Discharge less than 3 NM is associated with which waste type?

• A. Gray water
• B. Oily water
• C. Unprocessed garbage
• D. CHT

Answer: (A)

Discharge distances are about how harmful or persistent a waste can be and how it’s treated onboard. Gray water, which is the wastewater from sinks, showers, and laundries, is the least hazardous of the options and is allowed to be discharged relatively close to shore—often within 3 nautical miles—as long as it’s free of oil and other pollutants. That makes it the waste type associated with discharges less than 3 NM. Oily water contains oil and is regulated tightly; it’s typically discharged only beyond 12 NM after using an oily water separator and meeting oil-content limits. Unprocessed garbage is generally not allowed to be discharged near shore; disposal usually must be far from land or at shore facilities, with strict distance rules. CHT, the sewage holding tank, is also controlled and discharged only at appropriate distant locations or shore facilities, not close in. So gray water fits the scenario of discharging within 3 NM.