Science

Prototype system removes air pollutants and generates heat for livestock barns

A prototype system has been created for cleaning and heating the air in chicken and swine barns (Pig barn via Shutterstock)
A prototype system has been created for cleaning and heating the air in chicken and swine barns (Pig barn via Shutterstock)
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A prototype system has been created for cleaning and heating the air in chicken and swine barns (Pig barn via Shutterstock)
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A prototype system has been created for cleaning and heating the air in chicken and swine barns (Pig barn via Shutterstock)

If you've ever so much as stepped into a chicken or swine barn, you'll know that they can be very, very smelly places. When vented outdoors, the air from these buildings does more than just make the area stink - it can actually be a major source of air pollution and greenhouse gases. Fortunately, however, researchers from North Carolina State University and West Virginia University have created a system that not only helps clean the air going out of the barns, but it heats up the air coming in from outside.

The system runs the polluted air through a biofiltration medium, such as compost or wood chips. Bacteria living within that material break down and neutralize the pollutants, much as they do in biofilters used for fish ponds or aquariums. Once it's time to replace the medium, the old material can be used as crop fertilizer, as it is full of valuable nitrogen.

The use of such a filtration system would increase costs for farmers on its own, so the researchers are hoping to offset those costs by allowing the system to assist in heating incoming air. This is done using a heat exchanger, which receives heat from both the warm, polluted air that is being treated, and from the biochemical reactions taking place within the biofilter.

So far the team has focused on the removal of ammonia, as it is very plentiful in such barns, and is a major source of pollution. When a prototype system was tested on a 5,000-bird chicken barn, it was found to remove up to 79 percent of the ammonia from the outgoing air, and recovered up to 8.3 kilowatts of heat.

"The technology is best suited for use when an operation wants to vent a facility that has high ammonia concentrations, and pump in cleaner air in preparation for a fresh batch of chicks or piglets - particularly in cold weather" said NC State's Dr. Sanjay Shah. "It is also suitable for use when supplemental heat is required for raising the young animals."

A paper on the research was recently published in the journal Applied Engineering in Agriculture.

12 comments
SpaceBagels
There should be a parallel offshoot of this technology for the Planet Earth. In a couple of hundred years we WILL be living in planet-wide-swine-barn so it\'s good to have a headstart.
Carlos Grados
These animals don\'t deserve to live like this-all stuffed together in factory farms. It is a regrettable technology.
Slowburn
Given the flammability of ammonia and methane running an ICE powered generator on the barn exhaust air, and bio gas from anaerobic digestion tanks treating the animal waste would clean the air, treat the sewage, generate good food compatible fertilizer, electricity, and hot water. If you get all the design curlycues right highly efficient as well.
Bill Bennett
Space your kinder will be living on a planet wide swine barn, mine as well, Carlos, agree, humans will destroy this ecosystem aka planet wanna guess how long we take to do it? Bestust, Bill
Bart Viaene
Finally : a cheap and easy way to remove the smell of pig and poultry farms ! And the generated heat can be used to roast the animals, too ;-)
Joel Joines
I agree with slowburn. Instead of filtering use the barn air as input for a gen-set running on methane from a waste digester. The ammonia and methane in the air will burn along with the input fuel. Then you use a heat exchanger to use the waste heat from the gen-set to heat the barn. Then the farmer gets electricity, cleaner air, sale-able fertilizer, heat and healthier livestock. The only loss is the cost of building the digester pool and the co-gen equipment. There are already farms that get all their electricity from digester methane. It\'s a small change to route the air intake for the generator from inside the barn and waste heat back to the fresh air intake. These digester powered farms are common enough that Mythbusters even found one for the running a lawnmower on cow poop myth.
Jim Clouse
How about we stop raising animals in these conditions. Free range is a cleaner, healthier method, albeit more expensive.
Gene Jordan
@Carlos Grados that photo is not a \"Factory Farm\". That\'s the standard size hog house that might be seen on most any small farm. Those pigs likely spend more time outside than you do. They actually enjoy being \"stuffed together\", also known as feeding time, as much as humans enjoy the company of others during a meal. Please do some research and visit an actual hog farm near you. They are good for the economy and good for the dinner table. ;)
voluntaryist
Free range chickens grow slower and smaller, but their eggs and meat are much healthier. So the end product justifies the greater cost. When we call for better conditions in producing animal products we have to put our money where our mouth is. When people only buy free range and certified humanly raised animals we will have only that. The consumer is king.
jerryd
I'm getting over the filth of these places and what they feed them. So I'm going to build a 6 nest movable coup and get he local chickens to move in. That will get me both meat and eggs delivered to my door fresh at little cost. Chickens are in many places already. Just give them a home until you are ready to eat. Tastes like chicken ;^P