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Recycled water recycles bedding sand on Minnesota farm

Karen Lee Published on 28 December 2009

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There’s no bedding like sand bedding and that’s all Vern Scherping wanted to use on his dairy after converting to a freestall setup. But once it started taking a toll on his manure-handling equipment and soils, he knew he needed to find a better way to manage the sand, so Scherping began looking for a way to reclaim the sand bedding.

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The old system required pushing manure down the center lane to a reception pit. They hauled 40 loads every six days and were also in need of long-term storage.Scherping Farms in Little Falls, Minnesota, is surrounded by wetlands and must keep to a 300-acre footprint. Knowing most manure management systems would not work in this scenario, Scherping contacted Matt Silbernick at Genex Farm Systems in Melrose, Minnesota, to help devise a plan that would suit his family’s land-locked 800-cow dairy.

They started touring other locations and looking into the Parkson sand reclamation equipment and Slurrystore storage systems. They considered sand settling lanes, but found them to have more pumps for water and manure than the Scherpings’ chosen system. This new system also has the advantage of being indoors and operating at the same temperature whether the snow is flying outside or the summer sun is shining. They noticed other sand separating systems left fiber with the sand that could lead to bacterial growth.

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The Scherpings’ new system starts the same way as the old with the scraping of manure to the center of the barn. From there it is vastly different. The manure is transferred through flumes to a 21,000-gallon reception pit. Even though it can hold a day’s worth of manure, the pit is emptied twice a day for sand separation. When it’s not emptied, sonar sensors detect the levels in the tank and agitate the manure as needed.

“It’s all automatic,” Silbernick says. “If something shuts down it calls them on the phone.”

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“It will tell you what’s wrong and you’ve just got to go take care if it,” Scherping adds, noting he’s first on the call list because he lives the closest.

A Houle piston pump feeds 52 gallons of manure per minute into the sand separator. Recycled water is used to wash the sand from the manure and an auger system lifts the sand from the water and piles it up for future use. Within hours it can be placed back in the barn for fresh bedding.

There’s no odor to the sand, Silbernick points out, even though it’s cleaned with grey water.

The Scherpings use coarser sand known as buckshot sand. It’s a byproduct of the concrete screening process. Since it cannot be used in concrete, Scherping says it’s available at a cheaper rate. Plus, he’s observed the cows seem to like it better than the fine, sugar sand. The buckshot can roll with the cows as they lie down, whereas the sugar sand packs into place and doesn’t shift as easily. He notes the cows are clean and more than once has walked into the barn to find every cow lying down.

With clean, comfortable cows, the Scherpings are enjoying somatic cell count levels in the low 100,000s.

Water from the separator is fed through a Parkson Gritmeister to remove fine sand particles. The combination of the two machines removes 97 percent of the sand from the manure. According to Scherping, he used to bring in 12 truckloads of sand a week at $75 per load; now, he has only needed 10 loads of new sand since installation was completed a year ago.

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Effluent from the second separator enters a 176-by-28-foot vertical manure storage unit. This tank can hold up to 4.3 million gallons and is emptied in the spring and fall. Liquids from the first tank are decanted into a smaller 90-by-28-foot storage unit that holds 1.9 million gallons. The smaller tank is emptied once per year each spring.

The Scherpings soil test every year and work with a consultant to know how much to apply. They now use a dragline to inject manure into the soil on their owned and rented 1,400 acres of corn and alfalfa.

Decanted water from the smaller storage tank is combined with wash water from the parlor and leachate from the feedlot when it rains. This water is strained through a Parkson Rotostrainer. The 20,000-openings-per-inch screen separates most fibers from the water. The fibers go to solid storage and the grey water is pumped into the sand separator at 32 gallons per minute. No fresh well water is needed to power the contained system, saving wear and tear on the well
pump and retaining ground water levels.

The only adjustment they make to the system in the winter is to ensure the level of water in the decanting tank does not dip below 12 feet. If it would, the ice buildup at the top could draw the sides of the structure in and damage the tank. Therefore, for every load that is drawn from the tank, a new load is brought in from the larger storage tank.

Compared to the old system that required four full-time workers for a full day every six days, this new system only needs one person for one hour each day. That person checks the computer and the water levels, cleans the Gritmeister and pushes the piled sand off to the side.

They are also seeing cost savings in labor and reduced fuel usage. The Scherpings were accustomed to replacing their spreader every other year and don’t foresee that happening again soon. Plus, the value of this manure has been so exceptional they don’t plan to purchase any starter fertilizer this spring.

At a total cost of $1.5 million, Vern Scherping has calculated the entire installation will pay for itself within eight years. That cost includes the equipment, storage units and small building with in-floor heat to house the system.

The faster payback is in part due to the reduced culling from added cow comfort. “We’ve got cows in the barn easily on their 12th lactation,” Scherping says, noting they are still producing plenty of milk.

Scherping and his wife, Ginny, who is the parlor manager, and their sons and their wives – Robert and Stephanie and son Dylan; Brian and Tracy; and Dan and Dean – plan to increase their herd size to 1,200 cows. This system was built with that number in mind. For the expansion, they would only need to add another large storage tank and increase the time the system is in operation each day. Right now it runs for six hours twice a day. This manure management system is also primed for a digester to be added after the separation stage and before storage.

“This system isn’t for everybody,” Scherping says. However, Silbernick mentions a lot of people have been by to look and they can implement parts, if not all of it, at their own dairies. PD

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