There is good reason that poultry farmers should be interested in improving air quality in and around their operations for the health of their birds – as well as for themselves and their neighbours.
“Fine particulate matter is a pollutant linked to increased cardiac and pulmonary disease and premature human death,” says Dr. Bill Van Heyst, a professor in the School of Engineering at the University of Guelph. “It should be a serious concern for those in Canadian agriculture since it’s estimated that this sector accounts for upwards of 85 per cent of all human-made emissions of ammonia, a precursor gas for fine particulate aerosols, across this country.”
Know your emissions
At the same time that simple steps such as planting trees can reduce odour and some fine particulate matter coming from a farm (see “The Buffer Zone” in the February 2010 issue of Canadian Poultry), a thorough understanding of all atmospheric emissions is key to developing the best ways to curb them substantially. “Emissions can occur at all stages in the farm operation including animal housing, manure storage, and subsequent field application of manure,” explains Van Heyst. “Poultry producers need to know which emissions and how much are created at all stages of production. Technologies and best management practices also need to be assessed.”
Investigate everything
Van Heyst and his research team have been investigating the whole emissions picture at broiler operations, quantifying the source strength and the interrelationships between air contaminants such as ammonia, greenhouse gases (methane and nitrous oxide), inorganic aerosol concentrations, and size-fractionated particulate matter. These are measured in two sizes – those 10 micrometres in diameter (PM10) and those 2.5 micrometres and less in diameter (PM2.5). Van Heyst says that although the larger particles can be troublesome to the human respiratory tract, they at least can mostly be expelled through coughing; the smaller particles cannot and are therefore much more dangerous.
“We studied emissions from a broiler house over four production cycles in order to measure changes in emissions during the seasons,” notes Van Heyst. From a barn containing 45,000 broilers raised over a 35-day growth cycle, there was an average of 170 kg of ammonia, 6.8 kg of PM10, 1.3 kg of PM2.5 and 260 kg of methane emitted per cycle. “Typically, the emissions increased as the broilers increased in size,” says Van Heyst. “We found that fine inorganic aerosols, composed mainly of chloride, nitrate, sulphate, ammonia and sodium, were being formed within the barn environment and could contribute significantly to small particulate emissions.”
From the litter storage bunker, he and his team measured an estimated daily average release of 1.8 kg of methane and 0.45 kg of nitrous oxide. Upon land application, broiler litter typically lost 22 per cent of the ammonium within the first 72 hours of surface application. Van Heyst says incorporating litter into the soil immediately following surface application reduced emissions of ammonia from the field.
Other investigations
His experiments have also covered the atmospheric emissions generated from composting dead chickens. Because the composting experiments demonstrated that piles with higher pH (more basic) emit more ammonia – and because broiler litter tends to be more basic than fresh wood chips or mature compost – broiler litter may not be the best carbon bulking material for mortality composting. Instead, fresh wood chips or even spent compost should be considered, as they generate lower ammonia emissions over the composting cycle.
Van Heyst and his team have now moved their measuring devices to a layer facility near Mooretown to see if or how layer and broiler operations differ in terms of emission during 2011. “After we’ve collected data this summer, we’ll start planning to test air pollution control equipment and how management practices can improve air quality both within and exiting poultry barns.” This will likely include litter additives that reduce ammonia to some extent, water misting equipment purported to reduce dust, and ionization dust control systems.
Dust control system tests continue in B.C.
Over the last two years, the B.C. Sustainable Poultry Farming Group (BC SPFG) has been testing a Baumgartner Environics Inc. Electrostatic Particulate Ionization (EPI) dust control system. It’s composed of a power supply of 30,000 volts x 2 mAmps with an ionization discharge line that negatively charges the dust in the air. Dust is then deposited on the grounded surfaces of the barn, such as the walls, floor and ceiling. Testing has occurred in three broiler barns and one turkey barn, and the BC SPFG recently reached an agreement with the B.C. Ministry of Agriculture to extend testing to September 2011.
“The results so far have shown a 50 to 70 per cent decrease in amount of dust in the air in the barns,” says Michael Willcock, BC SPFG’s new manager. The organization’s analysis over more than 10 cycles shows the cost for an installed system in a broiler barn is about $0.85 per square foot, with a return –on investment of about $0.045 per bird per production cycle. Other valuable but limited results suggest that the system can potentially be effective in reducing disease-producing microbial populations.
Dr. Karen Bartlett from the University of British Columbia and Dr. Shabtai Bittman from Agriculture and Agri-Food Canada (AAFC) are serving as research partners, and funding sources include the B.C. Investment Agriculture Foundation, the B.C. poultry industry, Agriculture Environment Initiatives, provincial and federal departments of agriculture and the B.C. Agriculture Council.
For more, visit BC SPFG at www.sustainablepoultry.com or Baumgartner Environics Inc. at www.beiagsolutions.com. (Note: The EPI system is distributed by Paradigm Agri-Solutions in provinces outside B.C. – visit www.paradigmag.ca)
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