Five McLanahan sand separators (four shown) pull the manure up their 36"-diameter augers to reclaim coarse sand particles.
The Disneyland of Manure. The Manure Factory. Manure Mecca. Call it what you will, but the manure processing facility at the Rosendale Dairy is a jaw-dropping, $6 million–plus operation that has to be seen to be believed. Yes, it’s that impressive.
With manure flowing into the facility from 8,000 cows 24/7, it has to be. That’s especially true for Wisconsin’s largest single-site dairy, which faced bitter local opposition when it was first proposed some five years ago.
In operation since November 2008, the facility is living up to its promise of being an environmentally responsible neighbor while providing work for more than 80 employees and buying feed from 18 local growers.
Milk Source, the largest dairy producer in the state, owns the facility and milks 17,500 cows on three sites. Rosendale Dairy, near the village of Pickett in east central Wisconsin, is its largest. A fourth facility, with 4,300 cows, is being planned for the Central Sands region of the state.
The manure processing facility at Rosendale was designed to allow sand-bedded stalls to optimize cow comfort in the cross-ventilated barn. The extraordinary effort to process the manure involved "building a facility to reduce odors and capture and utilize manure nutrients without having to land-apply sand-laden manure," says Bill Eberle, operations manager.
The system not only reclaims 90% to 95% of the sand, it also segregates manure solids from the waste stream. One load of separated manure solids is equal to four loads of processed "tea water." In turn, solids separation reduces manure hauling and wear, tear and traffic on local roads. That’s not insignificant, since Rosendale reaches out as far as 10 miles for
Sand-laden manure is scraped from freestall alleys three times a day, each time cows are milked. It is scraped into cross augers, which carry it to the collection pit in the manure processing building. The building, 200'x250', is insulated and heated for year-round operation.
From the collection pit, five McLanahan sand separators pull the manure up their 36"-diameter
augers to reclaim coarse sand particles, which account for roughly two-thirds of the reclaimed sand.
From the separator screws, the remaining liquid, solids and sand moves to three McLanahan Hydro Cyclones, which remove finer particles of sand through high-speed centrifuge action. In total, the two-step process removes between 90% and 95% of the sand.
The reclaimed sand is then moved outside by front-end loader to a 170'x429' concrete pad with concrete walls. Here, sand is allowed to seep moisture for three to four weeks before it is re-used.
"A dairy our size would normally use about sixty 20-ton truckloads of new sand per week," says Bill Harke, public relations specialist with Milk Source. "We now normally bring in less than six truckloads per week of new sand."
Such re-use saves $700,000 to $800,000 annually in new sand purchases for an 8,000-cow dairy, based on a cost of $12 per ton.
- February 2011