Biogas and CAFOs in North Carolina by Carsten Pran

Over nine million hogs call North Carolina home and most of them live in densely-packed, windowless warehouses called Concentrated Animal Feeding Operations (CAFOs) in the state’s eastern floodplains.1 The livestock produce an immense amount of waste, which CAFO operators currently store in open air pits called ‘hog lagoons’.2 Pooling the noxious waste in such a way poses serious social and environmental risks, but a promising technology offers an innovative solution. The technology is called “Biogas” and it seeks to cover the hog lagoons, capturing the methane emitted by the excrement to be used as natural gas. Implementing these biogas initiatives in existing hog farms would greatly reduce the stench, emissions and flood risks associated with hog lagoons while producing a potent and renewable energy source.

Before discussing biogas itself, it is important to understand the geographic context of the hog industry in North Carolina. Most of the CAFOs in the state are concentrated around communities that are predominantly non-white and low-income. For instance, there is a region called Halifax County that is around 50% African American overall, yet the vast majority of CAFOs are located around communities that are 90-98% African American.3

Since hog lagoons are essentially open air pits, the stench wafts into these neighboring communities, creating unbearable living conditions, decreased property value and increased rates of asthma, pneumonia and cancer.4 When the lagoons begin to overflow, CAFO operators will spray the waste onto surrounding fields as fertilizer which can smatter homes with hog feces and exacerbate health risks.

Not only do hog lagoons pose serious social and health concerns, they also severely impact the environment. During flooding or hurricane episodes, the pits can overflow, washing nutrients into the ocean and causing a massive spike in algae growth in a process called eutrophication.5 When the algae die, they decompose and rob the water bodies of dissolved oxygen, leading to massive die-off of marine life. During last year’s Hurricane Florence, for instance, “7 million gallons of untreated swine feces were unleashed into surrounding waterways” creating massive ‘dead zones’ off of the coast of North Carolina in which millions of marine organisms died. (click here for visualization of post-Florence dead zones).6

Even when flooding episodes are not taking place, hog lagoons can harm the environment by emitting potent greenhouse gases into the atmosphere. As methane from the waste rises into the air it settles in the troposphere, where the molecules trap solar heat and contribute to global warming. In fact, a molecule of methane traps around twenty-five times more heat than carbon dioxide, making agricultural waste a leading driver of global warming.7

How would biogas technology solve these problems? Well, by covering the lagoons, the pits would emit less stench and less methane, while also making them less prone to flooding. It would also accumulate the methane, allowing technology to purify and harvest it to generate energy rather than simply let it leach into the atmosphere.

Loyd Ray Farms

Initiatives like Loyd Ray Farms8  (a project that Duke University has helped create) use bacteria to naturally break down toxic pollutants in waste like ammonia, purifying the biogas to be used in everything from heating to electricity. In 2009, Duke made the ambitious commitment to reach carbon neutrality by 2024, and in its 2018 Climate Action Plan Update the university cited biogas as having immense potential to reduce emissions by diminishing the amount of methane that enters the atmosphere.9

That being said, biogas can be a controversial topic, especially when it comes to environmental justice movements. While covering the open air hog lagoons would drastically reduce smell and emissions, some worry that this act would do little to counteract the injustice that neighboring communities have to face in regards to their health and wellness. They also argue that creating a commodity out of biogas would bolster the hog farming industry and lead to an expansion of the corporations into other parts of North Carolina.10 There is currently a permanent statewide moratorium on the construction of new hog farms that store their waste in lagoons, meaning that if they do not meet certain conditions, new CAFOs cannot be built.12 Some worry that biogas would be the perfect loophole to circumvent this ban and continue building CAFOs throughout Eastern North Carolina which could worsen the social inequalities in this region.

While it is difficult to argue against the importance of recognizing environmental racism and classism in Eastern North Carolina, I believe that biogas has the potential to mitigate both social and environmental issues if implemented with care. Corporations have the economic incentive to invest in the equipment necessary to harvest biogas as they can sell the resulting energy or allow outside organizations (like Duke) to buy the reduced methane emissions as a carbon offset. If the state of North Carolina can keep its moratorium regulations stringent enough to prevent expansion of the hog farming industry, biogas initiatives like Loyd Ray can be easily expandable to the corporations operating in the Eastern part of the state.

As the North Carolina pork industry is a nine billion dollar business upon which thousands of citizens rely for income, I do not see it disappearing anytime soon.12 To address the social and environmental issues created by open air hog lagoons with minimal disruption of the economy, biogas could be a promising answer.




(1) Blythe, Anne. “Jury Awards More than $25 Million to Duplin County Couple in Hog-Farm Case.” Newsobserver, News & Observer, 3 Aug. 2018,

(2)“A Million Tons of Feces and an Unbearable Stench: Life near Industrial Pig Farms.” The Guardian, Guardian News and Media, 20 Sept. 2017,

(3) “Environmental Justice Case Study: Hog Farming in North Carolina.” Women and the Law,

(4) Piccirilli Dorsey, Inc. “Stink, Swine, and Nuisance: The North Carolina Hog Industry and Its Waste Management Woes.” EESI – Environmental and Energy Study Institute,

(5) Pierre-louis, Kendra. “Lagoons of Pig Waste Are Overflowing After Florence. Yes, That’s as Nasty as It Sounds.” The New York Times, The New York Times, 19 Sept. 2018,

(6) Bennett, Abbie. “NASA Can See Dark, Polluted Carolina Rivers Spilling into the Ocean from Space.” Newsobserver, News & Observer, 25 Sept. 2018,

(7) “Sources of Greenhouse Gas Emissions.” EPA, Environmental Protection Agency, 9 Oct. 2018,

(8) “Loyd Ray Farms Swine Waste-to-Energy Project | Cavanaugh.” Cavanaugh & Associates, P.A. | Stewardship Through Innovation,

(9) Duke University Climate Action Plan, Updated 2018

(10) “Various Advantages and Disadvantages of Biogas.” Conserve Energy Future, 22 May 2017,

(11) “North Carolina Department of Environmental Quality.” NC DEQ,

(12) “Hog Farming.” North Carolina in the Global Economy,

3 thoughts on “Biogas and CAFOs in North Carolina by Carsten Pran

  1. Carsten, I think you did a good job detailing the environmental hazards, health concerns, and environmental justice implications of open-air hog lagoons. Capturing biogas from enclosed pens appears to be an efficient solution to combat methane emissions and issues regarding odor.

    I was a little confused by the idea that biogas capture could further environmental justice issues by providing cause to circumvent a ban. I would be interested to see what kind of evidence the people making this argument cite. In my mind, biogas is not meant to be an end all solution to justice issues but is rather a practical solution to a set of environmental problems involved with CAFOS.

    Additionally, I’m interested in the economics of biogas capture. Is there a demand for methane that makes biogas modifications on farms economical in North Carolina? I also wonder if there is refining/transporting infrastructure available to handle an influx of biogas from farms.

  2. The idea of turning pig waste to energy is extremely interesting, especially given how much excess waste hog farms produce and the growing demand for energy. Your article is very thought provoking. Personally, coming from the heavily fracked state of Oklahoma, I believe that if the energy-rich biogas is able to replace natural gas and prevent fracking in North Carolina, then it should be looked into further. Another important factor you mention is the reduction in flood risks; as we all know, the number and severity of extreme weather events are expected to grow in the coming years due to climate change. If biogas technologies effectively reduce the negative impacts that happen during flooding events, then they offer vital protection for the communities living around these agricultural facilities. I am curious to how the storage of biogas would be regulated, as there are inherit issues in properly storing any waste or gas.

  3. Great blog! The hog industry presents a complex environmental issue which you very comprehensively laid out in your blog. I agree that biogas could be an effective solution for North Carolina’s CAFOs. It is hard to come to terms with the potential environmental justice issues that this solution could potentially exacerbate, but, on the other hand, if nothing is done, these farms will just continue business as usual. At least biogas is a solution which the hog industry will sign on to, so the environmental damage CAFOs are causing will begin to be addressed. This seems to be a common issue when it comes to environmental solutions; there will always be tradeoffs, so it is nearly impossible to have a perfect solution.

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