Assessment and management of construction and demolition waste in tier 2 cities of Karnataka, India: a case study of Hubli-Dharwad and Davanagere.

The present study examines the current practices for managing construction and demolition waste (CDW) in two tier-2 cities of Karnataka state: Hubli-Dharwad and Davanagere. The research highlights the quantification, characterization, and effective management strategies for CDW. CDW dumping sites were identified through field visits conducted across all wards of the cities and recorded using a mobile-based app. At each site, data were collected on the types of vehicles dumping CDW, the frequency of dumping, the volume of waste in the vehicles, and the quantity of CDW removed for reuse. The dumping sites were categorized into large, medium, and small based on the area and volume of waste. In total, 130 unauthorised dumping sites were identified in Hubli-Dharwad and 62 in Davanagere. The study estimated that Hubli-Dharwad generates approximately 607 tonnes per day (TPD) of CDW, while Davanagere produces around 287 TPD. The characterization of CDW revealed that in Hubli-Dharwad, CDW consists of 14.4% concrete, 25.5% brick and mortar, 39.1% soil and aggregates, and 20% other materials. In Davanagere, the composition includes 19% concrete, 29% brick and mortar, 38% soil, and 14% other materials. Based on these findings, the study proposes a system for the collection and transportation of CDW and recommends suitable recycling technologies. While the approach outlined in this paper is well-suited for urban local bodies to assess CDW, the data on CDW reuse and recycling is primarily based on informal practices. This makes accurate quantification challenging and subject to variation over time due to a lack of regulatory oversight. Additionally, the study provides only a snapshot of CDW generation and management at a specific point in time, potentially missing seasonal variations or long-term trends in waste handling.