Japanese shipping company Mitsui O.S.K. Lines (MOL) and compatriot manufacturer of industrial boilers and related equipment Miura have developed a new centrifugal-type microplastic collection device, which can continuously collect microplastic while a vessel is underway.
The device is based on the technology and knowledge of an earlier microplastic collection device , which was co-developed by the companies in 2020.
As described, the collection device captures microplastic and traps it in a filter with a backwashing function, which constitutes the ballast water treatment system.
It was installed on a total of five vessels, three of which were bulk carriers and two wood chip carriers.
While these vessels were at unloading ports, the systems treated a total of about 16,000m3 of seawater. The development of this new model was intended to further increase treatment times, area, and capacity, MOL said.
According to the developers, the new microplastic collection device was installed on the MOL-operated car carrier Emerald Ace last month for a demonstration test.
The addition of a centrifuge allows the new device to efficiently separate floating microplastics from concentrated seawater with a high density of floating debris, without closed plumbing.
This enables it to treat 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, which was limited to a part of treatment in the previous device, the developers explained.
By installing the device in Emerald Ace, microplastics can be continuously collected while sailing, by connecting the system to the cooling seawater line, which always draws in seawater. This is said to give the system an annual seawater treatment capacity of about 70 times that of the previous device.
As car carriers operate all over the world, the vessel contributes to the conservation of the marine environment by cleaning all sea areas while operating this device, MOL claims.
Going forward, MOL intends to take into consideration data such as components, amounts, places, and periods of microplastics collected with the device for future research.
On the other hand, Miura is moving ahead with the 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 microplastic collection device and cooling seawater.
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