Phytocapping: an alternate cover option for municipal solid waste landfills

Area of Science:

• Environmental Science
• Waste Management
• Bioremediation

Background:

• Landfill gases, primarily methane (CH4), are generated from municipal solid waste (MSW) decomposition under anaerobic conditions.
• Conventional landfill management in India often relies on expensive techniques like clay capping and gas extraction systems.
• Phytocapping presents a potentially cost-effective alternative for mitigating landfill gas emissions and reducing water percolation.

Purpose of the Study:

• To evaluate the efficacy of laboratory-scale phytocapping using native Indian plants.
• To assess methane (CH4) oxidation rates and heavy metal remediation capabilities.
• To investigate plant-soil interactions within a phytocapped landfill model.

Main Methods:

• A laboratory-scale phytocap system was established using planters containing MSW.
• Six native plant species were cultivated in the planters under simulated Indian climatic conditions.
• Methane (CH4) emissions, root zone methane concentrations, and heavy metal concentrations in soil and plants were monitored.

Main Results:

• Vegetated planters demonstrated significant methane (CH4) oxidation compared to non-vegetated controls.
• Highest methane (CH4) reduction was observed in the root zones of *Agave sisalana* and *Bambusa sulfurea*.
• Effective remediation of heavy metals was achieved, with *Brassica juncea* and *Helianthus annus* showing the highest potential.
• Overall, 96-98% CH4 oxidation and 85-89% heavy metal remediation were recorded.

Conclusions:

• Phytocapping is a viable strategy for mitigating landfill methane (CH4) emissions and remediating heavy metals.
• Specific native plant species show promise for enhancing phytocapping efficiency in Indian conditions.
• This approach offers a sustainable and potentially economical solution for MSW management.