Gwyneth Perseveranda

Bubbles, the light orbs often seen in soaps, function as more than just an entertaining sight for kids.


Researchers from Oxford Brookes University pioneered a machine which uses bubbles to combat the contamination of global water supplies with toxic chemicals.

In the study titled, “Removal of per- and polyfluoroalkyl substances (PFAS) from wastewater using the hydrodynamic cavitation on a chip concept” the team developed a machine called hydrodynamic reactor, an eco-friendly and low-cost water treatment solution.

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals which persist in the environment and human body, hence the nickname forever chemicals.

Since the 1930s PFAS have been widely used in manufacturing products that need to resist water, grease, oil, and heat.

These products include teflons, food packagings, firefighting foam, and stain-resistant carpets and furniture.

PFAS do not break down easily and remain in water, soil, and living organisms for decades.

Additionally, the chemicals that have been stored in the body for a long time may induce severe health risks.

“Once contaminated water is released into rivers, lakes and seas, it eventually infiltrates our public water supplies, including our domestic drinking water,” Professor Iakovos Tzanakis, the lead researcher said.

“Our challenge has been to find a way of effectively treating water to remove PFAS chemicals sustainably and at a scale,” Tzanakis said.

The hydrodynamic reactor eradicates toxic PFAS and works via a process called cavitation.

Cavitation pertains to the process where bubbles form in a liquid due to rapid changes in pressure and then collapse violently.

With the bubbles collapsing aggressively, it generates heat which creates localized high pressures and breaks chemical bonds which contain PFAS.

In this reactor, due to the fast movement of the liquid, the bubbles are created and controlled in small spaces; making the process efficient for water treatment.

The scientists tested the hydrodynamic reactor at the Hammarby Sjöstad wastewater treatment plant in Sweden by processing wastewater containing PFAS.

It was found that the reactor degraded 36% of 11 common PFAS variants in just 30 minutes, and did not even require additional chemicals.

“The results were impressive. We didn’t expect that level of PFAS processing in such a short space of time,” Dr. Morteza Ghorbani, co-author of the study said.

“We are now exploring the fundamental mechanisms of PFAS removal in depth at Oxford Brookes University to better control and optimize the process,” Ghorbani said.