<P> Commercial vessels are required to obtain NPDES permits pursuant to Section 402 of the Clean Water Act . Section 312 of the Act prohibits the dumping of untreated or inadequately treated sewage from vessels into the navigable waters of the United States ( defined in the act as within 3 miles ( 4.8 km ) of shore ) . Cruise ships are subject to this prohibition . Commercial and recreational vessels with installed toilets are required to have marine sanitation devices , which are designed to prevent the discharge of untreated sewage . Beyond 3 miles ( 4.8 km ) , raw sewage can be discharged . On some cruise ships , especially many of those that travel in Alaskan waters , sewage is treated using Advanced Wastewater Treatment ( AWT ) systems that generally provide improved screening , treatment , disinfection , and sludge processing as compared with traditional MSDs . AWTs are believed to be very effective in removing pathogens , oxygen - demanding substances , suspended solids , oil and grease , and particulate metals from sewage , but only moderately effective in removing dissolved metals and nutrients ( ammonia , nitrogen and phosphorus ) . </P>
<P> Commercial vessels are required to obtain NPDES permits pursuant to Section 402 of the Clean Water Act . Section 312 of the Act prohibits the dumping of untreated or inadequately treated sewage from vessels into the navigable waters of the United States ( defined in the act as within 3 miles ( 4.8 km ) of shore ) . Cruise ships are subject to this prohibition . Commercial and recreational vessels with installed toilets are required to have marine sanitation devices , which are designed to prevent the discharge of untreated sewage . Beyond 3 miles ( 4.8 km ) , raw sewage can be discharged . On some cruise ships , especially many of those that travel in Alaskan waters , sewage is treated using Advanced Wastewater Treatment ( AWT ) systems that generally provide improved screening , treatment , disinfection , and sludge processing as compared with traditional MSDs . AWTs are believed to be very effective in removing pathogens , oxygen - demanding substances , suspended solids , oil and grease , and particulate metals from sewage , but only moderately effective in removing dissolved metals and nutrients ( ammonia , nitrogen and phosphorus ) . </P>
where does the poop go on cruise ships
where does the poop go on cruise ships
navigable waters
navigable waters