Quantifying and managing plastic waste generated from building construction in Auckland, New Zealand

Each year, construction and demolition (C&D) waste contributes at least 25,000 tonnes to the total amount of plastic landfilled in Auckland, New Zealand. The growing use of plastic in the packaging of building materials, use of polystyrene and products, such as building wrap, are contributing to this. Unlike countries such as the UK, most construction waste in New Zealand is not sorted on-site, and C&D waste is often co-mingled; therefore, minimal analysis on the recoverability of plastics has been attempted. This study identified and quantified the plastic waste stream produced from four construction sites, generated from various stages of construction in Auckland, New Zealand. Plastic waste was taken over three construction stages including demolition, exterior and weatherproofing and services and cladding, amounting to 112 kg (or 11.2 m³). The main types of plastic analysed were polyethylene, contributing 77% (by mass), and polyvinyl chloride, representing 31% (by mass). The main reason for the generation of plastic waste across the four sites was highly variable and dependent on construction stage. However, it was apparent that plastic packaging of materials was not the single area of concern, and plastic building componentry and protection materials should also be investigated for their contribution. This study supports the requirement for improved understanding and awareness around the composition and fate of plastic C&D waste. Long-term benefits to the construction industry are from raising awareness of the potential to make profits from valuable waste products and to improve environmental performance and reputation, for a competitive advantage in New Zealand.