Ships to become ‘vacuum cleaners’ for seas with Grimaldi & Wärtsilä

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.

Wärtsilä and Grimaldi
Photo: Wärtsilä and Grimaldi

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

To tackle the growing amount of microplastics in the world’s seas, 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.

As explained, the new system requires very little changes to onboard procedure and uses the natural capabilities of an open-loop scrubber to contribute to cleaning the oceans during each voyage.

Currently, a 10-megawatt engine will require scrubbers to process approximately 450 cbm 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/cbm.

“Reducing microplastics pollution in our world’s oceans is an important challenge, and we are pleased to provide a solution for the shipping industry. The idea for this innovative technology originated from recognising that open loop exhaust gas cleaning systems can draw seawater for exhaust scrubbing and simultaneously collect microplastic present in the oceans as part of their normal operation”, 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. We are glad that Wärtsilä also recognises the potential of this system, and we look forward to further collaboration to tackle microplastics in our oceans”.

“Microplastics are a pressing environmental challenge and we’re proud to work together with Grimaldi to tackle cleaning up the oceans. Even more importantly, the ability to capture microplastics shows how scrubbers are a platform for solving a wide range of sustainability challenges – and now even ones that are beyond the stack,” Tamara de Gruyter, President Marine Systems at Wärtsilä, said.

The announcement by Wärtsilä and Grimaldi coincided with the recent move of the the European Investment Bank (EIB), the Agence Française de Développement (AFD) and KfW acting on behalf of the German Federal Government. Together, they have committed to double the target of the Clean Oceans Initiative, which aims to reduce the amount of plastic waste in oceans.

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The initiative is to raise its target to provide €4 billion (around $4.6 billion) of financing by the end of 2025, instead of the €2 billion (around $2.28 billion) initially expected to be reached by 2023.

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