3-D Dairy’s Stage 1 lagoon is cement- lined for easy clean-out of sand fines that accumulate. “We go through a fair amount of sand. I tell our guys we want clean stalls, dry and manure free as possible,” says 3-D’s John Diedrich.
Simple is good. That’s the basic concept driving the flush-flume sand separation system at 3-D Dairy, a 1,350-cow operation in Malone in east central Wisconsin.
The facility, built by brothers John, Joe and Bill Diederich, began as a 600-cow operation on shavings-bedded mattresses in 2000. Two hundred cows were added in 2005 and an additional 550-cow barn was built in 2009.
"In 2009, we had to decide whether to stay with sawdust or switch to sand," says John Diederich. "Shavings were hard to get and were expensive. And sand offered better cow comfort and traction. All the studies say there is nothing better than sand."
Cow footing was one of the driving forces in the switch. "Alley floors can get slippery with shavings, especially in the fall," Diederich says. "We always had some injured and downer cows, though we couldn’t pin it to the floor surface. But since we’ve switched to sand, the number of injuries has drastically changed."
Sand brings its own set of problems: what to do with it after it gets kicked out of the stalls and mixes with manure. The layout and topography of 3-D Dairy lent itself to a flush-flume system.
The third stage of 3-D Dairy’s lagoon system lies 40' to 50' below the three freestall barns and one heifer barn. Every time a pen is emptied of cows for milking, workers switch on a 60-hp pump that pushes 1,300 to 1,400 gal. of water/sand/manure per minute to a cross-barn flume. The pump runs for a preset 20 minutes, which is enough time for workers to scrape pen alleys.
Workers in the barns then scrape manure into the flume. (They only scrape when the flush water is running.) The flume, some 500' long, crosses all three freestall barns, where it flushes sand into the sand separation building.
The sand is deposited into a sand separation lane, 72' long, 4' wide and 3' deep. The water/manure/sand mixture slows down to 1' per second and the sand simply settles out. A 12" auger at the bottom of the pit moves the sand to the center, where it is dropped into an 18" inclined McLanahan auger for "dewatering."
Clean, fresh water is used for this dewatering. It floats out additional manure solids and augers out the reclaimed sand. The process uses just 600 to 800 gal. of clean, new water per day, or roughly ½ gal. per cow per day.
"When we’re using new sand, we reclaim about 75%," Diederich says. The fines get flushed along with manure solids into the 1.1-million-gal., concrete-lined Stage 1 lagoon. From there, the sand/manure can be land-applied.
"When we’re using reclaimed sand, we’ll reclaim 90% to 95%," Diedrich says. This sand is then stockpiled with a payloader or backhoe onto an outside 120'x120' concrete-floored stacking slab. The Diederichs like to let the sand drain for six weeks or so before re-using it.
Sand can also be stockpiled in the 55'x90' sand separation building. The facility has in-floor heat and insulated, 20' sidewalls.
- February 2011