The Sargassum seaweed plague is increasingly affecting coastal areas in the Caribbean region causing wide spread economic and ecologic damage. The tourist sector is hit hard and complete bays included corals and other sealife are destructed by layers of sinking and rotting seaweed.

The Response to this phenomenon requires a combination of expertise’s. First, to prevent the seaweed from arriving to the shores, an intelligent reconnaissance technology is needed for early identification of the off-shore Sargassum fields heading to the coast.

Secondly, specially designed vessels are needed for the harvesting and also for preprocessing of fresh Sargassum and for cleaning up Sargassum that have already sunk close to the shore and in the bays.

The next step is to turn the problem into an economic viable activity that contributes to the economy of the region. This is achieved by developing and testing scalable and economically viable valorization technologies like turning the seaweed into biogas.

seaweed solution - step 1

Harvesting & Packaging

Harvesting & Packaging

Sargassum is found floating as well as sunken on the sea bed. In order to valorize it, it should be removed from the water first. Damen has a long history in research and development as well as commercializing dredging equipment for removing (contaminated) soil from the bottom and transporting it. The vessel design for harvesting the seaweed will be flexible and capable of harvesting from the sea bed as well as floating Sargassum.

The design will be modular and dismountable to relocate the vessel quickly to other places where Sargassum forms a problem. The modularity of the vessel makes it possible to increase it in size and capacity when needed in the future The vessel will can be equipped with spud poles for dredging operations to reach the seaweed on the bottom and also have propulsion to reach floating seaweed beds.

Sargassum is a natural phenomenon and therefor sometimes present abundantly and in other times or seasons scarce to be found. In order to feed a constant production process to make biogas, storage is a necessity. To stop the rotting process and to conserve the seaweed, bacteria’s are directly added on board after harvesting and the seaweed is packed in bales. These bales are shipped to the shore.

seaweed solution - step 2

Digestion & Conversion

Anaerobic digestion & Thermal conversion

From Seaweed to Biogas will require a two-step approach. First we will digest the relatively easily to digest molecules using anaerobic bacteria. After that the remaining, more complex to digest hydrocarbons, will be fed into an anaerobic thermal convertor. This two-step approach is the most economical way to produce a maximum amount of natural gas from the Sargassum.

The remaining from the biomass digester will be put in a thermal convertor and heated without oxygen until the Sargassum disintegrates. The residual flows will be gas and ash. The first pilot plant of a thermal convertor is build and operational in the Netherlands where it successfully makes diesel and gas from plastics and CNG from biomass. This technology is available for testing with Sargassum.

With Maris’ experience we have state-of-the-art knowledge and know-how available to our consortium we expect that after the digester and thermal conversion steps a percentage of the input will remain as ash. Depending on the chemical composition of the ash it can be turned into valuable components such as activated carbon, fertilizer, bio coal or filler for building materials. Post-processing of ashes will focus on the cost-effective production of high value components and safe immobilization and deactivation of heavy metals and other hazardous components.

Maris Projects has ample experience with upgrading of ashes from other organic feedstocks. Sargassum is new and its ashes need to be thoroughly tested, but on the bases of our current knowledge we are confident that the ashes can be turned into valuable products and that this can generate additional benefits to the Caribbean islands.

seaweed solution - step 3

Biogas to Products

Biogas to products

Biogas can be bottled and used for local use or be used a fuel for a generator set to provide a flexible and green solution to local electricity grids. Most island burn fossil fuels to power their grid and are looking for cleaner solutions.

More about Maris Projects

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The key activities from Maris Projects B.V. are processing waste to valued products. This has been our key activities for a long period. In the last years we gained experience especially in waste to bio-fuel and sub-products process, well before processing waste became fashionable and well before the carbon markets came into being. Therfore in 2004 Maris Projects B.V. and Maris Machines B.V. is created. Maris Projects B.V. main focus is on projects and problem solving for our clients. Maris Machines B.V. main focus is giving used machines a second life.

Maris Projects company website


Damen customer finance

Damen Customer Finance offers a wide range of financing arrangements. These are available for any type of vessel, equipment or related services, including the prefabricated shipbuilding kits supplied by the Damen Technical Cooperation department.

Damen’s Customer Finance facilities are not just for privately-owned, small and medium-sized companies, we also assist government bodies such as coastguards, police and port authorities. Damen maintains relations with all Netherlands-based commercial banks, as well as with numerous banks abroad. As a major client of the Dutch Export Credit Agency, Atradius, Damen is highly experienced in arranging export loans with export credit insurance facilities.

24/7 Spares & Services

Damen Parts Services offers competitive prices, efficient and cost-effective delivery and short response times. With our years of experience we have established strong buying power and an extensive supplier network. By expanding our network of global service hubs, we are able to shorten our response times. Our service goes beyond fast part delivery; we also offer different replenishment solutions resulting in having parts in stock just before you need them.

To minimise lifecycle costs and to improve a vessel’s performance, it’s crucial to have the right spare parts. Our Computerised Maintenance Management System (CMMS) allows stock control replenishment to be completely automated.



To support our customers on a 24/7 basis, Damen has created an online parts store on our Services Portal Here you can order directly from our online catalogue of spare parts. Our scope of supply is neither limited to Damen-vessels only, nor to the catalogue. If your required parts are not available online, we invite you to make online requests. Your services manager will gladly do what it takes to source the relevant component. With Damen as your partner you can experience the benefits of a one-stop-shop.


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