OWS

Question 1

Provide an overview of the OWS operation and functionality?

Answer 1

Made up of two stages, the first stage is oily water from the pump. Oil and water will separate at the top of the chamber by oil rising to the top. further separation occurs in the lower chamber as it is passes the catch plates. Oil is collect by under going a tortoise path within the baffles and funnelled upwards.

Oil is removed from the top by an automatic control valve. A capacitance probe is used to sense oil quantity, energising the solenoid to transfer the oil to the oil tank.

Water passes to the second stage and into the coalescer. The right hand removes solids and oil. the left hand removes the last of the small droplets until they form a large enough droplet to float to the top. Oil is then drained manually in this stage.

Water will then be allowed to discharge via the 15ppm monitoring system, if to high then it shall alarm and return to tank rather than overboard.

Question 2

How would you test an OWS system?

Answer 2

I would run it up but have two hoses for the discharge overboard and the return to tank going into buckets. I would then run the system ensuring it is operating correctly then using a brush to block the light scatter in the alarm monitor. this will then alarm and cause the flow to go back to tank which would be visual in the bucket

Question 3

How does it work?

Answer 3

You can install different gravity disks for different fluids.
Adding a heater can help drop the viscosity of the oil and assist with separation
Positive displacement pump is installed to reduce any risk of emulsifying the mixture.
15 ppm sensor installed with an automatic 3 way valve

Question 4

Draw a sketch of an OWS?

Answer 4

See one note

Question 5

MARPOL Annex I, IOPPC, Maintenance and surveys?

Answer 5

Annex I - Prevention of Pollution by Oil

IOPPC - International Oil Pollution Prevention Certificate

Applies for tankers above 150GT

Applies for vessels above 400GT

Valid for 5 years plus annual and intermediate surveys

Must enter into ORB when used

Testing of the 15ppm monitor to be done monthly

Manual maintenance gives hours and time line for changing filters, cleaning sensors, replacing/ calibrating 15ppm

Question 6

What are the regulations for using an OWS?

Answer 6

Outside of special area above 400gt
- Vessel enroute
- Oil content below 15ppm
- Vessel has OWS equipment and discharge monitoring

Inside special area
- All of the above
- Automatic 15ppm stopping device

Question 7

What would be recorded in the ORB?

Answer 7

• Start and stop time and date
• Long and Lats
• Amount before, pumped and after
• New and old sealing number
• Signed officer in charger

Question 8

How is the monitoring device calibrated and how often?

Answer 8

Performing verification tests using known oil content concentrations or certified calibration fluids. Every 5 years

Question 9

How would you test a 3 way valve?

Answer 9

By testing it every month with the brush when running to distort the light scatter