I.S.U. researcher focuses on nuisance farm odors
March 23, 2010
by Bryan Salvage
AMES, IOWA — Few people can afford to run their air conditioning 24 hours a day during summer months. But even if you could afford it, there are times when you just don’t need it. This same logic should apply to odor mitigation for concentrated animal-feeding operations, said Steven Hoff, an Iowa State University (I.S.U.) professor of agricultural and biosystems engineering.
Mr. Hoff has developed a system for operating odor mitigation systems only when the weather is most likely to cause the odors to become a nuisance to neighbors. This miniature weather station includes locations of neighbors as part of its programming.
“The idea is to keep track of atmospheric stability, which we know affects how far odors will travel, and whether a neighbor may be impacted because of the atmospheric conditions — the wind direction, and those types of things,” Mr. Hoff said. “But if no one is going to be impacted by the odors emitting from a pig house, let’s say, or a poultry house, then save the farmer some money and don’t mitigate.”
The system can be used with any odor-scrubbing system that can be controlled in an on/off mode, Mr. Hoff said. “Whatever the method is, bio-filters, or any other mitigation technique, it will be turned on when the conditions dictate,” he added.
Mr. Hoff feels the most important weather aspect of the system is monitoring atmospheric stability. When the atmosphere is unstable, odors will travel less and affect fewer neighbors. When the atmosphere is more stable, odors will travel farther and can be a nuisance to more neighbors.
“We call it ‘impact-based odor control’ because the idea is going to be to mitigate only when needed,” he said.
Humidity, wind speed, wind direction, temperature and solar impact are atmospheric conditions the system monitors most closely; all of these are likely to affect stability.
Since two of the important inputs of the system are wind speed and direction, the system can also tell where the odor may be headed. Mr. Hoff and Lun Tong, adjunct assistant professor in agricultural and biosystems engineering, currently can take into account the locations of five different neighbors. Within a year, the program will be able to expand to as many as 20 neighbors that might be affected.
Another system benefit is the effect on emissions that have environmental impact. “This is not geared to gas-emission reduction; however, one of the side benefits is that you are still mitigating some of the gases that have environmental concern,” Mr. Hoff said.
The researchers have developed a system through two summers of research that will provide “significant reduction in operation time while still maximizing the benefit to the neighbor” and also be affordable for the producer, according to Mr. Hoff.
The greatest limiting factor for current odor mitigation systems is the cost of operation, Mr. Hoff said. This system will allow producers to invest greater amounts in the mitigation system without having to worry as much about operating costs.