ROANOKE, Va. — Virginia Department of Transportation officials describe the latest project happening at their Hanging Rock Area Headquarters near Salem as a national model.
Yet, they also understand that the initiative — composting road kill carcasses — can turn some stomachs.
"We don't necessarily want to put one of these right next to a subdivision," said Jimmy White, VDOT project manager.
The Hanging Rock composter is set just inside a tree line on state property north of Interstate 81.
This breakthrough in highway-management technology is straightforward. A dead deer goes inside a bin. A month later, brown compost tumbles out.
The composting bin array off Thompson Memorial Drive and a unit near South Boston in Halifax County are an experiment designed to reduce the state's $4 million annual cost incurred by driving dead animals to landfills.
Officials are becoming convinced on-site decomposition could be cheaper. A worker stacks wild or domestic dead animals collected on state property in concrete bins with lots of sawdust. Naturally occurring microbes do the rest, assisted by forced air jets in the floor.
But there is a side benefit. What was once waste becomes a fertilizer-like resource inside the composter, and VDOT has no intention of giving the valuable material away. It plans to spread it. Some of the Halifax-made compost, when spread on an eroding area along Virginia 360 outside Halifax, contributed to rapid grass growth, White said.
Applying composting, which farmers have used for years, to road kill management is exciting to state officials.
The completeness of the animal breakdown is "fantastic," said Stan Philpott, superintendent of the Hanging Rock yard, who is also pleased that his crews no longer have to drive about 10 dead animals each weekday to the New River Valley. The animals went to the landfill near Dublin operated by the New River Resource Authority, which is still used by some VDOT regional offices that don't compost.
Once usable quantities of the compost are produced, crews are expected to apply it as a fertilizer to stimulate vegetation growth where the ground has been disturbed or eroded. The agency will also employ it as a landscaping and flower bed mulch, White said.
The state's composting venture complies with Department of Environmental Quality regulations, said DEQ solid waste permit writer Jenny Poland. The material is not required to be pathogen-free, though the pathogens "are at levels that should not be harmful to human health," according to Poland.
"The compost will be used by VDOT. They have a lot of projects where they will be able to use that," said Poland, "It has good soil amendment properties."
Based on the project's success so far, VDOT is contracting for four more composting units at $115,000 apiece at locations yet to be announced. Barring a glitch, the state could someday operate enough composters to serve large tracts of the state, White said.
Highway workers are on course to collect more than 5,000 dead animals in the Roanoke and New River valleys and nearby communities this year, most of it roadkill. The statewide count could exceed 50,000. VDOT must dispose of the carcasses but wants to lower the cost. The annual, average disposal cost was $4.1 million from fiscal 2007 through fiscal 2011 for personnel, transportation costs and landfill fees. The mileage alone, to and from landfills, averages 252,000 miles yearly.
When White ran a VDOT yard in Rockbridge County 20 years ago, sometimes the carcasses were fed to the big cats at the Natural Bridge Zoo, he said.
Those days are long gone.
VDOT workers have buried roadkill beside highways. However, that system worked better before utilities placed infrastructure along highways, where it is tracked and safeguarded by Miss Utility, and environmental regulations came into force that further regulate digging. It isn't done much anymore.
In recent years, the best available solution was to drive the carcasses in a pickup to landfills. But White said some Virginia landfills charge a lot, perhaps $60 to $100 a deer, and have become reluctant to accept animal carcasses because "it hurts their management of the landfill."
Joe Levine, who directs the New River Resource Authority, said the waste-management agency's facility continues to accept dead animals without any operational issues at the municipal waste rate of $32 a ton. That said, the authority is in favor of recycling, waste reduction and reuse.
"All compliant composting systems are great ideas," Levine said.
Convinced the state needed a new plan, the Virginia Center for Transportation Innovation and Research, an arm of VDOT, studied composting and decided the state should try it as a possible new, long-term solution to animal disposal. After some early attempts, and input from Advanced Composting Technologies LLC, in Candler, N.C., the state focused its efforts on rectangular bins equipped with blowers. Microbial action, which requires food, water and oxygen, can rot a batch of animals in a month or two in such a container, according to White, who said temperatures hit a pathogen-killing 160 degrees or more.
A crew built the state's first forced-air, animal composter in 2012 at a VDOT yard just outside Halifax, a small town near South Boston. Workers converted three steel roll-off garbage containers at a cost of $48,000. In a sign of the tool's versatility, it processed a couple of donkeys in addition to the usual roadkill of primarily deer but also bears and smaller animals, White said.
Halifax Mayor Dick Moore recently heard about the system.
"It didn't bother me. There was no odor involved that I can tell by just riding by there," he said.
To further the experiment, crews retrofitted four concrete material storage bins at the Hanging Rock VDOT yard for $28,000 and the state started up that composter in July. Each bin can hold about 10,000 pounds of animals, about 100 deer. The temperature inside of one of its bins stood at 150 degrees one recent morning.
The system features forced-air jets that fuel decomposition and a trough that routes the run off from the topless bins into a tank underground. Using a hose sprayer, an attendant applies a couple of spritzes of the fluid every so often to help keep the piles cooking.
VDOT thinks the money it saves in avoided disposal expenses will cover the cost of each forced-air device in as few as five years for those VDOT yards at least 25 miles from a landfill. The payback period is likely to be longer, but well within the composter's lifetime, for VDOT yards closer to a landfill, a VDOT research report said.
Cristina Siegel, who directs the Clean Valley Council, a Roanoke-based nonprofit organization dedicated to litter prevention, recycling, waste stream reduction and stormwater pollution prevention, reacted positively to VDOT's composting project. She said DEQ approval likely means VDOT has demonstrated it can ensure the proper heat and moisture recipe for full decomposition of organic matter — a breakdown much greater than area residents may achieve in backyard composting piles.
"There certainly is an initial 'yuck' factor when you hear the idea," she said. However, given the exacting standards VDOT appears to be using, "a compostable plate or a head of old lettuce or a road-killed deer ultimately break down to the same organic components."
To report a dead animal on a highway, call 800-367-7623 (800-FOR-ROAD).
Information from: The Roanoke Times, http://www.roanoke.com