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  • Rob Furness

Methane - The Potent Greenhouse Gas Emitted by Landfills

This article follows up on our first article "The Environmental Hazards of Landfill Leachate, and How it Can be Remedied.” It aims to dive deeper into the methane problem, the causes, risks, and remedies.


A landfill site giving off noxious fumes

Modern sanitary landfills are constructed with engineered containment systems to prevent groundwater contamination from leachate. However, these same containment properties create an anaerobic (oxygen-free) environment as organic waste decomposes. Under these anaerobic conditions, microorganisms produce significant quantities of methane gas within the landfill.


Methane (CH4) is the primary component of natural gas and a potent greenhouse gas, with over 25 times greater global warming potential than carbon dioxide over a 100-year timescale. As methane escapes from landfill sites into the atmosphere, it contributes to climate change.

 

Methane Risks and Hazards

While not directly toxic, methane is an asphyxiant gas that can displace oxygen in confined spaces, posing a suffocation hazard. It is also an extremely flammable and explosive gas. If allowed to accumulate in buildings, utility corridors, or underground subsurface formations, methane creates a severe fire and explosion risk. Even a small ignition source like a spark could trigger a catastrophic blast.


Landfill sites must be particularly vigilant about preventing methane migration offsite. If methane seeps out from the landfill boundary and accumulates in nearby structures or subterranean spaces, finding an ignition source like a pilot light or electrical equipment could cause devastating fires or explosions. Such offsite incidents involving migrating methane from landfills have resulted in injuries, fatalities, and significant property damage when ignition occurs.


Worse, methane released into the air mixes with nitrogen oxides and volatile organic compounds from other emissions sources in the presence of sunlight to produce ground-level ozone. Elevated tropospheric ozone levels are linked to decreased lung function, aggravated asthma, and increased risk of premature death from respiratory causes.


Children are particularly vulnerable, as ozone exposure can cause chronic respiratory issues and irreversible lung damage during development years. Studies show days with higher ozone levels are linked to increased hospitalisations and emergency room visits for asthma attacks, pneumonia, and other respiratory illnesses - especially among the young and elderly.




Collection And Management Challenges

To mitigate methane hazards, sanitary landfills install gas extraction systems with vertical wells or horizontal collectors to capture the gas as it is generated. However, complete collection is difficult due to the mixed nature of landfilled waste and preferred pathways for gas migration.


Even with active gas collection systems in place, between 25-60% of generated methane can escape into the atmosphere through the landfill cap or surface areas. Efficient methane oxidation biocovers can reduce these surficial emissions, but require careful engineering design, construction and monitoring to ensure performance.


One initiative-taking alternative is using specialised composting enzyme products to minimise methane generation from the outset. Methane is produced anaerobically through anaerobic microbial decomposition of organic waste within the oxygen-deprived landfill environment. Introducing blends of composting enzymes and microbes helps facilitate aerobic decomposition pathways instead.


The enzyme formulations contain actinobacteria, bacilli and fungi species that accelerate aerobic composting processes when combined with aeration. When applied through surface layering or direct injection into the waste mass, these microbial inoculants rapidly establish aerobic conditions and out-compete the anaerobic methane-producing microbes.


Aerobic composting facilitated by the enzymes rapidly biodegrades the organic fraction of the waste while generating mostly carbon dioxide instead of methane. By essentially engineering an aerobic landfill environment, the risk of methane production and accumulation is minimised at the source through proactive prevention strategies.

Deploying composting enzyme technologies eliminates methane generation upfront, creating a safer operating scenario rather than relying solely on gas extraction systems to capture emissions after they have already formed within anaerobic zones of the landfill.

 

Flaring Versus Energy Recovery

Methane collected from remaining anaerobic zones through gas wells, is typically combusted and flared to convert it into carbon dioxide - a less potent but still significant greenhouse gas. However, this process wastes the potential energy content of the methane. Furthermore, flaring is not always permitted at some landfill sites due to regulatory restrictions or proximity to populated areas. Where flaring cannot be implemented, the collected methane may be vented directly into the atmosphere in its original potent greenhouse gas form.


Increasingly, environmentally conscious landfill operators are pursuing gas-to-energy projects as a more sustainable alternative. The collected biogas is used to generate electricity through combustion turbines or upgrading it into pipeline-quality renewable natural gas as a fossil fuel substitute.


While capturing methane for energy recovery is preferable to flaring, it still relies on extracting a potent greenhouse gas from the landfill. A more elegant solution is to minimise methane generation altogether by helping control aerobic biodegradation through composting enzymes and aeration - avoiding problematic anaerobic conditions in the first place.

 

Regulatory Compliance

In many countries, stringent regulatory limits apply for monitoring and reporting of methane and greenhouse gas emissions from landfill operations. Exceeding permit limits can lead to enforcement actions such as fines, requirements for operational adjustments or corrective measures, and potentially even cease-and-desist orders that disrupt operations.


Thus, the waste management industry is responsible for implementing best practices and innovative mitigation technologies for methane capture, beneficial utilisation and overall emissions control - minimising climate change impacts from landfill operations. With methane being such a potent and problematic greenhouse gas, reducing these emissions is a high priority from environmental protection, public health, and sustainability standpoints.

 

Creating a Healthy, Sustainable Environment Through Enzymes

By adopting composting enzyme technologies, responsible waste management companies can position themselves as environmental leaders creating a healthier, more sustainable future for local communities. Proactively minimizing methane generation through controlled aerobic biodegradation isn't simply good for the planet - it directly benefits the people living near landfill sites.


Reducing methane emissions means improving regional air quality by preventing ground-level ozone formation that can worsen respiratory issues like asthma. Families will breathe easier knowing the neighbourhood’s air is free from this potent greenhouse gas and other noxious landfill odours.


Utilizing enzyme-driven aerobic composting also reduces the risk of landfill fires and methane accumulation hazards that could endanger workers and nearby properties. The enhanced workplace safety protocols give employees greater peace of mind.

From an environmental stewardship perspective, enzymatic methane mitigation allows landfill operators to slash their carbon footprint and climate change impacts. This commitment to sustainability resonates with environmentally conscious consumers.


But the benefits extend far beyond just minimizing emissions. By avoiding anaerobic conditions, composting enzymes prevent nutrient-rich runoff and leachate contamination that could damage fragile ecosystems in streams, marshes and coastal areas surrounding the site.


With less toxicity leaching out, nearby waters stay pristine - protecting aquatic habitats that support diverse species of plants, fish, birds and other wildlife. Responsible stewardship of these natural areas preserves precious biodiversity for future generations to appreciate.


Forward-thinking waste firms can raise their environmental credentials by harnessing composting enzymes to mitigate many ecological impacts from landfill operations. In doing so, they create value for their business while fostering goodwill in communities - safeguarding public health and providing a legacy of environmental sustainability.


email for more information wecare@customenzymes.com

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