VanDerHyde Dairy ready to move forward with anaerobic digester

VanDerHyde Dairy in Chatham has the money it needs to build its innovative anaerobic digester to convert manure into energy.

Since getting $1 million from Virginia’s Biomass Energy Grant Program last month, inclement weather has been the only thing holding the dairy back from breaking ground on the $2.5 million project, said Roy VanDerHyde, president of VanDerHyde Dairy.

Even before the VanDerHydes undertook a feasibility study to determine whether the project would be worth its cost, they were sure of its profitability.

“We knew it would cash-flow,” VanDerHyde said Friday.

The study took about four months and was performed to show banks and investors the idea would work, VanDerHyde said.

The dairy’s owners plan to use the anaerobic digester to process manure from their nearly 1,000 cows, expand use of its by-product to make electricity and take dairy farming into the 21st century. The digester would recover methane from animal waste through anaerobic — or airless — digestion. The technology processes the waste to produce electricity, bedding and liquid fertilizer. It also produces waste heat, which can replace hot-water production and used for in-floor heating.

The anaerobic digester will be 200 feet long, 72 feet wide and 16 feet deep, and would process waste in 21-day cycles. The project, which VanDerHyde hopes will start in about 10 days if weather permits, will take about nine months to build.

The technology’s arrival in the county would enable other dairy farmers to research anaerobic digesters and possibly buy bedding as well as liquid fertilizer with reduced phosphorous content, which is regulated by the federal government to ensure water safety. In addition, the project would place agriculture at the forefront and identify the county as progressive, increasing opportunities for grant funding. Also, it would reduce the farm’s carbon footprint.

Other benefits from the digester include production of higher-quality cow bedding, reduced nitrogen and phosphorous levels, waste-odor reduction and improved energy distribution in rural areas. The machine breaks down fatty-acid levels in waste to get rid of odor.

The VanDerHydes would also be able to sell electricity. With the technology, the VanDerHydes would be able to earn carbon credits through destroyed methane, increase their milk quality, reduce pathogens in spread manure and lower pesticide/herbicide expenses because of reduced fly hatching.

Besides $1 million from Virginia’s Biomass Energy Grant Program, which received the money from the American Recovery and Reinvestment Act of 2009, a $448,000 Tobacco Commission grant and $150,000 from the U.S. Department of Agriculture will help pay for the digester’s construction. The VanDerHydes will pay for the rest.

The digester will produce clean bedding for the farm’s dairy cows to lie in, reduce odor from cow manure, reduce pathogens in manure spread on fields and increase the fertilizer’s value, VanDerHyde said. The dairy intends to sell electricity to Dominion Power and hopes there is a market for its fertilizer.

The digester will be the first of its kind in Virginia.

There are about 100 anaerobic digesters at dairy farms across the United States, said Steve Dvorak, president of GMD, Inc. in Chilton, Wisc., which engineers and designs anaerobic digesters and builds parts for them. While the digester holds potential for other dairy farmers, it will never be mass-produced for farmers to select from a lot like a Ford, Chevy or Honda vehicle.

“They’re all going to have to be engineered specifically,” Dvorak said during a telephone interview Friday.

Each machine must be built on site, like constructing a house, he said.

“Every digester project is basically custom-built to each farm,” said Fred Wydner, director of Pittsylvania County Agricultural Development, adding that “with this technology, one size does not fit all.”

The anaerobic digester includes a gen-set — a motor and generator — which GHD buys for each product, and also includes GHD-constructed heat exchangers and process controllers. Contractors build the concrete vessel and electrical system, Dvorak said.

A gen-set costs about $225,000 and has to be specially designed to handle corrosive biogas, Wydner said. If a farm doesn’t produce enough methane, the digester becomes inefficient, which is why estimates are needed for methane production, Wydner said. The digester itself takes about four months to build, Dvorak said.

The VanDerHydes’ cows produce about 40,000 gallons of manure a day. VanDerHyde said the digester will generate about 1 kilowatt of electricity for every four cows. For a project of the VanDerHydes’ size, a farm would need a minimum of 500 cows to make it cost-effective, Wydner said. Farmers — there are six dairy farms in Pittsylvania County —pursuing a similar project should conduct a feasibility study, he said.

Dvorak said GHD is contemplating designing and building smaller anaerobic digesters for 15-20 cows and also chickens, hogs, human waste in overseas markets, including villages in Africa.