OICEW Task 4.3.W

Start and secure a reverse osmosis plant

MMA Method

In order to satisfy NVIC 17-14 Task 4.3.W , MMA students must:

NVIC Method

See NVIC method.

STCW Competence Knowledge, Understanding, and Proficiency

Operate main and auxiliary machinery and associated control systems

OICEW-A4.3 Preparation, operation, fault detection and necessary measures to prevent damage for the following machinery items and control systems

Other auxiliaries including refrigeration, air- conditioning and ventilation systems
Condition Behavior Standard

On a vessel of at least 1,000 HP at sea or at anchor in clean water, on a simulator, or in a laboratory,

the candidate starts and shuts down a reverse osmosis plant.


Note 2 May be used as substitute for Task Nos. 4.3.N and 4.3.O A candidate who does not perform this task will receive an endorsement that is limited to motor and/or gas-turbine propelled vessels without distilling plants.

The candidate starts and shuts down a reverse osmosis plant as follows:

Reverse-osmosis unit start-up procedure

  1. Performs a cursory examination of the plant to ensure that the system is intact, that all components are fully assembled, and that the unit is in a state of operational readiness;

  2. Ensures that all pre-filter, media filter and cartridge filter drain and vent valves are closed;

  3. Opens all sea water valves from the sea chest up to the unit, the sea water inlet cock valve, and the feed water pump isolation valves if the unit is so equipped;

  4. Positions the 3-way feed/rinse/clean/store valve to the normal feed position and lines up the media filter isolation, back-flush, and waste outlet valve for normal operation;

  5. Positions the 3-way media filter outlet valve to the normal feed position to the cartridge pre-filters;

  6. Opens the back pressure regulator bypass valve fully and completely backs off on the back pressure regulator valve;

  7. Positions the 3-way brine discharge/rinse/clean/store valve to the normal overboard position and ensures that all the brine discharge valves to the overboard skin valve are all open;

  8. Ensures that electrical power is established to the unit by closing the appropriate circuit breaker;

  9. Checks oil level in high pressure pump crankcase, and adds oil as necessary;

  10. Places feed pump and feed booster pump switches in the automatic mode as appropriate if so equipped;

  11. Depresses the unit salinity controller start switch, observes feed pump, booster feed pump, and high pressure pump pressures and feed flow meter, bleeds air from pre-filter, media filter, and cartridge pre-filters as needed, and checks for system leaks;

  12. Once proper feed has been established, slowly closes the back pressure regulator bypass valve, and closes in on back pressure regulator until manufacturer recommended design pressure is reached for the existing sea water salinity, and observes fresh water product flow meter;

  13. Lines up fresh water system valves to permit delivery of fresh water to the fresh water storage tank on service and monitors the salinity of the fresh water product;

  14. Ensures that an acceptable salinity is eventually reached on fresh water product and that the 3-way fresh water product diverting valve switches from the overboard discharge to the fresh water delivery mode; and

  15. Monitors system, pressures, flows, and salinity to ensure that parameters remain within acceptable limits.

Reverse-osmosis unit procedure for short term shut-down

  1. Depresses the unit salinity controller stop switch and ensures that the feed pump, booster feed pump, and high pressure pump all stop rotating and that their respective indicator lights go out;

  2. Closes all sea water valves from the sea chest up to the unit, the sea water inlet cock valve, and the feed water pump isolation valves if the unit is so equipped;

  3. Opens any valves in the cleaning tank discharge line to the unit 3-way feed feed/rinse/clean/store valve;

  4. Positions the 3-way feed/rinse/clean/store valve to the rinse position and lines up the media filter isolation, back-flush, and waste outlet valve for normal operation;

  5. Ensures that multi-media filter and cartridge pre-filter drain valves are closed;

  6. Opens the back pressure regulator bypass valve, and backs off on the back pressure regulator valve fully to release the pressure from the unit;

  7. Ensures that the 3-way brine/clean/store/rinse valve is in the normal brine discharge position;

  8. Fills the cleaning tank with chlorine free product fresh water;

  9. Places the booster pump control switch to the “hand” position and observes the feed flow meter;

  10. When the feed flow meter indicates no flow (and the cleaning tank is now empty and short-term rinsing is complete), places the booster pump to the “off” position, then “auto”; and

  11. Secures electrical power to the unit by opening the appropriate circuit breaker.