Beyond 12 nautical miles, what condition must be met regarding solids in sewage discharge?

• A. No visible solids
• B. No discharge at night
• C. Temperature below 20C
• D. Only during daylight

Answer: (A)

The key idea is that offshore sewage discharges are governed by cleanliness standards that focus on what you can see in the water. Beyond 12 nautical miles, the rule is that the discharged sewage must not contain solids visible to the naked eye. This makes the effluent much less grossly polluted and reduces the risk of floating debris, sediment buildup, or harm to marine life from larger particles.

Visibly solid material indicates inadequate treatment or containment, so requiring no visible solids establishes a clear, observable bar that ships can meet with standard treatment or filtration processes. The other options—discharging only at day or night, or applying a temperature limit—don’t reflect pollution-control priorities and aren’t practical markers of sewage cleanliness, so they don’t fit the standard as well.