The Hong Kong SAR Marine Department has advised that as of 1st July the existing Merchant Shipping regulation (Cap 413J) has been replaced by a new Regulation (Cap 413O) which applies to all Hong Kong registered vessels and those within Hong Kong Waters.
Full details of the Cap 4130 can be found on the website here but include the following requirements:
2.1 the discharge of any garbage from a ship within Hong Kong waters is prohibited except cargo hold, deck and external surfaces wash water which does not contain cleaning agents and additives harmful to the marine environment;
2.2 a ship of 12 metres or more in length overall must display a Garbage Discharge Placard (GDP) onboard to notify crew and passengers of the garbage discharge requirements.
2.3 A ship which is:
(i) of 100 gross tonnage or above, or
(ii) certified to carry 15 or more persons
must have onboard a Garbage Management Plan (GMP). The GMP must provide written procedures for minimizing, collecting, storing, processing and disposing of garbage.
2.4 A ship which is:
(i) of 400 GT or above and is certified to carry less than 15 persons;
(ii) of 400 GT or above, certified to carry 15 or more persons and engaged in a voyage of more than one hour in duration;
must have onboard a Garbage Record Book (GRB) to record the handling of shipboard garbage. Each discharge of garbage into the sea or to a reception facility must be recorded in the GRB and signed by the person in charge of the discharge on the date of the discharge. Each completed page of the GRB shall be signed by the coxswain of a local vessel, or the master of other vessels. The GRB can be purchased from the Marine Department on the 3/F of Harbor Building.