Using optimization to manage quarries in the recycling of construction and demolition waste -

Abstract

The construction industry consumes large amounts of aggregates, sand, and stone causing a strain on the limited sources of these natural materials (e.g., quarries). The industry is also a major source of waste. Waste, commonly referred to as Construction and Demolition Waste (CandDW), is generated at various stages of construction and in demolition processes. Increased construction activities and limited landfill space have encouraged efforts to divert CandDW away from landfills to sorting, recycling, and reusing. While these efforts have been successful in some countries (e.g., Germany, Netherlands), developing countries such as Lebanon suffer from illegal and haphazard dumping of CandDW. This study presents an optimization based decision support tool to select a cost and environmentally effective set of abandoned quarries to serve as CandDW landfills and processing facilities. The tool is composed of a GIS model and a mixed linear integer program. The developed model was then applied to the Mohafazas of Mount Lebanon and Beirut. The results show how the estimated CandDW generated over the next 20 years can be best managed by determining where and how much CandDW will be recycled and-or landfilled. Last, an estimation of the costs of this operation was also obtained which assists in refining the legal framework recommended to enforce these recycling practices.