Thursday, April 1, 2010

Nightmare on Hog Street

The nightmare is always the same: I’m a kid again, riding in the passenger seat of my mom’s 1997 Chrysler Town and Country, playing Pokémon happily with the wind blowing in my face. All of the sudden, I feel it creep up my spine – a dark matter with properties beyond comparison.

I’m talking, of course, about the foul, foul, foul odors emitted by hog and chicken farms. Driving two hours from Raleigh in any direction is putting your nose at serious risk and heading toward the beach is a death wish.

In fact, North Carolina produced 781,000,000 chickens and produced 2.96 billion eggs in 2007, compromising 38.8% of North Carolina’s total farm income. However, the process of taking animal byproducts like skin, bones, and feathers and processing them into useful products produces extremely foul odors.

There may finally be a solution!

Dr. Praveen Kolar, assistant professor of biological and agricultural engineering at NC State, has devised a new inexpensive treatment process that significantly eliminates foul odors and air pollutants emitted by Concentrated Animal Feeding Operations (CAFOs).

Working with Dr. James Kastner at the University of Georgia, Dr. Kolar “has designed an effective filtration system that takes advantage of catalytic oxidation to remove these odor-causing pollutants.”

Catalytic oxidation uses specially-designed catalysts and ozone to break down the odor-causing compounds.

Catalysts are things that are added to a process to start or change the rate of the process’ chemical reaction, and the catalyst is not consumed by the reaction itself, meaning a catalyst can be used many times.

Kolar and Kastner developed the catalysts by “coating structures made of activated carbon with a nanoscale film made of cobalt or nickel oxide.”

Activated Carbon’s porous structure gives it a very large surface area in which to expose the odorous agents.

“The cobalt and nickel oxide nanofilms make excellent catalysts, Kolar explains, ‘because they increase the rate of the chemical reaction between the odor-causing compounds and the ozone, making the process more efficient. They are also metals that are both readily available and relatively inexpensive.’”

Another advantage of catalytic oxidation is that it takes place at room temperature, meaning there are no energy costs, and the only two byproducts created are carbon dioxide and water.

The current system, which uses chemical “scrubbers” to remove the odor-causing agents, has many disadvantages.

Most obviously, it is ineffective. All the empirical evidence you need is your nose.

Also, some of the odor-causing animal compounds are aldehydes, which are used in making plasticizers and detergents. These aldehydes can “combine with other atmospheric compounds to form ozone – triggering asthma attacks and causing other adverse respiratory health effects.”

Although Kolar has only targeted industrial poultry farms, he is using his research to target hog farms next. "’This technology could be applied to swine operations to address odors and ammonia emissions,’ Kolar says. ‘My next step is to try to pursue this research on a large scale."

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