Valorization of landfill mined plastic waste and soil-like fractions in polymer composites - A comprehensive solution for sustainable landfill mining

Utilization of Landfill-Mined Plastic Waste (LMPW) and LandFill-Mined-Soil like-Fractions (LFMSF), which together contribute to & AP;85-90% of the landfill residues, read as Socio-Economic Refuses (SERs), is the need of the hour. Though earlier researchers have tried to utilize LMPW through energy recovery options, the emission of chlorine-based organic compounds and H2S became big concerns. Similarly, LFMSF has been investigated for its suitability as a manmade resource to produce compost, refuse-derived fuel, pH buffering material and for structural filling applications. However, its potential for leaching salts, heavy metals and microplastics remains a primary environmental concern. To overcome these issues, developing innovative solutions by using LMPW and LFSMF, in tandem, which would result in sustainable landfill mining, is necessary. One of the ways to achieve this could be the creation of polymer Composites, designated as CompoSERs, in which LMPW and LFSMF work as binder and filler, respectively. Such a strategy would help in restricting the negative impact of both these constituents on the geoenvironment in terms of leaching and/or fugitive dust in the surrounding. Keeping this in view, the influence of LFMSF (read filler content) on the overall characteristics of CompoSERs, including macroand micro-mechanical, functional group, morphological, thermal, and leaching, has been investigated. Since the LMPW consists of inherent fillers in the form of additives/fillers used in the original plastics and adhered contaminants, the experimental (read actual) filler content (designated as FCexp) would be higher than LFMSF added in the process of manufacturing. Hence, easy-to-use empirical relationships between FCexp and mechanical properties of the CompoSERs that can be employed for field-scale applications have been proposed. Based on these relationships, the critical FCexp, which defines a change in the trends of the FCexp and mechanical properties of the CompoSERs, has been observed as 30% by weight. Moreover, unlike other existing utilization schemes of LFMSF, this strategy turns out to be an efficient way to avoid the contamination of the geoenvironment owing to the leaching of heavy metals and dissolved organic matter present in it.