Over 30 percent of all installed ballast water treatment systems fail Port State compliance inspections despite 95 percent of systems having successfully passed commissioning tests according to a new analysis submitted to the International Maritime Organization as it is reviewing BWTS requirements. The report highlights issues with maintenance, record keeping, and crew training while warning that additional requirements are coming into effect in 2025 ahead of completing amendments by the end of 2026.
The information was submitted by Global TestNet, an association of testing organizations set up in 2010 under the GloBallast Partnership, to the IMO looking at compliance with the D-2 standard of the BWM Convention, which entered fully into force on September 8. Ships are required to discharge ballast water with fewer than 10 viable organisms per 1m3 that are at least 50µm in size but the data revealed that 29 to 44 percent of operational systems are failing to remove invasive species in the >50µm range, with more than 100 organisms of this size routinely found in every 1m3 of treated water.
“These results show that even if a vessel with a type-approved ballast water treatment system passes initial commissioning tests, the BWM system alone cannot assure against non-compliance,” said Charlène Ceresola, BIO-UV Group’s BWT Project Manager.
According to the findings, the most common reasons for non-compliance were contamination of the ballast water tank from mixing treated and untreated waters or improperly opening/closing valves; organism regrowth due to insufficient and infrequent cleaning of the ballast water tanks; and human error due to insufficient system knowledge, maintenance, and training.
“When a BWMS is properly installed, a high efficacy in removing organisms is achieved but IMO MEPC reports have acknowledged that this efficacy may not be sufficient to constantly meet the D-2 discharge standard,” said Ceresola. “If operators do not fully understand the impacts of Ballast Water Management on board, and if bypassing cleaning procedures for ballast tanks occurs frequently, non-compliance will be unavoidable.”
The most frequent deficiencies reported by the Paris Memorandum of Understanding on Port State control also related to poor ballast water record bookkeeping, inadequate crew training, system unfamiliarity, and invalid or missing certificates. Of the 907 ballast water non-compliance deficiencies reported by the Paris MoU in 2023,760 related to record-keeping and administration (58%), BWTS system and system knowledge (16%), and certification (16.9%), resulting in 33 ship detention. This year to date, 505 ballast water management deficiencies have been reported, resulting in 17 ship detentions.
“We are encouraging BIO-SEA system operators to refer to the new guidance on ballast water record-keeping and reporting (due to enter into force on February 1, 2025) to safeguard against port delays and detentions,” said Ceresola. “While there remains a two-year grace period for treatment performance issues, ships can still be delayed for poor administration. Maintenance and crew training are also areas where ships can be detained.
“There is certainly a need for strengthening maintenance and system knowledge, and this will be part of the package of amendments IMO is preparing,” she noted.
The IMO’s Convention Review Plan for the BWMS experience-building phase aims to address the 13 priority issues identified at MEPC80. The amendments package is expected to be completed by the end of 2026, with implementation taking place 12 to 18 months afterward. The primary focus areas include BTWS maintenance, crew training, and addressing challenging water conditions.
