Over a third of BWMS problematic or inoperable
Reduction of ballast water throughput during both uptake and discharge is a recurring theme, found a ABS survey
Ship owners and operators have reported in a survey that 43% of BWMS are either inoperable or have problematic operations.
Most newbuild installations carried out by respondents to the American Bureau of Shipping (ABS) survey were aboard vessels not designed to have a BWMS.
14% of BWMS were reported as regularly operated and subject to monitoring and/or efficacy testing.
Another 43% said that their BWTS was running but not subjected to monitoring or efficacy testing to date.
In its report following the survey, ABS said that many systems employ TRO (total residual oxidant) measurement during neutralisation and some systems use TRO measurement to determine disinfectant dosage during ballast water uptake.
Many owners responded that the reagents used for TRO measurement were highly susceptible to improper storage and handling. This had an apparent knock-on effect on TRO sensor abnormalities.
Responses indicated that sensor calibration is a repeated problem for both TRO and oxygen measurement, where applicable.
Additionally, owners with UV systems reported that the cost and frequency of UV lamp replacement was a significant concern.
Reduction of ballast water throughput during both uptake and discharge is a recurring theme. In many cases this appears linked to filter clogging and cleaning, said ABS. It was noted that this may also be associated with the ballast practices
The surveyed group agreed that design and installation should be completed with maintenance and repair in mind and should consider all the spaces necessary to accommodate BWMS filters.
The Total Residual Oxidant (TRO) sampling lines should also be reviewed to make sure they are large enough for in-service cleaning.
Service engineers and shipboard crews should conduct maintenance walk-throughs to verify adequate clearance and maintenance access and confirm appropriate spare parts are onboard, especially during sea trials.
In testing in port or at sea the ABS stated that running a full ballast and deballast cycle, including a stripping operation is recommended.
The surveyed group agreed that these observations may also be applied to retrofit projects.