Cassilly: Anaerobic digestion a smart solution


Andrew Cassilly is the vice president of government relations for Bioenergy Devco.

Around the world, food waste is a leading contributor to greenhouse gas emissions, a major cause of climate change. In the United States alone, up to 40% of the food supply goes uneaten, equivalent to $444 billion in waste per year. Globally, over 1.3 billion tons of food gets wasted annually across the supply chain. Wasted food makes up the largest single category of material being landfilled or incinerated here in the U.S., making up 24% and 22% of municipal solid waste, respectively.

Landfilling this enormous amount of organic waste has a significant, deleterious environmental impact. Food waste decomposing in landfills generates methane, a greenhouse gas over 28 times more potent than carbon dioxide in the short term. Landfills are the third-largest source of methane emissions in the U.S., releasing the equivalent of emissions from nearly 23.1 million gasoline-powered passenger vehicles driven for one year. The shocking reality is that approximately 30% of total greenhouse gas emissions come from food waste.

In 2023, groundbreaking Environmental Protection Agency research revealed that food waste is the primary contributor to landfill methane, underscoring the urgency of prioritizing food waste reduction as a crucial mechanism for combating climate change. Additionally, the U.S. government published its first Draft National Strategy for Reducing Food Loss and Waste and Recycling Organics to address food waste. These actions by the federal government are emblematic of a wider national interest in reducing food waste to reduce greenhouse emissions, while bringing greater visibility to the power of organics recycling as a means to address climate change.

In the broader context of environmental sustainability, organic waste management is an often overlooked but extremely valuable tool for building a green energy future, while mitigating the impacts of greenhouse gas emissions. One of the most promising trends in food waste reduction is the growing adoption of anaerobic digestion systems. Used for centuries and in countries around the globe, the process is gaining traction in North America as a scalable means of organics recycling. AD is a process where microorganisms break down organic materials like food scraps in an oxygen-free environment. This produces biogas, which is used for clean, renewable energy, while also creating a nutrient-rich soil amendment. The Environmental Protection Agency has introduced a ranking system, the Wasted Food Scale, which highlights anaerobic digestion as a preferable pathway for food waste management.

Locally, addressing the waste generated by food production has recently become a topic of much discussion. In March, a Wicomico County, Maryland, town hall meeting addressed the issue of waste disposal from dissolved air flotation processes associated with poultry processing. The discussion centered on community concerns over the environmental and social consequences of spreading untreated DAF waste on agricultural fields as fertilizer. Residents raised issues regarding odor and polluted stormwater runoff affecting their quality of life. However, attendees were encouraged by the pending passage of legislation, particularly House Bill 991, which aims to establish regulations for processing this waste. Additionally, the construction of a large anaerobic digester by Bioenergy Devco is expected to mitigate these concerns.

Through anaerobic digestion, organic materials such as DAF are broken down by microorganisms in the absence of oxygen, in a closed-loop system that generates biogas for fuel and digestate for soil amendment, while containing odors and mitigating potential harmful pathogens from the residuals. The remaining granular soil amendment can then be used as fertilizer on fields to improve soil health and reduce runoff issues. Commercial-scale anaerobic digesters are able to recycle organic materials that may otherwise cause serious issues, creating a wholly circular system.

Anaerobic digestion is an environmentally sound, safe and secure way to manage organic waste and create economic opportunities in communities across the U.S. Anaerobic digestion is the way we can address the local and national challenge of carbon and greenhouse gas emissions. By recycling organic waste and creating green energy and nutrient-rich soil additives, anaerobic digestion provides multiple benefits — preventing potent methane emissions from organic waste rotting in landfills, while also generating clean renewable energy and organic soil amendments. According to the American Biogas Council, there are currently 2,300 operational biogas systems in the U.S. with the potential to triple this capacity.

A commercial-scale anaerobic digester facility can ingest 115,000 tons of excess food scraps, fats, oils and greases, along with other organic material, such as DAF. The renewable natural gas it generates reduces carbon dioxide, equivalent to taking more than 18,861 gasoline-powered cars off the road for a year. The fully closed circular system captures greenhouse gases that would otherwise be released into the atmosphere, having the equivalent environmental impact of nearly 70,000 acres of U.S. forests in one year — 82 times the size of Central Park. The renewable natural gas can easily be converted to clean, renewable electricity, produced exactly where it is needed, reducing transportation costs and pollutants.

Concerted efforts must be made on the local, national and global levels to prioritize food waste reduction and embrace innovative solutions like anaerobic digestion. By harnessing the power of technology, policy and collective action, we can pave the way for a more sustainable future, where food waste is minimized, greenhouse gas emissions are curtailed, and communities are powered by clean, renewable energy. To truly combat the climate crisis facing our country, we must adopt a wide range of solutions, including anaerobic digestion — a safe, proven method of organics recycling that reduces food waste, curtails its negative environmental impacts and harnesses its potential to create a greener, more sustainable future for communities across the country.

Reader reactions, pro or con, are welcomed at

Members and subscribers make this story possible.
You can help support non-partisan, community journalism.