Answer
The Oil Discharge Monitoring Equipment (ODME) is a critical MARPOL Annex I requirement to
ensure oily water discharge does not exceed the statutory limit of 30 litres per nautical mile.
Input Values (Signals fed into the ODME computer):
Flow Rate: From the flow meter installed in the discharge line.
Oil Content (ppm): From the optical analyzer/sample cell.
Ship’s Speed: Directly integrated from the ship’s GPS/Speed Log (crucial for calculating litres/nautical mile).
Date & Time: Synchronized UTC.
Output Values (Signals generated by the ODME):
Instantaneous Rate of Discharge: Calculated and recorded in Litres/Nautical Mile (L/NM).
Total Quantity Discharged: Cumulative total in litres or cubic meters.
Control Signal to Overboard Valve: An automated pneumatic/electrical signal that immediately shuts the 3-way overboard discharge valve and opens the slop tank return valve if limits are exceeded or signals are lost.
Alarms: Visual and audible alarms for exceeding 30 L/NM, exceeding 1/30,000 of the total cargo quantity, or system faults.