Wärtsilä and Grimaldi unveil new filter system to tackle ocean microplastics

Finnish technology group Wärtsilä and Italian shipowner Grimaldi Group, have unveiled a new system that uses exhaust gas scrubber washwater to tackle the amount of microplastics in the world’s oceans.

According to the association Plastic Europe, 368m tonnes of plastic were produced in 2019 worldwide, and around 3%, or 11.4m tonnes, of this plastic ultimately ends up in the ocean.

Grimaldi has developed and patented a system that filters out microplastics from open loop scrubber washwater.

Wärtsilä, in partnership with the Neapolitan group, will take the microplastics filtration system – which traps plastic particles before the washwater is returned to the ocean – to market. The capability to filter microplastics will be an integrated feature of Wärtsilä’s future wash-water treatment system.

The new system requires very little changes to onboard procedure. Currently, a 10-megawatt engine will require scrubbers to process approximately 450 cu m of water per hour, potentially resulting in a large amount of microplastics being captured from seawater. According to early test results, the microplastics filtration system is efficient in capturing particles smaller than 10µm and the captured concentration by volume equals around 76 particles per cu m.

Emanuele Grimaldi, managing director of the Grimaldi Group, commented: “We have already completed pilot testing of this system onboard one of our vessels deployed between Civitavecchia and Barcelona.

The results are promising, with 64,680 microplastic particles collected on a single voyage between these two ports.”

In Asia, Japan’s largest shipping line, Mitsui OSK Lines (MOL), has detailed recently how the microplastics fished out of the sea via a special device it has developed and installed on one of its woodchip carriers have been converted into energy products not dissimilar to wood pellets. MOL’s microplastic collection device works during operation of the ballast water treatment system.

Sam Chambers

Starting out with the Informa Group in 2000 in Hong Kong, Sam Chambers became editor of Maritime Asia magazine as well as East Asia Editor for the world’s oldest newspaper, Lloyd’s List. In 2005 he pursued a freelance career and wrote for a variety of titles including taking on the role of Asia Editor at Seatrade magazine and China correspondent for Supply Chain Asia. His work has also appeared in The Economist, The New York Times, The Sunday Times and The International Herald Tribune.
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