Combating harmful algal blooms

19th Oct 2020
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COMBATING HARMFUL ALGAL BLOOMS

How our solutions are combating harmful algal blooms for water-link in Duffel, Belgium

Climate change scientists predict that as the world’s temperatures continue to rise, we will see a number of effects on our freshwater and marine environments. These effects, along with nutrient pollution, has the potential to cause harmful algal blooms to occur more often, in more waterbodies and to be more intense.

These algal blooms can have several severe impacts, including destroying aquatic environments, contaminating surface and groundwater reserves, and disrupting drinking water supplies. They can be caused by a variety of reasons, such as the concentration of nutrients increasing in water bodies during dry periods, or even when there is heavy rainfall, large amounts of sediment can be flushed into water systems.

Both events are becoming increasingly common due to climate change, while the use of synthetic fertilisers in agriculture, increased sewage due to population growth and extensive livestock farming, are all contributing risk factors.

At Ecocoast, we were recently tasked by a client with finding a way to resolve an algal bloom issue they were having, on a reservoir in Belgium. This was for a client called water-link, who asked us to help them come up with a solution to prevent the migration of light blue algal blooms towards a raw water intake.

Gregory Duquennois, Ecocoast Agent
G. Duquennois

“I had contact with water-link two years ago about this problem on a big water reservoir in Duffel, Belgium. Every year, on the water reservoir, they get blue-green algae, and it can be for a few days, or even a few weeks, as it depends on the weather, the temperature, etc,” says Gregory Duquennois, our agent in Belgium.

“The problem is that the very small filter units (installed at the raw water intake) couldn’t cope with the large amounts of algae, and because drink water distribution must be maintained at all times, they had to put a lot of effort into keeping the plant running in those periods,” he explains.

Therefore, in order to combat the problem, in August this year it was decided that a floating boom be installed on the 7-metre-deep reservoir to help filter out the algae and allow clean water to flow into the intake.

“The idea was to put a triangle form before the water intake to keep out the algae and to pump out the floating algae, which would collect to the shore and in front of the barrier. At first, I proposed a Bolina PDB-600 boom, but because the Bolina boom doesn’t have a screen, we went for another solution.”

“As Bolina is now part of the Ecocoast family, I was able to propose an Ecocoast solution. The material is much lighter and has the needed draft of around one metre,” Duquennois explains.

Combating harmful algal blooms

The Ecobarrier Solid Flotation Booms used on this project were the ESFB-1060, which can be deployed in a variety of water environments, ranging from low to moderate and high currents.

These general-purpose booms can provide years of performance and are made of UV stabilised PVC membranes with chain ballasts, grab handles and anchor points, making them very easy to install. They are available in different sizes and tensile strengths.

All material for the boom project was provided by Ecocoast, with Duquennois doing all the coordination and proposals with the client. Installation was carried out by the Dutch contractor, Boeren BV, who does all Bolina booms installations, he adds.

The deployment of the boom was a huge success, Duquennois says, highlighting that this year, the blue-green algae bloom was not a big issue for water-link as the barrier has done its job.

“In fact, water-link has even bought an additional 25-metre barrier to collect algae by two small boats but weren’t able to test it this year. They intend to remove the barrier in winter and will only install it again the next summer.”

“If it works well next year, then they intend to install this system on other reservoirs,” he states, adding that a 100-metre and 50-metre boom from Bolina were also installed on two other reservoirs.

“This was not for blue-green algae, but to counter waterweed. This performed well and I expect a request for three other projects next year,” he concludes.

If you would like to discuss algae bloom or waterweed solutions, please contact us if you need any further information or have any questions. We’re here to offer you advice on any marine problem you encounter.