Research
It’s a beautiful spring day as you drive along a country road. The sun is out and your windows are rolled down when suddenly an offensive odor hits you right in the nostrils. Someone hit a skunk. What is it about this smell that makes it so offensive? Does this have any relation to the odor of livestock manure?
Published in Air quality
Research is underway in southern Alberta to assess how housing feedlot cattle in roller compacted concrete (RCC) floor pens compares to traditional clay floor pens.

Traditionally, feedlot pen floors in Alberta are constructed of compacted clay. Annual feedlot pen maintenance requires clay to repair damaged pen floors, which can significantly add to input costs and the environmental footprint of feedlots.

Constructing feedlot pen floors with RCC is one possible sustainable solution for stabilizing the pen floors, subsequently improving efficiencies of feedlot operations and animal performance, among other potential benefits.

This research project aims to assess the social, environmental, technological and economic performance - positive, negative or neutral - associated with housing feedlot cattle in RCC floor pens versus traditional clay floor pens. Examples of a few objectives being examined are animal welfare, water runoff, emissions, manure volume, durability and strength of pen floor, as well as average daily gain.

This project is anticipated to be completed by February 2019. For more information, contact Ike Edeogu, technology development engineer with Alberta Agriculture and Forestry, at 780-415-2359.
Published in Beef
With water quality in the Chesapeake Bay suffering from excess nutrients and fish populations in rivers such as the Susquehanna experiencing gender skewing and other reproductive abnormalities, understanding how to minimize runoff of both nutrients and endocrine-disrupting compounds from farm fields after manure applications is a critical objective for agriculture.
Published in Other
A week spent in a feedyard pen is helping researchers gain a better understanding of greenhouse gas emissions. Their goal is to improve the national inventory of greenhouse gases and determine potential mitigation measures.
Published in Beef
A multi-disciplinary team of researchers at the University of Nebraska–Lincoln will conduct a project transforming manure and cedar mulch from waste to worth. The project is funded by a $132,663 grant from the Nebraska Environmental Trust.

Leading the research will be Amy Millmier Schmidt, assistant professor in biological systems engineering and animal science, and Rick Koelsch, professor in biological systems engineering and animal science. The project is designed to provide natural resource benefits to Nebraska through increased utilization of livestock manure and cedar mulch among crop farmers.

"When manure is applied to cropland at agronomic rates using recommended best management practices, it provides agronomic, soil health, and environmental benefits," said Schmidt.

As the management of eastern red cedar trees has become a critical issue in many parts of the state, Schmidt and others have been studying practices that utilize the biomass created during forest management activities in ways that add value to this product.

"Combining wood chips with manure prior to land application could provide a market for the woody biomass generated during tree management activities and help offset the cost that landowners bear for tree removal," she said.

The team's on-farm research to date has demonstrated that manure-mulch mixtures improve soil characteristics without negatively impacting crop productivity. This new award will allow an expanded project team to demonstrate the practice more widely throughout the state, complete an economic analysis of the practice, and engage high school students in educational experiences related to soil health, conservation and cedar tree management. It will also introduce the students to on-farm research for evaluating a proposed practice change.

"On-farm research is at the core of extension and research programs at land-grant universities like Nebraska," said Koelsch. "Giving high school students hands-on experience evaluating a practice to understand how it impacts farm profitability is a unique way to improve science literacy, critical thinking skills, and interest in agricultural careers."

Outreach activities will focus on improving understanding among crop farmers of the benefits these amendments provide and motivating implementation of this new practice. The long-term goal of the project is to improve soil health properties for Nebraska soils, reduce nutrient losses to Nebraska water resources, and reduce eastern red cedar tree encroachment on Nebraska's pasture and grassland resources.

The project is one of the 105 projects receiving $18,301,819 in grant awards from the Nebraska Environmental Trust this year. The Nebraska Legislature created the Nebraska Environmental Trust in 1992. Using revenue from the Nebraska Lottery, the Trust has provided over $289 million in grants to over 2,000 projects across the state.
Published in News
Manure Manager strives to provide U.S. and Canadian livestock producers plus custom applicators with timely information to help them manage their businesses in the most efficient, safe and economical way possible. Whether through our printed publication, website or social media accounts, we do our best to keep you in the know about manure management issues.

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Everyone who takes the time to complete the survey will be entered into a draw for $500.

Thank-you in advance for your valuable insights and opinions.
Published in Companies
A Vancouver college is looking for new ways to manage manure in British Columbia's Fraser Valley.

Working with Muddy River Technologies of Delta, B.C., researchers at Langara College are seeking a cost effective way to prevent soil degradation and water contamination by removing phosphorus, nitrogen and other byproducts from animal manure.

The Fraser Valley is home to about 500 dairies, and the high amounts of slurry cause environmental and economic problems. Farmers do not have enough land to dispose of it, and they cannot expand because of the limitations placed on them by excess manure, said Langara researcher Kelly Sveinson.

This spring the college received $90,000 from the B.C. Innovation Council Ignite Award to support the project involving Sveinson, chemist Todd Stuckless and Rob Stephenson, chief technical officer of Muddy River Technologies, which works on water and waste treatments.

The project involves removing phosphates from manure using an electrochemical process similar to that used in environmental cleanups. The second step is to use a biochar carbon filter to capture ammonia that can be released as nitrogen. Ultimately those products could go back on the land as fertilizer. | READ MORE
Published in News
On June 6, 2018, the Center for Limnology reported that a toxic algae bloom had begun to spread across Lake Mendota. It quickly led to the closure of beaches around Madison's largest lake.

It also coincided with the launch of a new, four-year effort by Dane County, called Suck the Muck, designed to literally suck a century's-worth of phosphorus from 33-miles of streams that feed the county's lakes.

Phosphorus, a nutrient found in the manure applied to agricultural fields, makes its way to Wisconsin waters (and waterways elsewhere) in runoff following rain storms. When the weather is warm, it can lead to the foul-smelling water and toxic algae blooms that plague lakes like Mendota, which is situated in an agricultural landscape.

This runoff may be getting worse, according to a recent study from researchers with the Water Sustainability and Climate Project at the University of Wisconsin–Madison. With a changing climate, the frequency of high-intensity rain events is on the rise. These storms bring heavy rains over a short period of time and exacerbate phosphorus runoff from manure-covered agricultural fields, more so than scientists expected.

"Both things are bad for water quality – too much manure is bad and too many intense storms are bad, too," says lead author of the study in Environmental Research Letters, Melissa Motew. "This is a story about how one problem really compounds another problem."

Indeed, the Lake Mendota algal bloom came on the heels of the second-wettest May in Madison's recorded history, and its eighth warmest. The National Weather Service reported that May 2018 was the wettest on record for the contiguous United States.

But Motew didn't start out asking how heavy storms and manure interact synergistically to affect water quality. It was while studying legacy phosphorus in soils ­– the accumulation of the nutrient over time – that she and the research team noticed something interesting in the data.

"We knew that heavy rain transports a lot of phosphorus off of a field and in 2014, (co-author Stephen Carpenter, emeritus professor and director of CFL) found that a relatively small number of rain events each year were delivering the majority of phosphorus to the lakes," she explains. "We happened to notice that it seemed like when we had periods of heavy rainfall we were seeing worse water quality than we expected. It prompted us to set up this study."

Climate change is bringing more intense rainfall across the U.S., particularly in the Midwest and Northeast. The 2014 study from Carpenter and colleagues showed that 74 percent of the phosphorus load in Lake Mendota is now delivered across just 29 days each year, and a 2016 study from scientists at Marylhurst University in Oregon and UW–Madison showed that annual precipitation in the Yahara watershed, which includes Lake Mendota, increased by 2.1 mm each year between 1930 and 2010.

This amounts to an increase of about seven inches of additional rain today, Motew explains. That same study also showed that while the frequency of large storm events in the region averaged 9.5 events per decade between 1930 and 1990, between 1991 and 2010, the number of large storm events nearly doubled, reaching 18 events per decade.

Using simulation models, Motew and the study team asked how more extreme rain events might interact with manure-and-fertilizer phosphorus supply on croplands to affect runoff at the level of an individual lake and the streams that feed it. That is, what happens when a given amount of rain falls on a field over the course of two hours instead of 24 hours?

"The model lets us scale up and make interesting observations from the scale of one field to the entire watershed," she says. "Models let us home in and study the process of how phosphorus moves in great detail."

Using two 60-year climate scenarios, one which assumed daily precipitation, maximum and minimum temperatures, wind speeds, relative humidity and solar radiation similar to current mean annual values in Madison, and another assuming more extreme rain events, Motew's model explored what happens to phosphorus concentrations in Lake Mendota and its tributary streams under low- and high-intensity precipitation conditions.

It took into account the real-life practices of farmers in the watershed – including their typical fertilizer and manure applications and tillage practices, the amount of phosphorus already stored in the surface layers of the soil, and the composition of the land around Lake Mendota. More than half of the land surrounding it is agricultural.

Motew found that dissolved phosphorus – the kind found in manure, as compared to other fertilizers and that found in soil – combined synergistically with heavy rain events to increase the amount of phosphorus running off into Lake Mendota and its streams.

"This puts us at even greater risk of worsening water quality," says Christopher Kucharik, study co-author and Motew's former graduate advisor. "This result also has wide-reaching implications because the synergistic relationship will likely be present in many agricultural watersheds around the world, where livestock and surface water co-exist."

Phosphorus is a critical nutrient for living organisms like crops. But what it does on land, it also does in water: encourages growth of organisms like plants and algae. When they die, these organisms fall to the bottom of an affected waterway, decomposing and consuming oxygen. This kills wildlife and encourages the growth of cyanobacteria, the organism behind toxic algae blooms. In some parts of the country, it can lead to dead zones, like in the Gulf of Mexico.

Farmers in Dane County and elsewhere are already applying less manure and doing so more precisely, Motew says, and she is hopeful these strategies will help to reduce phosphorus runoff from their croplands.

Motew, who is now a research fellow at The Nature Conservancy, also thinks farmers should be a part of continuing efforts to improve water quality. "We need to partner more with farmers so we can not only improve our own research by using better data, but so we can work together and build on their ideas, too." she says. "They know the problems up-close-and-personal and can provide insights we haven't considered. We as scientists can help explore where those insights may lead."

Motew adds: "Farmers are key to solving the problem, even though they are frequently blamed. We all need to take responsibility for our food system and find ways to support farmers in better manure management."

The study was supported by the National Science Foundation (grant numbers DEB-1038759 and DEB-1440297).
Published in Other
Iowa State University researchers have completed testing of a new concept for disposing of animal carcasses following a disease outbreak.
Published in Compost
Findings by a team of University of B.C. wastewater engineering researchers at the Okanagan campus have revealed a low-cost solution to many of the problems plaguing anaerobic digesters used by municipalities.

Anaerobic digesters are seen as a popular solution to wastewater treatment as they offer the potential for producing green energy and associated products.

Anaerobic digestion uses a series of biological micro-organism processes to break down wastewater material to produce biogas, which can then be combusted to generate electricity and heat, or can be further processed into renewable natural gas or transportation fuels. Dewatered material can also be used for compost. | READ MORE
Published in News
Not the first thing you think of when you see elephant dung, but this material turns out to be an excellent source of cellulose for paper manufacturing, scientists report. And in regions with plenty of farm animals, upcycling manure into paper products could be a cheap and environmentally sound method to use manure.
Published in Beef
Farmers and manure managers in North America have known for years that phosphorus is a huge concern, but solutions for handling this nutrient have not come easy. Hauling manure away to locations where fields aren’t already saturated isn’t always practical or cost-effective.
Published in Dairy
The California Department of Food and Agriculture has awarded a $213,349 research grant to the California Dairy Research Foundation in collaboration with University of California scientists to study methane emissions at California dairies. The project is titled, "Small Dairy Climate Change Research: An economic evaluation of strategies for methane emission reduction effectiveness and appropriateness in small and large California dairies."

Supported by a $250,000 appropriation from the Budget Act of 2017, the research will focus on understanding the differences in methane emissions from large and small dairies.

Researchers will also examine cost-saving techniques, evaluate emerging technologies, and investigate the economic impacts of methane regulations on California dairies.

The research will contribute to the Small Dairy Climate Action Plan which is required as part of the 2017-18 Budget Act (Item 8570-101-3228 (1) (b)). For more details on the awarded project, please visit www.cdfa.ca.gov/oefi/research/

Published in News
Regina, Sask – Despite their reputation, flatulent cows aren’t capable of destroying the world, an environmental politics professor argues in a forthcoming research paper.

But still, livestock are saddled with an outsized share of the blame for climate change. And if that misunderstanding persists, and pushes policymakers to force a societal shift from meat-eating, it could lead to disaster, says Ryan Katz-Rosene at the University of Ottawa’s school of political studies. READ MORE



Published in Air quality
A week spent in a feedyard pen is helping researchers gain a better understanding of greenhouse gas emissions. Their goal is to improve the national inventory of greenhouse gases and determine potential mitigation measures.

Texas A&M AgriLife Research and the U.S. Department of Agriculture-Agricultural Research Service are collaborating to analyze nitrous oxide and methane emissions from an area feedyard pen.

Dr. Ken Casey, AgriLife Research air quality engineer in Amarillo, and Dr. David Parker and Dr. Heidi Waldrip, USDA-ARS livestock nutrient management researchers at Bushland, spent the better part of a week sitting inside a feedyard pen just vacated by cattle.

The project is funded by USDA-ARS and AgriLife Research, with instrumentation used in the study partly supported by the Texas Cattle Feeders Association.

Using six automated chambers, more than 575 automated flux measurements were taken, as were 60 manual flux measurements from separate static chambers, to help monitor nitrous oxide and methane gas emissions.

Halfway through the experiment, a half-inch of water was applied to the pen surface within the measurement chamber bases to simulate a rainfall.

"We're looking to understand better what controls nitrous oxide and methane coming off feedlot pen surfaces," Casey said. "We're interested in the emissions of these gases because of their contribution to climate change. We want to improve the national emissions inventories as they pertain to greenhouse gases from feedyards in the Texas High Plains.

"Secondly, we are also very interested in obtaining a better mechanistic understanding of the evolution of these gases from the pen surfaces. What controls the release of these gases? If we are able to gain a better understanding of that, then we will potentially be able to provide advice to the industry about mitigation practices when it comes to pen management."

Casey said their testing demonstrated areas of the pen with shallower manure packs on the surface primarily emitted nitrous oxide, while two chambers sitting over deeper manure where the pen drain was located emitted almost no nitrous oxide, but were emitting methane.

"We are trying to understand the interplay of those two gases, because the processes that are producing them are related," he said.

The different factors that influence the creation and release of the gases include temperature, moisture content and the amount of manure on the pen surface, Casey said.

"By understanding how those factors play together in the production of those gases, we can develop a greater understanding and potentially develop mitigation strategies," he said.

"However, it's complicated, because a strategy that reduces one emission may in fact increase the other. So our understanding of the production of these gases and the environmental factors that influence them are important."

During the study, gas samples were collected twice a day from the static chambers and then taken to Casey's air quality lab to be analyzed on a gas chromatograph. Six automated chambers took measurements each hour, around the clock. The automated chambers were linked through a multiplexer to automated nitrous oxide and methane analyzers.

"We know emissions are influenced by temperature, and by taking diurnal measurements, we can understand the variability throughout the day and night, as well as that of the effects of moisture."

The week of measurements is only part of ongoing research being conducted by Casey and Parker. Casey said the results will be reported to the industry, as well as in various journals along the way, and will be used for extended air quality research.

Parker said their research is also relevant to manure quality.

"Not only is this research important for greenhouse gas emissions, but through this and ongoing laboratory studies, we are learning more about nutrient transformations and water losses from the feedyard surface," he said.
Published in Air quality
Each year, farmers in the U.S. purchase tens of millions of pounds of antibiotics that are approved for use in cows, pigs, fowl and other livestock.

When farmers repurpose the animals' manure as fertilizer or bedding, traces of the medicines leach into the environment, raising concerns that agriculture may be contributing to the rise of antibiotic-resistant bacteria.

New research holds troublesome insights with regard to the scope of this problem.

According to a pair of new studies led by Diana Aga, PhD, Henry M. Woodburn Professor of Chemistry in the University at Buffalo College of Arts and Sciences, two of the most elite waste treatment systems available today on farms do not fully remove antibiotics from manure.

Both technologies — advanced anaerobic digestion and reverse osmosis filtration — leave behind concerning levels of antibiotic residues, which can include both the drugs themselves and molecules that the drugs break down into.

In addition, the study uncovered new findings about solid excrement, which is often filtered out from raw, wet manure before the treatment technologies are implemented.

Researchers found that this solid matter may contain higher concentrations of antibiotics than unprocessed manure, a discovery that is particularly disturbing because this material is often released into the environment when it's used as animal bedding or sold as fertilizer.

"We were hoping that these advanced treatment technologies could remove antibiotics. As it turns out, they were not as effective as we thought they could be," Aga says.

She does offer some hope, however: "On the positive side, I think that a multistep process that also includes composting at the end of the system could significantly reduce the levels of antibiotics. Our earlier studies on poultry litter demonstrated that up to 70 percent reduction in antibiotics called ionophores can be achieved after 150 days of composting. Testing this hypothesis on dairy farm manure is the next phase of our project, and we are seeing some positive results."

The research on reverse osmosis filtration was published online in January in the journal Chemosphere. The study on advanced anaerobic digestion — a collaboration between UB and Virginia Tech — appeared online in March in the journal Environmental Pollution.

Waste treatment systems are not designed to remove antibiotics

According to the U.S. Food and Drug Administration, more than 30 million pounds of antibiotics approved for use in food-producing livestock were sold or distributed in the United States in 2016. And these are just a fraction of the total antibiotics used annually around the world in humans and animals.

Though the new research focuses on dairy farms, the findings point to a larger problem.

"Neither of the treatment systems we studied was designed to remove antibiotics from waste as the primary goal," Aga says. "Advanced anaerobic digestion is used to reduce odors and produce biogas, and reverse osmosis is used to recycle water. They were not meant to address removal of antibiotic compounds.

"This problem is not limited to agriculture: Waste treatment systems today, including those designed to handle municipal wastewater, hospital wastes and even waste from antibiotic manufacturing industries, do not have treatment of antibiotics in mind. This is an extremely important global issue because the rise of antibiotic resistance in the environment is unprecedented. We need to start thinking about this if we want to prevent the continued spread of resistance in the environment."

Aga is a proponent of the "One Health" approach to fighting antimicrobial resistance, which encourages experts working in hospitals, agriculture and other sectors related to both human and animal health to work together, as humans and animals are often treated with the same or similar antibiotics.

Aga was an invited presenter at an international forum last week on the latest research about antimicrobial resistance. The event, in Vancouver, Canada, was co-chaired by representatives of the UK Science and Innovation Network, Wellcome Trust and U.S. Centers for Disease Control and Prevention.

To conduct the research, scientists visited two dairy farms in Upstate New York.

Both facilities extract much of the solid matter from cow manure before subjecting the remaining sludge to high-tech waste management techniques. To process the remaining goop, one farm uses advanced anaerobic digestion, which employs microorganisms and pasteurization to break down and convert organic matter into products that include biogas, while the other farm uses reverse osmosis, which passes the slurry through a series of membranes to purify water.

Both technologies reduced antibiotic residues in liquid manure, but did little to cut down levels in the remaining solid matter. This is particularly worrisome as the research also revealed that antibiotic compounds tend to migrate from the liquid parts of the manure into the solids during treatment, making it arguably more important to treat than the latter.

The concern over solid excrement is heightened by the fact that the treatment techniques are implemented only after most solids are already separated from the raw manure, meaning that the bulk of the solid matter may go untreated.

Some key findings from each study:

The research on advanced anaerobic digestion examined a popular class of antibiotics called tetracyclines, finding that these drugs and their breakdown products migrated from the fluid part of the sludge into the solid part during treatment. At the end of the process, the solids contained higher levels of tetracycline antibiotics than the original raw manure. The study also found that both the liquid and solid parts of the sludge contained genes that confer resistance to these antibiotics.

The study on reverse osmosis looked at how well this water purification technique removed synthetic antimicrobials called ionophores, which are used to promote growth in dairy cows and to treat coccidiosis, a costly, parasitic disease in the cattle industry that affects mostly young calves.

The research found that reverse osmosis effectively filtered ionophores from the liquid portion of manure. However, low levels of the drugs persisted in "purified" water after treatment due to the deterioration of membranes used in the filtration process. Also, solid matter extracted from the water during reverse osmosis still harbored high levels of ionophores. Finally, the study found that prior to treatment, many of the ionophores appear to have already migrated into the solid part of the raw manure that is removed before the reverse osmosis even begins.

"Both of the systems we studied are a good first step in reducing the spread of antibiotics and potentially reduce resistance in the environment, but our study shows that more must be done," Aga says. "We need to look at different waste management practices that, maybe in combination, could reduce the spread of antibiotic compounds and resistance in the environment."

Aga points to composting as one area to explore. Her team is studying how advanced anaerobic digestion can be used in conjunction with composting of solid materials to remove antibiotics and their breakdown products from manure. The preliminary results of the research, not yet published, are promising, Aga says.
Published in News
One of the big challenges when using manure as a fertilizer source is knowing the amount of plant nutrients that are present and available in the manure.

This uncertainty increases the risk of over-applying or under-applying nutrients to the field.

The risk is greatest with nitrogen (N), which can easily move out of manure during storage and is a source of drinking water concerns. However, there are ways that producers can lower that risk. One of those ways is by getting manure tested.

Studies from Minnesota and elsewhere have shown how important it is to get manure tested rather than relying on published book nutrient values, says Gregory Klinger, Extension educator for the University of Minnesota.

Book values suggest a specific nitrogen credit for specific manure types. They are useful for planning where to spread your manure, but can lead to over- or under-application of nutrients if used as the basis for actual application rates.

Manure nitrogen content is highly variable. Consider the case of liquid dairy manure, which has book values of 31 or 32 lbs N/1,000 gallons in Minnesota. Different studies on lab-tested dairy manure have found that individual manure N contents are typically anywhere from 20 to 40 percent higher or lower than these book values.

With a book value of 32 lbs N/1,000 gallons, the nitrogen in your dairy manure could be anywhere from 19.2 to 44.8 lbs/1,000 gallons. That creates quite a risk of over- or under-applying nitrogen.

Agitating and testing manure reduces that variability. While there is still variability in the results you get when you test manure, it is lower than relying on book values. Studies suggest 10 to 30 percent for unmixed manure, but as low as three to seven percent for well-mixed or agitated manure.

That means if you have 24 lbs N/1,000 gallons in your manure and it has been agitated and analyzed, you could reasonably expect the measured results to be from 22.3 to 25.7 lbs/1,000 gallons.

Much better than the 19.2 to 44.8 lbs/1000 gallons range you could expect without testing. While dairy manure is the example used here, these trends are true of other manure sources as well. Just by mixing and analyzing your manure, the risk of over- or under-applying nitrogen goes down immensely.

If you can't agitate your manure, try to take a number of subsamples from across the manure stockpile and mix them. Studies show that 15 to 25 subsamples will get the variation below 10 percent. For manure with an actual nitrogen concentration of 24 lbs N/ton, this would mean the N content reported by the lab would likely be 21.6 to 26.4 lbs/ton.

Many soil scientists in the Midwest have noted that when nitrogen application rates are less than 25 pounds above or below the best rate for a field, it usually has a negligible effect on yields and profitability, regardless of form.

That means that you don't need to hit a magical number that is best for your field, you just want to get within 25 pounds of that number. Testing manure will minimize how much uncertainty there is in manure N concentrations and help you hit that goal.
Published in News
Wisconsin - Last spring, University of Wisconsin–Madison researcher Michel Wattiaux began using a specialized device to measure the methane being exhaled or belched by a group of Holsteins and Jerseys.

It was the first step in an ongoing study by dairy scientists, engineers and agronomists to see how a cow's breed and forage consumption affect the greenhouse gases generated by her gut and her manure.

The U.S. dairy industry has set a goal of reducing its greenhouse gas emissions by 25 percent by the year 2020, and UW–Madison researchers are helping identify strategies to accomplish that. | For the full story, CLICK HERE.
Published in News
The Nutrient Management Centre at the Agri-Food and Biosciences Institute (AFBI), Hillsborough, is currently being commissioned with a key goal to explore technologies which offer opportunities for better nutrient management of slurry and digestate.

Screw Press Separation and Centrifugation are the two established technologies currently being investigated for their impact and effectiveness in removing, off farm, large quantities of solids from farm slurries and digestates i.e. feedstock.

Separation of feedstock produces a solids fraction containing a high proportion of phosphorus (P) which is more economical to transport off farm for both agricultural and non-agricultural purposes.

This is especially important for Northern Ireland, since oversupply of P to grassland has increased soil P levels beyond crop requirement optimum, leading to increased risk of P runoff to water courses and a negative impact on water quality. | For the full story, CLICK HERE
Published in News

Iowa State University researchers have completed testing of a key component of a new concept for disposing of animal carcasses following a disease outbreak.

The research someday may help producers facing animal disease emergencies, such as in 2015 when avian influenza resulted in disposal of millions of chickens and turkeys in Iowa and other states.

Jacek Koziel, associate professor of agricultural and biosystems engineering, said animal health emergencies occur around the globe each year due, not only to disease, but also to hurricanes, flooding, fire and blizzards.

These incidents often require the disposal of numerous animal carcasses, usually accomplished via burial. In research published recently in the scientific journal Waste Management, Koziel and his team analyzed a method that could help livestock, poultry and egg producers deal more efficiently and safely with crises that lead to sudden increases in animal mortality.

Koziel and his team focused their research on improving on-farm burial, the method most commonly employed for large-scale carcass disposal due to its low cost and ability to quickly reduce the spread of airborne disease and foul odors. But emergency burial can contaminate nearby water resources with chemical and biological pollutants, and many locations in Iowa are considered unsuitable for such practices by the Iowa Department of Natural Resources.

Buried carcasses also decay slowly, sometimes delaying use of burial sites for crop production and other uses for years, Koziel said.

To overcome these problems, the researchers studied a hybrid disposal concept conceived at the National Institute of Animal Science in South Korea following a massive outbreak of foot-and-mouth disease in 2011.

The method combines burial with aerobic digestion, a method commonly used for treating sewage in which air is pumped through the content to speed decomposition.

The experiment also included burial trenches lined with flexible geomembranes like those used to prevent seepage from landfills and wastewater treatment ponds to protect water quality. The researchers then injected low levels of air into the bottom of the trench to accelerate carcass decomposition and treat the resulting liquid contaminants.

The experiment tested the performance of the aerobic component of the hybrid method in a lab using tanks containing whole chicken carcasses, water, and low levels of oxygen that occasionally dropped to zero as would be likely in emergency burial trenches.

Results of the study showed low levels of oxygen accelerated carcass decay significantly, reducing carcass mass by 95 percent within 13 weeks, while similar tests without air produced no noticeable decay. The air and water used for the experimental method create an ideal environment for bacteria to break down the carcasses quickly, a "shark tank," as Koziel described it.

Chemical contamination in the liquid waste met U.S. Environmental Protection Agency criteria for safe discharge to surface waters. The hybrid method also eliminated two common poultry pathogens, salmonella and staphylococcus. Aeration also reduced odorous gases sometimes associated with mass burial.

Koziel said the the encouraging laboratory results could pave the way for follow-up field studies that will include evaluation of alternative geomembrane liners, aeration system designs and components, and performance testing of the complete hybrid disposal system.

The research was supported by funding from the Korean Rural Development Administration.

Published in Other
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