What are the D-2 performance standard limits for a BWMS?
Short answer
| Parameter | Discharge limit |
|---|---|
| Organisms >= 50 µm | < 10 viable organisms per m³ |
| Organisms >= 10 and < 50 µm | < 10 viable organisms per ml |
| Toxicogenic Vibrio cholerae (O1 and O139) | < 1 cfu per 100 ml or < 1 cfu per g (wet weight) of zooplankton |
| Escherichia coli | < 250 cfu per 100 ml |
| Intestinal Enterococci | < 100 cfu per 100 ml |
- D-2 standard: strict numeric limits for organisms and pathogens.
- Trap: D-1 only required 95% volumetric exchange, D-2 mandates treatment to these exact counts.
- Limits apply at rated flow, within approved water conditions, voyage after voyage.
- Vibrio cholerae limit includes zooplankton sample alternative.
Full answer
The full answer explains each point step by step, with the regulations and figures behind it and the discussion from other candidates. It is in the MEO Class I section of the Marine One forum, open to members enrolled for the MEO Class I exam.