Phosphorus has long been a challenge in nutrient-management plans. Now feedyards have a new tool in their compliance toolbox.
Remember that old saying — the one about necessity being the mother of invention? While that's true, what do you do when the necessity and the inventions don't intersect?
You do what feedyards have always done — adapt and innovate.
This, then, is a tale of necessity becoming the mother of innovation. The necessity was provided by the heavy hand of the federal government. The innovation, in the form of a phosphorus-reduction (Phred) system for feedyard wastewater, came courtesy of the Environmental Services division of the Kansas Livestock Association (KLA).
Defining the problem
Some years ago, the U.S. Environmental Protection Agency (EPA) dictated that feedyards develop and comply with a nutrient-management plan for manure and wastewater. Under the plan, manure or wastewater must be applied to a crop field at agronomic rates. For example, if a corn crop removes X lbs. of nitrogen and phosphorus from the soil, and the soil contains Y amounts of each, a feedyard can only apply enough manure or wastewater to make up the difference.
“The real problem we saw with the nutrient-management plans we were writing was with wastewater,” says Kylo Heller, agronomist with KLA Environmental Services. Wastewater can't be trucked as easily as solid manure, and it often results from runoff after rainstorms. That means it comes all at once and requires a significant amount of infrastructure, such as pipes, pumps and center pivots.
Beyond that, phosphorus is the limiting factor when determining agronomic rates for applying waste. “You typically hit that phosphorus limit first, even though you haven't met the nitrogen needs of the crop yet,” Heller says.
In some cases, feedyards can work with neighboring farms to dispose of their waste. When that's not an option, a feedyard is left with only one choice — buy enough land to handle all the manure and wastewater it produces. “Obviously, that got very expensive very quick,” Heller notes.
Here is where KLA Environmental Services found it appropriate to splice in some innovation. Working with the Advanced Manufacturing Institute at Kansas State University and DT Search and Design of St. Joseph, MO, they put an innovative spin on existing science and developed Phred. After three years of research, development and testing, Phred is ready to help feedyards meet federally mandated environmental regulations.
What it does
Phred is a system that removes part of the phosphorus from water. Wastewater is run through a fluidized-bed reactor, which causes phosphorus to precipitate out in the form of magnesium ammonium phosphate, otherwise known as struvite.
Struvite, Heller says, is a true solid and makes a great slow-release phosphorus fertilizer that grades around 5-29-0. It has value to the feedyard by providing opportunity for the operation to return some revenue to help cover operation costs. In addition, Heller says, it's a “green” fertilizer in that it's made from a waste product.
After developing and testing several small-scale prototypes, KLA Environmental Services installed a Phred system at a Southwest Kansas feedyard in 2008, where they operated it under real-time conditions for more than 18 months. It passed that test and is now ready for commercial application in feedyards, dairies and hog operations.
The system operates at around 600 gal./min., Heller says, and can remove as much as 60% of the phosphorus in wastewater. Depending on the amount of phosphorus in the water, it will produce an average of 1,300 lbs. of struvite/million gals. of water.
“It's designed to be simple, robust and easy to operate so it can sit at a CAFO (concentrated animal feeding operation) and operate without a babysitter,” Heller says. It's also designed to function continuously, 24 hours/day.
“But obviously, they're only going to operate it when they have wastewater to process,” Heller says. “In a feedlot, that water is primarily rainfall runoff. So they'll have a big slug of it, process it and pump it out on fields, then be sitting around waiting. That was part of what we designed the system to be able to handle — multiple startups and shutdowns as well as continuous, long-term operation.”
Do you need it?
Whether or not a feedyard needs Phred's help depends on the nutrient-management plan, Heller says. “If they've got adequate land and their current soil test levels are in good shape, there may be no immediate need to add a system like this. Others may have a real problem with high soil test levels on their current fields, and they don't have adequate land to apply their waste.”
When he's working with a feedyard to determine whether or not Phred is an option, Heller calculates how many acres the facility can offset by reducing its phosphorus load. “Does it either get them in compliance and help them stay in compliance long-term, or give them some flexibility for expansion in the future and still maintain compliance?”
In round terms, Phred costs about $300,000. Compared with land prices, however, that's an investment some feedyards may be willing to make. And in Kansas, the system is eligible for EQIP funding, which means feedyards can receive cost-share up to $187,500. KLA Environmental Services and DT Search and Design have formed a partnership called Kansas Environmental Management Associates, which will market Phred systems to CAFOs nationwide.
Not every feedyard will need to reduce the phosphorus in its wastewater. “It's going to be a site-by-site decision as to whether or not it makes sense for a particular feedyard,” Heller says.
But for feedyards trying to balance the requirements of their nutrient-management plan with neighbor relations and day-to-day operations, a high-tech solution to an ongoing problem is now available.