Environmental Impact Assessment of Mobile Recycling of Demolition Waste in Shenzhen, China

Abstract

In recent years Shenzhen has witnessed a significant amount of demolition waste as a result of large scale of urban renewal. A notification enacted in early of 2017 required demolition waste to be recycled and encouraged the usage of mobile recycling facility to handle waste on demolition site. The mobile recycling may help reduce environmental impact as it avoids the long distance transportation of demolition waste to stationary recycling plants. This study aims to assess the environmental impact of mobile recycling of demolition waste and estimate the potential environmental benefit of avoiding transportation using the Life Cycle Assessment method (LCA). The studying scope includes waste pretreatment, waste crushing and screening, recycled aggregate transportation and disposal of residue. Four mobile recycling projects were investigated to collect the information about mobile recycling equipments and energy consumption. Accordingly, environmental impact inventory of one ton waste was presented with five types of environmental emissions and occupied land for disposal of residue. The environmental emissions were classified into the five types of environmental impact, i.e. global warming, photochemical smog, eutrophication, and environmental acidification, as well as land occupation. After characterization, the impacts of different pollutants were transformed into a unified characteristic index referring the representative pollutants of each kind of environmental impact. Applying social willingness to pay for each environmental impact category as a weighting factor, the monetization value of each environmental impact category was calculated. By comparing the environmental impact in term of stage and type, the differences of the environmental impact of all projects were discussed. The main reasons causing the differences were explored. Also, the potential environmental benefit of avoiding waste transportation is analyzed. Based on these results, some suggestions on reducing the environmental impact of the recycling process were put forward.

Keywords: demolition waste, mobile recycling, environmental impact, Life cycle assessment (LCA)