Integrated Bilge Water Treatment System: the New Regulation 12A
Instead of two separate systems to coordinate (separator and 15ppm alarm), MEPC 84 opens the way to a single integrated system for bilge water treatment: a change in architecture, not just in threshold.
Operational Explanation
MEPC 84 approved a new Regulation 12A under MARPOL Annex I permitting the installation of an integrated bilge water treatment system, together with related supporting guidance. Unlike the traditional architecture, based on a separate oil separator (OWS) and a separate 15ppm alarm/monitoring system, the integrated system unifies treatment and monitoring in a single certified unit.
For the crew and the Chief Engineer, this is not just a technical update: it changes how operational compliance is verified, the maintenance required, and the training needed, since a fault or anomaly in the integrated system can have a different impact than the logic of the two separate systems the crew is historically used to.
Regulatory Reference
MARPOL Annex I, new Regulation 12A (approved at MEPC 84, 2026): permits the installation of an integrated bilge water treatment system that unifies oil separation and 15ppm monitoring/alarm functions in a single certified unit, together with related supporting guidance.
Scope of Application
Ships installing, as an alternative to the traditional separator + alarm architecture, an integrated bilge water treatment system compliant with the new Regulation 12A.
Procedure / How to Complete It
- For new installations, assess whether to adopt the integrated system under the new Regulation 12A or retain the traditional separator + alarm architecture.
- If the integrated system is adopted, verify the single unit's certification against the supporting guidance associated with Regulation 12A.
- Update planned maintenance procedures to reflect the integrated system's architecture, distinct from that of the two separate systems.
- Train the Chief Engineer and engine room personnel on the integrated system's operating logic, including anomaly and alarm management.
- Keep onboard documentation updated on the installed system's architecture (integrated or traditional), for reference in the event of an inspection.
Practical Example
Example: a shipyard fitting out a newbuilding assesses, at the design stage, the adoption of the integrated bilge water treatment system under the new Regulation 12A, simplifying the plant architecture compared with the traditional two-system solution.
Real Cases
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Engine room personnel trained only on the traditional separator + alarm architecture, without updated training for the integrated system installed | Inadequate handling of anomalies or alarms specific to the integrated system | Always train personnel on the operating logic specific to the architecture actually installed on board |
| Onboard documentation not updated to reflect the integrated system's architecture after a retrofit | Documentary confusion in the event of an inspection or survey | Always update onboard documentation after every installation or retrofit of bilge water treatment systems |
PSC Observations
Operational Tips
- If you are considering a retrofit or a newbuilding, compare the costs/benefits of the integrated system against the traditional architecture before deciding.
- Do not assume that generic bilge water treatment system training automatically covers the specifics of the integrated system.
- Always update onboard documentation after any change to the bilge water treatment system's architecture.
Checklist
- Bilge water treatment system architecture (integrated or traditional) clearly documented on board
- Integrated system's certification verified against the Regulation 12A supporting guidance, if applicable
- Planned maintenance updated for the specific architecture installed
- Engine room personnel trained on the actual system's operating logic
- Documentation updated after every retrofit or new installation