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Tuesday, February 26, 2019 

Japanís Ministry of Land, Infrastructure, Transport and Tourism (MLIT) presented a paper on the quality of washwater discharges from open-looped SOx scrubber systems to IMOís recent PPR6, concluding that Japan is unlikely to ban use of the system in its waters.

The paper, based on the results of CFD modelling of a scrubber-operating 82,000dwt vessel, indicated the turbulent wake of the ship dilutes the discharged sulphate to levels that are not expected to cause any short or long-term effects on marine organisms.

“Japan concluded that either any short-or long-term effects on marine organisms cannot be caused by the use of open-looped scrubber,” says the paper’s authors, going on to state that actual amount of heavy metals in the discharge water from scrubber “were substantially less than the emission standard for on land sources in Japan, by order of 100”.

MLIT concluded the use of scrubbers can mitigate against potential risks to human health by reducing SOx and particulate matter, PAHs and other materials that would otherwise be emitted into the atmospheric air.

“Japan is of the position that there would NOT be a scientific justification to prohibit the use of open-looped scrubber, as long as the IMO’s discharge criteria were met,” concluded the authors.

The MLIT study coincided with the results of a three-year study led By Carnival Corporation in to the quality of the washwater from 53 EGCS-equipped cruise ships. The results compared favourably with national and International water quality standards and land-based wastewater discharge limits, including the German Waste Water Ordinance, the EU Industrial Emissions Directive 2010/75/EU, and the EU Surface Water Standards Directive 2013/39/EU.

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