Verburg & Son Dairy, Modesto, Calif.

Verburg Farms is located in Modesto, Calif. This 800-cow dairy started composting four years ago. “We looked at composting to cut the volume of manure we had to manage,” says owner Pete Verburg. Composting reduces the volume of manure by 50 percent.

To separate the solids from liquids, the dairy uses two screen separators. The first separator removes approximately 40 percent of the solids with a 0.0625-inch screen. The second screen separator removes another 32 percent with a 0.03125-inch screen. This separation results in approximately 200 yards of solids every four and one-half to five days.

Solids are then moved from the separators to the composting area to form windrows. Four acres are dedicated to the composting portion of the operation. Windrows are turned every sixth day. In the summer, it takes six weeks to finish the compost and in winter it takes eight weeks. During this time period, the compost is heated to 150 degrees F and all weed seeds and pathogens are killed.

Finished compost is used for bedding. Prior to using compost, stalls were bedded with dried manure. “We were already bedding with dried manure, so we didn’t gain financially in reduced bedding costs. But, where we found the true value was the improvement in herd health,” Verburg says. The dairy’s somatic cell count has dropped from 340,000 to 110,000, qualifying it for milk-quality premiums. In addition, milk production improved and there were fewer overall health problems.

Surplus compost is spread on 320 acres of walnuts, almonds and row-crops. “We do not purchase commercial fertilizer for our orchards. We are able to utilize the liquids from our lagoon and our compost to meet our fertilizer needs,” says Verburg.

“There is such a demand for manure that if I had extra I would sell it, but our ranch comes first,” Verburg says.

Manure is valuable, but it takes management, he adds. “I have never thought of my manure as waste, but rather as nutrients in transition to somewhere.”

Holsum Dairy and Elm Dairy, N.E. Wisconsin

Elm Dairy and Holsum Dairy are located near Green Bay, Wis. These two dairies house a combined 6,900 milking cows. Two digesters are used on each dairy to manage manure. Both use a modified plug-and-flow digester. Elm Dairy’s digester has been operating for six years and Holsum Dairy’s digesters have been operating for two years.

“We originally installed the digesters to control odor and provide energy,” says Kenn Buelow, co-owner of the dairies. “The plan was to break even on our investment. But, since installing the digesters, we have been able to increase revenues and reduce our cost.”

In fact, Buelow says, “Everything we’ve done environmentally has made us money.”

The digesters produce more energy than the dairies can utilize. Excess energy is sold back to the utility company. But the digesters produce more than just energy. Solids from the digester are used as bedding for both dairies, saving approximately $360,000 each year in bedding cost. In addition, separated solids are sold for bedding to 10 other dairies at $15 per ton.

Liquids from the lagoons are utilized as fertilizer by the 40 farmers who grow feed for the dairies. The liquids are 3 to 4 percent solids, and are transported via surface hose or dragline to the cropland; 20 percent is trucked. The cropping agreements include arrangements to use the liquids from the lagoon.

Buelow has also found that between the digesters and separation process, the phosphorous level in the lagoon water has decreased. There are approximately 1 to 2 pounds of phosphorous for every 1,000 gallons of lagoon water. “This is not something we expected, but it definitely works to our benefit,” Buelow says.

The dairies can’t make enough manure to meet their demand for fertilizer. To increase the nutrient content, food-processing waste, malt ingredients and slaughter-cow waste is brought in. These businesses are charged a tipping fee to deliver them to the dairy.

Buelow continues to look for the highest value for his manure. Currently, he is looking at pelleting the solids for wood-burning stoves. He is also working with a forage-products lab to make particle board and plastic piping from the solids.

“The options, usage and market for manure will only continue to grow,” he says. 

Dairy Doo, Sears, Mich.

Brad Morgan owned and operated a 240-cow dairy in Sears, Mich., until four years ago when he sold his dairy and started managing manure full-time. It was then that he opened the doors to his new operation called Dairy Doo.

“Our market is manure,” says Brad Morgan. “I understand what it’s like to operate a dairy and try to manage your waste stream simultaneously — it’s challenging.” Like many other dairy producers, Morgan saw the value in the nutrients produced, but it was a full-time job to manage them. “We didn’t have the manpower or time needed to do a quality job, nor did we have the time to market it.”

Since selling the cows, Morgan is able to focus all of his attention on managing manure. “We now produce a very high-quality compost product and are able to market it.”

“Dairymen have a lot on their plates, and the revenue generated from manure is very small compared to sales in milk,” says Morgan. “It’s not as simple as walking into a gold mine. Managing and marketing your nutrients takes time and money.”

Morgan provides a solution to more than 30 farms in his area. Dairy Doo purchases manure from these operations and turns it into a valuable product.