Technical and Economic Parameters Affecting Reuse of Construction and Demolition Waste in India: Case Studies from Bengaluru and Ahmedabad

Abstract

The construction sector in India requires enormous amounts of natural resources such as sand, soil, stones, and the demand is expected to increase manifold in coming decades. Serious environmental impacts of extraction of these resources have often led to bans and restrictions, leading to price spikes and supply disruptions. Construction and demolition (C&D) waste can be used as a substitute for construction materials with proper management and processing, but such practice is still at a nascent stage in India. Under the new Construction and Demolition Waste Management Rules 2016, all cities will have to institute C&D waste management within a specified timeframe, and there is a dire need of capacity development to make this happen. The GIZ Resource Efficiency project is working to promote sound management and utilisation of C&D waste in Ahmedabad and Bengaluru. The main challenge was found to be the lack of a solid business case for processing in the absence of a reliable market for C&D waste-based products due to negative perception among buyers. Paving blocks made with C&D waste from Ahmedabad exceeded BIS standards for strength and were cost competitive with conventional blocks; therefore, a recognised certification scheme would help their market uptake. In addition, the processing facility being located in the south, a decentralized option for waste generated in the northern part of the city was found to be optimal. In Bengaluru, preliminary analysis showed that C&D waste processing enterprises located close to designated C&D waste disposal sites as well as to product markets are likely to be commercially viable under high-capacity utilisation scenarios. Attractive payback periods of 5 years or less were found for existing stone crushing units with idle capacity. Lessons from these cases can benefit C&D waste management planning in other cities in India.