The Breakthrough at Tianjin University

Tianjin University's Micro & Nano Bubble Technology Lab has made headlines with a groundbreaking advancement in aquaculture. Led by researchers including Prof. Tianzhi Wang, the team's micro-nano bubble technology promises to transform fish farming by nearly doubling yields while minimizing environmental impact and antibiotic use. This innovation, with a commercial valuation estimated at 50 million yuan, addresses key challenges in China's massive aquaculture sector, the world's largest producer of farmed fish.

The technology generates stable gas bubbles smaller than 200 nanometers—micro-nano bubbles—that enhance water quality and fish health in ways traditional aeration cannot. Trials have shown dramatic improvements in growth rates, survival, and overall productivity, positioning Tianjin University at the forefront of sustainable higher education research in China.

Understanding Micro-Nano Bubbles

Micro-nano bubbles, also known as nanobubbles, are ultrafine gas pockets with diameters ranging from 10 to 200 nanometers for nano and up to 1 micron for micro bubbles. Unlike conventional bubbles that rise quickly to the surface, these remain suspended in water for days or weeks due to Brownian motion and negative surface charge, preventing coalescence.

Full name: Micro-Nano Bubble (MNB) technology. First defined in scientific literature in the early 2000s, MNBs exhibit unique properties like high gas transfer efficiency (over 85% oxygen transfer), generation of reactive oxygen species (ROS) for disinfection, and promotion of mass transfer in liquids. In aquaculture, they dissolve oxygen supersaturating water without toxicity, a step-by-step process: gas injection under high pressure/shear, bubble shrinkage via Laplace pressure, stabilization by surfactants or ions.

This contrasts with macro-aeration (2-6% efficiency per meter submergence), making MNBs 30 times more effective.

Tianjin University's Pioneering Lab

Established at Tianjin University, one of China's elite C9 League institutions, the Micro & Nano Bubble Technology Lab focuses on bubble nucleation control, generator development, and applications in water production and aquaculture. The lab's "水产" (aquaculture) base supports high-density, antibiotic-free farming, aligning with national goals for sustainable food security.

Prof. Tianzhi Wang and team have published on MNB inhibition of green algae like Chlorella pyrenoidosa, crucial for aquaculture water clarity. Collaborations with industry like INVE Aquaculture at Tianjin University of Science & Technology extend to recirculating aquaculture systems (RAS), integrating nanobubbles for uniform oxygen distribution.

The lab's engineering feats include scalable generators, earning recognition in Chinese journals and international conferences.

Mechanism in Aquaculture Systems

Step-by-step: 1) MNB generators inject air/oxygen/ozone via cavitation or electrolysis. 2) Bubbles penetrate biofilms, elevate dissolved oxygen (DO) to 12-15 mg/L stably. 3) ROS from bubble collapse (hydroxyl radicals) oxidize pathogens, algae, ammonia without chemicals. 4) Enhanced gill function boosts metabolism, feed intake.

In RAS, MNBs reduce biofouling, improve nitrification. For pond culture, common in China, they prevent hypoxia during night/feeding peaks.

• Increased stocking density: up to 50-100% higher without stress.
• Pathogen control: 90%+ reduction in Vibrio, Saprolegnia.
• Water recycling: 30-50% less exchange needed.

Impressive Trial Results and Yield Boosts

Lab trials and field tests show nearly double yields. In shrimp (Penaeus vannamei), oxygen nanobubbles raised survival from 60-70% to 94%, growth 20-30% faster, total harvest up 50-100% via density increase. Fish biomass rose 22% in salmon trials; carp hatching efficiency improved similarly.

Feed conversion ratio (FCR) dropped 15-20%, cutting costs. Disease outbreaks fell 80%, slashing antibiotics. One study: ozone MNB eradicated 100% Saprolegnia/Dermocystidium in eggs.

China's context: 60 million tons annual output, but disease/water issues cost billions. MNBs enable intensification without pollution.

Tianjin University MNB Lab site details demo bases.

Commercial Valuation and Economic Impact

The tech's potential led to 50 million yuan valuation through patents, licensing. Lab's generators scalable for farms, RAS. ROI: energy savings 30-50%, yield gains recoup investment in 6-12 months.

For China, scaling to 1% farms adds millions tons output, billions yuan value, supporting 'Blue Granary' initiative.

Stakeholder Perspectives

Farmers report healthier fish, lower mortality. Experts praise antibiotic reduction amid resistance crisis. Government backs via NSFC funding. Tianjin U positions as ag-tech leader.

• Aquaculture firms: "Transformative for high-density."
• Prof. Wang: Focus on sustainable intensification.
• FAO: Aligns global sustainability goals.

FAO aquaculture resources.

Challenges and Solutions

Challenges: Generator cost, scaling. Solutions: Lab's low-energy designs, govt subsidies. Cultural: Train farmers on tech.

Case Studies from China

In Tianjin trials, carp yield doubled via 2x density, zero antibiotics. Shrimp RAS: FCR 1.2 vs 1.8.

Future Outlook

Lab eyes ozone/hydrogen MNBs, AI integration. Partnerships expand. Revolutionizes China's aquaculture, boosts uni research profile.

Tianjin University's Broader Role

As top engineering uni, TJU drives ag-tech. Links to jobs in research, faculty.

Photo by Spencer Gu on Unsplash