Using hog manure on golf-course fairways may seem far-fetched to some, but not to the folks at Premium Standard Farms. The company recently broke ground on a new Crystal Peak fertilizer plant at its Valley View farm in Sullivan County, Mo. (See illustration for a final view.)
The plant will convert hog manure from 125,000 finishing pigs annually into a high-value, commercial fertilizer. The process will eliminate the use of traditional anaerobic lagoons for manure treatment and storage.
The $10-million plant at Valley View will produce 8,000 tons of 12-8-8 (nitrogen, potassium and phosphorus) slow-release, odor-free and pathogen-free fertilizer each year. PSF officials already have an agreement with the J.R. Simplot Company to buy 100 percent of the product from this plant to fertilize golf courses.
“This process will dramatically change the way we handle hog manure,” says Dave Townsend, environmental affairs president for PSF. Once the plant is in place, PSF will land-apply only 10 percent of the manure from Valley View as opposed to nearly 90 percent of the total manure volume. Using most of the manure in the fertilizer plant will reduce the land amounts needed for manure application.
Here’s how the process works. Valley View consists of 14, eight-barn complexes. Water is flushed beneath the slats every two hours through an internal re-circulation process. It’s then pumped to one of five covered methane digesters. As for the remaining liquid, the pH is adjusted to prevent ammonia release and it’s used to flush the barns.
The remaining solids stay in the digester for about a month, after which they are transferred to a settling basin. Solids are then pumped into a centrifuge, where they are spun at a high-RMP rate to further separate water and solids. The end result is a cake-like consistency.
Any remaining liquid goes back into storage ponds, while the “cake” is blended with other inputs before it moves on to the dryer. This liquid is accumulated throughout the year. Water from these storage ponds is sprinkled on a freeze/thaw pad for processing. This allows the more dense nutrients to freeze last, which allows the more nutrient-rich liquid to move into a brine basin.
Clean water from this process is sent to a new treated water-storage pond, where the solids and nutrients are removed for use in crop irrigation. It also could receive further treatment, allowing it to be fed back to pigs.
The concentrated brine (the nutrient-rich liquid that comes off the freeze/thaw pad) is stored in a covered lagoon before transferring to a mixer with the cake, which adds nitrogen, phosphorus and potassium to the fertilizer. Once the material is mixed, it’s transferred to the dryer where it’s pelleted and dried.
Gases generated during the digestion process will fuel the manure-solids dryer. As the gasses are burned, the emissions are scrubbed and the nitrogen and sulfur compounds are returned to the fertilizer. Dust emissions, generated during the solids’ drying process, are pumped back into the fertilizer product to produce a richer product.
Once the pelleted product leaves the dryer, it’s transferred to a second drum and charred. The charring process removes odor and any remaining pathogens.
“The Crystal Peak process represents a new generation of environmental technology for agriculture,” says John Meyer, PSF’s chief executive officer. “Down the road, we may use the methane to produce electricity for the units.”
He adds that the process could have applications for other livestock sectors that use lagoons, such as the poultry and dairy industries.
In addition to the fertilizer plant, USDA and Purdue University have conducted research on PSF’s behalf for other environmental technologies at PSF, including: air dams, lagoon covers and essential oils in barns to reduce odor, hydrogen sulfide and ammonia.
PSF officials anticipate that the plant will be up and running by year’s end. This means hog manure from Valley View will soon end up on a lush, green fairway instead of a lagoon in the frozen Midwest.