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MARPOL Annex IV

MARPOL ANNEX IV
Regulations for prevention of pollution by sewage in ships




Regulation 1: Definition Sewage;
  • Drainage & other wastes from;
             ✧ Toilets & urinals
             ✧ Hospital
             ✧ Spaces with living animals
  • Other waste water mixed with above.
Regulation 2: Application
  • Ships above 400 GT &/or ships carrying more than 15 persons engaged in international voyages.
Regulation 3: Exceptions
  • For safety of ship and those on board or to save life at sea.
  • Due to damage to ship or equipment (all reasonable precautions taken).
Regulation 4: Surveys
  • Initial (issue certificate), Renewal (not exceeding 5 yrs.).
  • Certificate issued by Administration or by a Recognized Organization authorized by it.
  • Certificate: International Sewage Pollution Prevention Certificate (Valid: 5 yrs.).
Regulation 9: Sewage systems
  • Every ship (according to reg. 2) shall be equipped with one of the following;
            ✧ A STP approved by Administration (MEPC effluent standards).
            ✧ Sewage comminuting & disinfecting system approved by the Administration.
            ✧ A holding tank of capacity satisfying the Administration.

Regulation 10: Standard discharge connection
  • OD: 210mm 
  • PCD: 170mm 
  • Thickness 16mm
  • 4 holes 18mm diam. Slotted Slot: 18mm
  • Steel
  • Bolt: M16
Regulation 11: Discharge
  • Ships, other than passenger ships in all areas; and
  • Passenger ships outside special areas;

From STP 
Comminuted & Disinfected
Untreated

✓ Certified STP meeting requirements.

✓ No visible floating solids & no discoloration of surrounding water 

✓ At least 3 nm away from nearest land. 

✓ At least 12 nm away from    nearest land.

✓ Approved disch. Rate.

✓ Proceeding en route.

✓ Minimum speed 4 kts.

  • When sewage is mixed with matter covered by other Annexes, the requirements of those annexes will be applied in addition to requirements of this annex.
Within a Special Area (Baltic Sea)
  • Discharge of Sewage Prohibited for passenger ships except when;
            Ship has a STP certified by Administration meeting the Effluent Standards + remove Nitrogen & Phosphorous (total N: 20 mg/l, P: 1 mg/l)

STP Effluent Standards (MEPC.227(64))

    Testing methods: according to MEPC.227(64) Guidelines

 Thermotolerant Coliform   
  100/100 ml  
 Total Suspended Solids
35 mg/l
 BOD5
25 mg/l
 COD
125 mg/l
 pH
6 – 8.5

Untreated sewage discharge rate
  • 1/200 000 of swept volume
  • Disch. Rate Max  = 0.00926   V    D    B
           Disch. Rate Max - (m3/h) Average rate for a period of 24 hours
           0.00926 - Kts. → m/h
                              200 000
           V - Speed (kts)
           D - Draft (m)
           B - Ship’s Breadth (m)
  • Calculated up to max Summer draft & max Speed and a table is prepared.
  • Then the pump is calibrated to a moderate rate.
Example

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