Ultrasonic Microplastic Separation

The premise is simple in principle, tricky in practice. A standing wave in water creates pressure nodes where particles collect by density. Tune the frequency and the geometry, and microplastics congregate along a pressure minimum that runs the length of the channel. No filters, no consumables, no pressure drop to speak of.

The hard part is sustaining a clean resonance at scale. The chamber wants to couple with its mountings; the amplifier wants to drift; cavitation wants to break symmetry the moment the field gets pushed any higher. Most of the thesis is spent characterising the failure modes, not the successes.