Ballast Water Treatment: Self Monitoring

MEPC69

By Wendy Laursen 2016-04-19 19:04:23

Over 30 documents relating to the Ballast Water Management Convention have been submitted to IMO's Marine Environment Protection Committee (MEPC) which is meeting for its 69th session this week. One of the documents relates to the potential for ballast water treatment systems to be used in conjunction with self-monitoring systems to ensure they are functioning to the discharge standards set out in the Convention.

Port states face challenges in developing a verification process for inspections, and it is anticipated that a variety of methods will be used. These will include methods to determine “indicative” compliance as a routine practice and more stringent methods that could be used to test for compliance should port state control officers suspect that appropriate treatment of ballast water has not been undertaken on board a ship.  

The main reason for different types of tests is that the statistical requirements for looking for a tiny number of organisms in a massive volume of discharging water are expected to be arduous. The U.S. requirements in the ETV protocol demonstrate the practical issues involved. The Protocol states that 30 cubic meters of ballast water is needed to enumerate 10 organisms per cubic meter with the desired level of precision. These samples should be continuously acquired on a time-averaged basis. 

The total sample volume may be reduced if, for example, the volume of subsample analyzed is increased say from 20 ml to 40 ml. However, the protocol states that if this is done, the testing facility should conduct validation experiments to ensure counting accuracy remains high. 

Denmark has submitted a document for consideration at MEPC 69 that examines self-monitoring of ballast water management systems for indicative compliance. Self-monitoring would give ship operators and crews their own way of evaluating compliance which could also be used when dealing with port state control inspections.

An earlier IMO meeting considered a proposal from Germany to introduce a detailed self-monitoring standard for treatment systems that would record their proper functioning or any failures. Another document that has been considered, from Germany and South Korea, which offers a list of parameters for monitoring the operational status of a treatment system. The idea is to create a standard for self-monitoring.

Denmark’s proposal states that it is important to include other relevant parameters regarding separation and disinfection unit performance in the development of the standard. This would include particle concentrations or size distributions and indicators for viable algae (chlorophyll) or organism energy processes (ATP). In this way, the self-monitoring systems would report on the efficacy of the treatment system, and ultimately the compliance with regulation D-2 of the Convention, as well as the operational history of the treatment system.

The proposal mentions the bw-monitor in-line system which offers this type of self-monitoring functionality and is suitable for most treatment systems regardless of the technologies applied. The system analyses two locations in the ballasting process and compares before and after treatment levels. It can also be fitted to a system treating on discharge.

The bw-monitor measures particle density to assess filter retention and also the viability of microalgae as an indicator of disinfection performance. The parameters are measured with optical techniques (viable algae by fluorescence and particles by laser scattering.) There is no removal or manipulation of water samples nor any addition of chemicals. Performance indicators are displayed to the crew and also logged for potential inspection by port state control.

The purchase of this type of equipment is an added consideration for shipowners already concerned about the cost of treatment systems. Representing shipowners and others, the International Chamber of Shipping and Intertanko have also submitted a document to MEPC 69. The organizations are concerned about the available supply of approved ballast water treatment systems that will be suitable as a result of potential changes to type approval requirements also being discussed at MEPC 69

They are also concerned about the availability of systems that will be suitable for global operation, including within United States waters as a result of the viability debate. The organizations are concerned that there will not be enough systems to choose from and that manufacturers will not be able to meet demand from both the newbuild and retrofit markets should the Convention enter into force in the near future as is now expected.

There is another equipment concern for shipowers. Another study to be discussed at MEPC 69 suggests that ballast water treatment system testing and type approval approaches currently employed are not uniform. The testing facilities studied follow the IMO guidelines for approval of ballast water treatment systems, but some interpret the guidelines differently to others. 

This has led to several differences in how systems have been tested for type approval. Additionally, a lack of publicly available documentation on exactly what protocols were used hinders transparency, and not all facilities have been audited by an accredited body. 

The study states that this may impair confidence in the testing and approval regime currently being used. Nonetheless, MEPC 69 will also be evaluating a number of applications from equipment manufacturers currently progressing through the type approval process. Type approvals have already been issued for 65 ballast water treatment systems.