Harn Wei Kua

Factors Determining the Potential of Biochar As a Carbon Capturing and Sequestering Construction Material: Critical Review

AbstractBiochar is relatively well understood as a soil enhancement. Recently, it has been explored as a construction material. While works had been conducted on deploying biochar for road construc...

Are People Responsive to a More Sustainable, Decentralized, and User-Driven Management of Urban Metabolism?

Smart, green, and resilient city paradigms have been mainly promoted through top-down and technocratic approaches. However, based on the notion to return to “the right to the city”, emerging community-driven initiatives are providing self-managed infrastructures contributing to urban sustainability transitions. This paper explores the relevance of the behavioral aspects of people-centered approaches in dealing with two different facets of urban metabolism: physical infrastructure (involvement with the management of decentralized infrastructures) and consumption patterns (involvement in proactive reduction of resources used). In the first case we assessed community perceptions about the roles, benefits, and willingness to proactively engage in the management of decentralized green infrastructures in Bogota City, Colombia. For the second facet, we measured the effectiveness of change agents in re-shaping energy consumption decisions within urban social networks in South Africa and Saudi Arabia. This paper’s results show that pre-determined and standardized strategies do not guarantee positive, nor homogeneous, results in terms of meeting sustainability targets, or promoting community involvement. Hence, a better integration of people-centered and top-down approaches is needed through context-dependent policies, for enhancing both users’ appreciation of and commitment to urban metabolism participative management.

Improving the clean development mechanism with sustainability-rating and rewarding system.

As the world contemplates a post-Kyoto Protocol climate change policy architecture, some key observations of the clean development mechanism (CDM) remind us that climate change policies should be linked more closely to the promotion of sustainability. A sustainability-rated CDM (SR-CDM) is proposed in this paper; it applies the gold standard as a way of assessing the sustainability value of projects with respect to the millennium development goals. These values can be converted into sustainability credits that can qualify project host countries and Annex 1 investing parties for sustainability assistance funds; these funds can be used for developing projects that further promote sustainability. To encourage fund-providers to contribute to these funds, a portion of the certified emission reductions and voluntary emission reductions generated by the projects will be rewarded to these fund-providers. The overall objective of SR-CDM is to promote local and global emission reduction, technology transfer, sustainability and renewable energy/energy efficiency by providing explicit incentives to all key parties involved in the CDM project development and financing.

Some key barriers to technology transfer under the clean development mechanism

Technology transfer is not an explicit objective of the clean development mechanism (CDM) of the Kyoto Protocol, but if well structured, it could be a vehicle for transferring environmentally sustainable technologies from Annex I countries to non-Annex I countries. In this paper, a few key barriers to technology transfer which concern the conflicts between CDM and international investment laws, protection of intellectual property rights (IPR) of the project developers and the capacity of developing countries to accept and benefit from technology transfer are examined. The paper makes suggestions on how to address these barriers in order to create an investment and project development environment that would encourage the developed countries to participate in sustainable development projects in developing countries without fear of their IPR being violated. Furthermore, the paper makes suggestions on how the developing countries could benefit from investment inflows and technology transfer that would boost sustainable development in their jurisdictions.

A total building performance approach to evaluating building acoustics performance

Acoustic comfort is an important consideration in the design and construction of office buildings. Since the acoustic performance of a building will affect its inhabitants psychologically, sociologically and physiologically, post-occupancy evaluations of acoustic performance are often necessary to ensure that acoustic design features are effective. Since acoustic quality is often affected by the interplay among the buildings interior, structural, envelope and mechanical systems, it is critical to assess acoustic quality in an integrated manner. This article presents a detailed acoustic evaluation of a three-storeyed office building by adopting a total building performance (TBP) approach. Through plan/archive analysis, expert walkthrough, objective acoustic measurements and analysis, the existing acoustic problems are identified. Subjective views of occupants regarding acoustic quality in the office and warehouse spaces are also sought. It was found that both objective and subjective data support each other. By understanding how these problems are caused by the interactions among the different building systems, specific solutions were proposed. In summary, this work highlights the usefulness of using a TBP concept to diagnose the acoustic quality of a multi-storeyed office building in an integrated manner. This project is motivated by an effort to promote workplace comfort and sustainability within the framework of corporate social responsibility.

Application of biochar from food and wood waste as green admixture for cement mortar

Landfilling of food waste due to its low recycling rate is raising serious concerns because of associated soil and water contamination, and emission of methane and other greenhouse gases during the degradation process. This paper explores feasibility of using biochar derived from mixed food waste (FWBC), rice waste (RWBC) and wood waste (mixed wood saw dust, MWBC) as carbon sequestering additive in mortar. RWBC is prepared from boiled plain rice, while FWBC is prepared from combination of rice, meat, and vegetables in fixed proportion. Carbon content in FWBC, RWBC and MWBC were found to be 71%, 66% and 87% by weight respectively. Results show that addition of 1-2wt% of FWBC and RWBC in mortar results in similar mechanical strength as control mix (without biochar). 1wt% of FWBC led to 40% and 35% reduction in water penetration and sorptivity respectively, indicating higher impermeability of mortar. Biochar from mixed wood saw dust performed better in terms of mechanical and permeability properties. Increase in compressive strength and tensile strength by up to 20% was recorded, while depth of water penetration and sorptivity was reduced by about 60% and 38% respectively compared to control. Both FWBC and MWBC were found to act as reinforcement to mortar paste, which resulted in higher ductility than control at failure under flexure. This study suggests that biochar from food waste and mixed wood saw dust has the potential to be successfully deployed as additive in cement mortar, which would also promote waste recycling, and sequester high volume carbon in civil infrastructure.

Editorial: Policy and legislative architecture to deal with climate change and sustainable development in a post-Kyoto framework

This Editorial identifies challenges that need to be addressed post-Kyoto, which include the continuing debate between the developed nations and developing nations on the responsibility for climate change and the impacts mitigatory action would have on economic development. Despite the ongoing debate on who should be more responsible in leading the battle against climate change, the evidence available shows the need for urgent action. It then introduces the papers, presented during the 14th International Sustainable Research Conference, by highlighting a common theme which runs across them: that greenhouse gas emission abatement should be achieved within the larger and more far-reaching framework of sustainable development.

A review of some key climate change legislations and policies: lessons for Singapore's construction industry

There is overwhelming scientific consensus that the climate is changing due to primarily human-induced activities. Emission of greenhouse gases from the energy and construction sectors is one of the main human induced causes. Most legislative and policy initiatives by countries to deal with climate change will have a significant impact on the energy and construction sectors. In proposing the appropriate sustainability lessons for Singapores construction industry, this paper briefly examines the international framework for dealing with climate change and the key legislative and policy initiatives in the USA and Australia, two of the largest GHG emitters in the world. This paper argues that the relevant mechanism introduced in all three countries is insufficient to deal with the impacts of climate change, as their main focus is on mitigation. The most rigorous mitigation efforts currently might not be able to prevent climate changes in the near future; hence, adaptation to climate change should become an integral part of the planning process, especially in the construction sector.