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Sustainably managing municipal solid waste (MSW) is a global challenge since the existing MSW processing procedure releases greenhouse gases and is economically unfriendly. An emissions trading scheme (ETS) is a market-based approach for policymakers to reduce sectoral carbon emissions while maintaining economic efficiency. Hitherto, no waste optimisation framework links ETS to carbon reduction and identifies the trade-offs between the cost of carbon credit trading and waste expenses, rendering doubt of ETS's effectiveness in the waste sector. In this study, an MSW-ETS framework is developed to analyse the potential impact of ETS on the MSW management system incorporating multiple waste types, disposal and treatment facilities, and waste-based products. A multi-objective optimisation model is integrated with the MSW-ETS framework to achieve mutual environmental and economic benefits. Malaysia is selected as an illustrative case study considering its unsustainable MSW disposal and the recent carbon trading plans announced by the government. Simulation of the carbon prices alters Malaysia's MSW management configuration at 363 MYR/tonne CO2-eq, providing insights on developing the carbon price floor for a Malaysian ETS. Six MSW management configurations under different scenarios that can achieve up to 160% GHG emissions reduction were also proposed. The MSW-ETS framework integrated with the multi-objective optimisation model could be replicated by other countries planning to phase the waste sector into ETS coverage. [ABSTRACT FROM AUTHOR]

The construction industry will play a crucial rule in global carbon emission reduction as the embodied carbon of construction materials shares an increasing portion of a building's life-cycle carbon dioxide (CO2) emissions. In order to reduce CO2 emissions by selecting low-carbon construction materials, it is inevitable that a proper benchmarking mechanism and severity representation of different emission levels should be established, as benchmarking is a useful tool for pursuing consumer purchasing habits toward selection of low-carbon materials. In addition, high variation of carbon emissions is observed among the large number of studies and databases, and there is no consensus on how these should be used in practice. Therefore, standardization and benchmarking of emissions for construction materials are essential. In this study, a novel benchmarking approach was developed for embodied carbon emissions of commonly used construction materials by applying a fuzzy set theory. Given that a reliable local database is lacking, the benchmark was developed by referring to the existing carbon inventories, linguistic variables of severity levels from a questionnaire survey, and the fuzzy set analysis. A six-step method was proposed based on a horizontal and graphical approach. This study offers an alternative approach in benchmarking where a database or a set of real data is not available. It is expected that the developed benchmarks will help practitioners and decision-makers compare the embodied CO2 emissions of a specific batch of construction materials and select low-carbon materials in construction projects. [ABSTRACT FROM AUTHOR]

In recent years, considerable efforts have been devoted to minimizing the environmental consequences from building industry globally, as the industry is notorious for its significant resource consumption and environmental emissions. However, due to a lack of data representativeness in many parts of the world, considerable variations were observed among studies, and thus makes life cycle assessment (LCA) results difficult for the decision-making purpose. In addition, the selection of low impact materials and the management of end-of-life building waste are the most important concern. By considering several strategies including data representativeness, low carbon material, and end-of-life building waste management, this study aimed to enhance the accuracy of such assessment and sustainability performance of building. An integrated LCA framework is proposed for implementing those strategies through a case specific high-rise residential building in Hong Kong. Based on case-specific/regional data, carbon emission of building was evaluated with a cradle-to-construction system boundary with the functional unit of 1 m2 of gross floor area using the IMPACT 2002+ method, and then compared to that of selecting generic databases under different scenarios. The results demonstrate that the application of case-specific and generic data would significantly influence the outcomes of the case study, as the deviations of certain magnitudes were mostly derived from different building materials that it can lead to an underestimation of carbon emissions of up to 28%. Along with using alternative materials, the adoption of the proposed materials cycling and resource recovery approach at the end-of-life building could lead to a reduction of 14% of the total emissions (i.e. excluding the use and renovation of building). The results would support data selection for accuracy of evaluation which can be used as benchmark where recognized database is not available and promote sustainability performance of buildings locally, while the proposed framework could be adopted for comprehensive evaluation globally. • Proposed integrated framework for enhancing accuracy and sustainability of building. • Data representativeness is a prerequisite for the accuracy of building LCA. • Representative data induced significantly higher carbon emission than generic data. • Using alternative materials for concrete reduced building's carbon emission. • Adopting resource recover approach in EoL significantly reduced carbon emission. [ABSTRACT FROM AUTHOR]