A new state-of-the art facility uses the latest equipment along with human panelists to decipher what really causes air and water contamination and how to correct those concerns.

Last summer, the new Purdue Swine Environmental Research Building was completed, supported by the U.S. Environmental Protection Agency (EPA), the U.S. Department of Agriculture and the National Pork Board.

Studies are focusing on diet modification, management practices and the impact of manure on odors and water pollutants.

“Large livestock facilities don't fall under current emissions standards because there is insufficient baseline data for such operations, and there is even less information on the odor issue,” says Brian Richert, one of the animal scientists leading the effort at Purdue.

Agricultural engineers in six states (including Purdue) are currently evaluating baseline gas, odor and dust emission rates from mechanically ventilated hog and poultry buildings. Data was collected using climate-controlled mobile laboratories.

Farm Replication

The 15,500-sq.-ft. facility at Purdue can closely replicate conditions at an actual farm, says Richert. It features 12 rooms that hold a total of 720 hogs.

“Replication is important for testing abatement technology,” states Al Heber, an agricultural engineer at Purdue, who is coordinating a two-year benchmarking study, part of EPA's national air emissions consent agreement.

“For example, if you want to modify a diet, then you want to know if the new diet will affect emissions from a pig. To do this properly, you need at least two rooms with the new diet and two rooms with the old diet.

“This building allows proper replication and controlled measurements that we just can't do out in the field on actual farms,” adds Heber. “This facility gives us statistical power.”

In the middle of the facility is a large area with a complex gas sampling system that takes samples at 25 sites per 12 rooms. The system automatically records continuous, around-the-clock measurements of emissions being studied. Gases monitored include ammonia; hydrogen sulfide; methane; and carbon dioxide and nitrous oxide, which are byproducts of ammonia. The heart of the gas-sensing system is a top-of-the-line analyzer that can test five gases at one time, says Heber. Particulate matter (dust) will also be monitored.

“There are several ways to measure ammonia, and we are using top-of-the line, EPA-approved instruments that use a chemiluminescence method to mix nitric oxide with ozone to create a glow,” says Heber. “We also use a pulsed fluorescence and similar methods for hydrogen sulfide.”

Separate Rooms

The facility features 12 identical rooms, enabling researchers to feed hogs varying diets to determine which factors cause manure and urine to emit offending chemicals and gases.

Rooms include self-contained manure pits and ventilation systems that can be set to mimic large confinement barns.

“We are going to be watching the activity of the animals, humidity and temperature, static pressure and air flow,” explains Heber.

“The fans are computer-controlled, so we know the air exchange rates exactly,” adds Richert. “Then we can sample the gases and determine precise emission rates for any compound we're monitoring. We've mimicked exactly what the industry has today, so we think we will have the best data available.”

The Nose Knows

After sampling and measuring the main gases, Heber still relies on the human nose to determine offensive odors. The researchers bag the odors and transport the bags 10 miles from the Purdue research farm complex at Montmorenci, IN, to the school's main campus at West Lafayette, IN.

There, eight trained panelists sniff the samples. A $30,000 olfactometer dilutes the odor in each bag with odor-free air in order to determine how much smell is offensive.

“We determine each panelist's odor dilution to threshold,” says Heber. “For example, in some cases we might have to dilute the odor 500 times before they can't smell it. For another person it might be 1,000 times.”

Combining all of the data from the continuous monitoring and the bags will allow scientists to calculate how far a farm should be from a neighbor to minimize odors.

“This facility allows us to measure odor concentration directly,” says Heber. “If we know the odor concentration and the air flow through the fan, we can calculate the odor emissions.

“We're establishing and refining methods and techniques that are being used around the country. Hopefully, our measurement protocol will become the official EPA standard,” he adds.

Purdue has received $500,000 in federal monies to establish baseline emission data and another $1.3 million to pursue abatement strategies.