The role of waste-management practices in our journey towards a more sustainable future cannot be overstated. Anaerobic digestion’s multitude of benefits demonstrate its potential to turn ‘waste’ into valuable resources.
Each week, more than 1 million tons of food waste are incinerated or sent to landfills in the United States — more than any other country in the world. Historically, the predominant approach for handling organic waste has been landfills. However, there's a promising shift towards embracing organic recycling methods such as anaerobic digestion (AD) — a process in which organic materials are broken down naturally by microorganisms in the absence of oxygen. AD provides numerous environmental advantages over sending organic waste to landfills, where its breakdown results in the emission of harmful greenhouse gases (GHGs). Increasingly, AD is proving to be the preferred method for managing organic waste.
Anaerobic digestion
AD relies on microorganisms to break down organic waste — such as food scraps, fats, oils, and grease — while creating additional value:
- Renewable energy generation: One of the most compelling benefits of anaerobic digestion is the production of biogas — primarily composed of methane and carbon dioxide — which can be used to generate electricity and heat. This process reduces our dependence on fossil fuels, mitigates GHGs and paves the way for a cleaner energy future.
- Mitigation of methane emissions: Organic waste decomposes anaerobically in landfills, releasing methane — a potent greenhouse gas that exacerbates climate change. Anaerobic digestion captures this methane, preventing its release into the atmosphere — curbing climate-altering emissions while transforming organic waste into a valuable resource.
- Production of high-quality, organic soil amendment: The solid residue from anaerobic digestion, known as digestate, is a nutrient-rich organic soil amendment that can replace chemical fertilizers in agriculture — enhancing soil health, reducing environmental harm and promoting sustainable farming practices.
- Effective organic waste diversion: Anaerobic digestion significantly reduces the volume of organic waste destined for landfills — enabling the reuse of organic material to create renewable energy, and mitigating the environmental and social impacts that landfills have on communities.
Landfills: An outdated approach
Landfills, once the standard solution for waste disposal, are now recognized as environmentally problematic. As the global population continues to expand, the volume of waste in landfills is set to increase exponentially — with food waste comprising the largest portion at over 24 percent. In addition to releasing climate-changing methane emissions, here are more key reasons why landfills fall short of anaerobic digestion:
- Consumption of valuable land: Landfills occupy extensive tracts of land — often in prime locations that could be repurposed for more sustainable uses such as agriculture, recreation or urban development. Land scarcity makes landfill expansion an unsustainable option.
- Groundwater contamination risk: Landfills pose a threat to groundwater quality. The liquid produced from decomposing waste — known as leachate — can contain hazardous substances that leach into the groundwater, potentially contaminating drinking water sources.
- Inefficient gas management: While some landfills capture and utilize methane for energy, many lack the infrastructure to do so effectively.
- Wasted resources: Waste dumped in a landfill is likely to never be recycled.
The sustainable alternative
In the quest to select the optimal organic-waste management approach, the advantages of anaerobic digestion over landfills are clear. AD not only curbs the release of potent GHGs, particularly methane — the renewable energy it generates also offers the potential to replace fossil fuels, thus contributing to a cleaner, sustainable energy future. Moreover, anaerobic digestion enhances soil health for a more productive agricultural ecosystem, allows us to preserve invaluable land resources that would otherwise be consumed by landfills, and notably reduces the threat of groundwater contamination associated with landfills.
The role of waste-management practices in our journey towards a more sustainable future cannot be overstated. Anaerobic digestion’s multitude of benefits demonstrate its potential to turn ‘waste’ into valuable resources. It is imperative that we prioritize the widespread adoption of AD as the preeminent and responsible solution. By doing so, we will effectively combat climate change and safeguard our environment for present and future generations, establishing a legacy of prudent and sustainable waste-management practices.
Shawn Kreloff, CEO Bioenergy Devco