Innovations in Manure Management

Innovations in Manure Management

Photo: Stephanie L. Church, Editor-in-Chief

Turn your mismanaged manure pile into an asset with these new technologies.

Equine veterinarian Colleen Gelvin, DVM, has a vision for her 10-horse state-of-the-art equine facility, Drouin Spring Equine Center, in Fairbanks, Alaska. What she'd like to do is find a way to turn her horses' manure into fuel. "I hope to use the stall waste as a fuel for a manure-burning stove," Gelvin explains, gesturing toward a growing manure pile. "The design keeps evolving, but I want the stove to provide heat for my indoor arena. I want to heat to about 35°F, which is a fine temperature for working a horse and not freezing your hands."

Whatever our motivations for managing manure, the environmental handwriting is on the wall. Gone are the days of the unmanaged manure pile behind the barn, strategically placed to be forgotten and ignored; manure has too many potential ecological consequences. Mixed with rain water, manure's nutrients and pathogens such as bacteria can leach into creeks, wetlands, lakes, or irrigation ditches--all of which usually lead to larger bodies of water such as sounds, estuaries, or oceans. Fish, shellfish, and other aquatic life are easily affected by increased nutrient levels that cause algae blooms, robbing the water of oxygen. The presence of certain bacteria can also make human recreation unsafe. This leachate from manure piles can contaminate groundwater, a particular concern for families in rural areas that rely on wells as their water source. Then there are the other problems that accompany manure piles such as increased flies and odors, which are a nuisance for urban horse owners on small acreage with neighbors close by. Additionally, health issues for horses exposed to manure include possible parasite or pathogen infection.

Aside from the negative impacts of the mismanaged manure pile, we have come to a point in time when we realize we can turn that liability into an asset--something that can save us money or perhaps even make us money. Many new and interesting manure management technologies are on the horizon to help us do just that.

The Cutting Edge

Some of the technologies potentially useful for horse owners are currently being employed by other livestock farms with overwhelming manure management requirements, such as those raising hogs and dairy cattle. To be cost-effective, farmers often raise these animals in huge expanses where manure is contained and gathered. In different parts of the world dairies are coming up with creative ways to manage the 70 or 80 pounds of liquid manure each dairy cow produces daily. Although these technologies require vast amounts of manure to be effective, far beyond the output of the largest commercial horse stables, several have exciting implications for horse owners. They offer hope that scaled-down versions of these high-tech, money-making options are on the horizon and that horse owners might someday be able to piggyback on environmentally sensitive, cost-effective manure management solutions.

Washington State, for instance, supports a relatively large human population base with decreasing amounts of open land, yet dairies still abound, particularly in the milder western portion of the state--along with many thousands of horse owners. Here manure management is an issue for all livestock, especially considering the rainy climate that can potentially wash manure's nutrients and pathogens into surface waters.

Kevin Maas is president and co-founder of Farm Power Northwest, a company that is building multimillion-dollar manure digesters to handle the thousands of gallons of manure a dairy puts out daily--and potentially horse waste from nearby farms. "We work primarily with dairy farms by collecting manure every day," explains Maas. "We process the manure and make it into energy, which we sell. The byproducts are bedding material and a liquid fertilizer, which we send back to the dairies."

Through this process, raw, liquid dairy manure is pumped into the digester where already-present natural bacteria break down manure and produce methane. Methane is trapped and forced to exit the tank through a pipe into an engine that creates electricity. The electricity is sold back to the grid and might eventually be used for heating nearby buildings.

"We can take food waste and other solid manures (such as horse manure) and blend it in," adds Maas. Horse owners located in urbanizing areas with insufficient land for spreading manure or compost, or with commercial facilities that house many horses on few acres, might take interest in these digesters. Tipping fees (the cost for dropping off material) at Farm Power Northwest's manure digester, for instance, are much less than at a landfill or compost operation, so "hauling manure and stall waste becomes affordable," explains Maas.

Another horse manure management prospect is in-vessel composting. Tom Wojtowicz works for a startup company, Eco-Value Technology Inc., in northeastern Michigan. His company manufactures long metal tubes, some four feet in diameter and up to 20 feet long, for composting. Organic material is placed directly into one end of the slowly rotating tube. Aerobic composting takes place inside the turning vessel using thermophilic, or heat-loving, organisms. "Depending on the type of material, some things will compost as quickly as in four days," he explains. "If it is going to be used on gardens, it still needs to be windrowed (composted in a pile)." This allows the very hot compost to "finish" and drop to temperatures below 90°F.

For commercial facilities with biosecurity concerns, such as breeding farms or veterinary clinics, this option might be particularly useful. "Finished compost can be used on site for landscaping or as bedding," Wojtowicz adds. "It cleans up the facility and makes it nicer, with less flies. (It) eliminates rodents, odors, and runoff." And in a very short time it creates a safe product you can sell and not have to pay disposal or hauling costs for.

The cost to install this manure management tool? Wojtowicz reports that a 4-by-8-foot unit would set you back about $30,000, but keep in mind you can potentially sell the finished product at close to $15-20/yard. "Many people will accept other recycling products (like food waste from groceries or yard waste from homeowners) and charge a tipping fee," he adds.

Overall, the impression is that most innovative options might be more applicable for larger equine operations such as racetracks, show grounds, or fairgrounds. So what about options for backyard facilities?

The Cost-Effective

One option that is easier on the pocketbook and works for smaller scale horse farms (as well as for much larger ones) is aerated static pile (ASP) composting. Peter Moon, creator, president, and principal engineer for O2 Compost, in Snohomish, Wash., has made a career of helping horse farms of all scales better manage and compost horse manure.

In the early 1990s Moon, a licensed civil engineer, worked mainly with large-scale municipal projects and biosolids. Both the influence of living in an agricultural area and dealing with the manure from his wife's two horses made him curious as to whether ASP composting would work with livestock. The method is an aerobic composting process that forces air into a stationary pile so you don't have to ¬physically turn it--a simple concept with a fine, finished compost product.

Moon first began experimenting with ASP composting at a local dairy and "u-pick" farm by mixing dairy waste with horse manure and crop residue. Next, he moved to an 18-horse Warmblood facility. "I believed the concept would work but until we really tried it we didn't know," he explains. In two short months, by teaching the horse-owning clients how to manage and sell ASP compost, Moon converted a $750 per month cost into a $500 per month profit.

Years later Moon's company has worked with every form of agriculture imaginable: racetracks, dairies, poultry operations, and universities, along with programs such as prisons, parks, and schools. "So many are going the direction of composting yard and food waste," says Moon.

For horse owners Moon's system utilizes a three-step process: filling the compost bin, active composting, and curing. Each compost bin is sized to accommodate three to six weeks worth of manure and soiled bedding. Manure is added daily, and the airflow begins when the bin is full. During the active 30-day phase of composting the bacteria-driven process generates heat, which destroys parasites, pathogens, and weed seeds. The subsequent curing phase is fungi-driven and reduces the compost mix to a more uniform, soil-like texture. The curing phase takes approximately 30 to 60 days to produce finished compost. The whole process, from raw manure to finished compost, is complete in approximately 90 days.

O2 Compost sells packages that include all materials and training. Depending on the customer's needs, systems can cost as little as $100 or they can reach into the tens of thousands for large-scale operations.

"Everything we do is one version or another of aerated composted. With aerated composting you are really improving sustainability," Moon explains. "It takes less fossil fuel to accomplish; we're mitigating methane and nitrous oxide emissions, which have a serious impact on climate change. We are able to sequester carbon in the soil, improve plant growth response, create biomass to put back into the soil, generate more food, create less dependence on chemical fertilizers, and reduce (polluted storm water) runoff."

Take-Home Message

Besides benefiting the environment, composting is a substantial benefit to the horse owner. "Most of our clients are using the (finished) compost back on the pastures and are seeing a tremendous benefit in plant growth as well as reduced parasites, pathogens, and weed seeds," reports Moon. "We have a number of clients composting and selling it in bulk or by the bag. We also have clients using compost as bedding."

Back in Fairbanks the future is bright for horse owners like Colleen Gelvin who hope to someday try something innovative with stall waste. With a bit of ingenuity and a little hard work, exciting options are available that can improve horse health, chore efficiency, farm productivity, and neighborhood aesthetics; make (or save) you money; and benefit the environment. So, choose a way to change that overlooked manure pile behind the barn into a valuable commodity.

About the Author

Alayne Blickle

Alayne Renée Blickle, a lifelong equestrian and reining competitor, is the creator/director of Horses for Clean Water, an award-winning, nationally acclaimed environmental education program for horse owners. Well known for her enthusiastic, down-to-earth approaches, Alayne is an educator and photojournalist who has worked with horse and livestock owners since 1990 teaching manure composting, pasture management, mud and dust control, water conservation, chemical use reduction, firewise controls and wildlife enhancement. She teaches and travels North America and writes for horse publications. Alayne and her husband raise and train their reining horses at their eco-sensitive guest ranch, Sweet Pepper Ranch, in sunny Nampa, Idaho. She also authors the Smart Horse Keeping blog.

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