Ozone - a very controversial and misunderstood gas - may prove to be a lifesaver for the pork industry.
Ozone protects us from ultraviolet rays in the atmosphere, but comparable levels at ground level could be toxic. It has been used commercially for years to disinfect drinking water and swimming pools and to treat sewage and industrial wastes.
Now the pungent gas is coming to the forefront as a possible odor control solution for hog facilities and outside waste storage basins.
And, the very reactive form of oxygen (O3), is also being touted by a handful of companies trying to sell ozone-generating systems as a means of enhancing animal health and, thus, hog performance.
Most industry observers agree that without both odor control and performance enhancement elements, the cost of ozone systems on the market today is probably prohibitive.
However, as soon as data bears out what some supporters say is already occurring in on-farm tests, the rush may be on to have a system installed. North Carolina Experience
In the view of Peter Moss, complex manager, Laurinburg Division, Carroll's Foods of Warsaw, NC, the ozone system can reduce odors. But, he adds, before Carroll's buys an ozone system, one of two things must occur - some yet-to-be-seen, big performance advantages or the price will have to come down.
Carroll's is testing air and water versions of the Extreme Clean Machine, an ozone oxidation generator manufactured by Oxyzone Systems Inc., distributed by Aerotech Inc., Mason, MI. The ozone system depends on ultraviolet light to produce a super-reactive oxidizing agent, used by both air and water machines to attack and eliminate odors.
At Carroll's, the ozone system is being tested in one 880-head, tunnel-ventilated, totally slotted finishing building, and in one single-stage, anaerobic lagoon sited just 20 ft. from the finisher's huge exhaust fans.
"There is certainly less odor perceived in the finishing building," remarks Moss. "You can go in that hog house in your street clothes and go back outside and on your way without anyone noticing where you've been."
A couple of Carroll's employees put the claim to the test. They spent time in that finishing building and then got on an airplane for Tennessee without a change of clothes. There was no hint of hog odors on their clothes, attests Moss.
"We are also monitoring performance of the 'ozonated' building," points out Moss. "At first, we were starting to get pretty excited, but at the end of the turn, we realized that all five of the control group finishers (no ozone) were also performing at high levels. We didn't discern any difference in performance."
But Moss admits the finisher has been through just one production turn with ozone. He says there was a slight advantage in culling percentage in favor of the ozone-treated barn. In fact, there were no culls at market time for the ozonated barn.
Death loss was also very acceptable. Moss notes health was very good in all six of the finishers. Hogs are fed from 50 to 250 lb. in those units.
As for the ozone-treated lagoon, Moss says it looks "very healthy" and stayed that way all winter. "There are definitely less solids on top. There is usually quite a buildup in the corners of the surface area." Moss says Carroll's plans to poll nearby residents on perceptions of odor levels emanating from the lagoon. Carroll's has been testing the low-level ozone system for about eight months.
Research Thrust Scientists at North Carolina State University (NCSU) are supervising testing of the Aerotech ozone system on farms in the state. Agricultural engineer Bob Bottcher says he has been surprised that there has been a 50% reduction in dust levels between the ozonated finisher at Carroll's and the non-treated finishers. Dust was measured using particle counters and air sampling pumps with filters. Odor was measured from air samples at Duke University.
But, he says there may have been some complications regarding their tests of odor levels. Casual observation indicates less odor, but it has not been borne out in their research to date. He says adding to the confusion is the well-known fact that dust carries odor-causing particles.
At this point, Bottcher is unsure how adding ozone inside a hog barn reduces dust levels. He surmises it may be partly due to the electrostatic properties that are generated in a room by ozone. The air ionization produced by the "ozonation" system may help remove dust from the air, and seems to help reduce overall dust levels in a hog room, he theorizes.
Still, indoor dust and ammonia levels are generally not that bad anyway in a tunnel-ventilated barn in warm weather because the high ventilation rates tend to dilute odors and dust. But he is still concerned there may be a problem to solve.
Bottcher observes, "You could have a low odor level and it may not smell or be dangerous for workers in warm weather when the fans are running on high. The air quality inside the building could still be pretty reasonable, but the high air flow rate produces emissions that could be sending a high level of odors or dust impacting neighbors downwind."
Bottcher says he is studying ozone and windbreaks and a few other options to cut down on odors and gases being exhausted from hog barns. Windbreak walls downwind of exhaust fans are commonly used in Taiwan to slow down dust particles and odors from poultry barns.
For a hog barn, an ozone generator located outside the building is used to produce ozone. Fans producing negative pressure are used to pull the ozone into a barn and push it through separate PVC ducts. Spaced holes in the ducts distribute the ozone throughout a room.
Aerotech's ozone-treated lagoon research at Carroll's is being carried out by NCSU environmental engineer Jay Cheng. Results are being compared with a similar, non-treated finishing farm lagoon less than a mile away.
In water, ozone created by the ozone generator is mixed with air and pumped into the lagoon through a surface aerator mounted on a float, treating the top foot and a half of lagoon water, explains Craig Morley, Aerotech marketing director.
"What we are doing is taking some samples from ozonated and control lagoons to an odor panel at Duke University to let them evaluate what the difference is," explains Cheng.
He says because of ozone's ability to kill pathogens in drinking water, it is assumed it will have the same impact in reducing pathogen levels in lagoons. Theoretically, ozone can oxidize odorous compounds such as volatile organic acids. But he says the research is very preliminary at this point.
Assuming it works to destroy odorous compounds in the lagoon, in his mind the key question is still how do you make the system cost effective? "That is the biggest concern for using that kind of system," says Cheng. That's why he has enlisted the help of Kelly Zering, NCSU extension ag economist, to help evaluate the economics. Working with Aerotech engineers and the test farms, he says NCSU researchers plan to complete the first set of technical and economic data on the Michigan company's ozone system by the end of the year.
Michigan State University (MSU) has done research on using ozone to treat hog farm waste odors for several years. MSU has focused on the use of ozone to primarily treat stored manure slurry. MSU researchers led by Susan Masten, civil and environmental engineering, and Mel Yokoyama, animal science, have shown reduced odors and disease-causing bacteria by treating swine manure slurry with relatively high concentrations of ozone. Levels of 1, 2 and 3 grams/liter, (1,000-3,000 ppm) were used in fresh and stored hog manure slurry.
A later study by this team of MSU scientists showed that acceptable odor levels in swine manure slurry were achieved at a much lower dose level of 0.5 grams/liter of ozone.
According to Masten and Yokoyama, studies have shown that the oxidation (breakdown) of phenolics, indolics and other metabolites that are produced by the bacteria in manure during storage are responsible for the odor reduction. "They are destroyed by the ozone treatment thereby eliminating the odor. We also see a reduction in the total number of aerobes and anaerobes and a reduction in pathogen indicators such as E. coli. We don't kill all the bacteria because the ozone treatment is quenched by the large amount of biologic material. But I don't think we want to kill all the bacteria in manure slurry."
Yokoyama adds, "I think ozone is a very environmentally safe way of treating livestock waste, it is more environmentally friendly than other chemical means to control waste odors and it does have application in the environment."
He says MSU just completed a greenhouse study of the toxic effects of ozonated slurry on corn, wheat and soybeans and could find no harmful effects.
Yokoyama agrees treating swine manure with ozone is fairly expensive. If the solid wastes can be removed and just liquid wastes treated, the system possibly could be less expensive, he says.
MSU researchers would also like to delve into using ozone inside hog barns. It's part of the Department of Animal Science's commitment to building a full-scale ozonation system at their commercial swine research farm. "If we can show a definite improvement in animal health and performance, and other benefits of the treatment, perhaps producers will buy into the technology," observes Yokoyama.
University of Minnesota extension ag engineer Jose Bicudo agrees the economics may be a stumbling block to use of the ozone technology.
One particular ozone system installed in North Carolina for a finishing farm is projected to cost about $10,000/building or $11/pig space for the ozone-generating equipment and fans and tubes to distribute the gas throughout the building. Figure another $50,000-60,000 for ozonating equipment for a large lagoon for 10 buildings served by the lagoon ($6-7/pig space). The ultraviolet lamps (from 4 to 12 are used per building based on building size) last about a year and cost about $50 each to replace. Annual maintenance is also required on the ozone system. Also, lamps must be wiped down monthly, 1-2 hours annually for lagoon pumping unit inspection and cleaning.
A full-scale approach to providing ozone systems to pork producers is what is uniquely offered by Aerotech Inc. "I believe that we are the only company in the country that offers ozone treatment for both inside hog buildings and in lagoons," says Morley.
Aerotech has set up test exercises with its equipment with large pork producers in North Carolina and Colorado. The system is also available to be purchased. The Extreme Clean Machine oxidation generator was introduced last year.
Aerotech's Morley explains that when hog odor occurs, certain molecules combine. "We are trying to break those bonds and that's basically what our ozone system does. It breaks down that bond and by doing so also affects the dust level by which a lot of the odor is carried around," says Morley.
Ozonation provides a better environment for both pigs and people and the people who live downwind of the hog operation. Along with that, it reduces moisture levels in buildings. Right now, he says, the goal is to prove Aerotech's ozone system enhances pig performance. Morley speculates Aerotech may also look at ozonating hog manure pits. Iowa Experiences Doon, IA, pork producer Mike Kats is one of half a dozen hog farmers in the Upper Midwest testing the ozone system from Ozone Solutions Inc., Sioux Center, IA. Kats is also the company founder and part owner.
He says he discovered ozone's use for his hog operation by accident. He had been using an ozone generator to purify the farm well. The problem was the compressor failed unless the pump ran all the time. To keep the pump running all the time meant having to dispose of excess ozone, explains Kats. His answer was to dump it into the attic of his hog barns. The ozone made its way into the inlets and he noticed a dramatic reduction in odor in the buildings.
That led to the birth of Ozone Solutions Inc. Kats has been researching ozone production for 6-7 years. He feels the generator and distribution system he and research engineer, Scott Postma, have developed will evenly spread ozone throughout hog rooms. Company literature boasts the ozone-oxygen mixture has reduced hydrogen sulfide levels by 80%.
Postma stresses ozonating the air also may kill airborne bacteria and disinfects all of the building's equipment. Hogs are healthier and more active, adds Kats.
He is testing the system in a 1,200-head finisher. He says ventilation can be dramatically reduced in winter because the ozone system holds down the odor. Without ammonia, you basically ventilate to maintain low humidity, reducing heating bills as you reduce ventilation.
As air quality has improved, Kats says you can stock pens fuller without adding to pig health problems. He has been running his finisher at 1,400-1,500 head.
Rick Wagner of LeMars, IA, has only had the Ozone Solutions system in his 2,500-head nursery for a few months. There are five identical, 500-head rooms where pigs are fed from 12 lb. to 50 lb.; two rooms are ozonated.
He comments, "I'd walk into one of those (ozonated) rooms and I couldn't smell a hog ever. You can kind of smell the ozone, but I was just tickled pink with it. He wears dust masks around hogs, but doesn't have to in the ozonated rooms.
Company spokesman Postma says the goal is to keep ozone levels down to where producers can hardly smell the gas inside hog barns. They shoot for setting of 0.01 ppm, one-tenth the allowable exposure limit of 0.1 ppm for an average 8-hour period.
According to Wagner, the nursery pigs perform well with ozone. He figures if ozone improves air quality for him, it must also be helping his pigs perform better. And that could convert to improved performance, though he doesn't have hard evidence of that yet.
In Canada, Envron Inc. reports tests reveal adding ozone reduces the smell of liquid manure, doesn't hurt hog health and improves their performance by a small amount.
Used in poultry farms, ozone treatment has eliminated salmonella in routine tests, greatly reduced ammonia levels (up to 60%) and slightly improved egg production and egg quality, reports Envron's Allan Finney.
One well-known ventilation firm, one small company, a southwest firm and one Canadian company are actively seeking buyers for their ozone systems to reduce hog odors and improve pig performance. They are:
Offering a closed circuit odor and waste management system featuring the use of ozone is Environmental Remediation Applications Corp., 3908 E. 26th St., Tulsa, OK 74114-4712; phone, (888) 554-0474; fax, (918) 712-0501; e-mail, jocan email@example.com.
There are several other U.S. companies that produce ozone systems which may be adaptable to hog operations.
In Canada, Envron Inc. sells a ozone system for agriculture. They can be reached at 4317 Robinson St., Regina, Saskatchewan S4S 3E4; phone, (306) 586-3353; fax, (306) 584-2595; e-mail, allan.finney@sk. sympatico.ca.