The technique, developed at the University of Sheffield, builds on previous research in which microbubbles were used to improve the way algae is cultivated.

Algae produce an oil which can be processed to create a useful biofuel. Until now however, there has been no cost-effective method of harvesting and removing the water from the algae for it to be processed effectively.

But a team led by Professor Will Zimmerman in the university’s department of chemical & process engineering believe they have solved the problem by devising an inexpensive way of producing microbubbles that can float algae particles to the surface of the water.

This not only makes harvesting easier, but should save biofuel-producing companies both time and money. The system developed uses up to 1,000 times less energy to produce the microbubbles and the cost of installing it is predicted to be much less than existing flotation systems.

Previously Professor Zimmerman and his team won recognition for their earlier work which used microbubble technology to improve algae production methods, allowing producers to grow crops more rapidly and more densely.

“We thought we had solved the major barrier to biofuel companies processing algae to use as fuel when we used microbubbles to grow the algae more densely,” said Professor Zimmerman.

“It turned out, however, that algae biofuels still couldn’t be produced economically, because of the difficulty in harvesting and dewatering the algae. We had to develop a solution to this problem and once again, microbubbles provided a solution.”

The next step in the project is to develop a pilot plant to test the system on an industrial scale. Professor Zimmerman is already working with Tata Steel at its Scunthorpe site, using CO2 from the flue-gas stacks, and plans to continue this partnership to trial the technology.

Maxine Perella

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