6.2 A bilge-water holding tank is arranged to
receive the daily generation of bilge-water before this water is discharged
ashore or discharged through the 15 ppm or 100 ppm equipment overboard.
A bilge-water holding tank is not mandatory, but will enable ships
to operate safetly during port visits, during operation in special
areas and coastal waters and during periods of maintenance of the
15 ppm and 100 ppm equipment.
6.3 A bilge-water holding tank will also provide
additional safeguards in the purification of oily bilge-water should
quick-separating detergents be used for cleaning purposes.