Sewage Holding Tank - Capacity Check
Required sewage holding-tank capacity for a given POB and passage length per MARPOL Annex IV special-area carriage rules - baseline 70 L/person·day.
Gross generation
6,720L
Minimum tank capacity
7.73m³
Formula, assumptions, and limits
$$V_{holding} = \text{POB} \cdot d \cdot q_{pc} \cdot (1 + m)$$
70 L/person·day is the classic IMO planning figure; some flag states allow 40–50 L for vacuum systems. Cruise/passenger vessels must add grey-water (often 3–4 × black water volumes).
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $POB$ | Persons on board (crew + pax) | pax | muster list |
| $d$ | Retention days required | day | voyage plan |
| $q_{pc}$ | Per-capita generation rate | L/day | MEPC.159(55) guidance |
| $m$ | Safety margin | - | company policy |
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