Quantitative Analysis of Critical Factors for the Climate Impact of Landfill Mining

Abstract

Landfill mining has been proposed as an innovative strategy to mitigate environmental risks associated with landfills, to recover secondary raw materials and energy from the deposited waste, and to enable high-valued land uses at the site. The present study quantitatively assesses the importance of specific factors and conditions for the net contribution of landfill mining to global warming using a novel, set-based modeling approach and provides policy recommendations for facilitating the development of projects contributing to global warming mitigation. Building on life-cycle assessment, scenario modeling and sensitivity analysis methods are used to identify critical factors for the climate impact of landfill mining. The net contributions to global warming of the scenarios range from -1550 (saving) to 640 (burden) kg CO2e per Mg of excavated waste. Nearly 90% of the results' total variation can be explained by changes in four factors, namely the landfill gas management in the reference case (i.e., alternative to mining the landfill), the background energy system, the composition of the excavated waste, and the applied waste-to-energy technology. Based on the analyses, circumstances under which landfill mining should be prioritized or not are identified and sensitive parameters for the climate impact assessment of landfill mining are highlighted.

Landfill Mining : Institutional challenges for the implementation of resource extraction from waste deposits

“…In many cases, industrial waste has been deposited mixed with household waste in municipal landfills. Furthermore, landfills can vary significantly in capacity, content, and design Frändegård et al, 2013;Laner et al, 2016). In Sweden, modern active landfills are bottom sealed with drainage and gas collection system, while old inactive landfills are often just covered with soil and unlined, some of which have become ski slopes while others are just grassy hills.…”

“…Sampling and material characterization of municipal European landfills have demonstrated large variations between landfills, with 70-25% of soil material, 25-2% plastics, 15-10% stones and inert material, 12-2% paper, 7-3% wood, 5-2% textiles, 2% organic matter, 5-2% ferrous metals, 1.5-0.5% non-ferrous metals and 0.2% hazardous material (e.g. Cossu et al, 1995;Godio et al, 1999;Bernstone et al, 2000;Kurian et al, 2007;Krook et al, 2012;Frändegård et al, 2013;Laner et al, 2016).…”

“…According to Frändegård et al (2013) and Laner et al (2016), about 50-80% of the minerals found in municipal landfills are possible to recover, depending on site-specific conditions such as sorting technology, the type and quality of the material. However, these calculations are based on the use of sorting technology developed for traditional fresh waste rather than deposited waste.…”

“…Frändegård et al, 2013;Jones et al, 2013;Laner et al, 2016). Energy recovery of combustibles from landfills may also replace conventional energy generation, which in many parts of the world is fossil based.…”

“…After all, compared to traditional mines, deposited minerals in a landfill are more refined and significantly closer to the market with its location on the outskirts of cities. However, some studies demonstrate moderate climate savings from recycling deposited waste and sometimes even negative impact (Winterstetter et al, 2015;Laner et al, 2016).…”