Composting 101…DON’T put meat, fat or bones in your compost bin. But now we’re hearing that the third largest DOT (Department of Transportation) in the country is planning on composting the thousands of animals that end up dead on the roadside every year.
The idea may sound morbid…grotesque even…but the benefits of composting these carcasses instead of landfilling or incinerating them are both environmental and financial.
The Virginia Department of Transportation (VDOT) spends approximately $4.1 million per year on road kill disposal. Currently those animals are brought to a landfill to be deposited as general refuse. And the numbers of animals are significant; the insurance industry estimates that there were 52,400 deer-car crashes in Virginia last year. The economic issue is the cost of disposal. The environmental issue is that these animals are organic waste. In a landfill, that means methane production.
VDOT began experimenting with animal composting in 2012 at their Hanging Rock facility. The Virginia Center for Transportation Innovation and Research (VCTIR), a subdivision of VDOT, tried several different compost bin configurations before seeking help from Advanced Composting Technologies LLC, in Candler, N.C. The initial experiment involved converting three metal roll-off trash containers, installing large blowers in the floor to force air into the system at a cost of $48,000. When that experiment proved to be a success, VDOT workers retro-fitted three concrete material storage bins at a cost of $28,000. Those units became operational in July, 2013.
The method of using large, open-topped bins and using air forced into the pile from the bottom to fuel decomposition is known as vessel composting. A simple system, such as the ones built at VDOT, can reduce a full load of deer carcasses to compost in a month. Advanced Composting Technologies claims that their systems can reduce ‘huge’ quantities of organic matter to clean compost in a matter of days by maintaining pile temperatures around 160°F. It requires no chemicals. Water and air feed the microbes that decompose the waste and produce the pathogen-killing heat in the process.
Based on the success of the current project, the agency has contracted four more composting units at $115,000 apiece. Composting units have now been added at VDOT’s Bethel and Fishersville facilities. VDOT expects to realize the following benefits from expansion of the animal composting program:
- Significantly reduce cost of animal carcass disposal, realizing savings that will enable each composting unit to pay for itself in approximately 5 years. VDOT estimates these savings at half a million dollars per year.
- Save 252,000 road miles traveled each year transporting carcasses to landfills.
- Produce high-quality compost material that can be used on eroding slopes and in state-owned gardens, further increasing savings in the form of lower material costs.
While VDOT is the first state DOT to pilot vessel composting technology to address their road kill issue, composting animal carcasses has been a viable solution for livestock mortalities for more than a decade. For more information on animal composting see the following resources:
Composting Dead Livestock: A new solution to an old problem, Iowa State University Extension, November 1999
Whole Animal Composting of Dairy Cattle, New Mexico State University, August 2013
Composting Animal Mortalities, Minnesota Department of Agriculture, May 2009
on-farm composting of large animal mortalities, Washington State University Extension, May 2008
Video Animal Composting Part I
Advanced Composting Technologies, LLC., http://advancedcomposting.com/our-benefits/
Sturgeon, J., The Roanoke Times, October 12, 2013, Composters transform roadkill into landscape
VDOT Employee News, The Weekly Report, October 17, 2013, We’re Composting What? Pilot Program Studies Deer-Carcass Composting
Virginia Center for Transportation Innovation & Research, June 2012, Composting Animal Carcasses Removed From Roads: An Analysis of Pathogen Destruction and leachate Constituents in Deer Mortality Static Windrow Composting