| Summary: | 碩士 === 國立臺灣大學 === 環境工程學研究所 === 103 === Bottom ash is a byproduct of municipal solid waste incineration, which has become an increasingly important issue as urbanization increases waste generation, particularly in countries where population density is high and land is scarce. Bottom ash contains environmental pollutants, instigating research into analysis of its life cycle assessment, to seek treatments which prevent further environmental harm, in order to develop better management approaches and regulation.
The research employs the concept of life cycle sustainability assessment to analyze bottom ash treatment in five scenarios. Life cycle assessment, CalTOX (a multi-media transport model), cost-benefit analysis, and analytical hierarchy process are used to evaluate the five scenarios regarding environmental, social, and economic aspects.
In the case study of bottom ash treatment in Macao, five scenarios were used for analysis, scenario 0: bottom ash and construction waste are buried together (current status); scenario 1: pretreated bottom ash is used to replace 25% of natural aggregate portion in asphalt concrete; scenario 2: pretreated bottom ash is used to replace 25% of natural aggregate in cement concrete; scenario 3: pretreated bottom ash is used to replace 25% of cement in cement concrete; scenario 4: pretreated bottom ash is sent to China and blended with municipal solid waste for landfill.
A comprehensive results of the aforementioned quantitative approach reveals the following ranking: scenario 3 > 0 > 2 > 1 > 4. It can thus be seen that scenario 3 boasts the best conditions for bottom ash recycling, because output is the highest and it brings highest economic benefits. Nevertheless, the test results of the four target pollutants (Cd, Cr, As, Pb) indicate that regional and receptor parameters are very important determiners. It can be concluded that regional assessment is of great significance; a more comprehensive consideration can be obtained by other assessment criteria and different analytic aspects. Apart from this research, which involves the analysis of bottom ash management, the same research framework can be applied into different environmental issues to forge a more integrated environmental management structure in Macao.
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