Sewage Treatment Unit SBT 25,

Sewage Treatment Unit SBT 25, #SewageTreatmentOnboard, #SewageTreatmentOperation, #HowToTreatSewage
Construction, operation and maintenance of Sewage Treatment Plant (SBT-25) On board ship
Sewage Treatment Unit
(MARPOL Annex IV Regulation)
1. General
1. General
1. General
2. Starting
1. Apply power to control panel.
- Confirm “Source lamp” is lit.
2. Starting
 Piping arrangement
2. Starting
2. Shut stop valve ④
and Open drain valve for bio-filter tank ⑤.
2. Starting
3. Introduce cleaning water into the device
by opening cleaning water inlet valve.
When the indicator lamp marked “High
water level”, immediately close the valve.
- Confirm external “HL” alarm.
2. Starting
4. Open treatment water
outlet valve ③,
discharge pump outlet
valve and all valves
to storm valve.
2. Starting
6. Check the quantity of
oil in aeration blower.
- Add oil if necessary.
(Turbine oil)
2. Starting
8. Turn aeration blower
switch to “Run”.
- Confirm delivery press.
2. Starting
10. Remove the cap of
sterilizer and check
the disinfectant tablet.
If sterilizer is not full,
add additional tablets.
 Sterilizer : 16 Tablets
can be accommodated
 Average consumption
(SBT-25) : 9 Tab/week
2. Starting
11. Open Sewage inlet
valve (3 way valve)
3. Stoppage
 When the device must be shut down
for inspection/maintenance,
the following procedure should be taken.
1. Open direct overboard valve (3 way valve)
- When only vessel is in unrestricted waters.
2. Turn off “Aeration Blower” switch.
3. Turn off “Discharge pump” switch.
4. Turn off “Power source”.
4. Cautions
 Do not turn off the power source for aeration
blower under any circumstances.
 Microorganism will die
 Reduce the effectiveness of device
 Production of poisonous gas / Bad smell
 Possibility that air discharge nozzle clogs
 Do not use chemicals for cleaning of toilet.
 Kill the microorganisms in the tank
When used, they should be directly discharged
overboard only in unrestricted waters.
4. Cautions
 Do not use insoluble paper in water.
 Do not throw any foreign substances
into the toilet bowls.
 Do not mix (use alternately) flush water
for the toilet bowl (Sea / Fresh water)
 Adverse effect to the microorganisms
* The incubation period which microorganisms
are generated and stabilized is approx. one week
* While cleaning the bio-filter tank,
Use the same kind of cleaning water
as flush water used in the system.
5. Maintenance
5. Maintenance
5. Maintenance (Level Probe)
MARPOL Annex IV (Sewage)
- General
"Sewage" means:
.1 drainage and other wastes from any form
of toilets and urinals;
.2 drainage from medical premises
(dispensary, sick bay, etc.) via wash basins,
wash tubs and scuppers located in such
premises;
.3 drainage from spaces containing living
animals; or
.4 other waste waters when mixed with
the drainages defined above.
MARPOL Annex IV (Sewage)
- General
Ships constructed on or after 27 September 2003 shall comply with this regulation.
Ships constructed before 27 September 2003 shall comply with this regulation
not later than 27 September 2008.
International Sewage Pollution Prevention Certificate
(A renewal survey: five years)
MARPOL Annex IV (Sewage)
- Regulation 11 / Discharge of sewage
1 the discharge of sewage into the sea is
prohibited, except when:
.1 the ship is discharging comminuted and
disinfected sewage using a system approved
by the Administration in accordance with
regulation 9.1.2 of this Annex at a distance of
more than 3 nautical miles from the nearest
land, or sewage which is not comminuted or
disinfected at a distance of more than
12 nautical miles from the nearest land; or
.2 the ship has in operation an approved
sewage treatment plant which has been
certified by the Administration to meet
the operational requirements referred to
in regulation 9.1.1 of this Annex, and
.2.1 the test results of the plant are laid down
in the ship’s International Sewage
Pollution Prevention Certificate; and
.2.2 additionally, the effluent shall not produce
visible floating solids nor cause
discoloration of the surrounding water.
MARPOL Annex IV (Sewage)
- Company’s QSMS Manual
 Sewage treatment plant should be operated
12 miles from the nearest land
 The fact of close/open of the direct discharge valve
of sewage system and operation time of the sewage
treatment plant with ship’s position should be
recorded in the sewage operation log
 Special local regulation such as no sewage allow
to dispose - Portable toilets
Many thanks for your time
and kind attention!
Any questions?

[@Nagaraju8700]

Thanq very much sir , very beautifully explained with all the required regulations , thanq you very much

[@mathanraj.a1613]

How to order spare parts for this type STP -25 , I want to order 3 way valve and mechanical seal for discharge pump sir

[@mec6953]

sir, can you pls reply?
where is the drain valve is fitted? on sterilization tank or biofilter tank?
and second question why we need a drain valve?