Laboratory-based assessment of geotechnical characteristics of organic waste-amended soil for landfill biocover

Abstract

A landfill biocover is essential for addressing environmental concerns, especially in waste management, as it plays a crucial role in mitigating the release of methane gas. This study investigates the geotechnical characteristics of soil amended with organic wastes for landfill biocover applications. Various organic waste amendments, viz., rice husk, crushed coconut coir, and compost, were examined at different percentages (0%, 25%, 50%, and 75%) compared with conventional landfill cover material, i.e. natural clay, as biocovers. Laboratory experiments analysed geotechnical characteristics, including organic content, Atterberg limit, compaction, consolidation, and desiccation cracking. The study revealed that organic waste amendment significantly impacted the geotechnical characteristics of landfill biocover, enhancing organic content and porosity and reducing permeability and desiccation susceptibility. Soils amended with organic content support methanotrophic bacteria growth and reduce methane emissions in landfills. The most promising biocovers were identified as 75CR (crushed coconut coir/wastewater sludge/clay in percentage ratio of 70:5:25), followed by 75CT (compost/wastewater sludge/clay in percentage ratio of 70:5:25), and 25RH (rice husk/wastewater sludge/clay in percentage ratio of 20:5:75). Biocovers offer sustainable landfill alternatives, underscoring the need to understand their geotechnical characteristics for successful installation in landfills.