ONTARIO, Ore. – Onion farming is big business in Malheur County, where over 12,000 acres are dedicated to growing the vegetable that makes food taste good.
But with onion production comes an unexpected drawback: plastic pollution from the irrigation systems that are instrumental to crop success. Drip tape irrigation in particular produces two million pounds of plastic waste each year in Malheur County.
Stuart Reitz, the director of the OSU Malheur Experiment Station, said finding a solution to plastic pollution has been a top priority of the station.
“This has been an ongoing concern and a building problem over the last several years,” Reitz said.
Craig Yano, an onion farmer in Malheur County and Oregon State University graduate, has been using drip tape irrigation on his 800-acre farm for 20 years. “There are a lot of advantages” to this method, Yano said. “We moved all of our onion production under drip.”
However, most landfills won’t accept the tape and recyclers aren’t able to process it. So, Yano’s farm pays to transport his tape to the sole remaining landfill that still takes it.
Some onion operations simply store their waste tape on site to save money. “There's really not good alternatives,” he said.
But there might be one in the future, thanks to an OSU collaboration borne of conversations between Marina Denny, the Oregon Department of Environmental Quality, and members of the OSU Engagement Council that explored what research could be applied to solving the county’s plastic problem. Denny leads community engagement through her role as an associate vice provost in the Division of Extension and Engagement.
“My role is to identify where we have resources and expertise at the university and then leverage that to co-create solutions to problems with our external stakeholders,” Denny said.
The answer ended up being easy: Call Skip Rochefort and Lucas Ellis, Chemical Engineering Faculty in the School of CBEE, who just happened to be working on a process that could turn drip tape plastic into diesel fuel, that could be put right into growers’ tractors.
A simple and cost-effective process
Pyrolysis involves heating a material to a very high temperature without access to oxygen. The outcome produces a carbon-rich substance. Charring wood, for example, is a simple version of this process.
Rochefort has been fascinated by pyrolysis for 30 years.
What Rochefort and Ellis are doing is much more complex than charring wood. It involves heating plastic in a kiln to a temperature that is so high that the material vaporizes and condenses into diesel fuel.
“It sometimes just seems like magic,” Rochefort said. “We can put almost any type of plastic in the kiln and turn it into diesel fuel.” Rochefort’s research group has successfully converted plastic waste like Dutch Bros cups, syringes, and milk jugs.
Rochefort constructed his first pyrolysis reactor 6 years ago with the help of funding from OSU parent Helen Liu. Since then, his research has grown into a team of over 20.
While the reactor requires energy, Rochefort and his students have figured out to use solar energy to power it. He created the design to help undeserved and island communities facing barriers to import fuels or access off-island recycling systems. Making it self-sustainable is a major goal.
Making it farm-ready
While the research is exciting, there is more research to be conducted prior to use by the onion farmers, such as making the units simple and safe for farm workers in the field or testing the blended diesel fuel.
Yano, who has a degree in agricultural engineering, explained that “one of the challenges in agricultural technology is how you cope with dust and dirt.” However, Rochefort mentioned that one advantage of the pyrolysis technique is that it is very robust, so dirt is not a problem and simply ends-up as bottom product in the reactor.
Ellis, Rochefort, Reitz and Denny secured a $25,000 transdisciplinary seed grant to launch a pilot program to apply the pyrolysis research to agricultural and Malheur County’s needs.
While Denny isn’t an expert in onions, plastic or pyrolysis, she says, “I’m here to make connections, support innovation, and get momentum.”
Rochefort’s students demonstrated the technology for local growers at Malheur Experiment Station Field Day on July 10. The event was impactful for everyone involved.
“Usually when we present this research, our audience has less of a personal connection to the plastics issue,” said student Abbie Marshall. “The people at this presentation have the problem directly in their backyard and community at large.”
Growers were amazed by the research, as well. “A grower came up to me and said, ‘Why the heck did we not know about this before?’ They were just very excited that it was an option,” said Reitz.
Rochefort’s team met with Malheur growers after the field day to guide their next steps.
“This was just the beginning of our interaction with those farmers,” said Rochefort.
Yano and four other Malheur County onion growers have agreed to host a pilot pyrolysis unit on their farms. “I expect there's to be some growing pains,” he said, “But I'm encouraged. There's a lot of smart people out there that can work on these problems.”
