Air Quality

Modifying Hen Diets Reduces Egg Facility Emissions

Issue

Iowa is the nation's number-one state in egg production. Iowa has 55 million laying hens and the industry continues to grow. Egg producers need practical steps to reduce air emissions from production facilities, especially for ammonia.

 

So What?

Iowa State scientists have conducted lab-scale and field commercial-scale studies to examine both treatment of bird manure and nutritional changes in the bird diet. Their studies show that dietary modification holds promise.

 

Impact

A year-long field monitoring study revealed that a nutritionally balanced, 1 percent lower crude protein diet will lead to about a 10 percent reduction in ammonia emissions while maintaining bird production performance. Another project has shown that increasing dietary fiber in the feed of laying hens can reduce ammonia emissions by up to 40 percent without adverse effects on egg production. Three diets with increased fiber all were effective. One of the diets involves the addition of dried distillers grains, a by-product of corn ethanol production.

 

Contact: Kristjan Bregendahl, Animal Science, (515) 294-5132, kristjan@iastate.edu

 

Model's Community Approach Aids Decisions on Swine Sites

Issue

Iowa livestock producers interested in building new facilities face a delicate balancing act when deciding where to locate those facilities so they will be neighbor-friendly.

 

So What?

Iowa State University agricultural engineers developed the Community Assessment Model for Odor Dispersion which has been applied on a voluntary basis to help site more than 100 facilities in Iowa. The model assesses the odor impact on neighbors and attempts to answer questions that members of a community might have about a new hog facility. The model makes predictions based on predominant local weather patterns, type and size of facility, number of animals and ventilation systems. The model factors in location of neighbors and any other area swine facilities.

 

Impact

The model helps to predict impact on neighbors, the amount of time neighbors may be exposed to different odor levels and the impact of implementing odor-mitigation strategies.

 

Contact: Steve Hoff, Agricultural and Biosystems Engineering, (515) 294-6180, hoffer@iastate.edu

 

Scrubbing Exhaust Air From Livestock Facilities Reduces Odor

Issue

Researchers have been testing in the lab and in the field at cooperator sites the effectiveness of using wood chips to reduce ammonia, hydrogen sulfide and odors from fan-ventilated swine facilities. These so-called biofilters have been in use for years in other industries.

 

So What?

Results show at least a 70% reduction in ammonia, hydrogen sulfide and odor at a cost of roughly 45 cents per pig produced.

 

Impact

The next step is to develop "smart controls" for this biofiltration by incorporating atmospheric conditions to make decisions on when a mitigation strategy is needed. The research shows that in most cases, a mitigation strategy is needed no more than 5-10% of the time in any given day. Having the ability to predict when a technique is needed will maximize the usefulness and reduce costs.

 

Contact: Steve Hoff, Agricultural and Biosystems Engineering, (515) 294-6180, hoffer@iastate.edu

 

Using Ultraviolet Light to Destroy Odor

Issue

Iowa's livestock industry is an important part of the state's economy. All avenues to reducing odor from livestock production facilities must be explored to help make it possible for the industry to continue.

 

So What?

Techniques are being developed for using ultraviolet light to destroy both odor producing compounds and pathogens from swine production facilities. This method uses the expertise of Agricultural and Biosystems Engineering along with microbiological expertise from the College of Veterinary Medicine.

 

Impact

The techniques being developed are currently lab-scale methods that eventually will be transferred to practice. The technique so far looks promising but challenges lie ahead in making this technique viable for in-field use.

 

Contact: Jacek Koziel, Agricultural and Biosystems Engineering, (515) 294-4206, koziel@iastate.edu

 

Investigating the Purifying Potential of Plants

Issue

Phenol is a gas that causes the foul odors found in automobile exhaust, cigarette smoke, decomposing manure and emissions from burning wood, coal and municipal waste.

 

So What?

Plant pathologists at Iowa State are researching whether bacteria on a leaf can utilize the organic compounds that are air pollutants. The process is called phylloremediation, a natural cleaning process that uses the leaves and its micro flora to clean the air. Plants remove phenol from the air by moving it into the plant through its pores.

 

Impact

The researchers found phenol adheres to the leaf surface where the microbes may be able to use it. It was the first conclusive demonstration that bacteria could take an airborne compound and degrade it on the leaf. Studies like this could provide tools to help eliminate air pollutants near livestock and industrial facilities.

 

Contact: Gwyn Beattie, Plant Pathology, (515) 294-5571, gbeattie@iastate.edu