Cost-benefit analysis of demolition waste management via agent-based modelling: A case study in Shenzhen

The economic instrument is an effective approach to encourage demolition contractors to conduct low-impact waste management. It is essential for project managers and decision-makers to better understand the cost-benefit of demolition waste (DW) management, to promote development of an effective waste management plan. This study explores the interactive dynamics and adaptive nature between stakeholders, where the cost-benefit of DW management is analysed through the agent-based modelling approach. Shenzhen, a leading city in China in the management of DW, was selected as the study area. It was revealed that if the traditional demolition method is adopted as the primary choice, the net benefit of demolition of buildings in the study case will reach -131.4 billion yuan, i.e. the cost will surpass the revenue. If the selective demolition method is widely used by demolition contractors, simulation results indicate that the net benefit will reach 33.3 billion yuan, an increase of 125.34%, compared to the situation in which the traditional demolition method is widely implemented. Based on the simulation, an optimal management framework for DW management stakeholders was constructed. The research results can provide a decision-making basis for the government and relevant departments to formulate DW management measures.

Life cycle assessment of the end-of-life phase of a residential building

The study investigates the potential environmental impacts related to the end-of-life phase of a residential building, identified in a multifamily dwelling of three levels, constructed in the South of Italy by utilizing conventional materials and up-to-date procedures. An attributional life cycle assessment has been utilised to quantify the contributions of each stage of the end-of-life phase, with a particular attention to the management of the demolition waste. The investigation takes into account the selective demolition, preliminary sorting and collection of main components of the building, together with the processes of sorting, recycling and/or disposal of main fractions of the demolition waste. It quantifies the connections between these on-site and off-site processes as well as the main streams of materials sent to recycling, energy recovery, and final disposal. A sensitivity analysis has been eventually carried out by comparing the overall environmental performances of some alternative scenarios, characterised by different criteria for the demolition of the reference building, management of demolition waste and assessment of avoided burdens of the main recycled materials. The results quantify the advantage of an appropriate technique of selective demolition, which could increase the quality and quantity of residues sent to the treatment of resource recovery and safe disposal. They also highlight the contributions to the positive or negative environmental impact of each stage of the investigated waste management system. The recycling of reinforcing steel appears to play a paramount role, accounting for 65% of the total avoided impacts related to respiratory inorganics, 89% of those for global warming and 73% of those for mineral extraction.