Progress 05/01/05 to 04/30/08
Outputs
OUTPUTS: The commercial project collaborator was once again unable to make the promised 1 kg/h ozone generator available so the proposed field trials in Indiana and Illinois could not be replicated during the final project phase, nor could the benefit-cost analysis be completed to compare ozonation against conventional pest management practices. However, the field trials conducted in the Purdue pilot bin facility were continued during the final project year with conventional yellow corn. Corn had been in storage for five consecutive seasons and was treated repeatedly with ozone during four summer periods. In each of the three bins, corn quality was preserved and stored grain insects were controlled in combination with conventional aeration practices. Additionally, laboratory trials were continued using corn and wheat to further quantify control of stored product insects, fungi and other microorganisms, and off-odors. It was also concluded that static bed ozonation has limits with respect to the treatment of large grain quantities in on-farm and commercial storage structures. This needs to be overcome by utilizing a semi-continuous flow ozone treatment system, which was developed and tested in a related project. Results will determine the potential for scale-up and commercial implementation in order to use semi-continuous flow ozonation treatment systems to effectively remove objectionable odor from grain, sterilize fungi, and control insects. PARTICIPANTS: Purdue Staff: Dirk E. Maier, PI & PD, Professor of Ag & Bio Engineering; Charles P. Woloshuk, Co-PI, Professor of Botany & Plant Pathology; Linda J. Mason, Co-PI, Associate Professor of Entomology; Corinne E. Alexander, Co-PI, Assistant Professor of Agricultural Economics; Dale Moog, Post-doctoral Research Associate, Ag & Bio Engineering; Carlos Campabadal, PhD Student, Ag & Bio Engineering; JD McClurkin, MS student, Ag & Bio Engineering; Partner Organizations: O3Co, Idaho Falls, ID; Several commercial food grain producers and processors; TARGET AUDIENCES: Results of this research were presented at several national and international conferences (2006 International Working Conference on Stored Product Protection, Campinas, Brazil; 2006, 2007 Methyl Bromide Alternatives Conference; 2005, 2006, 2007 Annual Meeting of the Entomology Society of America; 2005, 2006, 2007 International Meeting of the American Society of Agricultural & Biological Engineers) and industry conferences (2005, 2006, 2007 NC-213 Annual Technical Meeting) attended by researchers, government regulators, and representatives of the U.S. grain handling and food processing industry as well as the pest control industry. PROJECT MODIFICATIONS: During the final project year we experienced another problem with the availability of the commercial ozone generator for use in the planned treatment demonstrations in Indiana and Illinois. Therefore, pilot scale trials were repeated at Purdue University, and the development of the semi-continuous flow ozonation treatment system design was pursued. Unfortunately, the benefit-cost analysis could not be completed due to the unavailability of the 1kg/h commercial ozone generator.
Impacts
There is a substantial interest in the application of ozone by U.S. grain producers, handlers and processors. Ozone is a powerful oxidant that has regulatory acceptance by the FDA (FDA 2001). EPA's MSDS defines it as "pure air". Numerous beneficial applications have been developed, such as water treatment to disinfect and eliminate odors, taste, and color, as well as to remove pesticides, inorganic and organic compounds. Ozone (O3) is an allotrope of oxygen, which can be generated by electrical discharges in air. In agitated air ozone has a half-life of 20-50 min, and rapidly decomposes to diatomic oxygen, a natural component in the atmosphere. Because ozone can be easily generated at the treatment site using only electricity and air, it offers several safety advantages over other post-harvest treatments such as conventional pesticides. First, there are no stores of toxic chemicals, chemical mixing hazards, or disposal of left over insecticides or containers. Second, with a short half-life, it reverts back to naturally occurring oxygen. Third, if needed it would be possible to neutralize ozone through techniques such as thermal activated charcoal, as well as catalytic and chemical abatement. Research on the efficacy of ozone on insect mortality indicated 92-100% mortality of larvae of adult maize weevils (MW), Indianmeal moth (IMM) and adult red flour beetles (RFB) in infested corn when fumigated with 50 ppm ozone for three days. The same treatment also significantly reduced the viability of Aspergillus parasiticus Speare and other fungi on the kernel surface as well as removed off-odors from sour/musty grain. Data also indicated that repeated ozone treatments did not decrease the end use quality of grains. A number of grain producers, handlers and processors have expressed interest in ozonation technology and generators are becoming commercially available for use. Due in part to findings from this project, large scale tests at commercial grain handling locations conducted in 2007 and 2008 have proven the commercial feasibility of removing odor from grain using ozonation. Over 8 million bushels of odor-damaged grain was reconditioned, which resulted in an economic return to the grain handler in excess of $4 million. This has resulted in additional funding that allows us to continue with the development of the semi-continuous flow ozonation treatment system that will further confirm the efficacy of ozonation for the control of pests and spoilage agents, and the removal of off-odors. Ozonation serves as a preventative strategy against insect infestation and at the same time reduces/eliminates the microbial load (fungal and bacterial spores), as well as guards against off-odors. There are many producers and handlers of food and feed grains (including conventional and organic food corn, wheat and barley) who continue to express interest in utilizing this new technology throughout the North Central Region.
Publications
- Maier, D.E., Khandelwal, S., Lawrence, J., and Campabadal, C.A. 2007. Modeling airflow in outdoor grain pile aeration systems using computational fluid dynamics software. Paper No. 06-6085; ASABE, St. Joseph, MI.
- Campabadal, C.A., Maier, D.E. and Moog, D.J. 2007. Engineering design parameters for recirculation, flow of ozone through grain storage structures. Paper No. 07-6168. ASABE, St. Joseph, MI.
- McClurkin, J.D., Campabadal, C.A. and Maier, D.E. 2008. Semi-continuous ozonation system for pest control. Proceedings of the 8th International Conference on Controlled Atmosphere and Fumigation in Stored Products. p.170-174. Chengdu, China, September 21-26, 2008.
- McClurkin, J.D., Maier, D.E. and Woloshuk, C.P. 2008. Effect of ozone treatment on common stored grain molds. Proceedings of the 2008 International Grain Quality & Technology Congress. (on-line). Chicago, Illinois, July 15-18, 2008.
- Campabadal, C.A. and Maier, D.E. 2008. Semi-continuous ozonation of grain. Annual International Meeting of the American Association of Cereal Chemists. (Abstract; Poster). Honolulu, Hawaii, September 21-23, 2008.
- Campabadal, C.A. and Maier, D.E. 2008. Semi-continuous ozonation of grain. Proceedings of the 2008 International Grain Quality & Technology Congress. (on-line). Chicago, Illinois, July 15-18, 2008.
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Progress 05/01/06 to 04/30/07
Outputs
OUTPUTS: Scale-up trials were repeated at the pilot bin facility of the Purdue University Post-Harvest Education & Research Center in May through September 2006 with conventional corn that has been in storage since fall 2003. The primary objective of this trial was to determine the efficacy of ozonation to control insect pests during summer storage in comparison to other treatments (ambient aeration, ambient aeration plus physical exclusion, chilled aeration). The basic setup for ozonation at this site consisted of generating ozone with an older 2-chamber commercial generator, introduction in the headspace, drawdown to the plenum with a suction fan, and re-circulation of ozone back into the bin headspace. Ozonation was done to attain an ozone concentration of 50 ppm in the plenum and maintained for a period of 3 days to achieve mortality of insects comparable to phosphine fumigation. The trials were performed using insect bioassays with adults of maize weevil and red flour beetle
that were placed 0.6 m below the grain surface and in the plenum of the silos. The concept of two phases of ozonation was confirmed because the same corn was previously ozonated in the summer 2005. In comparison to not previously ozonated corn it took only a few hours to re-establish the ozone front from top to bottom of the grain mass. Once established, it was maintained for 3 days. Mortality of the bioassays was 100%. The trials further proved the efficacy of ozonation in achieving stored product insect mortality comparable to phosphine fumigation.
PARTICIPANTS: Purdue Staff: Dirk E. Maier, PI & PD, Professor of Ag & Bio Engineering; Charles P. Woloshuk, Co-PI, Professor of Botany & Plant Pathology; Linda J. Mason, Co-PI, Associate Professor of Entomology; Corinne E. Alexander, Co-PI, Assistant Professor of Agricultural Economics; Dale Moog, Post-doctoral Research Associate, Ag & Bio Engineering; Carlos Campabadal, PhD Student, Ag & Bio Engineering; Partner Organizations: O3Co, Idaho Falls, ID; Several commercial food grain producers and processors;
TARGET AUDIENCES: Results of this research were presented at several national and international conferences (2006 International Working Conference on Stored Product Protection, Campinas, Brazil; 2006, 2007 Methyl Bromide Alternatives Conference; 2005, 2006 Annual Meeting of the Entomology Society of America; 2005, 2006, 2007 International Meeting of the American Society of Agricultural & Biological Engineers) and industry conferences (2005, 2006, 2007 NC-213 Annual Technical Meeting) attended by researchers, government regulators, and representatives of the U.S. grain handling and food processing industry as well as the pest control industry.
PROJECT MODIFICATIONS: During the summer 2006 we experienced a problem with the availability of the commercial ozone generator for use in the planned treatment demonstrations in Illinois. Therefore, a 1-year no cost extension was obtained to schedule the planned field demonstrations next summer.
Impacts
Based on the results of our demonstration trials with ozonation of food corn and popcorn, a new ozone generator was designed and built that can generate 1 kg/hour of ozone. This will further improve and refine the application of ozone as an alternative, non-chemical stored product pest control technology. Completion of this project will provide the producers, handlers and processors of food grains (conventional and organic popcorn and food corn) valued at more than $2.3 billion, who seek alternatives to pesticides, with the information they need for decision-making about utilizing this new technology in the North Central Region.
Publications
- No publications reported this period
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Progress 05/01/05 to 05/01/06
Outputs
This project was initiated during the summer of 2005. Two 2,000 bu corn bins at the pilot facility of the Purdue University Post-Harvest Education & Research Facility were ozonated intermittently between May and October. One of the bins was exposed to a Phase I ozonation in November 2004, and the second one in May 2005. Repeated ozonations during the storage season confirmed that the corn remained in the Phase II state in both bins as expected. Additionally, the efficacy of ozonation was tested under field conditions in three 500 bu pilot bins filled with corn, in a 15,000 bu popcorn bin and in a 1,500 bu organic corn bin. In each field test, pitfall and larval traps were placed near the grain surface to monitor for natural populations of stored product insects. During each ozonation, cages with stored product insects were placed in the upper layer of the grain mass as well as the plenum of the bin. Each ozonation treatment resulted in 100% mortality of all live
stages of all insect species. Additional laboratory observation up to 60 days resulted in zero progeny. Additionally, ozonation did not affect the end use quality of the treated popcorn or specialty food corn negatively.
Impacts
Based on the results of our current demonstration trials with ozonation of food corn, the application of ozone as an alternative, non-chemical stored product pest control technology will be further refined. Completion of this project will provide the producers, handlers and processors of food grains (conventional and organic popcorn and food corn) valued at more than $2.3 billion, who seek alternatives to pesticides, with the information they need for decision-making about utilizing this new technology in the North Central Region.
Publications
- No publications reported this period
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