Tuesday, October 22, 2019

Partners Address Noxious Seaweed Problem with Holistic Solutions

Caribbean Region Plagued with Invasive Species
Shipping News Feature

CARIBBEAN – The so far unexplained rise of levels of invasive Sargassum seaweed in the region is being addressed by partners Damen Shipyards and 'waste to value' group, Maris Projects with an attempt to find a truly holistic solution to a problem for vessels in the region and local communities.

The weed is causing considerable problems, aside from the stench it gives off when decomposing, which has led to beach closures, the seaweed also clogs the engines and nets of fishing vessels. Additionally it is also smothering sea grasses and coral reefs as well as releasing greenhouse gases as it decomposes. Whilst an essential habitat for creatures in the Sargasso Sea, changes in water chemistry are blamed for this huge expansion.

In July scientists described the growing problem as ‘the biggest seaweed bloom in the world’, with an estimated 20 million tonnes stretching over 5,500 miles. Recent years have seen a significant increase in the problem and the work of the two companies is expected to greatly increase knowledge of bioprocessing, leading to the design of efficient and scalable technologies with the capability to deliver both environmental and socio-economic benefits.

To attempt to find a solution, Damen Green Solutions has partnered with Maris. Damen’s role in the partnership is to develop a dedicated solution based on a specially developed MultiCat for harvesting, pre-processing and transportation Sargassum. Maris brings experience in scalable pre-processing and anaerobic conversion technology. With this, the consortium is assessing the viability of turning the Sargassum into methane for energy purposes.

The two partners have identified a local operating partner, CMC, that can harvest the seaweed in Martinique and Guadeloupe. Currently, the partners are discussing a contract that will create the consortium to be known as Blue Caribbean Energy Solutions. The consortium aims to collect and purify Sargassum, then turn it into biogas via a two-step process using low temperature anaerobic digestion as the first step. The residues of this process will then be fed into a high temperature anaerobic thermal reactor to turn them into usable methane. Damen Green Solutions director Marcel Karsijns explains:

“Currently, the solutions to the Sargassum challenge only go as far as removing the weed from the sea. Often it is brought onto land and left to decompose, where it gives off damaging greenhouse emissions. What we are attempting to do is develop a holistic, circular solution that turns a negative into a positive. As well as offering clean energy, the aim of the project is also to deliver sustainable benefit to local economies.”

As well as the short term aim of turning Sargassum into energy, the partnership will consider the economic viability of turning the harvest into fertiliser and/or feedstock for the agriculture industry and will present the developments of their solution thus far at the forthcoming The Decade SARG EXPO between 24 and 26 October in Guadeloupe.

Photo: A decaying swathe of weed stretches, decomposing, along a Martinique beach.