Assessment of waste generation and diversion rates in residential construction projects in Australia

Construction and Demolition (C&D) waste has received major attention due to its adverse impact to the environment and this has led to the development of waste management as an essential function of construction project management. Zero waste strategy targets to achieve 100% waste diversion rate from landfill and optimize resource recovery from waste. The Australian green star rating tool aims to encourage and reward waste management practices that minimize the amount of construction and demolition waste disposed to landfill. In Australia, C&D waste account for 27% of overall landfill and the resource recovery rate is around 64% which is relatively low compared with other developed nations. The Australian government has set targets to increase the rate of construction to meet ongoing and future residential property demand. Thus, there is a pressing need to avoid and minimize the waste at all stages of construction projects by implementing dynamic waste avoidance measures such as promoting the use of modular and prefabricated systems and the need for reuse/recycling waste into new products and services. The aim of this research is to evaluate the waste generation and diversion rates of residential projects in Australia. Waste generation data of 10 material streams from 10 residential projects were collected and analyzed based on the Waste Generation Rates (WGR) and the New Construction Green Star points. The results revealed that concrete, timber, metal and masonry are the most wasted materials in the residential projects. The WGRs indicated a consistent pattern with ‘good’ performance ranking. In addition, the assessment of green star rating for waste management credit revealed that all the projects are eligible for green star credit point 1 out of 14 as they demonstrated above 92% diversion rate of wasted materials. Although the studied projects showed higher recycling rate, this study claims that achieving a higher rate of recovery could not be assured unless accurate waste estimation is carried out with reliable and verifiable data. Such has to consider as the limitation of this study with the lack of reliable data on non-recyclable waste that is dumped either by the developer or waste processing facilities. Future studies on waste estimation and managing waste through re-use and recycling with the use of smart technologies would provide a holistic solution to improve the waste management practices towards achieving sustainability in construction projects