USCG issued the first U.S. Coast Guard Ballast Water Management System Type Approval Certificate to Norwegian manufacturer Optimarin AS on December 2, 2016 after a detailed review of the type approval application determined the system met the requirements of 46 CFR 162.060

Now that a type approved BWMS is available, USCG informs  that any owner/operator requesting an extension must provide the Coast Guard with an explicit statement supported by documentary evidence (e.g., a delay in commercial availability) that installation of the type approved system is not possible for purposes of compliance with the regulatory implementation schedule.

Extension letters will remain valid until the extended compliance date specified in the extension letter.

Commercial seagoing ships operating in U.S. waters (within 12 nautical miles), and not otherwise exempted, are required to manage ballast water in one of five ways:

1. Use a U.S. type-approved BWMS to meet the discharge standard
2. Temporarily use a foreign type-approved BWMS that has been accepted by the U.S. Coast Guard as an Alternate Management System (AMS)
3. Use and discharge ballast water obtained exclusively from a U.S. Public Water System (PWS); 4. Discharge ballast water to a reception facility
4. Do not discharge ballast water inside 12 nautical miles.

Further details may be found by reading USCG Marine Safety Information Bulletin including updates for the BWM Extension program

source (article & photo): http://www.green4sea.com/uscg-updates-bwm-extension-program/