| New tools on the way will give producers cost-effective solutions for reducing odour while keeping them competitive.
Today's livestock producers know reducing odour is vital to the long-term success of their industry. But the proven, cost-effective technology is essential to do the job right and keep it manageable.
"Successful odour control strategies go hand-in-hand with strong research and development to back new technologies," says Ike Edeogu, odour control specialist with Alberta Agriculture, Food and Rural Development (AAFRD). "We're getting a lot of interest from producers about odour reduction options, and the good news is advances in technology are giving them new tools with good, practical potential."
In Alberta, helping drive these advances is the Odour Control Team, a group of scientists and engineers from AAFRD - which includes the AgTech Centre in Lethbridge - the Alberta Research Council and the University of Alberta. This effort and the broader movement toward improved odour reduction technology is a developing area, but already there is significant progress, particularly in evaluating current technology and identifying areas for improvement.
"The evaluation criterion that is critical to producers is cost-effectiveness," says Edeogu. "In our various studies, we've identified several technologies at various stages of development that all look promising for the future".
Biofilters for cleaner, fresher air
Biofilters are used as part of a barn's ventilation system. Biofiltration systems require a biodegradable porous material for the air to flow through, such as bark mulch, and a device that applies moisture to the filter. A moist filter attracts valuable microorganisms, which are needed to break down odorous compounds in the air as it flows through the system.
"Biofiltration is likely one of the best options to control livestock odours," says Edeogu. "Biofilters are relatively cheap to use, maintenance is simple, and odour reduction can be as high as 90 percent."
The microorganisms are key to the process, says Edeogu. "Some people think they need to add microorganisms to these systems, but honestly, if you build it right, they will come."
The Odour Control Team is working to develop low-cost systems that use material readily available in Alberta. The Team is also examining operational parameters for the most effective biocontrol systems.
Lagoon covers keep a lid on odour
On the surface, lagoon covers are self-explanatory - they cover the entire lagoon and trap the odorous gases emitted by the manure. But there's more to the process than that. Modern-day lagoon covers not only trap odour, they release it in a controlled way that dramatically reduces its potency. This is accomplished by a series of pipes and exhaust fans regulated by the producer. Producers can choose between man-made or natural materials for the cover.
"Geotextile covers, made from a synthetic fabric, are highly effective, but are costly and difficult to install," says Edeogu. "They can also be hard to manoeuvre when emptying the lagoon. Straw covers are relatively inexpensive but require monitoring to ensure that rain or wind has not reduced the cover's effectiveness. A straw cover works best when spread evenly and with consistent thickness."
Today's lagoon covers trap odour, but further technological improvements to make them more practical for producers are still needed, says Edeogu.
Manure additives offer broad options
Producers have a number of options when it comes to using manure pit additives to control odour, but all have varying degrees of effectiveness. They come in four main categories.
Masking agents - These compounds have a strong, but non-offensive odour of their own. When added to manure, the compound's odours mask the offensive odours.
Counteractants - Compounds that cancel out odours or neutralize them.
Adsorbent additives - Additives that have a large surface area that can adsorb odour compounds before they are released into the environment.
Chemical Oxidants - Compounds that chemically oxidize odorous compounds or that reduce the microbial activity responsible for the offensive odours.
Both the cost and effectiveness of these additives depends on the type of additive and the type of odorous compound being dealt with. "There isn't one miracle cure - additive or otherwise - for eliminating all livestock odours," says Edeogu. "We have to remember that odour is a complex entity, made of numerous compounds, and every situation is different."
Future Odour Control Team research into manure pit additives may help remove the guesswork for producers, says Edeogu.
Composting delivers results for manure solids
To compost or not to compost. That decision is largely made based on the amount of manure produced by the operation and the amount of time and money the producer is willing to spend, says Edeogu. Using aerobic decomposition, which means with oxygen present, composting turns manure into a valuable resource by breaking down into a humus-like product that can be applied as a soil amendment. The resulting product is less odorous than raw manure and producers can benefit from its nutrient value.
"There are several benefits to composting manure," says Edeogu. "It helps eliminate odour by reducing ammonia in the manure while at the same time increasing the manure's value."
A composting system is relatively easy to set up, but it requires significant space and capital investment. A windrow-type system requires land that meets provincial regulations for composting.
The capital investments are the windrow turners, which are key to compost production. They help optimize the temperature and oxygen levels of the compost windrow. AAFRD researchers at the AgTech Centre in Lethbridge have tested seven turners for their ability to produce high quality compost to help producers choose the right compost turner for their operations.
Producers must also keep in mind that composting can only be used with manure solids. That makes it a good choice for feedlot and poultry operations, but difficult for swine operations that produce largely liquid manure.
Diet manipulation stops odour before it hits
Diet manipulation involves altering the animal's diet in order to produce manure with fewer odorous compounds. There's a general hypothesis that if the amount of nitrogen in an animal's diet is reduced, the manure odour will be reduced as well.
"There's a fair bit of diet manipulation research work around the world," says Edeogu. "But, there is still a lot more needed. This is a relatively new area and it will take some time before we have good information for producers."
Alberta researchers are concentrating much of their effort in projects that alter the amount of protein in an animal's diet.
But this research is challenging, due to a lack of commercial feed options, says Edeogu. Commercial feed producers haven't released feed lines that have lower nitrogen levels, and it will likely take some convincing on the part of researchers before feed companies start altering their feed formulas.
A key part of the overall diet manipulation research effort will be projects that study the gain of animals fed altered diets, says Edeogu. "It'll be great if diet manipulation is successful in reducing manure odour. But we have to make sure that gain isn't compromised. In one current study, we're examining the carcass quality of animals fed non-traditional diets."
Oil sprinkling research still needed
Oil sprinkling is most often used to control dust in barns, and for that, it's very effective. Producers spray their animals manually with biodegradable oil, often canola oil, which reduces the amount of dust given off by the animals. Oil sprinkling can reduce dust in the air by as much as 75 percent.
New research is now underway to determine if oil sprinkling is an effective way to control livestock odours. "The idea is that dust may trap odour and carry it in the air," says Edeogu. "This may be a myth, but if there's something to it, oil sprinkling may have some potential."
Until there's better information, Edeogu suggests producers choose proven odour control technology. "Research will determine if oil sprinkling is effective for odour control. But until we have conclusive proof of its effectiveness, it shouldn't be introduced into a livestock operation." |