Det Norske Veritas (DNV) has just IMO-approved the biological sewage treatment plant from Gertsen & Olufsen (G&O), a leading Scandinavian developer of a.o. sewage treatment systems targeted for ships and offshore use. The revised guidelines on treatment of black water, IMO MECP 159(55) Resolution, comes into effect on Jan. 1, 2010. As the resolution entails new and significantly stricter standards, it represents a massive challenge to shipbuilders and designers. The guidelines apply to sewage treatment plants on ships of 400 grt and above as well as on smaller ships certified to carry a crew of more than 15. One answer to the technological challenge has surfaced following DNV’s approval of the G&O Bioreactor in accordance with the new IMO resolution.