1 The washwater discharge criteria are intended to act as initial guidance
for implementing EGC system designs. The criteria should be revised in the future as
more data becomes available on the contents of the discharge and its effects, taking
into account any advice given by GESAMP.
2 Administrations should therefore provide for collection of relevant data.
To this end, shipowners in conjunction with the EGC manufacturer are requested to sample
and analyse samples of:
- inlet water (for background);
- water after the scrubber (but before any treatment system); and
- discharge water.
3 This sampling could be made during approval testing or shortly after
commissioning and at about twelve-month intervals for a period of two years of operation
(minimum of three samples). Sampling guidance and analysis should be undertaken by
laboratories using EPA or ISO test procedures for the following parameters:
- pH
- PAH and oil (detailed GC-MS analysis)
- Nitrate
- Nitrite
- Cd
- Cu
- Ni
- Pb
- Zn
- As
- Cr
- V
4 The extent of laboratory testing may be varied or enhanced in the light of developing
knowledge.
5 When submitting sample data to the Administration, information should also be included
on washwater discharge flow rates, dilution of discharge, if applicable, and engine
power should be included as well as specifications of the fuel used from the bunker
delivery note as a minimum.
6 It is recommended that the ship that has provided this information to the satisfaction
of the Administration should be granted a waiver for compliance of the existing
installation(s) to possible future stricter washwater discharge standards. The
Administration should forward information submitted on this issue to the Organization
for dissemination by the appropriate mechanisms.