For years, Paul Danbom let good fertilizer go to waste.
On his 900-head dairy farm in Turlock, California, he was buying fertilizer for his distant cornfields. Meanwhile, he was paying to dispose of millions of gallons of perfectly good “brown gold” because there was no easy and ecologically friendly way to get it from his cattle to these fields.
Storing and transporting wet manure via tanker trucks to use for fertilizer can be a costly logistical challenge. The manure on Danbom’s farm was what is known as slurry, a heavy mix of wet and solid waste that requires special trucks and technology to move and pump onto fields.
That heft makes it expensive to transport, which creates incentives for farmers to over-apply manure directly on their nearest fields, polluting nearby waterways. Danbom said that’s precisely what was happening on his farm: He was applying more waste to fields closer to his cattle and paying for fertilizers or waste transportation farther afield.
About three years ago, Danbom invested in a separator system that would allow him to easily transport dry waste to those distant fields and apply the remaining liquid closer to the source, all while curbing emissions and preventing toxic runoff.
“When I separated [dry waste from wet manure], it allowed me to get manure to [fields] where I couldn’t get it before,” Danbom said.
Manure is a messy, costly hassle for livestock farms. It’s also the agriculture sector’s biggest climate culprit.
Waste makes up roughly 11% of the industry’s greenhouse gas emissions, according to the Environmental Protection Agency (EPA). Manure is also a primary polluter of groundwater, streams and drinking water, with nitrate and phosphorus runoff leading to aquatic dead zones across the country.
The federal government knows this. In its 2021 Methane Emissions Reduction Action Plan, the Biden Administration outlined how programs funded by the Farm Bill should “adopt new practices that improve manure management and can substantially reduce methane emissions.”
Ahead of this year’s Farm Bill, a massive piece of legislation approved every five years, advocates are asking for increased funding to do just that.
There are currently three major ways livestock farmers deal with waste. The first is manure lagoons, where wet, slurry manure is held on the farm property. Though widely used, they contribute to groundwater contamination, odor pollution and methane emissions.
Inside manure lagoons, waste isn’t exposed to oxygen and the natural process known as anaerobic digestion begins. This process eventually results in the release of methane, the primary ingredient in methane gas, a major driver of climate change.
The second way farmers deal with livestock waste is through anaerobic digesters, which have grown in popularity in recent years, capture methane emitted from manure and sell the gas as a fuel source to utilities. Instead of trucking the wet waste, it is captured and placed into a giant, covered building, triggering the digestion process.
Digesters, from poultry operations in Delaware to hog farms in North Carolina, were once heralded as a major solution to the industry’s emissions problems, but they’re expensive, still cause groundwater pollution and still release methane (though not as much as lagoons).
And last, there are dry manure management systems, like Danbom’s. These practices reduce methane production, as the waste is not deprived of oxygen, so the natural anaerobic process can’t begin.
Danbom’s separator works in the same way California gold panners screened for deposits in the mid-19th century: It funnels wet waste onto a screen that separates nutrient-dense solids from liquid, and the dried waste is used as fertilizer. Separating liquids from solids halts the methane-producing process of waste decomposing in a liquid environment. The process also prevents runoff into the watershed, as the dirty wastewater is reused to clean out the separator system.
Like roughly 150 other farmers in his state, Danbom received funding from California’s Alternative Manure Management Program (AMMP) to implement a separator system that he uses to create bedding and fertilizer for his farm. This state-run pilot program helps livestock producers move away from the old standards of manure management; it’s estimated that it has reduced the equivalent of 1.3 million metric tons of emissions in the past five years.
But for non-California farmers looking to switch their farms to these practices, the necessary changes and technologies can be costly. Separators can cost anywhere from $500 to $1,000 per head of cattle. On the other hand, digesters are estimated to cost anywhere from $400,000 to $5 million “depending on the size, design, and features.”
There are some piecemeal efforts to help farmers shoulder the financial burden of adding separators to their operations. For instance, the Idaho Department of Agriculture recently awarded grants to some of the state’s largest Concentrated Animal Feeding Operations (CAFOs) to implement dry management systems. And Ben & Jerry’s has funded separators for some of the farms they source their dairy from. Democratic lawmakers from New Mexico and Maine have pushed for making manure management programs, like California’s, accessible nationwide.
But given the promise of the technology — and the urgency of the climate crisis — advocates say more farmers across the country should implement dry manure management. The Farm Bill could help.
Renata Brillinger, executive director of California Climate and Agriculture Network (CalCAN), an advocacy group that helped found California’s AMMP program, said separators are “a prime candidate for inclusion in the Farm Bill. “If producers use technologies that avoid or minimize the anaerobic conditions in the first place, then we don’t create methane.”
Cathy Day, climate policy coordinator for the National Sustainable Agriculture Coalition (NSAC), said that as farms become larger, more operations see waste as a potential commodity. She agreed with Brillinger that alternatives to wet manure management are prime practices to be included in the Farm Bill. NSAC wants legislation that includes more funding for dry and other non-digester practices.
The two organizations have been pushing for a national model for non-digester manure management practices based on the California pilot program. “There would be a lot more of these alternative manure management projects on the landscape if there was more money for them,” Brillinger said. “The waiting list is long and the interest is really high.”
This article is copublished with Ambrook Research as part of a series that looks at ways the 2023 Farm Bill can help address the climate crisis. A longer version of this article appears on Ambrook Research. Nexus Media News is an editorially independent, nonprofit news service covering climate change. Follow us @NexusMediaNews.