Wastewater neutralization and cleaning can be challenging at the best of times but consider the challenges faced by cruise ships, which are floating cities with a population of up to 10,000. Not only do they create their own potable water supply, but the ship’s collection, holding, and transfer system (CHT) must collect and transfer graywater and sewage generated onboard to the ship’s graywater and sewage/graywater treatment systems or to overboard discharge. (Graywater refers to non-sewage wastewaters that are collected by the CHT system). The CHT system is composed of five subsystems, referred to by the ships crew as the galley, food pulper, accommodations, laundry, and sewage systems. Potable water is used as source water for all ship operations that generate graywater and sewage (e.g., laundry, galley, food pulper, sinks, showers, and toilets). This complicated wastewater sampling equipment must work 24/7 with no faults. The ships graywater treatment system operates continuously, regardless of the ship’s location (e.g., in port, at sea within Alaska waters, at sea outside Alaska waters). The vessel typically continuously discharges treated wastewater from this system overboard. When overboard discharge is suspended, such as when the ship is alongside or when it cruised Hubbard Glacier, the treated effluent is diverted to double-bottom holding tanks, where it is held for eventual discharge outside of 12 nautical miles (nm) from shore.
Glossary for Water Quality Testing Terms
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