Coast Guard ruling extends uncertainty over treatment of ballast water


The latest U.S. Coast Guard decision on ballast water management systems (BWMS) leaves vessel owners in uncertain waters.

In May, the Coast Guard issued the results of a review to determine if technology existed to achieve a significant improvement in ballast water treatment efficacy. The Coast Guard determined that “there are no data demonstrating that ballast water management systems can meet a discharge standard more stringent than the existing performance standards.”

That failed to clarify the issue for many in the shipping industry who are unsure how to proceed on BWMS. Vessel owners fear investing in a system type approved by the International Maritime Organization (IMO) that would not then meet Coast Guard approval. Some 60,000 vessels worldwide will be subject to the IMO’s BWM Convention, which will go into effect 12 months after ratification by 30 member states.

One of the major sticking points is the method used to evaluate effectiveness of the systems. Many manufacturers and the IMO use the most probable number, or MPN, which measures organisms that are viable or able to reproduce. By contrast, the U.S. sets limits for the number of organisms that are living in a sample using the vital stain method.

In December 2015, the Coast Guard notified four manufacturers of ultraviolet BWMS that using the MPN was not an acceptable testing method because it does not measure the ability of the systems to kill organisms. The manufacturers filed appeals that were rejected by the Coast Guard in July.

An industry group has established a website,, to advocate the use of the MPN. 

The organization points out that at this time, there are no Coast Guard type-approved systems that will meet the new regulations in a final rule published by the USCG in 2012. A provision was added to allow vessels that installed systems before the IMO’s regulations come into effect to operate in U.S. waters, but it is only good for five years after the vessel is required to meet those rules.

The U.S. and IMO discharge standards are the same, but the procedures for type approvals are different. Industry experts fear a situation in which a system installed in a vessel is approved by the IMO but does not meet U.S. requirements.

Manufacturers that produce UV treatment systems are advocating the MPN method, which is used by numerous landside water treatment systems in the U.S. and other countries. The UV systems do not kill the organisms but damage their ability to reproduce, effectively rendering them harmless.

“We’re talking about achieving the same objective but accomplishing it in different manner,” said Mark Kustermans, marketing manager for Trojan Marinex, one of the manufacturers seeking Coast Guard certification for its system. “We’re asking for the regulation to not be biased to any one technology. If the technology can accomplish the same objective, we should be able to do what works.”

In a blog post, Rear Adm. Paul Thomas, assistant commandant for prevention policy, outlined the Coast Guard’s desire to spur innovation in meeting environmental challenges. He called the IMO BWM Convention and the U.S. BWM regulations “stretch goals” to drive investment to meet higher environmental standards.

According to the World Shipping Council, at the present time there is no way a vessel owner can install a system that meets both global requirements because there are no Coast Guard type-approved systems.

“We’re seeing that this market has been put on hold until there is some clarity on what systems will get approved and how the USCG will deal with the MPN issue, which hasn’t been resolved,” Kustermans said

By Professional Mariner Staff