Iowa State filling info gap on swine facility air emissions

Published on: Sep 4, 2013

A first-of-its-kind study by Iowa State University scientists is seeking to fill the information gap that exists regarding air emissions from swine facilities.

"Farmers need reliable data to determine if air emissions are above regulatory thresholds and to help make better decisions on where to invest in emission controls," said Hongwei Xin, professor in Iowa State's department of agriculture and biosystems engineering. However, "research and information on ammonia and greenhouse gas emissions from swine operations — particularly from breeding, gestation and farrowing facilities in the Midwest — has been meager."

Through the study, which was funded in part by the Iowa Pork Producers Assn. (IPPA), Xin and his research team are beginning to fill the information gap. Since January 2011, his research team has been quantifying ammonia and greenhouse gas emissions from a 4,300-sow breeding, gestation and farrowing facility located in central Iowa. The facility is owned and operated by Iowa Select Farms.

Although the study does not include testing technologies designed to mitigate emissions, Xin noted that a lot of work has gone into developing mitigation techniques for certain gases. He hopes more work will be done to make those techniques more affordable for producers.

"We have to make sure that producers can employ the technology without driving themselves out of business," Xin said.

The project concluded monitoring in early June, and final data processing is underway. Xin said he expects the 29-month study to help provide information and implications in areas that include:

* The number of sows that would produce 100 lb. of ammonia per day — a figure that triggers the need for a farm to report ammonia emissions to EPA.

* The benchmark values for ammonia and greenhouse gas emissions from facilities for each production stage: breeding/gestation, farrowing and manure storage.

* Identification of hot spots of different gaseous emissions for potential mitigation. For example, barns may be the primary source of ammonia emissions, and manure storage (both deep pits and outside storage) may be the main source for methane and nitrous oxide emissions.

* The predominant emission may be methane, making up 95% or more of total greenhouse gas emissions from a farm.

"Results of this study will provide a benchmark for the industry, especially in the area of greenhouse gas emissions reporting. We want to know what the numbers are out there," Xin said.