Mitsui O.S.K. Lines (MOL) and Miura have developed a centrifugal-type microplastic collection device, which can continuously collect microplastics while a vessel is underway. The new device was installed on the MOL-operated car carrier Emerald Ace last month for a demonstration test.

With the aim of collecting microplastics, which are a source of ocean pollution, MOL and Miura have developed a collection device that collects and traps microplastics in a filter with a backwashing function, which constitutes the ballast water treatment system. This device was then and installed on five vessels: three bulk carriers and two wood chip carriers.

While these vessels were at unloading ports, the systems treated a total of about 16,000 m3 of seawater. The new model that has now been developed and tested on the Emeral Ace further increases treatment times and capacity.

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Characteristics of the new centrifugal-type device

The addition of a centrifuge allows the device to efficiently separate floating microplastics from concentrated seawater with a high density of floating debris, without closed plumbing. This enables it to treat the seawater line, which continually draws in seawater, and even treat the full amount of discharge water after passing through the filter with the backwashing function of the ballast water treatment system. This was limited to a part of treatment in the previous device.

On Emerald Ace, microplastics can be continuously collected while sailing, by connecting the system to the cooling seawater line, which always draws in seawater. This gives the system an annual seawater treatment capacity about seventy times that of the previous device.

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Future development

Today, demand for data regarding the amount of floating microplastics in seawater is growing among research institutes, as this data can be applied to research microplastic movement and measure the effects of various approaches to microplastics reduction. MOL takes into consideration data such as components, amounts, places, and periods of microplastics collected with the device for future research.

Miura is moving ahead with development of the product, which has a larger treatment capacity, and a full treatment system for ballast discharge water by combining a ballast water treatment system and MP collection device and cooling seawater.

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