Characterization of Fine Fractions From Landfill Mining: A Review of Previous Investigations

Abstract

Several landfill mining (LFM) studies have been carried out in recent years all around the world. From these studies qualitative and quantitative information regarding the composition and characteristics of the different fractions excavated from landfills has been obtained. This information comprises data from various landfill sites around the globe from which useful correlations for future LFM projects can be identified. Of particular interest to this paper is the information regarding the fine fractions, which represent to this day a crucial obstacle in the implementation of LFM and enhanced landfill mining (ELFM). The fine fractions make up a considerable portion of the total amount of waste disposed of in landfills. Depending on the particle size chosen as upper limit to define the fines fraction, the portion of this fraction can be as high as 40-80 wt.% of the total excavated waste. These fractions consist of decomposed organic substances, e.g. humic substances, partly weathered mineral waste, e.g. sand, brick fragments, concrete, but also of fine metal particles, especially non-ferrous metals, and still a significant amount of plastics, paper and other calorific fractions. However, although calorific fractions might be used for energy recovery and inorganic fractions for material (especially metal) recovery, current LFM studies are discarding the fine fraction due to lacking or too expensive processing routes. Therefore, it is of critical interest to LFM and ELFM projects to reduce the particle size down to which the excavated material can be processed. This paper, which was elaborated within the framework of the EU Training Network for Resource Recovery through Enhanced Landfill Mining -NEW-MINE, aims to review the obtained data from different LFM studies from municipal solid waste (MSW) landfills, concerning the fines fraction, in order to identify key aspects to be taken into consideration while designing the processing approach in future LFM and ELFM investigations.

Investigations on fine fraction of aged municipal solid waste recovered through landfill mining: Case study of three dumpsites from India

“…Significant moisture and organic matter contents are normally to be expected in the fine fractions. These interrelated parameters are of critical relevance, since processing routes and possible end uses for these fractions will depend on their quantities (Parrodi et al, 2017). The moisture content and organic content in finer fraction of MSW were found to be least at the Kadapa site, while at the Hyderabad landfill these were found to be higher.…”

“…The high soil-like content in the aged MSW is likely the result of daily covering soil, street sweepings, drain silt and construction and demolition (C&D) waste along with the humification of organic matter in the fresh MSW (Parrodi et al, 2017). Several definitions for 'finer fractions' are available in the literature depending upon the sieve size adopted.…”

Field Study on the Efficiency of a Methane Degradation Layer Composed of Fine Fraction Soil from Landfill Mining

“…Typical recoverable materials are metals, plastic and other combustibles, and mineral materials (stones, glass). One of the main barriers to landfill mining is the lack of use of the fine fraction [60,67,68].…”

Effects of “soil‐like” particle size on gas transport and water retention properties in aged municipal solid waste from a Sri Lankan open dumpsite

“…Owing to their similarities with natural soil, many previous studies indicated this fine material as "soil-like" fraction (e.g., Abreu & Vilar, 2017;Cheng-liang et al, 2016;Mohit, Manoj, Ramana, & Sreekrishnan, 2018;Quaghebeur et al, 2013). The high soil-like content in the aged MSW is likely the result of daily covering soil, street sweepings, drain silt, and construction and demolition waste along with the humification of organic matter in the fresh MSW (Parrodi, Hollen, & Pomberger, 2017). Notably, Humus is the stable state reached by organic matter after being degraded down to the point where organic matter resists further degradation and constitutes one of the main components of soil, together with liquid, gases, minerals and living microorganisms (Stevenson, 1994).…”