Recycle your manure gas onto fields


COLUMBUS — Many farmers are looking to manure as a way of combating high commercial fertilizer costs.

Now, new strides in technology may make it possible to capture and recycle gas emissions from livestock waste as an additional source of natural fertilizer.

Ohio State University air quality and bio-energy researchers, along with researchers from the University of Minnesota, have received a $599,836 USDA National Research Initiative grant to study the feasibility of capturing and recycling ammonia emissions from manure in poultry and swine operations using a new type of wet scrubber (pollution control) technology, and then reapplying the fertilizer on the farm.

Targeting ammonia

“Large amounts of ammonia emissions from animal feeding operations have caused significant environmental and health concerns,” said project director Lingying Zhao, an OSU Extension specialist in agricultural air quality and bioenvironmental control.

The U.S. Environmental Protection Agency estimates in 2002 that 2.4 million tons of ammonia were emitted into the air.

Zhao said this project is intended to offer livestock producers a tool to reduce air emission impact on the environment while generating an alternative product to commercial nitrogen fertilizer.

Project focus

The grant supports four main objectives: to develop a wet scrubber for trapping ammonia emissions from typical animal manure storage; evaluate the performance, maintenance and costs of wet scrubbers on commercial farms; explore processes to convert the ammonia captured in the wet scrubber into nitrogen fertilizer; and educate producers and livestock and poultry professionals on the technology.

Scrubber technology

Zhao said wet scrubber technology is not new, but the type of wet scrubber being used for the purposes of the research is.

Zhao and her colleagues have been focusing on a spray-type of wet scrubber that operates by capturing gas in water/acid liquid droplets normally sprayed in the device.

The ammonia gas is transferred to the liquid via air being passed through, and then recycled.

Testing prototype

Researchers developed a prototype of the scrubber in the lab, collecting 70 percent to 90 percent of ammonia emissions depending on the operating conditions, and are now interested in testing the prototype in the field.

”From our results in the lab, we see the potential the scrubber has on an animal farming operation,” said Zhao.

”Scrubber technology is complex. What we want to do is create a small-scale scrubber applicable to a farm. If a composting facility generates approximately 100 tons of ammonia annually, and the scrubber is efficient, even at only 70 percent collection efficiency, 70 tons of ammonia can be collected and recycled for use on the farm.”

The three-year grant is part of USDA’s Cooperative State Research, Education, and Extension Service air quality competitive grants program.

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