title: Sustainability assessment and prioritisation of bottom ash management in Macao.
abstract: In Macao, about 7200 t yr-1of bottom ash (BA) is generated and conventionally landfilled with construction waste. Because the properties of BA are similar to those of natural aggregates, it is suitable to be recycled as construction material. However, pre-treatment processes for BA reuse may require more resource input and may generate additional environmental impacts. Life cycle assessment, multi-media transport model analysis, cost-benefit analysis and the analytical hierarchy process were conducted to evaluate the impacts of current and potential BA management scenarios regarding environmental, economic, social and regulatory aspects. The five analysed scenarios are as follows: (0) BA buried with construction and demolition waste (current system); (1) pre-treated BA used to replace 25% of the natural aggregate in asphalt concrete; (2) pre-treated BA used to replace 25% of the natural aggregate in cement concrete; (3) pre-treated BA used to replace 25% of cement in cement concrete; and (4) pre-treated BA sent to China, blended with municipal solid waste for landfill. The results reveal the following ranking of the scenarios: 3 > 2 > 0 > 1 > 4. Scenario 3 shows the best conditions for BA recycling, because the quantity of cement concrete output is the highest and this brings the greatest economic benefits. Our use of integrated analysis provides multi-aspect investigations for BA management systems, particularly in accounting for site-specific characteristics. This approach is suitable for application in other non-western regions.
authors.affiliation: Graduate Institute of Environmental Engineering, National Taiwan University, ROC.
authors.forename: W I
authors.initials: WI
authors.lastname: Sou
authors.affiliation: Graduate Institute of Environmental Engineering, National Taiwan University, ROC.
authors.forename: Andrea
authors.initials: A
authors.lastname: Chu
authors.affiliation: Graduate Institute of Environmental Engineering, National Taiwan University, ROC ptchueh@ntu.edu.tw.
authors.forename: P T
authors.initials: PT
authors.lastname: Chiueh
mesh_terms: D002273:Carcinogens / Q000633:toxicity; D002681:China; D060729:Coal Ash / Q000032:analysis / Q000737:chemistry / Q000633:toxicity; D003252:Construction Materials; D003362:Cost-Benefit Analysis; D004777:Environment; D017143:Fuzzy Logic; D006801:Humans; D017745:Incineration; D008256:Macau; D008962:Models, Theoretical; D011639:Public Opinion; D059027:Recycling; D012037:Refuse Disposal / Q000379:methods; D064091:Waste Disposal Facilities; D018505:Waste Management / Q000191:economics / Q000379:methods*
chemical_list: D002273:Carcinogens; D060729:Coal Ash
keywords: Bottom ash; Macao; analytical hierarchy process; cost–benefit analysis; life cycle assessment; life cycle sustainability assessment; multi-media transport model