Environmental benefits of construction and demolition debris recycling: Evidence from an Indian case study using life cycle assessment

Abstract

The adversarial effects of construction and demolition (C&D) waste on the environment are on the increase. While materials such as metals, wood, glass and plastics are segregated and diverted for reuse/recycling, C&D debris consisting of concrete, bricks and tiles are landfilled in most of the countries. LCA studies have indicated a clear preference for recycling. However, it has been inferred that the environmental credits obtained in these studies were mainly from recycling of metals and wood and studies focusing on environmental impacts/benefits evaluation of C&D debris recycling is limited. This is particularly relevant in the cases of developing countries like India, where C&D debris forms a bulk of C&D waste generation. Therefore, this paper evaluates the environmental impacts of four different scenarios for managing C&D debris comprising the present (S1) and future (S2) landfilling options and recycling options without transfer stations (S3) and with transfer stations (S4). LCA according to ISO methodology is performed based on locally sourced data supplemented with Ecoinvent database. IMPACT 2002+ impact assessment method has been applied for environmental impact quantification using SimaPro software. Landfilling of C&D debris generates environmental impacts, and recycling scenarios generate environmental benefits in all 15 impact categories. Single score values of landfilling scenarios are 1.83 mPt (S1) and 2.78 mpt (S2) and that of C&D debris recycling are −2.56 mPt (S3) and −1.91 mPt (S4). The robustness of the results was shown through sensitivity analysis. Recycling remains beneficial compared to landfilling as long as the diesel and electricity consumption of C&D debris recycling facility remains less than 475% of the current consumption. Furthermore, even if the transportation distance from quarry to crushing unit is reduced to zero, recycling still remains a better alternative. The merit of considering the future landfilling scenario in the decision making has been discussed since the challenges that might be encountered in setting up new landfills are underestimated. The implications of the findings and their relevance to urban local bodies have also been discussed to help policymakers take informed decisions while facing challenges of managing C&D debris.