Marine Sewage

Sewage on board ships

Sewage originating from toilet and hospital facilities and gray water from douches, sinks, laundry and galley cause severe damage to the marine environment. Organic pollutants and nutrients can disequilibrate the local ecosystems at the discharge point and thus endanger the aquatic flora and fauna. 

In order to prevent this, the International Convention for the Prevention of Pollution from Ships, MARPOL 73/78 Annex IV, allows the discharge of untreated sewage only under certain conditions after treatment in a type approved sewage treatment plant (STP) meeting the effluent standards under test conditions adopted by the Marine Environment Protection Committee by resolution MEPC.227(64). If ships do not comply with these regulations they can face heavy fines and penalties by local authorities. 

RWO’s sewage treatment on board ships

RWO Veolia’s CleanSewage Systems are based on biological treatment processes, ensuring a minimum of chemical consumption and byproducts. 

RWO Veolias recommendation for STP onboard ships are as follows

Operation outside special area inside special area 

< 400 GT; > 15 POB 
merchant vessels

RWO Veolia offers the CS-BIO for merchant vessels or small passenger vessels outside special areas. The treatment principle is based on the biological Moving-Bed Biofilm Reactor technology (MBBR) and serves as an all-in-one solution, integrating the holding tank into the STP, thus occupying less space. The robust design offers stable operation and very low maintenance.
> 400 GT
merchant vessels

passenger vessels < 12 passengers
passenger vessels < 200 persons  CS-BIO / CS-MBR CS-MBR
passenger vessels > 200 persons  
Operating in special areas (baltic sea), it is crucial that passenger ships meet the highest effluent quality according to IMO resolution MEPC.227(64) including nitrogen- and phosphorous- removal (chapter 4.2). Therefore RWO Veolia provides the advanced water purification plant CS-MBR for passenger vessels. 

Leading towards a more sustainable future, our RWO products for marine sewage are fit for treating besides sewage various additional wastewater streams such as gray water from accomodation, laundry and galleys. Thus our products are compatible with additional environmental class notations such as BV Clean, CleanSuper, DNV-GL Clean(Design) and AWT-A/B.


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Sewage Treatment Products

Biological Sewage Treatment maximising onboard space.

Advanced water purification and advanced wastewater treatment.

State-of-Art Galley Water Pretreatment

Sewage Treatment Brochure (771.05 KB)