Composting isn't just for veggie scraps. It's often the best way to deal with roadkill, livestock mortality and even large-scale animal deaths due to floods, fires or other catastrophes.
Many people, including some farmers, assume it's best to bury animals underground. In fact, it's safer and kills pathogens more effectively when carcasses are composted in unturned piles, according to Jean Bonhotal, director of the Cornell Waste Management Institute.
"Most of the time they get buried, but that brings them 6 feet closer to the water table," Bonhotal said.
Carcass fluids from improperly disposed animals can leach into wells, creeks or drain pipes, spreading bacteria and viruses.
"Composting is a fairly forgiving process. If we do it well, we can make a 1,200-pound animal disappear in three months. The bones will still be there, but the carcass will be gone," Bonhotal said.
But there are instances when composting is not appropriate. For example, animals with a prion disease, such as mad cow or chronic wasting disease, need to be incinerated or chemically treated. Cornell's alkaline hydrolysis digester, which uses high heat, high pressure and a chemical bath to quickly digest animal carcasses, is the state-designated facility to dispose of animals with prion diseases.
Most of the time, however, composting is the best way to go. It's faster, easier, more effective and, unlike burial, can be done year-round, Bonhotal said.
Rendering, a process that converts animal tissue into value-added materials such as tallow, is another option, but the industry can't manage as much of the dead stock as they have in the past, she said.
Bonhotal works with agencies and individuals to spread the message of proper animal waste disposal. Several years ago, the Waste Management Institute teamed up with the New York State Department of Transportation to address roadkill disposal; dead deer picked up by the agency are now composted.
She also helped organize the fourth International Animal By-products Symposium held in May in Dearborn, Mich., and funded by the Department of Homeland Security through the National Center for Foreign Animal and Zoonotic Disease Defense and Michigan State University. Other topics discussed at the event included safely dealing with euthanized animals; containing animal-originated food disease outbreaks; and state, federal and international agency disaster response planning and policy.
There's still progress to be made in achieving best practices for animal carcass disposal, Bonhotal said.
Earlier this year, for example, 300 pigs were killed in a fire on an upstate farm and buried.
"The day after a disaster, the farmers just want to have the animals gone. And they may not have the confidence that composting will work," Bonhotal said. "But they may pay for it later with environmental damage."
Krisy Gashler is a freelance writer for the College of Agriculture and Life Sciences.