Can anaerobic digestion help solve the growing issue of food waste?

David Pinsky
5 min readMay 12, 2022

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Why is food waste such an issue?

I grew up in a household where wasting food wasn’t an option, deeply rooted in the ethos of my immigrant parents who took very little for granted. Fortunately, there is a growing focus on food waste in the US and number of emerging startups aiming to combat it across all stages; prevention, rescue and recycling. The primary concern is food waste that ends up in landfills contributes to the production of methane, a greenhouse gas (“GHG”) that contributes to the warming of our atmosphere. Organic material such as a banana peel that ends up in a landfill takes years, even decades to decompose because there is little oxygen flow, emitting methane throughout the entire process.

Food waste market map

Methane makes up just ~11% of GHG emissions in this country but can be up to ~20x more effective at trapping heat in the atmosphere than carbon dioxide, so a small swing can have a meaningful impact. Methane is naturally produced in nature but humans’ acceleration of it through livestock farming and other industrial activities is unsustainable.

Source: US Environmental Protection Agency

What is anaerobic digestion?

Anaerobic digestion is a biological process in which organic matter is broken down by bacteria and other microorganisms in enclosed facilities, similar to composting but on a massive scale and without oxygen (hence “an-aerobic”). Put simply, think of anaerobic digestion as what happens in your stomach on an industrial scale.

The use of anaerobic digestion to divert food waste from landfills means that methane that would otherwise be released into the atmosphere as a potent greenhouse gas, can now be captured and utilized to provide heat, generate electricity or as a transportation fuel.

Inputs such as food waste go into an anaerobic digester tank, get processed over the span of several weeks and create high value outputs such as biogas and digestate, which can be monetized.

Does it make sense economically?

Yes. Anaerobic digestion can be monetized via a) tipping fees and b) the sale of byproducts, creating a viable and attractive business model that encourages the use of this technology.

1) Tipping fees: “Gate fees” paid for disposing of waste in a landfill or digester, typically based on tonnage

2) Byproducts: The process of anaerobic digestion produces two valuable byproducts which can be sold, biogas and digestate:

  • A) Biogas: Similar to natural gas, the energy in biogas can be used to provide heat, generate electricity or create renewable natural gas (RNG), which can be used as a vehicle fuel
  • B) Digestate: The residual matter left after the digestion process can be used in a number of applications such as an organic-rich fertilizer

What problems is it solving?

Anaerobic digestion solves several problems simultaneously…

  • Provides an alternative waste channel to landfills at competitive tip fee rates
  • Diverts waste material that otherwise would have been incinerated or landfilled
  • Creates and captures biogas (mostly methane) that would have been emitted into the environment

Why now?

Until 2000, land application and waste incineration were the only real alternatives to traditional landfilling.

With incinerators being legislated out of existence (CT, ME, MA, CA, MD), legislative pressures against land application and the growing cost of landfill tip fees, high volume waste producers are increasingly seeking cost efficient waste management alternatives.

  • Economic and public policy pressures are contributing to the urgency of organic waste diversion to AD plants
  • Increasing number of incineration and landfill bans, landfill closures and stricter water pollution runoff and land application standards
  • New landfills or incinerators are difficult to permit (NIMBY) and politically unpopular
  • Municipalities are implementing legislation that mandates organics recycling (NY, CT, VT, CA) and several states are banning organic waste from landfills altogether

Conclusion

The anaerobic digestion industry in the US is in its infancy, with just 2,200 facilities across the country today, mostly at water resource recovery facilities and dairy farms. By comparison, Europe has over 10,000 operating digesters due to a number of regulatory tailwinds that incentivized development over the last several decades. The opportunity for anaerobic digestion as a tool to help divert both pre and post-consumer food waste, is massive, with an estimated 15,000 sites ripe for development across the US.

The financial and environmental impact would be enormous too; equivalent to removing 117 million passenger vehicles from the road, catalyzing an estimated $45 billion in capital deployment for construction, resulting in approximately 374K construction jobs and 25K permanent jobs to operate them.

Anaerobic digestion is one helpful tool in the broader ecosystem focused on reducing food waste and mitigating climate change, but it is certainly not a panacea. Our first goal should always be to reduce food waste by only producing and buying what we need.

Emerging players in the anaerobic digestion space

That said, anaerobic digestion is a pretty attractive disposal alternative and should be the top choice before landfilling or land applying food waste. Anaerobic digestion is an economically viable and environmentally sustainable waste management alternative and I look forward to tracking the emerging players in the space.

Thanks for reading! Feel free to message me with any feedback and follow on @Medium for more insights.

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