If you’ve been following developments in flotation technology, you’ve probably started hearing more about aphron microbubbles. This post explains what they are, where the science comes from, and why they represent a meaningful advancement in how flotation systems remove solids from water.
The Physics of Standard Flotation
In a conventional dissolved air flotation (DAF) system, bubbles are generated by dissolving air into water under pressure, then releasing that pressure at the point of contact with the wastewater stream. The rapid pressure drop causes dissolved air to come out of solution as microbubbles, which attach to suspended particles and float them to the surface.
This works extremely well — and has for decades. But the bubble population produced is governed by the laws of gas solubility: Henry’s Law dictates how much air can dissolve at a given pressure and temperature. The result is a useful but physically bounded bubble generation mechanism.
What Makes Aphrons Different
Aphrons are a class of microbubble first described by Dr. Felix Sebba in the 1970s. Unlike pressure-release bubbles, aphrons are generated atmospherically — without pressurization — through high-shear mechanical action that encapsulates air in a thin liquid film, producing a stable, charged microbubble froth.
Two properties make aphrons particularly interesting for flotation:
Stability. Aphron bubbles resist coalescing significantly longer than conventional microbubbles. This extended lifespan means more bubble surface area remains available throughout the flotation zone.
Electrostatic affinity. The liquid film surrounding an aphron carries a surface charge. This charge creates an electrostatic attraction between the bubble and oppositely charged suspended particles — enhancing attachment efficiency beyond what physical collision alone achieves.
What This Means in Practice
The practical implication is a more efficient bubble-to-particle contact mechanism. For applications involving fine suspended solids, emulsified oils, or highly variable loading conditions, the additional attachment efficiency aphrons provide can meaningfully improve removal rates.
This doesn’t make conventional DAF obsolete — far from it. What it opens up is the possibility of combining the proven performance of dissolved air flotation with aphron bubble augmentation to address the applications where standard DAF is working hard but could be working better.
In our next post, we’ll explain exactly how Tenco Hydro has integrated a third-party aphron generator into our DAF platform — and what that means for system sizing, energy use, and performance.