Less than a mile from the Canadian border amid the rural landscape stands a nondescript, concrete structure no more than a few feet tall. Steve Vander Haak, manager of the Vander Haak Dairy farm, stands atop the 50 foot by 100 foot mass of concrete and pipes. Inside the structure beneath his rain boots, bacteria decompose several hundred thousand gallons of poop. The Vander Haak Dairy farm methane digester converts batches of cow manure into kilowatts of electricity.
"(The digester) utilizes anaerobic bacteria to convert organic materials into gas — primarily methane — which can be used as an energy source," said Craig MacConnell, chair of the horticulture department with the Washington State University Whatcom County Extension.
The digester, which is modeled after similar digesters in the Midwest, is the first commercial digester in Washington state. The digester prevents disease-causing bacteria in the manure from entering streams, lakes and rivers.
"Anything that biodegrades can go in there: corn, silage waste, fruit waste, anything that rots," said Brian Van Loo, the project manager for the digester and owner of Andgar Corporation.
Using cow manure to create electricity, Darryl Vander Haak, owner of Vander Haak Dairy, turns brown into green. The Vander Haaks sell the electricity to Puget Sound Energy’s Green Energy Program. According to the Department of Energy, the majority of electrical power in the United States comes from the combustion of coal, petroleum and natural gas. Burning these fossil fuels is a major source of air pollution and uses up nonrenewable resources. Locally produced and renewable, the methane the Vander Haak digester extracts provides energy from domestic animals instead of shrinking coal reserves.
Digesters also serve as a solution to increasingly strict policies for disposal of agricultural waste.
"As regulations have changed, dairy farmers have had to modify their operations, particularly in the way they deal with animal waste," said Tuana Jones, the area director for the U.S. Department of Agriculture’s Northwest Washington region. "An anaerobic digester allows the animal waste to be utilized to produce energy for on-farm use and, in some cases, to sell back to the grid."
Whether collected in a digester or left in a containment pond, manure will emit methane gas as it decomposes. Burning the methane on-site to generate power, however, prevents the gas from entering the atmosphere.
"Methane is a climate-changing gas," MacConnell said. "Agriculture is the largest source of controllable emissions."
According to the WSU Climate Friendly Farming program, methane is a greenhouse gas with 23 times the insulating effect of carbon dioxide. Instead of escaping into the atmosphere and acting as a solar insulator, the methane anaerobic digesters create is captured and burned.
Processing manure through the digester reduces the amount of manure in runoff entering streams. It also contains manure emissions and odor.
MacConnell contrasts the raw manure material with manure that has cycled through the digester: "There’s a significant difference in odor — the material smells. The anaerobic digester captures odor and destroys it through heat and pressure."
Less than 100 yards from the digester, a concrete and steel barn houses the source of the manure: dairy cows. The digester is located 1.5 miles from the main farm, where 600 cows live.
An advocate of everyday recycling, Vander Haak began to question how he could improve his cow-manure-management practices to be more environmentally sound and economical. With the use of his digester, he is now able to recycle the largest source of waste on his farm.
Vander Haak approached Van Loo to inquire about the possibility of building a digester. They began researching anaerobic digesters by visiting sites in the Midwest. Andgar Company began constructing the digester the first week of July 2004 and finished Oct. 1.
During the two years between initial research and the completion of the digester, the pair developed a positive relationship, Van Loo said.
"We commend (Darryl) for being the first in the area to try this and for the environmental soundness," Van Loo said.
Vander Haak and Van Loo apply a barnyard metaphor to explain the relatively simple way the digester operates.
"Basically, it works like a cow’s stomach," Vander Haak said.
Using this metaphor, the first step in the process begins where the cow’s stomach leaves off. Each day, the Vander Haaks can add up to 45,000 gallons of manure, Van Loo said.
The manure that enters the digester is a mix of liquid and solid materials. The workhorses of the digester are anaerobic bacteria. They break down the manure — changing the chemical composition of both the solid and the liquid waste.
Each day, the new manure pushes the older manure progressively farther along, Steve Vander Haak said, as he gestured toward the back of the rectangular-shaped concrete box.
Following a U-shaped path through the inside of the concrete apparatus, the manure travels twice the length of the structure. Throughout the 22-day trip, bacteria in the digester brake down the manure, separating it into three byproducts: gas, liquids and solids. A series of pipes carries a foamy substance to a containment pond where it will stay until applied to fields as fertilizer. Another pipe moves solids to a separating mechanism where they are brokenup and piled. And a pipe at the top of the digester carries the gas, 60 percent methane, to a building that houses the gas-combustion generator.
Inside the building, an orange Caterpillar engine fills the room with a rhythmic cacophony. Van Loo raised the volume of his voice to just below a shout to be heard over the roar. Methane from the digester, he said, fuels the engine which in turn powers the generator, producing electricity. PSE buys this electricity and resells it as green power.
The entire operation produces such a small amount of emissions that an air-quality permit is not necessary, Van Loo said.
At a gray electrical panel, Van Loo flipped open the clear plastic cover and began pressing buttons. A small screen illuminated, displaying the constant stream of data reflecting the engine and generator performance. Flipping past the current production numbers, he stopped at the total operation figures.
During the first four months of operation, the Vander Haak digester produced 285,000 kilowatts of electricity. According to the Environmental Protection Agency, the average home uses 10,700 kilowatt hours annually. After four months, the digester produced enough electricity to power 26 homes for an entire year.
The digester is processing approximately 18,000 gallons of manure a day, less than half of its capacity, Van Loo said.
In addition to the manure produced on-site and piped from the main farm, participating farmers also truck in manure. The digester also processes some food waste, mainly from local fish processing plants, Vander Haak said.
The generator burns the methane gas and the liquid waste fertilizes the fields. The solid remains are the only component of the process unaccounted for.
After passing through the digester and piling in large mounds, the solid waste resembles potting soil more than it resembles poop. The Vander Haaks use it as bedding for the cows, but Van Loo and others see additional markets developing.
Immediately out of the digester, the solids smell faintly of ammonia, but in a few weeks, the solids are indiscernible from normal soil. They are 99 percent free of pathogens and contain no weed seeds, Van Loo said. He pointed toward an ongoing soil test. In a cardboard box, rows of green grass were sprouting out of the digester’s solid byproduct, testifying to the fertility of the solid waste.
The development of additional markets for the waste products of digesters encourages more projects like the Vander Haak digester. But the large capital costs of digester technology and construction remain a crucial hurdle.
The total project cost for the digester was $1.2 million. A grant from Agriculture’s Rural Development Program paid for 25 percent, Van Loo said.
Vander Haak said it is too early to tell how successful of an investment the digester could be and emphasized the importance of government support.
"There’s some good potential," Steve Vander Haak said. "We’ve got some markets to develop with the solids. It’s new technology, so you’ve got to learn some things."
Van Loo said he estimates a seven-year payback on the Vander Haaks’ investment. But his calculation accounts for a 5 percent annual return only possible if running at full capacity.
"Basically, it’s sustaining the Whatcom County agriculture, and it will pay back with the returns," Van Loo said.
The role of government assistance on the Vander Haak project was important but could have an even larger impact on a national scale.
"We are optimistic that projects, such as this one for the Vander Haak Dairy, can be started with some seed money from USDA, become proven technology and then replicated by other such operations across the state and around the country," Jones said.
Digester technology is one solution to the problems poop poses.
"I think there’s a bigger picture here — there’s only so much land. What you do with the land is ultimately important to society, whether it goes to sprawl or to production, to sustain agriculture," MacConnell said. "This is one of the ways to ensure we do."