Nanobubbles (NBs) are ultrafine gas bubbles (<200 nm) with unique physics, neutral buoyancy, long term stability (lasting days to weeks in water), high surface-area-to-volume ratio, and charged surfaces. These features enable nanobubble generators to achieve oxygen transfer efficiencies of up to ~85%, substantially higher than conventional coarse-bubble and surface aeration systems (typically 5–25%) as well as most fine-bubble diffuser systems (typically 20–35%).
Upon formation, NBs gain a negative surface charge and remain suspended in water via Brownian motion for days or more. Because of their microscopic size, NBs have enormous interfacial area and high internal pressure, leading to efficient gas dissolution. Upon collapse (spontaneously or by stimulation), NBs can produce hydroxyl and other reactive oxygen species (ROS) that effectively destroy organic pollutants and microbes.
In aquaculture, NBs (utilizing air, O₂, O₃,.) are applied to raise dissolved oxygen (DO) level and oxidation‐reduction potential (ORP), break down waste, suppress pathogens and significantly improve fish and shrimp growth and survival rates.
1. Mechanisms of Action:
Nanobubbles improve aquaculture systems through several key mechanisms:
Enhanced O₂ transfer: NBs dramatically raise DO levels. Because they remain suspended and dissolve slowly, maintaining high DO concentration even in deep zones. For example, DO levels can be raised by up to 4× (from ~7.7 to 32 mg/L) using O₂-NBs. The high OTE (often >85%) means less O₂ input for the same DO gain. Uniform oxygenation stimulates fish metabolism, yielding faster growth and higher yield.
Gas retention and mixing: Because NBs do not rapidly float to the surface and escape, they keep water saturated longer. This persistent oxygen buffer (“battery” effect) stabilizes DO during high-demand periods (e.g. night-time), aiding animal welfare.
Reactive species and oxidation: Ozone or oxygen NBs collapse to generate ROS (e.g. hydroxyl radicals) that oxidize ammonia, nitrite and organic waste. In practice,
NB aeration enhances nitrification and can lower ammonia/nitrite levels faster than conventional aeration. Sources note NB treatment can remove upto >80% of ammonia from hatchery water. NB-generated O₃ combines the long life of NBs with ozone’s biocidal properties for superior disinfection.
Biofilm disruption and pathogen control: NBs physically scour surfaces like “sandpaper,” dislodging harmful biofilms and pathogens. The charged NB surfaces attract and bind contaminants (e.g. organic sludge, algae, microbes), lifting them to the surface. In addition, ROS from NB collapse rapidly kills bacteria and viruses. These effects reduce disease incidence and allow lower antibiotic/chemical use, as observed in shrimp trials.
2. Empirical Evidence (Water & Animal Outcomes):
Studies (lab and field) largely report positive effects of NB treatment on water quality and animal performance:
DO and ORP: Nearly all trials report higher DO levels under NB aeration. For instance, Rahmawati et al. (2021) found significantly higher DO in shrimp ponds with O₂-NBs vs a diffuser, leading to 95% shrimp survival. Tekile et al. (2016) showed oxygen-NBs kept water supersaturated for days. ORP typically rises with NB injection, reflecting more oxidizing conditions (important for disease control and biofilter efficiency).
Growth and Feed Conversion: Several experiments show enhanced growth. In one 81-day indoor shrimp pond trial (P. vannamei, 680/m³), O₂ NB aeration doubled total harvest (to ~8.7 kg/m³) and overall productivity while improved average body weight and feed conversion ratios (FCR). Survival reached 95% under NBs (versus lower rates in control). NB-treated fish often have better FCR (e.g. improved metabolic efficiency under stable high DO). One report claimed doubled production and survival using NBs vs diffusers.
Figure: Effects of Nanobubble Technology on Aquaculture Performance and Water
Survival and health: By preventing hypoxic stress and pathogen load, NBs tend to increase survival rates. The above shrimp study saw survival rates go to 95%. NB use in biofloc and RAS systems maintains uniform oxygenation at depth, reducing stress. Moreover, NB-driven pathogen reduction has saved losses (e.g. dramatic Vibrio kill, sea lice removal).
Turbidity/solids: By design, NBs attach to suspended particulates and float them to the surface. This process visibly clears water, with fish farmers reporting brighter, clear pond conditions after integrating NB systems.
Nitrogenous wastes: NB aeration accelerates natural nitrification. Some reports indicate faster ammonia reduction in NB systems (due to the stimulation by nitrifying bacteria) and higher ORP that helps oxidize nitrite and nitrate.
Microbiome and disease: NB aeration fosters beneficial aerobic bacteria (in biofilters/flocs) by supplying constant O₂ and shear. Some studies note shifts toward more nitrifiers and probiotic microbes. Overall, NB systems correlate with lower disease incidence (fewer outbreaks reported in pilot trials).
System Installation:
Nanokriti nanobubble generators are plug-and-play systems that can be easily retrofitted into both new and existing aquaculture facilities. The generator draws water from the system, infuses it with air or oxygen nanobubbles, and returns the oxygen-enriched water back to the culture unit with an oxygen transfer efficiency (OTE) of up to ~85%.
The technology is compatible with a wide range of aquaculture systems, including ponds & tanks, Biofloc Systems (BFT), Recirculating Aquaculture Systems (RAS), hatcheries, raceways, and other water recirculation systems, requiring minimal modifications to existing infrastructure.
Conclusion:
Nanobubble technology represents an effective process enhancement for modern aquaculture by improving oxygen transfer, water quality, and system stability. Its unique physicochemical properties enable sustained dissolved oxygen levels, enhanced nitrification, improved pathogen control, and better utilization of supplied oxygen compared with conventional aeration methods. Across laboratory studies and commercial trials, nanobubbles have been associated with improved growth performance, higher survival rates, increased productivity, and healthier culture conditions in fish and shrimp farming.
As a plug-and-play technology, nanobubble generators can be readily integrated into ponds, tanks, Biofloc Systems (BFT), Recirculating Aquaculture Systems (RAS), hatcheries, and other aquaculture facilities with minimal infrastructure modifications. While performance depends on factors such as system design, stocking density, water quality, and operational practices, current evidence indicates that nanobubbles are a promising and energy-efficient solution for enhancing aquaculture productivity and sustainability.
References
- Nirmalkar, N., Pacek, A. W., & Barigou, M. (2018). On the existence and stability of bulk nanobubbles. Langmuir, 34(39), 11857–11862.
- Agarwal, K., Trivedi, M., & Nirmalkar, N. (2022). Bulk Nanobubbles in Aqueous Salt Solution. Materials Today: Proceedings.
- Yaparatne, S., et al. (2024). Nanobubble applications in the aquaculture industry for improving harvest yield, wastewater treatment, and disease control. Science of the Total Environment.
- Agarwal, A., Ng, W. J., & Liu, Y. (2011). Principle and applications of microbubble and nanobubble technology for water treatment. Chemosphere.
- Jhunkeaw, C., et al. (2021). Ozone nanobubble treatment in freshwater effectively reduces pathogenic fish bacteria and is safe for Nile tilapia. Aquaculture.
- Linh, N. V., et al. (2021). Ozone nanobubbles modulates the innate defense system of Nile tilapia against Streptococcus agalactiae. Fish & Shellfish Immunology.
- Rahmawati, A. I., et al. (2021). Enhancement of Penaeus vannamei shrimp growth using nanobubbles in indoor raceway ponds. Aquaculture and Fisheries.
- Ramiro, B. O., et al. (2024). Nano- and microbubble aeration in a super-intensive biofloc system for Penaeus vannamei. Aquaculture.