Symposium on ballast treatment technology

Following the approval of the draft text for a ballast water Convention during the Marine Environment Protection Committee last week, the IMO this week staged a symposium on research and development in ballast treatment technology. This was the second of such symposiums held at the IMO and was seen as essential in gauging the status of advances in treatment technology.

Over the course of three days, five different sessions examined a cross-section of treatment types, the most dominant options being de-oxygenation, filtration, biocides and heat treatment. It was abundantly clear that none of the systems could combat all types of organisms to be found in ballast tanks. Each system in turn had different success rates on different types and sizes of organisms. The general feeling was that combination systems would have to be developed. This would allow the more advanced filtration and de-oxygenation systems to combat the human pathogens, which is now being required under the draft Convention.

It was noted that the new treatment standard that had been drafted last week during the IMO Committee meeting would still not be met by the equipment currently available, when fitted on most ship sizes and types. Flow rates and the need to target a broad range of organisms were the main restrictions in current technologies.

Some indication of the way forward could be gleaned from the discussions. For instance, the session on biocides as a treatment option was marked by a general concern on the part of the biologists present regarding the potential sub-lethal effects of the biocides once they had been discharged overboard with the ballast water. Developers of the biocide equipment had only assessed the lethal effects. Delegates at the symposium were reminded that it was the dramatic sub-lethal effects of TBT that raised concern and generated the eventual ban for its use in anti-fouling systems.

De-oxygenation technology has developed further over the past two years with some positive results in terms of ‘kill rates’ and flow rates now being demonstrated. Filtration still remains a popular option so long as the appropriate compatible technology can be found to destroy the smaller organisms.

Although there has been considerable investment in the technology by developers it was apparent that there is still a gap between the developers and the shipping industry. Many of those representing the shipping industry at the symposium argued that larger test scale scenarios would need to be developed and accompanied by more conclusive evidence of success before such  trials could go ahead on trading vessels.

Treatment technology was not the only subject of discussion. Certification and testing requirements were discussed and options for the sampling of ballast water and for testing/type approving equipment were also given. Although a host of suggestions were put forward on the matter of type approval, it will be for the IMO to decide exactly how to proceed with this aspect, with Guidelines for type approval and sampling on the list for development.

Contact:Tim Wilkins