Biofouling is the build-up of living organisms on a surface in contact with seawater. It can reduce performance of technological solutions such as OTEC. Ozonation is a chemical water treatment, which is already well known to neutralize biofouling. Over the course of the SIMBIOSE project, we aim to refine our ozonation process to limit the environmental impact.

How do we use ozonation?

When injected into seawater, ozone acts upon the microorganisms to prevent the formation of a biofilm on the machinery. To generate ozone, ambient air is passed through a molecular sieve of an integrated oxygen concentrator to produce a gas rich in oxygen. This gas is then injected into an ozone generator, which uses an electrical discharge. The final gas produced contains 90-100% dioxygen and the rest is ozone. A power potentiometer at the front of the generator adjusts this ozone concentration as needed.

What will we study in SIMBIOSE?

Preliminary tests using ozonation were very promising, producing only low levels of unwanted by-products. However, the only equipment currently available remains a laboratory-scale system. Hence, the technology requires regular human intervention to make adjustments. During SIMBIOSE, we aim to automate the equipment that could be used for ozonation at a larger, commercial, scale.

In addition, we could test the use of ozonation in combination with an exopolysaccharide produced by marine bacteria. This biopolymer acts as a surfactant, preventing adhesion of the microorganisms to the metallic surfaces. A combined approach could increase performance of ozonation as a biofouling treatment solution.