High Attenuation Recycled Materials as landfill liners (the HARM project) – A new concept for improved landfill liner design

Abstract

A new approach in landfill liner design which combines hydraulic containment of leachate with contaminant attenuation to improve the performance of these environmental control systems at landfills is described. The idea is to re-use readily available industrial waste residues (construction and biomass waste) as additives for natural clay liners, wherein the additives have specific properties which enhance the attenuation of contaminants by the mixture. The aim is to (1) evaluate the contaminant attenuation capacity of these mixtures, (2) develop design guidelines to construct liners for waste containment systems and similar applications, and (3) interpret their performance using numerical modelling. This is evaluated in permeation studies using a geotechnical centrifuge, which enables the performance of liner compositions to be tested for representive time-scales (100 years), pressures and temperatures at realistic experimental time-scales of days-weeks in the laboratory. The permeation experiments include liner compositions flushed with leachate to deduce contaminant transport and attenuation mechanisms, followed by rainwater to assess the potential for release of attenuated contaminants. This experimental methodology is illustrated with depth profiles from permeation studies conducted on different clay-additive compositions. The concept will be applicable for liner design at other waste disposal facilities and is a timely improvement which addresses the problem of managing large quantities of industrial residues. Instead of disposal these can be recycled as an additive in host clay to construct these liners, thus conserving natural resources (clay) and reducing construction costs. It also provides an effective and more environmentally sustainable basis to reduce risks from leachate leakage.

The Role of Natural Clays in the Sustainability of Landfill Liners

“…The hydraulic conductivity or permeability coefficient (K) was measured in aluminium permeation cylinders by centrifuging at 25 gravities (Regadío et al, 2020). Model liners were compacted into of 5 cm radius by 10 cm height cylinders after being hydrated with tap water at the OMC.…”

The role of natural clays in the sustainability of landfill liners

“…The hydraulic conductivity or permeability coef cient (K) was measured in aluminium permeation cylinders by centrifuging at 25 gravities (Regadío et al, 2020). Model liners were compacted into of 5 cm radius by 10 cm height cylinders after being hydrated with tap water at the OMC.…”