.3.5.2 Floor and RoofThe str
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- 37 -4.4 Multi-Storey Timber Build
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- 39 -Several different solutions h
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- 41 -5 Operational Energy5.1 Gener
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- 43 -Table 5.1: Simulation inputs
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- 45 -Table 5.3: Areas of office en
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- 47 -Modifying the design to achie
Page 49 and 50: - 49 -• Standards New Zealand (NZ
Page 51 and 52: - 51 -6 Life Cycle Assessment6.1 In
Page 53 and 54: - 53 -6.2.3.3 Impact AssessmentThe
Page 55 and 56: - 55 -6.3.2.2 System BoundariesThe
Page 57 and 58: - 57 -For more information see:http
Page 59 and 60: - 59 -6.3.3 Inventory Analysis6.3.3
Page 61 and 62: - 61 -Table 6.2: Net tonnes CO 2 eq
Page 63 and 64: - 63 -Growing timber takes up CO 2
Page 65 and 66: - 65 -6.3.4 Impact AssessmentTotal
Page 67 and 68: - 67 -8000700060005000GWP (t CO2 eq
Page 69 and 70: - 69 -As explained above, carbon st
Page 71 and 72: - 71 -Figure 6.10: Total embodied e
Page 73 and 74: - 73 -Table 6.9: Total GWP of each
Page 75 and 76: - 75 -8,0007,0006,0005,000GWP (t CO
Page 77 and 78: - 77 -45000400003500030000GWP (kg C
Page 79 and 80: - 79 -assumed to be identical for t
Page 81 and 82: - 81 -6.4.3.2 Green Star Recycling
Page 83 and 84: - 83 -Table 6.16: Green Star result
Page 85 and 86: - 85 -The contribution of initial e
Page 87 and 88: - 87 -results, the reutilisation sc
Page 89 and 90: - 89 -7.1.1 Platform and Balloon Co
Page 91 and 92: - 91 -buildings has been analysed a
Page 93 and 94: - 93 -Figure 7.5: Construction sche
Page 95 and 96: - 95 -8.2 Source and Availability o
Page 97 and 98: - 97 -It would be incorrect, howeve
Page 99: - 99 -8.5 Additional Opportunities
Page 103 and 104: - 103 -The Waste Minimisation Bill
Page 105 and 106: - 105 -9 Discussion9.1 The Building
Page 107 and 108: - 107 -• The buildings tend to be
Page 109 and 110: - 109 -9.4.3 Data Sets9.4.3.1 Gener
Page 111 and 112: - 111 -The following assessment wil
Page 113 and 114: - 113 -Table 9.1. GWP coefficients
Page 115 and 116: - 115 -Figure 9.2 shows that the ne
Page 117 and 118: - 117 -placing and retaining materi
Page 119 and 120: - 119 -Net CO 2 emissions - that is
Page 121 and 122: - 121 -The LVL specified for the st
Page 123 and 124: - 123 -10 ConclusionsThe following
Page 125 and 126: - 125 -building types, instead subs
Page 127 and 128: - 127 -In summary, reutilisation sh
Page 129 and 130: - 129 -• What is the ranking of t
Page 131 and 132: - 131 -• What is the comparison i
Page 133 and 134: - 133 -Connell Wagner (2007): Combu
Page 135 and 136: - 135 -Suzuki, Michiya, and Tatsuo
Page 137 and 138: - 137 -C O N C R E T E B U I L D I
Page 139 and 140: - 139 -S T E E L B U I L D I N Gm m
Page 141 and 142: - 141 -T I M B E R B U I L D I N Gm
Page 143 and 144: - 143 -T I M B E R B U I L D I N G
Page 145 and 146: - 145 -T Exterior Wall Cladding 581
Page 147 and 148: - 147 -Appendix B. Life times of bu
Page 149 and 150: - 149 -Appendix D: Transport scenar
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- 151 -Appendix F: Warren and Mahon
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Timber Plus ProjectSummary of the T
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Timber Plus ProjectGreen Star Ratin
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Timber Plus ProjectVolatile Organic
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Timber Plus ProjectThe Forest Stewa
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Timber Plus ProjectStain and Clear
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Timber Plus ProjectINTERIOR WALL CL
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Timber Plus ProjectWINDOW REVEALSMa
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Timber Plus ProjectSOFFIT FRAMINGMa
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Timber Plus ProjectEXTERIOR WALL CL
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Timber Plus ProjectAdditional Oppor
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Appendix AResene Expected Paint Sys
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- 152 -Appendix G: Green Star Asses
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New Zealand Forest Research Institu
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Executive SummaryA common building
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1 IntroductionA common building des
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Timber pluso The same assumptions a
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Table 1-1-1: Weightings in Green St
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The science behind LCA is still dev
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In comparison the LCA results have
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All four buildings in this research
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1.4 Further WorkThe difficulty in m
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