New milestone for NIVA: Meets American requirements for ballast water management methods

After NIVA was officially approved by the US Coast Guard and DNV-GL as a test facility subcontractor for ballast water treatment in March this year, NIVA’s ballast water team has worked intensively with Optimarin, a Norwegian provider of technology based on filtration and UV-treatment of ballast water. In November they had a breakthrough.

The International Ballast Water Convention, adopted by the International Maritime Organization (IMO) in 2004, has for several years been near ratification and is now about to be realized. The convention will enter into force one year after it has been ratified by 30 countries – representing 35 percent of the world’s ballast water tonnage. Norway approved the convention in 2006 and there is hope that the convention will be ratified in 2015.

The US government has chosen to set their own requirements for ships operating in US waters. These requirements have forced ship owners to comply with the regulations of the US Coast Guard (USCG) as well as the upcoming ratification of the IMO Convention.

Viability versus vitality

The challenge has been that where the IMO’s accepted enumeration method of living organisms in ballast water identifies the cells being able to multiply after treatment (viability) – by the so-called culture method – the United States requires the use of living cells enumeration method that identifies the organisms as immediately dead post water treatment (vitality)- by the so-called staining method.

This is a problem, especially for ballast purification equipment with ultraviolet radiation (UV) as an important component. UV acts primarily by damaging DNA, with relatively large doses of UV needed to instantly kill an organism – but significantly less is required to stop the organism’s ability to reproduce. This is the basis of the UV method of ballast water treatment; an organism which is unable to reproduce is not considered an ecosystem threat.

Using an UV dose that kills instantly would require so much energy that it – until recently – was unrealistic to use such equipment aboard boats to treat many hundreds or thousands of cubic meters of water per hour.

It is therefore with great joy and relief that NIVA has now succeeded in showing – for the first time – that Optimarin’s UV-technology now also meets USCG requirements.

– USCG unconsciously closed the market for UV-technologies because they require the use of a staining method that overestimates the number of living organisms after UV treatment – the so-called “false positive”, says Stephanie Delacroix, researcher at NIVA and head of NIVA’s ballast team.

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