Carbon dioxide: the answer to membrane biofouling?

The fouling of membranes is an ongoing concern for the water sector but a collaboration between Dutch drinking water company Vitens and WE Consult claim that C02 could hold the answer...

The fouling of membranes is an ongoing concern for the water sector but a collaboration between Dutch drinking water company Vitens and WE Consult claim that C02 could hold the answer.

Instead of using chemicals for cleaning, the partnership claimed that by cleaning the filters with a mixture of water and C02 (carbon dioxide) the filters are effectively scrubbed clean by small bubbles.

In contrast to air, C02 is easily soluble in water, as a result of which air-locking is no longer an issue, they said.

Joint owned by Vitens and WE Consult, the process takes 15 minutes and is claimed to increase the lifespan of the filters.

In a statement the companies said: “Membrane filters are currently cleaned throughout the world with chemical products, such as caustic soda and citric acid. The cleaning process takes hours and consequently delays operations. Furthermore, the filters never become 100% clean, as a result of which product quality deteriorates and the membrane filters require more frequent replacement.”

Bas Rietman, process technologist, said: “In effect we are rinsing the membranes with champagne. Indeed, that is also a mixture of carbon dioxide and water…the length of time that our business process is down is reduced".

The innovation was in part made possible by an ‘innoWATOR’ grant provided by NL Agency. The innovation came about in partnership with the University of Twente, RWB Water Services and WE-consult.

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