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Southern Plains: Updated Sept. 12, 2011

New technology could capture ammonia from liquid manure

Though it may not sound very glamorous, a new method of extracting ammonium from liquid animal manure could be exciting news for both confined animal operations and environmental groups, according to a Texas AgriLife Extension Service engineer.

The method uses gas-permeable membrane technology that tests have shown could remove 50 percent of the dissolved ammonium in liquid manure in 20 days. The removed ammonium is “not scrubbed but captured,” said Dr. Saqib Mukhtar, AgriLife Extension engineer and interim associate department head of the Texas A&M University department of biological and agricultural engineering.

By captured, Mukhtar means, the ammonium is concentrated as ammonia sulfate compound, which as commercial fertilizer could potentially offset the cost of the removal process.

Though still in the lab-bench test stage, the technology shows great promise to solve a long-standing, expensive well-documented problem that confined-animal feeding operations such as dairies and feedlots face daily, Mukhtar said.

“Excessive ammonia emissions from animal feeding operations are considered a source of odor and environmental pollution,” Mukhtar said. “Once emitted, ammonia may contribute to formation of fine airborne particulates in the presence of certain acidic compounds in the atmosphere.”

Also, ammonia emissions from improperly managed manure systems may contaminate groundwater and cause excessive vegetative growth in lakes and reservoirs, he said.

“And it may even be a constituent of nitrous oxide, a potent greenhouse gas,” he said.

There are other methods of mitigating ammonia emissions from manure storage and treatment facilities, including acidic solution-sprayed scrubbers and bio-filters, and chemicals such as acidified clays and sodium hydrogen sulfate, Mukhtar said.

“Several of these methods have been promising, but high costs, lack of ‘staying power’ of chemicals and other additives, lack of ammonia recovery for beneficial uses, and the complex operation and management of some of the technologies have restricted their extensive use in animal agriculture,” he said.

In comparison, the membrane technology Mukhtar and his associates have been testing is relatively simple.

Gas-permeable tubing is submersed in a tank of liquid manure. A very dilute solution of sulfuric acid is pumped through the tubing, which has a porosity of only 2 microns. To put this in perspective, a typical human hair is 70 microns in diameter.

The method takes advantage of a property of dissolved gases described by Fick’s first law of diffusion. A high concentration of a dissolved gas, such as ammonia, will migrate to regions of lower concentration. As the concentration of ammonium is high in the liquid manure and low to zero in the permeable tubing, the ammonium is drawn into the tubing and out of the liquid manure.

Also, the migration is enhanced by ammonium being a base and chemically attracted to the acid in the tubing.

The name of the tubular membrane they used is “expanded polytetrafluoroethylene, which is usually abbreviated ePTFE,” Mukhtar said.

The product has several uses including blood filtration and synthetic blood vessel and even dental floss, he said, and once was prohibitively expensive. But with the expiration of several patents for this material and its uses, the cost has dropped dramatically, allowing its use for other applications.

Mukhtar said the next step is to scale up from the small bench model to a large tank, perhaps 100 gallons, he said. The team also wants to experiment with how little tubing can be used, and how dilute the acid solution can be, while still capturing about 50 percent of the ammonium within a reasonable amount of time.

They are also looking ahead to learn how to economically scale up the process for use on the farm.

“Obviously, we can’t use a ‘gazillion’ feet of tubing in a large manure lagoon,” Mukhtar said. “Potentially, what we could do is divert some of the flushed manure in a much smaller basin and apply membrane technology to extract ammonia from it.”

The manure from which the ammonia has been extracted would then be transported back into the large lagoon, he said

“By doing this repeatedly, we could concentrate ammonia as a relatively high pH solution of ammonium sulfate,” Mukhtar said.

The team headed by Mukhtar includes Amir Samani Majd, a doctorate candidate; Dr. MD Borhan, assistant research scientist; and John Beseda, student technician, all based in College Station. The team presented the results of their study in a paper at the American Society of Agricultural and Biological Engineers annual international meeting at Louisville in mid-August. The title of the paper was “An Investigation of Ammonia Extraction from Liquid Manure Using a Gas-Permeable Membrane.”

“Remember, we are capturing ammonia with this process,” Mukhtar said. “Not just scrubbing it as other processes do. We might be able to return part or all of its cost of the process as ammonium sulfate, an expensive fertilizer.”


Midwest Dairy awards Kansas City, Ozark division scholarships

Midwest Dairy Association has announced the nine Kansas City Division and six Ozarks Division winners of the Midwest Dairy Educational Award, a $500 scholarship for college expenses.

The Kansas scholarship recipients are:

  • Rachel Becker, daughter of John and Cindy Becker of Argonia, a graduate of Conway Springs High School. Becker will study accounting and business management at Kansas University in the fall.
  • Casey George, son of Eugene and Laura George of Baldwin, a Baldwin High School graduate. He studies plumbing, heating, air conditioning and heavy equipment at North Central Kansas Technical College.
  • Austin Haverkamp, son of Brian and Kristina Haverkamp of Seneca, a Nemaha Valley High School graduate. Haverkamp will study biology at Kansas State University next fall.
  • Alex Linsey, the son of R.D. and Cindy Linsey of Lebo. Linsey, a Lebo High School graduate, will study dairy and animal science at Allen Community College.
  • Stacy Rottinghaus, daughter of David and Jan Rottinghaus of Seneca. She studies secondary mathematics education at Washburn University.
  • Andrea Steenbock, the daughter of Curtis and Kristine Steenbock of Longford. Steenbock plans to study agriculture business at Kansas State University.
  • Rachel Stuhlsatz, daughter of Kevin and Jackie Stuhlsatz of Goddard, a Garden Plain High school graduate who will study accounting at Kansas State University.
  • Roxanne Wallace, the daughter of Brad and Karen Wallace of Tipton. Wallace has received a biology degree from Pittsburg State University and studies veterinary medicine at Oklahoma State University Center for Veterinary Health Sciences.

The Missouri scholarship recipient is:

  • Colton Hardy, son of Steve and Jill Hardy of Browning. A Linn County R-1 graduate, Hardy will attend North Central Missouri College for the agriculture program with an emphasis in agriculture mechanics.


The Ozarks scholarship recipients are:

  • Ryan Brown, the son of Kent and Joann Brown of Long Lane, Mo. A Dallas County R-1 graduate, Brown will study agriculture business at Ozarks Technical Community College.
  • Whitney Coats, daughter of Tom and Karen Coats of Mountain Grove, Mo. Coats is a Mountain Grove High School graduate and plans to study biology at Southwest Baptist University.
  • Jenna Diehl, daughter of Michael and Lynn Diehl, of Elkland, Mo. A Marshfield High School graduate, Diehl will continue her education at Missouri State University-West Plains, studying agriculture business.
  • Mark Mareth, son of Tom and Melinda Mareth, of Monett, Mo. Mareth graduated from Monett High School and studies agriculture at Crowder College.
  • Kaylynn Million, daughter of Garry and Georgia Million of Tahlequah, Okla. A Tahlequah High School graduate, Million studies agribusiness at Northeastern State University.
  • Katie Noah, daughter of Dan and Joyce Noah, of Theodosia, Mo. A Lutie R-VI graduate, Noah will study business at the University of Missouri-Columbia.

Midwest Dairy Educational Award recipients excel academically and demonstrate leadership and participation in their school activities and within the dairy industry.


USDA designates areas in Missouri and Kansas for bioenergy feedstock production

USDA announced the establishment of the first Biomass Crop Assistance Program (BCAP) Project Area to promote the production of feedstocks for bioenergy. Producers in 39 contiguous counties in Missouri and Kansas are eligible to plant mixes of perennial native plants, such as switchgrass, for the manufacture of biomass pellet fuels and other biomass products to be used for power and heat generation. Those selected will be eligible for reimbursements of up to 75% of the cost of establishing a bioenergy perennial crop, plus annual payments. Visit www.fsa.usda.gov/bcap