Ballast Water Compliance Study Identifies Problems

Singapore MPA

By MarEx 2015-03-10 03:28:25

The Maritime and Port Authority of Singapore has released the results of its trial of testing ships for compliance with the IMO Ballast Water Management Convention. The report identified a number of practical problems for both port state control and ships’ crew.

The study was initiated in July 2014 when MPA charged SGS Testing & Control Services Singapore (SGS) with the execution of compliance tests were executed on six ships. The objective of the study was to assess the feasibility of indicative and detailed (in-depth) analysis of ballast water on board ships under realistic conditions. This included time constraints during cargo unloading and loading while the ships were berthed in harbors for just one day or even less.

The study allowed the Singapore MPA to identify potential practical challenges that vessels may face when MPA will execute its port state control role when the convention comes into force.

The sampling and analysis methods developed for use on board were executed on board all six ships without major problems and without causing delays to the ships. 

However, there were a number of conclusions drawn from the study that raise concerns for the industry:
•    The high turbidity of the water from the ballast water tanks can interfere with both indicative and detailed analysis methods.
•    There were only single sample points available, which meant the sampling system had to be run in ‘open’ mode, discharging waste water into the bilge. This put a limit on the amount of water that could be sampled, since not too much water was allowed to be discharged into the bilge. There was no provision onboard to collect and retain ballast water. Makeshift drums and portable pumps were used to collect and transfer collected sampled ballast water to the bilges.
•    While all ships were equipped with sampling points, these sampling points were not always designed for ease of access.
•    Both pitot tubes and sampling valves were not always optimal. Globe valves were used, which can have an effect on plankton viability. Pitot tubes were of large diameter, making it difficult to sample at a flow speed safe for sampling.
•    The pitch circle diameter of the sampling G2 valve fitted onboard was not always of the same standard for all the vessels. As such prior arrangement of the correct connecting flange for the sampler was needed.
•    Crew competence in the understanding of the convention and the expertise in operating and maintaining the equipment is important.
•    An average of 6.5 hours was spent onboard for conducting the sampling and analysis.
•    There was an additional workload on crew during the time the sample and analysis was being conducted. Apart from the arrival and cargo operations, ship crew were involved in picking up stores, stemming bunkers, attending to class surveys etc. As such there may be a possibility of crew not meeting the rest hours requirement by the time the vessel departs. (Although during this study MPA ensured that no rest hours were compromised)
•    Vessels following procedures like “trim optimization” may find it difficult to follow the holding time requirements of a ballast water treatment system.
•    Arrangements have to be made to ensure that the samples taken to the lab for detailed analysis were maintained at a temperature of between 3-5 degrees centigrade.

The detailed analysis methods found one of the ships to be non-compliant while the indicative analysis methods found two ships to be non-compliant. The ship which was found to be non-compliant using detailed methods was also found to be non-compliant using the indicative methods. For the other four ships the results of the indicative analyses were all in the uncertainty range of the method and were therefore reported as ‘possibly compliant’. 

The indicative methods did not provide false positives for compliance. This matches the principle of ‘gross non-compliance’ for which indicative methods should be used. However, no limit values for gross non-compliance have so far been determined.

The two different detailed bacteria methods that were tested, the classic bacteria plating according to APHA protocols and the Fluorescent In-Situ Hybridization method, provided very similar results for all ships and samples. There is no D-2 limit value for total heterotrophic bacteria. The results for this parameter were compared with the limit value from the California standard (< 1,000 cfu/100 mL). Since this is not an IMO limit value exceeding it did not cause non-compliance.

One of the six ships tested was found to be non-compliant by both indicative and detailed methods, which means it was non-compliant with the D-2 standard. This ship had retained the water inside the ballast tank for only one day. Furthermore the ballast water treatment equipment had to be stopped and started a couple of times during the sampling process due to some leakages in the control systems which needed attention. The same ballast water treatment equipment was tested onboard two other vessels for which the detailed analysis results were compliant.

The scale of this study does not allow generalizations to be drawn on the level of compliance of treatment systems, however, MPA concluded that execution of on board sampling and analysis is possible within the time constraints of vessel loading and unloading in a harbor.

The full report is available here.