(LONDON) — More than 30 percent of all installed ballast water treatment systems (BWTS) fail Port State Control D-2 compliance inspections despite 95 percent of systems having successfully passed commissioning tests.
Information submitted by Global TestNet to the International Maritime Organization’s (IMO) Marine Environment Protection Committee MEPC82, which took place in October, revealed that 29 percent to 44 percent of operational systems are failing to remove invasive species in the greater than 50-micrometer (µm) range, with more than 100 organisms of this size routinely found in every cubic meter of treated water.
The D-2 standard of the Ballast Water Management (BWM) Convention, which entered fully into force on Sept. 8, requires ships to discharge ballast water with fewer than 10 viable organisms per cubic meter that are at least 50 micrometers in size.
Global TestNet, an association of testing organizations set up in 2010 under the GloBallast Partnership, also reported instances where more organisms were found in discharged water than in inlet water.
According to the findings, the most common reasons for noncompliance 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.
“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 noncompliance,” said Charlene Ceresola, BIO-UV Group’s ballast water treatment project manager, who is currently participating in the BWM Convention review as a member of the French delegation to the IMO Ballast Water Review Group.
“When a BWMS is properly installed, a high efficacy in removing organisms is achieved (99.9 percent) but IMO MEPC reports have acknowledged that this efficacy may not be sufficient to constantly meet the D-2 discharge standard. Compliance tests often fail due to the presence of organisms in the tank or water contamination. If operators do not fully understand the impacts of ballast water management on board, and if bypassing cleaning procedures for ballast tanks occurs frequently, noncompliance will be unavoidable,” she said.
The most frequent deficiencies reported by the Paris Memorandum of Understanding (MoU) 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 noncompliance deficiencies reported by the Paris MoU in 2023, 760 related to record-keeping and administration (58 percent), BWTS system and system knowledge (16 percent), and certification (16.9 percent), resulting in 33 ship detentions. This year to date, 505 ballast water management deficiencies have been reported, resulting in 17 ship detentions.
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,” Ceresola said. “Shipowners want their systems to be in good working order, but how do you ensure this once the manufacturer has installed the system and left the ship or is no longer in the market?”
“Fit and forget is certainly not a BIO-UV Group policy, of course,” she added. “But there is agreement among ship operators and regulators that routine compliance checks are required. It is essential to assess whether systems efficiently prevent harmful aquatic organisms and pathogens from being discharged into the oceans.”
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.
– BIO-UV Group
