Evaluating the Economics of Construction and Demolition Waste Minimisation and Zero Waste in the New Zealand Construction Industry
Tran, Van Dai
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Currently, up to 50% of construction and demolition (C&D) waste is disposed of in landfills contributing to significant environmental, social and economic costs to New Zealand. However, current understanding of C&D costs is poor both internationally and within New Zealand. This thesis addresses this deficit by developing a framework to evaluate the economics of C&D waste minimisation. An understanding gained from this research could help New Zealand develop appropriate strategies to address C&D waste issues. As the research problem is complex and wide-ranging, this study used a mixed-method approach. Semi-structured elite interviews with highly experienced construction personnel were used to identify factors affecting a C&D waste minimisation strategy. This also established the context of the economic evaluation framework. Economic modelling was subsequently employed to develop the economic evaluation framework. The framework was then applied on two case studies: 1) a development of a large education facility and 2) a refurbishment of a commercial office space. The study found that: 1. a C&D waste landfill/cleanfill charge of $150 per tonne can a) deter construction from disposing of waste; and b) force construction to rethink waste disposal 2. C&D waste minimisation can offer clients benefits including tangible returns (i.e. cost savings) and intangible potentials (i.e. increased reputation) 3. there are costs of implementing C&D waste minimisation - but benefits gained can outweigh such costs; and 4. the optimal rate of reduction for C&D waste in the non-residential projects studied was 71% - 78% Overall, this research has made a contribution to knowledge through the development of a robust economic evaluation framework. Moreover, the study has also provided an impetus for future work in C&D waste minimisation economics in New Zealand.