Phytocapping: an alternate cover option for municipal solid waste landfills

Landfill gases are produced due to biodegradation of organic fraction of municipal solid waste (MSW) when water comes into contact with buried wastes under prevailing anaerobic conditions. To minimize the percolation of water in landfills, the conventional approaches such as clay capping is still practised in India. As landfill gas extraction system is an expensive technique,'Phytocapping' to mitigate landfill gases and to minimize percolation of water into the landfill can be one of the attractive alternatives. The present study aimed to determine efficiency of a laboratory-scale phytocap in terms of methane emissions, heavy metals' remediation and plant-soil interactions in Indian climatic conditions using six native plants in five planters (30 cm × 30 cm × 25 cm) with 5 kg of MSW. Overall methane oxidation due to vegetation was observed throughout the vegetated planters when compared to non-vegetated planters. Root zone methane concentrations were also monitored for the plant species, with the highest reduction occurring in root zones of Agave sisalana and Bambusa sulfurea and highest trace elements' remediation potential was observed in Brassica juncea and Helianthus annus plants. 96-98% of CH₄ oxidation and 85-89% of heavy metals remediation was achieved through the study.