KTH Develops New Method to Combat Algal Bloom, Tests Planned in Gotland Waters

When the water reaches a decent temperature of up to 20 degrees for swimmers in the summer time, the algal bloom arrive and cyanobacteria settle like a thick blanket on the surface. And every summer, there are warnings about ingesting the water with blue-green cyanobacteria that can make both humans and animals sick.

“This is a method that can really benefit society if it works,” Gröndahl says, explaining how the clean-up will be carried out:

The greenish sludge is captured with the help of bilges, which are also used in oil spill clean-up, and which are trawled over the water surface. The bilges are covered with a fine-mesh cloth, known as wire mesh, which is used in the wood industry to trap the cyanobacteria.

“Otherwise they are just whisked away to the side, and are still around. “

Can become biofuel

Another part of the algae remediation project is to collect the algae and analyze them to see how they could be reused as biofuel, for example.

“The cyanobacteria contain valuable things,” Gröndahl says, “and we will also try to utilize them in the project.

A third part of the work is to send underwater robots built at KTH under the algae cover to see what life looks like and how the Baltic Sea is doing underneith the surface.

If successful, the method could have major consequences around the world, as algal bloom is a major problem in many countries, affecting water quality and bathers.

“The bottom of the Baltic Sea has no oxygen. If we can capture biomass, we can help the sea to feel a little better,” Gröndahl says.