Taking manure-laden sand bedding and segregating it back into clean sand, useable crop nutrients and water clean enough to drink doesn’t come easy or cheap.
But once the separation system is refined and working, it definitely makes life a whole lot easier for Nate Hartway, finance and environmental compliance manager for McCormick Farms, Bliss, N.Y. The farm milks 2,000 cows and farms some 8,500 acres of corn, alfalfa and potatoes. The operation spans five counties with some fields up to 40 miles from the dairy operation.
McCormick Farms installed a Livestock Water Recycling (LWR) System a year ago. And after some initial hiccups and start-up problems, the system is now operating pretty much as designed and promised.
Manure-laden sand from three freestall barns is now being cleaned and can be re-bedded just a month after processing. The nutrients in the manure are being separated into nitrogen/potash and a phosphorus/organic matter components.
“Prior to installing the system, we were struggling to reclaim and clean-up the sand,” Hartway says. The farm had been recycling water from one of its lagoons, but the dissolved nutrients in the lagoon water stayed in suspension and created a syrup-like goo that clogged up the liquid/solids separation press to the point where nothing came out.
About the only solution was to completely drain the lagoon and start over with fresh water. The logistics of doing that with the dairy still in operation were daunting.
After visiting dairies in New York and Michigan, Hartway and Jim McCormick, owner of McCormick Dairy, decided to go with the LWR System. “The Michigan dairy was sand bedded and had a set-up similar to us,” Hartway says. “That convinced us to go this route.”
Sand f lushed from the freestall barns goes through a sand lane where the larger sand particles drop out. Then, the slurry is sent through a screen separator where the larger manure particles are pressed out.
From there, the liquid portion with dissolved nutrients goes into a “homogenization pond.” This liquid is then pumped into the LWR building where it is further processed and the manure slurry is separated into three components.
- The first, roughly 10% to 15% of the total volume, is a semi-solid material that is nearly all phosphorus and organic matter containing slow-release nitrogen. Synthetic polymers bind the organic matter and phosphorus. This material is run through another screw press to remove as much water as possible and ends up as concentrated phosphorus. Because it’s concentrated, this material can be more economically hauled to distant fields, which don’t receive as much manure as fields closer to the dairy facility.
- The second component, about 20% to 25% of the volume, contains the fastrelease nitrogen (ammonium sulfate) and potassium. This material is then targeted to nearby corn and potato fields where the nutrients can be readily utilized by the crops each year.
- The remaining water, which accounts for about 60% of the volume, is then run through a reverse osmosis system that removes any remaining impurities. In the end, it’s clean enough to be used as drinking water.
Currently, the water is being used for parlor clean-up and f lushing. The facility is using 7,500 gal. to 9,000 gal. of the reclaimed water for parlor clean-up per day, which equates to a truck load and half less hauling each day. Over the course of a year, that saves some 500 truckloads of lagoon water that has to be hauled and spread on fields.
Eventually, maybe yet this year, Hartway hopes to use the clean, recycled water for irrigating crops through nearby center pivots. The amount of water applied will only be limited by the hydrological capacity of the soils to which it’s being applied.
Pencil Out the Cost
There are substantial start-up costs to the system, including the 50’x100′ building erected to house the system at McCormick Dairy. Depending on the size of dairy, capital costs can run seven figures.
Plus, McCormick Dairy has hired a full-time person to manage the system. “There’s a lot of moving parts, and we need a dedicated person to keep it running smoothly,” Hartway says.
“While the system can be installed on any size dairy, it is most economical for farms with a 1,000 or more cows, or smaller dairies who have the intention to expand their herd,” says Lisa Fast, LWR spokesperson.
“Operating costs are about 1⁄2¢ per gallon of manure treated, with a lot of that being chemical/polymer costs needed to precipitate out the phosphorus,” Hartway says. “We’re working on getting the operating costs down to a 1⁄4¢ per gallon.
“It’s hard to put a dollar figure on the returns,” he adds. “We’re buying less sand because we’re recovering more, and there’s less hauling out of the lagoons. We’re also able to put nutrients where they need to go, and that definitely cuts down on fertilizer cost.”
Source – Dairy Today