During a typical one-week voyage, a large cruise ship (with 3,000 passengers and crew) is estimated to generate 210,000 US gallons (790,000 L) of sewage; 1 million US gallons (3,800 m3) of graywater (wastewater from sinks, showers, and laundries); more than 130 US gallons (490 L) of hazardous wastes; 8 tons of solid ...