At Son-Bow Farms near Spring Valley, Wisconsin, the sand-laden manure from 1,400 cows no longer goes straight to the lagoon.
It now passes through a sand separation and reclamation building before undergoing the two-phase NuWay process that further partitions it down to a unique trio of co-products: a high-phosphorus liquid fertilizer, a low-phosphorus liquid fertilizer and the equivalent of distilled water.
According to dairyman Jay Richardson, this system is whittling down his cost of production. “We anticipate a dollar and eighty cents per hundredweight of milk cost savings,” he says. “I don’t know if we are going to get there, but it’s certainly going to be a dollar fifty-plus, and that’s a big number.”
Cost control was the original impetus behind Richardson’s interest in an innovative manure management system. “When we were hauling a load of manure with all that water in it without nutrients, we were wasting money, and the same with hauling sand out to fields,” he recalls. “We weren’t getting any agronomic benefit. It was just a pure expense.”
Just how expensive? Richardson was writing the check for 2.5 cents per gallon hauling cost. In an effort to reduce that number, the farm purchased its own hauling and handling equipment.
But as he calculated fuel, labor, depreciation, wear and tear, and maintenance, he discovered while variable costs were lower, the total amount didn’t budge. “I thought we were under that number [2.5 cents per gallon] until we really dove into it, and once we dove in, I was shocked,” he says.
Determined to find a competitive advantage, Richardson began looking for a better way to control overall costs for the long term without sacrificing cow care and comfort or environmental sustainability.
“We were searching for something; we didn’t know what, but we knew we needed to figure something out different with the way we were handling manure and sand,” he recalls. “Other things weren’t nearly as expensive, but they just didn’t solve the problem.”
A chance meeting at a 2015 manure management conference led Richardson to that “something” he was looking for. Here, he met two Wisconsin-based companies working hard to make manure dewatering technology feasible and profitable, Aqua Innovations and Foxland Harvestore.
Though this was not the first system on the market to separate cow manure, according to Aqua Innovations President Chris Lenzendorf, the difference between this one and the others was a proprietary mechanical process that does not use any chemicals. Intrigued by the idea, Richardson dug deep into the research and the numbers – and realized he had found his solution.
“Our estimate is: This will take about 3,500 trucks off the road,” he says. That figure is based on 1,500 fewer truckloads of manure leaving the dairy, plus reduced truck traffic from bringing in 1,000 loads of sand and hauling out another 1,000 loads per year.
He took this information to his lender, who was quick to embrace the technology and fund the capital for the project.
“We were willing to increase our fixed capital cost in order to decrease operational variable costs,” he adds. “It’s a similar situation to people who are looking to expand and go into robots – investing a lot of money in capital up-front but doing it because they believe the payback will be in cash flow and overall expense – except we are doing it with handling manure.”
Today, what was once a vision is now in full action. The manure separation building (“solids building”) has been up and running since March 2018, followed by the start up of the ultrafiltration (UF) and reverse osmosis processes (“water building”) this past July. See how it works (Below).
So far, so good
After a few months of full operation, Richardson says the technology is working as planned for the most part, with a little learning and fine-tuning along the way.
“The sand part is definitely working,” he says, noting the herd didn’t miss a beat when changing from virgin to recycled sand bedding, maintaining a 90,000 somatic cell count even through the summer. “We knew we would see the benefits the quickest from that.”
Heat-stress season also brought with it an unexpected challenge: additional water volume from cow cooling. “We were processing two to three times more water over summer than we thought due to sprinklers running in the barn,” Richardson says.
The additional water pushed the centrifuge to run harder than planned and, though the equipment kept pace, he continues to work toward producing a drier solids product.
Despite dealing with more water, Richardson was pleased with the water-building equipment’s ability to keep up. The two UF units handled the volume with ease, and the reverse osmosis was still only operating for about one-and-a-half hours three to four times a day.
“Even though we are processing more throughput, we are still sized with extra capacity,” he says. “Probably, the bottleneck is the centrifuge at this stage in the game, but that’s just a compromise between throughput and wear.”
Running both UF units over the summer months drove power use a little higher than anticipated for the water building, but with only one UF needed to handle normal volumes, he expects to be back on track with original operational cost estimates. So far, electrical costs have come in on target for the solids building.
Heading into its first full-fledged Wisconsin winter, Richardson has some concern over the system’s flume quality. “We may have to add extra water to keep the flume running properly, but we’ve always had that issue,” he says. “We do know we’ll be able to decrease the amount of water added in the parlor and use it to clean the sand instead.”
He has little worry, however, over freezing. The solids building warmed quickly when it started up last spring, and heat exchangers from the UF equipment in the water building provide warmth, along with supplemental heat.
Learning the best management methods for the technology is a work in progress, but Richardson remains focused on the end game. “We’ve learned we need to balance the whole system better in terms of what the end products are,” Richardson says. “We know we still need to end up with clean water.”
The best is yet to come
While reusing sand, keeping solids out of the lagoon and reducing costs related to pit agitation are all wins, Richardson believes his true savings in hauling costs will be realized after the state grants him the permit to release clean water into local waterways instead of routing it back to the manure storage lagoon.
Once the blessing from the Wisconsin Department of Natural Resources is received, Richardson anticipates reaping the full benefits financially and environmentally.
Lenzendorf is hopeful this will happen soon. “In the next legislative cycle (January 2019), legislators will be focusing on streamlining the discharge permit process for farmers and using the nutrients derived from the [system] to be applied to fields during the growing season instead of being spread during the spring and fall,” he explains. “When the organics come out [of the system], they have virtually no pathogens and are able to be applied strategically when crops need them.
Manure irrigation has always been a highly debated subject but, with the virtual elimination of pathogens and control of nutrients, it will become a much more accepted practice.”
All in all, Richardson admits the system itself is not what has caused the most headaches. The biggest challenge of the entire venture has been dealing with the regulatory process, which nearly pushed him to the point of giving up. “It’s been the failure of government regulations and bureaucrats to keep up with technology,” he claims. “Above everything else, that has held this project up for one-and-a-half years at different stages, and we still are not discharging.”
However, Richardson channels his frustration into motivation and remains determined to push for the right to release clean water back to the environment. He’s driven not only by his own desire to succeed but also by the precedence this will set for other dairymen facing similar challenges with handling and hauling manure.
“If you can still handle most of your volume of manure through a dragline and keep your costs under about one-and-a-half cents per gallon, it’s probably not going to pay,” he says. “But once you start exceeding two cents per gallon of handling costs, I think this system is going to pay pretty good-sized dividends.”
Richardson foresees dairies that currently have technology for reusing sand or removing solids as well poised to incorporate the next step of water purification. A building for storing solids is a bonus, too. “The building for handling sand was 20 percent of the project cost,” he adds. “If that’s already in place, that’s a huge cost savings.”
Further, farms with working digesters may not need to purchase heat exchangers for the water building. Expanding dairies constructing new manure storage also make prime candidates. “You could trade those capital costs [manure storage] for these capital costs [UF and reverse osmosis] and see a reduction in overall costs,” he states.
Lenzendorf believes Wisconsin dairy farmers are not the only ones positioned to benefit from the technology. “The Aqua system is sought in other states for different reasons such as methane reduction and water reclamation. For example, in California, regulations are requiring farmers to reduce methane usage to levels from the early 1990s and are only allowed certain levels of water before being taxed heavily,” he explains. “With the [system], they can reclaim the water and use the nutrients for irrigation, allowing them to continue to farm in California.”
And with growing interest in global sustainability for farming and natural resources, it could go far beyond U.S. borders.
For some dairies, a manure dewatering system like Richardson’s could be the key to not only environmental sustainability but profitability, too.
“In today’s world, it’s all about cost savings; it’s all about pushing the pencil,” Richardson concludes. “This system is not for everyone but, for those people who can benefit from it, I think they will benefit from it big time.”
PHOTO 1: The NuWay process includes two phases: ultrafiltration and reverse osmosis. Ultrafiltration produces two products: a highly concentrated, high-phosphorus fertilizer (left) and a low-phosphorus tea water (center). Reverse osmosis further partitions the tea water into a “super” tea water that goes to the lagoon and finally, clean, clear water (right).
PHOTO 2: Jay Richardson awaits the permit that will allow him to discharge the clean water from his manure dewatering system into waterways instead of his manure lagoon. He is confident enough in the pathogen reduction and safety of the water to take a drink. Photos by Peggy Coffeen.
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The NuWay process: How it works
Two adjacent buildings downhill from the freestall barn at Son-Bow Farms house the equipment that transforms cow manure into multiple end products: recycled sand bedding, composted manure solids, liquid fertilizer and clean, clear water.
Manure enters the “solids building” first, where sand and large particles are separated from the liquid stream. “This is where we are making cleaner dirty water,” Richardson explains.
The separated sand is piled and moved twice before going back into stalls, while the remaining solids make their way through a multi-stage process to remove water. It first passes through a screen and then the roll press before an auger delivers it to the composting drums.
The liquid is then sent through a centrifuge to remove small solids, which are also sent to the composting drums. From there, two composting drums use the manure’s own bacteria to generate heat, heating to between 140ºF and 170ºF, holding it for 48 hours to ensure bad bugs are killed. The resulting composted manure solids are currently 72 percent moisture and 28 percent dry matter, with the goal of increasing dry matter to 32 percent.
Unique in its own right, Richardson has found a market for this soil-enriching compost. Though its nutrient value is negligible, commercial distributor Diamond T Ag finds value in the product’s high levels of organic matter, minerals, amino acids and desirable bacteria, all of which enhance soil profile in a different way than liquid manure, which no longer bears the “good bugs” after lagoon storage.
With most of the solids removed, the centrate resulting from the solids building begins its own journey. Containing only 1 percent total dissolved solids and just 1.6 percent total suspended solids, it is pumped underground to the “water building.” Here, it goes through a two-phase process: ultrafiltration (UF), then reverse osmosis.
Each day, up to 100,000 gallons of the liquid run through the UF process, which creates two streams: “UF concentrate” and “tea water.” The UF concentrate has a higher level of suspended solids with significantly more phosphorus, thus reducing costs of storage, hauling and lagoon maintenance while maintaining valuable nitrogen, phosphorus and potassium levels. One-third of the initial centrate volume per day enters the two-stage lagoon and awaits field application.
The remaining two-thirds of that tea water undergoes the second phase, reverse osmosis, to produce nearly equal amounts of a pair of co-products: “super tea water” and purified water. Sulfuric acid is introduced in this step to turn any remaining ammonia gas into ammonium, which can then be removed. The highly concentrated version of tea water has just a fraction of the phosphorus found in raw manure.
It’s stored in the lagoon and pumped or irrigated as a liquid fertilizer. With virtually all the measurable solids removed, Richardson says the final outcome is the equivalent of distilled water. Colorless, odorless and clear, this water is clean by all measurable standards; however, it is diverted to the lagoon at the present time while Richardson awaits the approval of a state permit to discharge it into waterways.
The self-cleaning system operates 24-7, only stopping every three or four days to clean itself for a few hours. It is monitored remotely at Aqua Innovation’s facility in southern Wisconsin.
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