Vernon farm maximizes its uses for manure
VERNON >> Vern-Mont Farm co-owner Jeff Dunklee chalks up changes in the way cow manure is handled at his farm to "Yankee frugality."
After a rotary drum compost system was purchased from DariTech and installed last year along with a manure-solid separator from EYS, the recycled excrement was then used for cow bedding.
"It's just the fibrous parts of manure," Dunklee said, talking about undigested forages such as corn and hay. "A cow's digestive system absorbs most of the nutrients. What passes through is more of the fiber, the less nutritious part. That's basically what we're trying to recapture."
The farm previously relied on saw dust shavings from Cersosimo Lumber Company in Brattleboro for bedding. But now, about 90 percent of that material has been replaced with the farm's own product.
Bedding is meant to make a clean environment for cows by absorbing and draining moisture. Comfort is another issue. Cows produce more milk when they are sitting rather than standing throughout the day, according to Dunklee.
"Essentially, when they're not eating or getting milked, you want them lying down," he said.
At Vern-Mont Farm, 575 cows are milked on a daily basis. Two storage tanks, one above ground and one in the ground, hold about 2.5 million gallons of manure.
The manure is pumped into a big concrete tank and the water is separated. The substance is then pushed into the compost drum and gets heated up to 140 degrees through "natural biology," said Bob Spencer, Windham Solid Waste Management District executive director who assisted in the project as a friend and neighbor to the farm.
"That's what's killing the pathogenic organisms. That makes it safe to use under cows for bedding," Spencer said. "This is an aerobic composting system."
Other farms in Vermont use anaerobic systems, which break down biodegradable materials without using oxygen. Dunklee said those systems cost significantly more to purchase.
Spencer and Dunklee started looking at options around composting six years ago. They visited several facilities in different states. Two years later, they met with DariTech and went to four farms using the manufacturer's technology.
Due to concerns about water quality, manure can only be spread on fields during certain months in Vermont. The practice is prohibited from December to April.
"Manure is a huge issue for Vermont farms," said Spencer. "So they're extracting more value from the bedding. Saw dust costs $12 per cubic yard. They were spending lots of money."
Transportation was another area expected to bring savings. While the manure will still get pumped into trucks and will be applied to the same fields, Spencer said there should be less trucking involved since he was seeing a reduced amount of phosphorous. That would make the manure lighter in weight.
The latest equipment
A new heat recovery system takes excess heat from the compost drum, which was previously sent to the exterior of a building via an exhaust system, and uses the energy to generate hot water to clean the milking system.
"It's a lot of heat 24 hours a day," said Spencer. "Heat exchange systems have been around forever. It's applying it to this that is new."
The equipment came from the Vermont-based Agrilab Technologies. A control room gives the company remote access to the system. An approximately 400-foot-long and 6-inch-thick insulated pipe was installed underground from the building housing the composting drum and heating recovery system to the milking parlor.
Agrilab Vice President of Sales and Marketing Gaelan Brown said the concept of the company's heat recovery systems has been subject to "upgrading and fine tuning" since the first system was installed in 2006. Several products related to compost heat recovery are offered by Agrilab.
Vern-Mont's project is the seventh system set up by the company. Three more systems are expected to be installed this summer.
"We're very excited," said Brown, who explained that environmental and economic benefits do not have to be mutually exclusive. "We're kind of building up out of the small, start-up world. But most projects are based in Vermont."
The system at Vern-Mont, called the Dragon Drum 200, is the company's newest product. Agrilab checks in on operations about once a week.
"The interesting thing about the drum system is you may have problems with the pumps, getting solids into the drum. So, there's several mechanical pieces that you may have periodic issues with, otherwise it's continuous," Brown said. "Heat capturing is basically totally predictable because it all has to do with the amount of hot water they're using in the cow parlor."
With the drums being spotted on more and more farms, Brown said he thinks the heating recovery system also will become more common. He looks at the system as a way to give farmers a strong economic incentive to improve watersheds and land fertility.
"My family's in dairy farming and I've always been scratching my head about the whole manure thing, about the way farms are using big liquid storage containers and spending lots of money to send manure-rich water in trucks over fields. It does a lot of soil compaction damage then all this liquid manure is raw and filled with pathogens, unstable phosphorous and nitrogen. When it rains, there's watershed issues," said Brown. "It seems to me a big mistake was made by the industry in going to the liquid manure system."
Dunklee expects the composting drum to pay for itself in four years while the heat recovery system should only take a couple years.
Over 700 acres are managed for cow feed at the farm. The milk is sold to the Dairy Farmers of America cooperative. Most of it is used for fluid consumption in Boston, said Dunklee.
"We're a conventional dairy farm. We use the latest management technologies that are available," he said, noting that Roundup herbcide kills alfalfa in conjunction with a no-till technique to reduce soil compaction and the farm's carbon footprint. "We're probably milking 19 out of 24 hours in a day. We don't have a lot of downtime."
Contact Chris Mays at email@example.com or 802-254-2311, ext. 273.
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