Landfill Bio-Stabilization through Aerobic Aeration

by Hilary Haskell

Landfill aeration serves as an economically and technologically viable option for decreasing the duration of landfill after-care, through the bio-stabilization of landfill contents. Ritzkowski and Stegmann (2013) based their analysis on the determination of carbon balances through waste characterizations and online monitoring. The biodegradable organic carbon (BOC) content of a landfill is the main determinant affecting landfill bio-stabilization rates, while landfill settlements and temperatures are also important indicators of stabilization. Using BOC, the authors determined the total and remaining stabilization periods for aerated landfills. This study used a landfill in Northern Germany that required 6.2 years to stabilize after a volume of 63 million m3 of air had been applied to increase the rate of bio-stabilization by a factor of six. These findings suggest that landfill aeration may substantially decrease time and costs associated with landfill after-care by reducing cumulative leachate and landfill gas emissions. Continue reading

Landfill Mining as Landfill Remediation in Sweden

by Hilary Haskell

Nonrenewable resource recovery and greenhouse gas emissions reductions make landfill mining both an economically and environmentally attractive landfill remediation option. Per Frändegård et al. (2013) studied the economic feasibility and environmental impact of landfill mining for Swedish municipal waste under mobile and advanced stationary separation plant scenarios. The authors used Monte Carlo sensitivity analysis to assess the effects of uncertain parameters on landfill composition and greenhouse gas mitigation potential. Of Sweden’s thousands of landfills holding more than 350 million tons of material, many are aging and require remediation. The study concludes that landfill mining could prevent emission of 50 million tons of carbon-dioxide equivalents, provide over five years of energy to Sweden’s district heating system, and supply Sweden with 7 million tons of ferrous and 2 million tons of nonferrous metal materials. Continue reading

Enhancing Landfill Gas Recovery

by Hilary Haskell

Post-closure, landfills require after-care and remediation. As waste decomposes in anaerobic landfill environments, methane emissions are released as a component of landfill gases. Landfill gases can be recovered through combined heat and power generation, district heating coupled with asphalt production, or incorporation of landfill gas into biomethane. Each method has a different collection and utilization efficiency. Niskanen et al. (2013) studied Kymenlaakso Jate Oy landfill in Finland, and found that the combined heat and power recovery scenario has the highest landfill gas utilization efficiency, resulting in greenhouse gas emissions reductions of 8,000 tCO2−eq/year. Landfill gas recovery serves as an economical landfill remediation option that decreases pollution of the surrounding environment. Continue reading

Restoring Floral and Pollinator Populations at Remediated Landfill Sites

by Hilary Haskell

Post-closure, landfills require after-care and remediation. Additional after-care may involve restoring landfills into semi-natural habitats for flowering plants and insect pollinators. Tarrant et al. (2013) compared the floral characteristics, species richness and abundance, and pollinator assemblages at reference sites of ecological value and restored landfill sites. Pollinator populations were similar across the reference and restored sites. The authors found no differences in floral species richness or abundance between reference sites and restored sites. Some seasonal differences in species richness and abundance occurred at restored landfill sites. There are over 28,000 ha of landfills in England and Wales, and habitats are rapidly declining due to agricultural practices. Landfill restoration may provide a means to both remediate landfills and mitigate habitat loss. Continue reading

Phytoremediation of Soils at Open Dump and Incineration Sites in Kerala, India

by Hilary Haskell

In the developing world, municipal solid waste management has become increasingly problematic. Remediation of open dumps and waste incineration sites present an additional issue, especially in removing contaminants from the soil that pose a threat to ecosystems and surrounding water resources. Ash et al. (2013) worked with a university in South India to remediate an open dump and incineration site, focusing on remediation techniques involving vermicomposting and phytoremediation to remove heavy metal compounds from the soil. The ultimate goal of the project is to demonstrate the feasibility of remediating similar dump sites so that native ecosystems can be restored and continue to function in the future.

India is now the world’s sixth largest generator of municipal solid waste, producing 110,000 tons each day according to a 2012 World Watch report. This report indicated that only 25% of the world’s waste is recycled or composted, while the remainder is Continue reading