How Ultrafine Nanobubble Technology Benefits Wastewater Treatment Processes

Against the backdrop of rapid industrial development, industrial wastewater is becoming increasingly complex, with prominent problems of refractory organics, high salinity and high organic loading. Conventional treatment processes face challenges of low mass transfer efficiency, incomplete pollutant removal and high energy consumption.

The ultrafine nanobubble generation technology developed by SINOKLE Technology, as a new and highly efficient auxiliary water treatment technology, demonstrates significant advantages in wastewater treatment thanks to its unique physicochemical properties, providing an efficient solution for advanced industrial wastewater treatment. The technology generates tiny bubbles with diameters at the micron or even nanometre scale, achieving breakthroughs in mass transfer efficiency, enhanced pollutant degradation and expanded process adaptability, effectively overcoming the technical bottlenecks of conventional wastewater treatment.

I. Core technical advantages: the unique properties of ultrafine nanobubbles

Compared with conventional bubbles, ultrafine nanobubbles have significant physicochemical advantages that lay the foundation for upgrading wastewater treatment processes:

• Extremely high specific surface area: ultrafine nanobubbles are small in diameter and densely distributed, with a specific surface area per unit volume far exceeding conventional bubbles. This greatly increases the gas-liquid contact area, providing ample interfacial conditions for reactions between pollutants, oxidants and microorganisms.

• Superior mass transfer efficiency: the bubbles rise slowly with a long residence time and have self-shrinking characteristics, continuously releasing dissolved oxygen or other gases into the water. This greatly increases gas solubility and solves the core problem of low gas-liquid mass transfer efficiency in conventional processes.

• Stable existence period: affected by surface charge, ultrafine nanobubbles resist coalescence and can exist stably in water for several hours or even longer, ensuring the continuity and sufficiency of reactions.

• In-situ generation of reactive species: during collapse, ultrafine nanobubbles create local high-temperature, high-pressure conditions that cause water molecules to dissociate, generating strongly oxidising reactive species such as hydroxyl radicals. These species can directly oxidise and decompose refractory organics, strengthening pollutant removal.

II. Multi-dimensional benefits for wastewater treatment processes

1. Enhancing refractory organics removal and treatment depth

For refractory organic wastewater from the pharmaceutical, petrochemical and printing and dyeing industries, ultrafine nanobubble technology strengthens treatment through a dual mechanism:

• abundant dissolved oxygen creates favourable conditions for advanced oxidation processes such as ozonation, improving oxidant utilisation and promoting the generation and transfer of reactive species such as hydroxyl radicals, accelerating the oxidative decomposition of benzene series compounds, antibiotics, chlorinated organics and other refractory pollutants;

• the strong oxidising power of ultrafine nanobubbles can directly attack key structural features of pollutants, avoiding the toxicity enhancement caused by accumulation of intermediate products.

2. Adapting to high-salinity and high-load water quality, expanding process applicability

The high-salinity environment in industrial wastewater (such as reverse osmosis concentrate, with TDS reaching 58,000 mg/L or more) often inhibits the performance of conventional treatment processes, whereas ultrafine nanobubble technology has strong water quality adaptability:

- For high-salinity wastewater, the reactive species generated by ultrafine nanobubbles can effectively decompose chlorinated organics while avoiding the inhibitory effect of salt ions on catalysts or microorganisms found in conventional processes. After several days of continuous operation, stable treatment performance is still maintained, with activity decay far lower than in conventional processes.

- For high organic load wastewater (such as ethylene wastewater from petrochemical enterprises, COD 1500–2000 mg/L), the efficient mass transfer of ultrafine nanobubbles rapidly supplies sufficient oxygen or oxidant to the reaction system, improving COD removal. Compared with conventional processes, introducing this technology raises COD removal from 42% to 83% and benzene series removal from 51% to 95%, greatly reducing the pollutant load.

3. Reducing operating energy consumption and improving process economics

- Conventional wastewater treatment processes (such as ozonation) suffer from high electricity consumption per tonne of water and large oxidant consumption, whereas ultrafine nanobubble technology achieves a dual reduction in energy and chemical consumption through optimised mass transfer efficiency, saving energy and reducing consumption.

- Ultrafine nanobubbles can significantly improve the utilisation of oxidants such as ozone, raising ozone utilisation from below 60% in conventional processes to over 95%, with oxidant consumption reduced by more than 40%.

- Their efficient oxygen dissolution capacity reduces the operating load of aeration equipment and lowers electricity consumption, while reducing chemical dosing, greatly cutting wastewater treatment operating costs and improving the economic feasibility of the process.

4. Ensuring process stability and extending operating cycles

Ultrafine nanobubble technology does not depend on complex catalyst or microbial systems, is little affected by water quality fluctuations, and does not cause secondary pollution such as metal leaching, meeting the heavy metal discharge standard of GB 8978-1996. The technology also reduces pollutant adhesion and scaling in reactors, lowering equipment maintenance frequency and extending operating cycles. Compared with conventional processes, operational stability is significantly improved and service life can be extended to more than 5 years (industry average 2–3 years).

Micro-nano bubbles

III. Conclusion

With core advantages including high specific surface area, strong mass transfer efficiency and broad water quality adaptability, the ultrafine nanobubble generation technology developed by SINOKLE Technology comprehensively optimises wastewater treatment processes across multiple dimensions — pollutant removal depth, process applicability, operating economics and stability.

The technology not only effectively solves the treatment difficulties of industrial wastewater with refractory organics, high salinity and high loads, but also greatly reduces treatment energy consumption and costs. It is in line with green development trends and provides an efficient, sustainable technical solution for advanced industrial wastewater treatment, with broad application prospects.