US efforts to turn farm animal poop into biofuel spark scrutiny

Industrial-sized livestock operations have long been known for contaminating the environment and mistreating animals. Now, amid growing government incentives to turn the manure generated at these operations into climate-friendly biofuels, there are mounting concerns that the efforts could make industrial farming bigger and more dangerous.

Critics say government support for the production of biogas through the use of what are known as manure digesters comes with an array of well-documented risks. The digesters break down manure and capture methane gas, which can be used as fuel, but they come with a history of fires, explosions, hydrogen sulfide poisoning, methane leaks, and even drowning.

Methane digesters “exacerbate the dangers that are already endemic to industrial animal farming… where animals are housed in the same location as malfunctioning equipment, flammable liquids, and dangerous manure management practices,” said Alicia Prygoski, strategic legislative affairs manager at the Animal Legal Defense Fund (ALDF) animal advocacy group.

“Encouraging mass amounts of manure production, to facilitate the mass capture of the flammable gas that results from its decomposition, is what creates the increase in risks for explosions,” said Prygoski. “All you need is a spark.”

The Biden Administration’s much-touted Inflation Reduction Act includes funding and tax credits incentivizing farmers to install more of these digesters, and the new Farm Bill could include funds incentivizing the practice.

The ALDF and more than 100 other organizations sent a letter in December to US Agriculture Secretary Tom Vilsack calling on the agency to stop any allocation of additional funding from the IRA for the use or expansion of methane digesters or “production of factory farm gas.”

The groups cited a “ballooning factory farm gas industry,” and warned, among other issues, that digesters can “leak methane and manure and can even explode.”

Biogas on the rise

Farms produce biogas using digesters – enclosed tanks in which bacteria and enzymes break down manure into methane gas, along with liquids and solids called “digestate”.  The waste, which contains concentrated forms of phosphorus and nitrogen, comes with its own risks as it is typically applied as fertilizer on farm fields where it can leach into – and pollute – waterways.

These systems have been applauded by the Biden administration as tools to cut methane emissions while converting animal waste into energy. Farmers can monetize the methane, which can be used for generating electricity or powering vehicles as compressed natural gas.

As of 2022, there were 331 biodigesters on hog, dairy, cattle and poultry farms. A study released in March by the US Department of Agriculture (USDA) says that, in the US, digesters have primarily been developed for and adopted by large farms (typically referred to as confined animal feeding operations, or CAFOs) with more than 1,000 animals. Large farms produce more energy with the technology and can expect better financial returns, the study says.

Biogas production on farms is “definitely increasing,” said Patrick Serfass, executive director of the American Biogas Council. “There’s a lot of interest in sustainability. A biogas system is almost always the top way to increase the sustainability of a farming operation, especially dairy or swine.”

To be sure, other risks beyond digester dangers loom large in industrialized livestock operations, critics say. And a major concern with rewarding farmers for the generation of manure that becomes biogas is the fear that the incentives encourage expansion of those already large hog, cattle, dairy and poultry farms.

With bigger farms and more manure come more health and environmental risks. Manure from CAFOs contains over 150 pathogens that can contaminate water, nitrates can cause dead zones in aquatic habitats, and harmful fumes can cause asthma and lung disease in people living near CAFOs, according to the National Resources Defense Council (NRDC). While CAFOs are regulated by the Environmental Protection Agency (EPA), their health threats are largely unmonitored, a 2019 NRDC report found.

Fire and explosion hazards

Fire and explosion are among the primary risks of biogas systems that rely on digesters, according to a  2021 report by BiogasWorld, an industry group that connects biogas suppliers and developers. The report mainly relies on data from Europe and looks at a variety of facilities that produce biogas, including farms and wastewater treatment plants.

The fires and explosions associated with the systems result mainly because of “inappropriate design or operation,” the report states.

A biogas that contains 60% methane is at risk of exploding if it is diluted 10% to 30% with air, according to a farm extension resource developed by US land grant universities and government agencies.

Fires within biogas systems may be caused by a number of issues, including gas leaks that result from corroded pipes or equipment failures, combustible materials onsite, electric fires, or blocked or frozen pipes, the BiogasWorld report states.

“With over 18,000 biogas facilities in Europe, just under 5% will experience some form of accident within their lifespan,” the report concludes. It finds that about 800 accidents (of all types) occurred on biogas plants in Europe between 2005 and 2015.

Dana Kirk, a digester researcher at Michigan State University, said the chance of a digester exploding “is really very minor” since the systems usually operate at low pressure.

“It really comes down to just following basic safety guidelines that are used in commercial and agricultural and industrial practices,” said Kirk.

Still, accidents do happen.

In 2014, an explosion at a farm in Dane County, Wisconsin blew the roof off a state-sponsored digester. Pipeline breaks from the same facility also caused three manures spills in three years, releasing more than 400,000 gallons of waste.

A biodigester in Lowell, Michigan ruptured from methane buildup and nearly exploded in 2016, resulting in citations from the state Department of Environmental Quality. In 2018, an explosion followed by a fire occurred at a farm in Saint-Fargeau, France, due to a faulty piece of digester equipment. Another digester caught fire at a Wisconsin dairy in 2020.

Accidents also occur at other types of facilities that use digesters. An explosion occurred at a wastewater treatment plant in Ontario, Canada that converts sewage sludge into fertilizer for agricultural fields in November 2020. And multiple biogas facilities suffered damage during storms in 2018 and 2019, releasing large quantities of biogas into the atmosphere, according to the BiogasWorld report.

Escalating barn fires

A massive explosion at the South Fork Dairy Farm in Dimmitt, Texas brought national attention to the barn fire issue, with a staggering 18,000 cows perishing in the blaze. The county sheriff said an overheated manure handling system may have ignited methane in the facility. The farm didn’t have a digester but was planning to install one.

US barn fires killed almost 3 million animals between 2018 and 2021, according to a report by the Animal Welfare Institute (AWI). The report included both traditional barns on small family farms and industrial confinement sheds on CAFOs.

“As we continue to see operations get larger and larger, the risks are going to continue to increase,” said Allie Granger, an AWI policy associate.

Beyond the potential for fires and explosions is the risk of leakage of hydrogen sulfide, a highly toxic, colorless gas that smells like rotten eggs, said Rebecca Wolf, a food policy analyst with non-governmental organization Food and Water Watch.

In 2005, a tank at a biogas plant that processed animal waste in Germany suffered a major hydrogen sulfide leak. A truck driver and three other workers died, while another worker was hospitalized, according to the BiogasWorld report.

In 2021, a contractor drowned in a digester tank that he was trying to repair in East Moline, Illinois. Officials said he was not wearing sufficient protective clothing or safety gear and the tank’s temperature may have been above the optimal range when the contractor entered it.

A “manure gold rush”?

As lawmakers discuss priorities for the 2023 Farm Bill, groups opposed to digesters are wary that conservation and renewable energy programs will again include funding for them. The energy title in the 2018 Farm Bill grouped digesters together with solar and wind as energy projects incentivized by the USDA.

The incentives have already created a ‘manure gold rush’ by establishing revenue streams for the manufacture of liquid manure, according to the December 2022 letter from ALDF and other opponents. “These incentivize the further expansion and consolidation of the largest factory farms, which are already major polluters and sources of environmental injustice.”

In February 2021, Food and Water Watch and other groups filed a complaint to the Federal Trade Commission alleging that the pork-producing giant Smithfield Foods has been engaging in a “greenwashing” marketing campaign that “conveniently fails to recognize the hard realities behind its investment in digesters; this investment is designed to monetize its dangerous waste rather than solving the root problems of its unsustainable factory farm model and the waste management practices inherent in that model.”

The complaint alleges that Smithfield has planned to build numerous new CAFOs in Utah with the express purpose of capitalizing on digesters.

Serfass, who supports an expansion of the digesters, disputes the idea of a “manure gold rush.” Farmers expand their herd to achieve economies of scale and “create a reliable profit margin,” he said.

But Wolf disagrees.

“Digesters’ goal is to maximize output,” she said. “So not only are we generating methane but we’re looking to maximize it.”

“In reality what we need to be doing is taking a closer look at why are we generating so much methane in these huge liquid cesspools. By saying digesters do this wonderful environmental thing, you’re necessarily saying ‘and we want to keep factory farms around.'”

(Featured Image by Jo-Anne McArthur on Unsplash.)