Australia has submitted a study to IMO MEPC 81 on the effectiveness of ballast water management systems (BWMS) in relation to the BWM Convention, and non-compliance was observed for 36% (16) of detailed tests for biological compliance
In a recent study conducted in Australian ports, comprising Gladstone, Dampier, Walcott and Newcastle, worrying findings regarding the non-compliance and failure rates of ballast water treatment systems have been revealed.
The study, which is a continuation of research initiated in 2021, sheds light on the performance of these systems between 2021 and 2023. The investigation involved voluntary sampling from ships intending to discharge treated ballast water in Australian ports.
Over the two-year period, 39 ships were sampled, totalling 44 ballast water samples. The testing, conducted against the D-2 performance standard, utilised both indicative and detailed analysis methods, following established guidelines.
The results are concerning, indicating 36% of detailed tests for biological compliance showed non-compliance. This figure is consistent with previous observations reported in 2021, emphasising a persistent issue in meeting regulatory standards.
Of the 44 samples, 39 were taken from BWMS using active substances.
It will be a concern that 5% of these samples did not comply with the maximum allowable discharge concentration measured as total residual olxidant (TRO). Two ships also initially exceeded TRO levels but managed to rectify the issue on board.
Determining the root cause of BWMS failures proved challenging, with operational issues such as introducing untreated ballast water or experiencing difficulties during the sampling process cited.
Some non-compliance was associated with the ≥50 µm size class, with a single exception for Enterococci.
Similar to other studies, the operational difficulties of BWMS, lack of preparation, or inadequate cleaning of tanks before BWMS installation were identified as potential contributing factors.
Although a small study size compared to global ballast water operations, it questions the inadequacy of BWMS in consistently meeting the D-2 standard (due in September 2024), and will be a major discussion point at MEPC 81 (18-22 March 2024).
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