Zero Discharge

Zero discharge is an operational standard prohibiting the release of specified wastes into the sea, applied either by regulation in sensitive areas or by voluntary vessel policy. MARPOL designates Special Areas and Particularly Sensitive Sea Areas where discharge of oil, garbage, or sewage is barred outright, and Annex V prohibits any disposal of plastics anywhere at sea. Many cruise operators and ports apply zero-discharge while alongside or within set distances, holding wastewater, garbage, and sludge for reception facilities ashore. The standard depends on adequate port reception capacity under MARPOL and on holding-tank and treatment systems sized for the no-discharge interval.