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Tiny Bubbles, Big Results: Nanobubble Technology: An interview with Dr. Zhang by Jolene Hansen. Jolene Hansen is an award-winning freelance writer and editor who has covered the horticulture, specialty ag and CEA industries for more than a decade. Reach her at [email protected]. See all author stories here.
Any time new technology comes into play in controlled environment agriculture (CEA), growers tend to balance optimism with skepticism. It’s an industry where the adage “seeing is believing” often applies. That attitude puts nanobubble technology at a distinct disadvantage.
Typically defined as measuring between 70 and 120 nanometers in diameter, nanobubbles can’t be seen with the naked eye. With one nanometer (nm) equal to just one billionth of a meter, nanobubbles are 2,500 times smaller than a grain of salt. But the visible results experienced by nanobubble researchers and CEA growers put these tiny workhorses in the limelight.
Due to their size, nanobubbles have qualities that regular bubbles can’t match. | Photo: Moleaer
Nanobubbles in CEA
Nanobubbles occur in nature, but technology has enabled nanobubble suppliers to recreate or even improve on nature’s work. Nanobubbles have made headlines in non-agricultural realms ranging from biomedical applications, such as drug delivery and cancer diagnostics, to environmental applications, including toxic algae bloom mitigation and wastewater treatment. But for CEA, and agriculture in general, the technology is still relatively new.
The CEA application at the forefront involves treating irrigation water with nano-size bubbles containing air or specific gases, such as oxygen, ozone or nitrogen. Both the gas involved and the bubble size vary, depending on the application and the nanobubble technology involved. For example, generators from U.S.-based nanobubble supplier Moleaer, who has more than 3,500 installations in 55 countries in a variety of industries, produce nanobubbles roughly 100 nm in size.
Professor and environmental engineer Wen Zhang, Ph.D., is director of New Jersey Institute of Technology’s Sustainable Environmental Nanotechnology and Nanointerfaces Laboratory. Dr. Zhang has conducted extensive nanobubble research, including CEA applications. He also holds the patent on an award-winning nanobubble generator brought to market through PureNanoTech, Inc. (PNT).
Dr. Zhang explained that, by virtue of their size, nanobubbles have qualities that regular bubbles can’t match. For example, rather than quickly rising to the surface and popping, nanobubbles remain suspended in water and stay in constant motion for as long as they persist.
Depending on the gas contained in the bubbles, nanobubbles can deliver the following benefits:
- significantly enhanced germination rates
- stable, increased dissolved oxygen levels
- improved nutrient uptake and utilization efficiency
- improved irrigation efficiency and water management
- increased beneficial microbial activity
- increased resilience to stress and disease
- reduced biofilm and pathogen pressure
- dramatically improved yields, and much more.
Justin Leavitt, Business De velopment Manager for Moleaer, shared that it’s often difficult for growers to grasp the breadth of the impact nanobubbles in irrigation water can make.
“Anytime you change your water, you change everything that that water touches,” said Leavitt, a hands-on grower himself, who has worked in horticulture for more than 15 years. “Very rarely do we get the opportunity to make a change that creates such a domino effect, that touches so many other inputs and parts of your business.”
As Leavitt noted, with so many aspects of cultivation impacted by any major change in water and water treatment, growers have a lot of checks to go through to understand how a technology like nanobubbles fits in their operation. Making use of the expertise of nanobubble researchers and industry leaders can help.
Side-by-side comparison of leafy greens grown without (L) and with (R) nanobubble technology. | Photo: Moleaer
Solving Grower Pain Points with Nanobubble Tech
In working with CEA growers, Leavitt shared that he stresses the “three p’s” — pathogens, production and profitability. As he points out, with food safety a priority, the tools CEA growers have to fight pathogens are limited compared to the chemical fungicides used in other markets. That distinction calls for a different approach, one where nanobubbles can help.
“Typically, when growers think about fungicides, they’re applying fungicides to the plant. So if a pathogen goes through the water and interacts with the plant, you hope that your fungicide is working well enough,” Leavitt explained. But with nanobubble technology, you can improve water quality at the source, creating an environment environment hostile to and reducing pressures from pathogens, including Pythium, before the water even touches the plant.
Production and profitability go hand in hand. For example, oxygenation and providing high amounts of dissolved oxygen through nanobubble treatments can significantly impact yields — while maintaining and/or improving other crop performance parameters and quality overall.
“Technology has unlocked this new class of science,” Leavitt said, noting that growing today is very different from a decade ago. “We’re able to transfer gas significantly more efficiently than what was possible in the past. So now we have to relook at things.”
In the past, Leavitt said, growers were happy with results when plants received 8 parts per million (ppm) dissolved oxygen. But technology — and people’s expectations — have changed. What happens when innovation enables you to provide 12, 15, 20 or even 30 ppm dissolved oxygen? “What we’re seeing is increases in yield by supplying higher levels of dissolved oxygen,” he added.
Dr. Zhang reported that CEA research revealed dramatic results with his nanobubble generation technology, which simply employed ambient air to produce nanobubbles in water for irrigation. In a trial with basil and parsley production at a commercial CEA grower in New Jersey, plants that received irrigation water with air nanobubbles for three weeks before harvest had significantly improved results.
Compared to the control plants, the dry weight of parsley increased more than 68% with nanobubble-infused water. With basil plants, dry weight increased more than 58%, along with a 34%+ increase in the number of leaves. In other research, Dr. Zhang found that germination rates increased up to 25% with water infused with air nanobubbles. With nitrogen nanobubble infusion, vegetables saw leaf and stem sizes increase up to 50%.
Exploring Nanobubble Technology and Suppliers
As results like these become more well known, entries into the nanobubble generation market are growing. Dr. Zhang worries that, because some of this technology is good and some is not, growers can become confused and miss out on the competitive advantages that nanobubbles can bring to their farm.
Dr. Wen Zhang
As a result, Dr. Zhang says, it is essential to be able to work with companies that have the research capacity to demonstrate and confirm the claims or value propositions they present to customers regarding plant yields, water quality, and other nanobubble benefits for CEA growers.
Moleaer and PNT both have sizable in-house R&D resources and work closely with third-party research firms or institutions and growers to explore new applications and validate results. Even with Moleaer as a global leader, both in agriculture and other markets, Leavitt stressed that due diligence in exploring suppliers and trialing nanobubble generators is crucial.
“Be wary of your nanobubble generator supplier, and treat this like an interview,” Leavitt said. He advised growers to ask companies for third-part validation of the equipment they offer, and ask for validation from customers who have benefited from their specific nanobubble technology. He also adds that nanobubble knowledge isn’t the only thing to consider.
“Your nanobubble supplier should not just know about nanobubbles. If you’re in horticulture — if you’re in deep water culture lettuce, if you’re growing tomatoes, if you’re growing petunias — your nanobubble generator supplier should know about those industries, “Leavitt said. “Because there’s a product and there’s a technology, and that is one half of the battle. But your nanobubble supplier should know your industry well enough to make sure that you know all the domino effects of how this will change your operation.”
Leavitt also encouraged growers to not dismiss nanobubbles because your facility is already high tech. He shared how one CEA grower questioned whether his greenhouse — already heavily invested in technologies including oxidizers, an ozone system, and climate control — could benefit from nanobubble generation. But a trial delivered significant yield increases, despite all the agtech already in place.
“I walk into high-tech greenhouses, and we see great environmental controls; we see excellent lighting. I really think that taking a look and adding oxygen nanobubbles to your water is really that next stone that you need to turn over to continuously increase yield,” Leavitt shared. He added that with advances in technology and transfer efficiency, the barriers of 10 years ago no longer exist.
