Environment Alert
Alert No.
Environment Alert / 05 / 2021
Type of Alert
Alert
Environment
Oil Tankers
Applicable to
Bulk carriers
Quality Assurance into the
21st Century and beyond
TSM Form
No. 204E
Experience Feedback
Gas
Chemical
Office Staff
Tankers
Tankers
Gen.
Offshore
Oil & Gas
cargo
vessels
vessels
All Ships
Date
25th Feb 2021
File No:
23.1
Approved
by
Sub folder
HOD Environmental Compliance
23.1.4
BILGE HOLDING TANK- CONCERNS & IMPACT
KEY ISSUES AND CONCERNS
This alert aims to provide guidance and reminder on the significant role Bilge tank condition plays in
the smooth operation of Oily water separator and OCM. Following points are dealt with in this alert:
1.
2.
3.
4.
5.
6.
7.
Bilge Holding Tank and its IOPP Nomination & OWS connect.
Bilge Holding Tank/ ER Bilge wells: Contamination Sources.
Impacts of above-mentioned ingress into bilge holding tank/ bilge well
Actions to be taken if any of listed designs are sighted on board.
Interim measure until such permanent piping changes are expedited.
Bilge tank disposals for cleaning, recording and refill for test
Miscellaneous aspects of bilge holding tank and bilge system
In view of several Port-state detentions and deficiencies experienced globally due to non-performance
of Oily water separator, performance of which is predominantly attributed to condition/concerns with
Bilge holding tank. Hence this alert aims to render a unified understanding wrt sources of ingress into
Bilge tank to ensure smooth functionality of the OWS/OCM, disposal of tanks contents, cleaning of
tank and relevant recording.
1.
BILGE HOLDING TANK- IOPP LISTING
Ref MEPC 187(59), Marpol Annex-1 reg 1 Para 1.33 states “Oily bilge water means water which may be
contaminated by oil resulting from things such as leakage or maintenance work in machinery spaces.
Any liquid entering the bilge system including bilge wells, bilge piping, tank top or bilge holding tanks is
considered oily bilge water. Hence any water/ liquid which touches tank top and bilge well, is
considered as bilge and must be discharged only through Oily water separator and/ or shore
receptions. Any tank which holds this water prior its discharge to shore or sea (via 15ppm equipment)
is bilge tank. Bilge tank is listed under Sec 3.3 of IOPP form B.
There may be a possibility on some ships having more than one Bilge tank in IOPP 3.3 listing.
Nevertheless, if tank or tanks are source tank for OWS, same must be cleaned annually.
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Environment Alert
2. BILGE HOLDING TANK- CONTAMINATION SOURCES
Depending on vessel piping designs, varied sources of transfers/ingress into the Bilge Holding tank has
been sighted and which though being an approved design, still can contaminate the bilge Holding tank
and interfere with the OCM functionality. Following Sources are listed for easy reference:
a. Exhaust gas economizer & Aux Boilers/ Composite Boilers save all drains into the Bilge
Holding tank.
b. Economizer wash water to Soot water tank, drains into Bilge Holding tank.
c. Scrubbers Wash-water drains or IGG Fan Drains.
d. Oily Condensate drains from Waste Oil settling/ Service tanks into BHT
e. Main Air Compressor unloader drains leading into bilges/ Bilge wells.
f. Grey water/ Treated sewage collection into the Bilge Holding tanks.
g. ER Bilge pump’s suction ability from the 3.1 listed tank.
h. ER wash basin drains to the Bilges or Bilge holding tank.
i. CFW Cooler & FWG condenser chemical cleaning drains to Bilge wells after Chemical
cleaning.
j. Funnel Mist Box Condensate drain.
Ps Note: The JCW drains (ME Unit overhauls), expansion tank content drains or cascade tank content
drains have presence of chemicals and may impact OWS functioning, similarly as above. Based on
operation experience, such changes can be evaluated with office & ECD.
CE to verify onboard bilge piping drawing and system. In case any or all above scenarios are found, CE
to approach office as described in Sec 4 below.
Note: All above mentioned sources in Sec2 have high potential to contaminate Bilge
Holding tank and interfere significantly with functioning of the 15ppm OCM. Such cases
may cause unsatisfactory demonstration of OWS/OCM test in Port for the PSC and may
lead to fines/ detentions.
3. IMPACTS OF ABOVE-MENTIONED INGRESS INTO BILGE HOLDING TANK/ BILGE WELL
One or all sources as mentioned in Sec 2 above can have following adverse impacts such as:
a. Bilge wells and Bilge Holding tank getting frequently dirty/ oily thus warranting
frequent cleaning intervals as well as maintenance in enclosed space related concerns.
b. OWS filters/ coalescer getting choked/ Oily and warranting frequent & expensive
renewals.
c. OCM functioning erratic due to following:
I.
Soot suspended in EGE wash water interferes with OCM and dirties optical cell
II.
Grey water and Treated sewage have suspensions solids which impacts OCM
functioning.
III.
CFW chemical Cleaning drain, Boiler water drains or any other such sources
that have chemicals, will possibly result into frothing/foaming thus causing
high ppm of OCM due to foaming.
IV.
ER wash basin drain have possibility of oil/ grease carry over into BHT
V.
Main air compressor condensate auto drains likely to impact the Bilge wells
and make it appear oily.
Below is some sample photo to enhance understanding on adverse impacts these bilge water sources
(Ref Sec 2) can have on Bilge holding tank and functioning of OCM. Needless to state such
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contamination impacts OWS/OCM function and at times in Port, failure to perform recirculation test
leads to delays, Detentions.
4. ACTIONS TO BE TAKEN IF ANY OF ABOVE DESIGNS ARE SIGHTED ON BOARD
The ships which has one or all above designs piping from sources as listed above in Sec 1 is strongly
recommended to do the following:
a. Inform VM and keep ECD in copy.
b. New piping layout is planned and reflected in the ER Bilge tank piping modification.
c. The piping proposed is to allow drainage/ transfer of above-mentioned sources in Sec
1 to any of the 3.1 listed tanks.
d. Piping modification drawing is sent to office (VM) who in turn will review and forward
to class for approval.
e. Class approval received for piping modification proposal after which Modifications
carried out.
f. Verification of piping modification if/ as required by Class.
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5.
SOME INTERIM MEASURE UNTIL SUCH PERMANENT PIPING CHANGES ARE EXPEDITED
All Vessels must approach VM with ECD in copy to propose following as interim measure until
permanent class approved modifications:
a. EGE wash water/ Soot Collecting tank drains to Bilge holding tank must be shut, seal
tagged and blanked. Any water collected post cleaning to be manually transferred to
any of 3.1 listed tank for evaporation (for MI flagged) and/ or discharged overboard by
fixed approved piping. Ref Alert 03-2021
b. Waste Oil Settling / Service tanks and or any other Waste oil tank drains to Bilge
Holding tank must be shut, blanked and seal tagged. Any condensate collected to be
evaporated and not drained.
c. Grey water tank or Treated sewage drains to Bilge Holding tank must be stopped at
earliest and alternate design to direct same to alternate tanks, to be expedited.
d. ER wash basin drains to be blanked and alternate location used for hand cleaning
e. The CFW cooler chemical cleaning effluent NOT to be drained to Bilge well or Bilge
tank as this will cause frothing and OCM malfunction. Same to be manually transferred
to 3.1 listed tank and due records made in ORB.
f. Any system with Bilge pump suction ability from sludge/ Waste Oil/ 3.1 Listed tanks,
must be immediately shut-blanked-seal tagged and informed to ECD. Such
arrangements are not in compliance.
g. Mist box drains should be checked for manually transferring to 3.1 listed tank and any
ingress to Bilge holding tank, should be blanked.
6.
BILGE TANK DISPOSALS FOR CLEANING, RECORDING AND REFILL FOR TEST
Bilge holding tanks must be annually cleaned as required vide TGP 1.3.5. The disposal of the Bilge Tank
contents can be done in any of the following conditions:
Scenario 1: Disposal by OWS. OWS functional and Bilge water condition normal in bilge well and
Bilge holding tank:
▪ Discharge through OWS in line with Marpol Annex 1 Reg 11 (TSM164) to reduce
contents Record in ORB as D 13/14/15.1
▪ Remaining unpumpable water to transfer to 3.1 listed manually by Portable pump.
(Office concurrence TSM 214). Record as D13/14/15.3 & C11.1/11.2/11.3/11.4
▪ Bilge tank cleaned (after safe enclosed space entry related permits /RA etc) and entry
made in ORB under “I” and AMOS updated.
Scenario 2: Disposal by evaporation (Ref TGP1.3.5 A10). OWS functional and Bilge holding Tank
water, Bilge wells if contaminated with dirty/ oily water:
▪ In such cases of contaminated Bilge tank, Manual Transfer by portable pump of dirty/
oily bilge water to IOPP 3.1 listed tank is recommended (Portable pump Office
concurrence TSM 214). Record in ORB part-I as D13/14/15.3 & C11.1/11.2/11.3/11.4
for transfers from Bilge Holding tank to IOPP 3.1 listed tank. If transferred manually
from Bilge wells only (non IOPP Listed) then only C11.1/11.2/11.3/11.4 to be used for
recording in ORB Part-1.
▪ Bilge tank cleaned (after safe enclosed space entry related permits /RA etc.) and entry
made in ORB under “I” and AMOS updated.
▪ Transferred contaminated Bilge water, evaporated from 3.1 Listed tanks, and recorded
as C12.4 in ORB -I.
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Environment Alert
▪
On ships with design of steam heating coil in Bilge Holding Tank, such can be disposed
cleanly by evaporation and recorded in ORB-I as “I”. Remainder Oily water is
transferred manually to 3.1 Listed tank (recorded as C11.1/11.2/11.3/11.4) and then
Bilge Holding tank cleaned & Recorded as “I” in ORB-I.
Scenario 3: Transfer from Bilge Holding tank to Deck Slop Tank/ ROT (Tanker):
▪ Such transfers can be done only if it’s mentioned in IOPP Form B Sec 3.2.3. Thereafter
the transfer to be recorded in ORB-I as D13/14/15.3 and in ORB-II as J 55/56/57.3.
Note: If such is not crossed in IOPP Form B sec 3.2.3, then transfers to slop/ ROT? Or
any other tank can be done only with Flag approval.
▪ Bilge tank cleaned (after safe enclosed space entry related permits /RA etc) and entry
made in ORB under “I” and AMOS updated.
Scenario 4: Shore landing of Bilge Holding tank:
▪ Bilge Holding tank contents can be landed ashore to Port reception facilities through
ship’s fixed pumping and piping system only. Entry to be made in ORB- as D13/14/15.2
▪ If such shore landing is to be made by shore Portable pump and flexible hose, Flag
approval will be mandatory for same and TSM 214 for office concurrence. Landing
receipt must be procured from the shore.
▪ Bilge tank cleaned (after safe enclosed space entry related permits /RA etc.) and entry
made in ORB under “I” and AMOS updated.
** Master/CE to clarify with ECD department in case of any doubts wrt ORB entry.
Note: All vessels MUST ensure Bilge water tank content is clean and in sufficient amount for a
port recirculation test as may be required by Port state. In case Bilge holding tank, content is
not enough for OWS recirculation test, Master to approach office with ECD in copy for guidance
on filling up and ORB record.
7.
MISCELLANEOUS ASPECTS OF BILGE HOLDING TANK AND BILGE SYSTEM
Following important aspects to be adhered to with respect to Bilge holding tank and its associated
systems and planned either in normal sailing or during dry dock:
▪
▪
▪
▪
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The Bilge pump suction piping should not have any connectivity from Sludge system. If
it’s found, ECD must be informed for way forward to isolate Bilge from Sludge systems.
Some ships have Bilge tank named in ships design/ Capacity plan but not necessarily in
the IOPP 3.3 listing. No ORB recording is required for such Non-IOPP tanks.
If Bilge Holding tank listed in IOPP Sec 3.3 is receiving a ME air cooler condensate or
Accommodation air-condition condensate as draining by gravity, no entry is required
in ORB for these drains. Weekly ROB entry in ORB-I, will suffice.
To prevent excessive Bilge loading by these clean condensates of ME air cooler and
accommodation AC drains, following is recommended:
✓ Modification can be proposed for routing the air-condition condensate water
to nearest direct overboard scupper, subject to class approval.
✓ ME Air cooler condensate drain to an alternate tank with direct pumping (Fire
& GS pump or Bilge pump) can be planned in next docking with class approval
to reduce bilge loading.
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Environment Alert
▪
▪
▪
Bilge pump and piping up to the OWS inlet is not required to be seal tagged. Only OWS
and its overboard discharge piping is to be seal tagged as per TGP 1.3.5 A3.
Bilge holding tank Manhole is recommended for seal tagging (2 tags spaced 180°).
Any tank which has approved design of direct overboard (Eg: Clean Drain tank, Grey
water tank, sewage holding tank, Soot water tank etc.), must have their manholes seal
tagged (2 seals 180° apart). Ref TGP 1.3.5 A3.
Additional/ Optional Recommendations for DD (To be proposed & done with Class approvals):
▪
▪
▪
▪
▪
8.
Soot Collection tank can be planned for Heating coil installation in dry dock for clean
disposal of same rather than leading to 3.1 or 3.3 listed tanks.
Bilge holding tank and/ or Bilge primary tank can be proposed for heating coils
installation in dry dock to ensure clean disposals for bilge water.
Good filter/ strainer is planned for installation at Bilge pup suction to eliminate rust/
dust/ dirt entering Bilge Holding tank
OWS pre-Filter unit is recommended to be installed for recirculating Bilge holding tank
to Bilge holding tank and eliminating undesired contents reaching and spoiling OWS
filters/ coalescers/ filter bed etc.
Ps Note: Any of IOPP 3.1 Listed Waste Oil/ Sludge tank Manholes and/or sludge piping
system are not required to be seal tagged (Except for shore discharge flanges). Ref TGP
1.3.5 Sec.
VERIFICATION REQUIRED ONBOARD BY VESSELS
✓ Master / CE to verify on the Bilge Holding tank, Various ingress possibilities, IOPP 3.3 Listing,
IOPP form B sec 3.2.3 verifications.
✓ If any of the conditions as mentioned in sec 2, then Master/CE to advise VM/FG with
modification proposal keeping ECD in copy.
✓ Master/CE to verify various ORB entries wrt Bilge Holding Tank including cleaning, its AMOS
records as well as seal tag records.
✓ Address any query pertaining to this alert and compliance to Fleet Group/ ECD.
9.
UPON RECEIPT OF THIS CIRCULAR
1. Shipboard Management Team to read and understand the contents for dissemination to
concerned ship staff for compliance.
2. Print the Environment Alert/ Circular and file.
3. Carry out Training of the ER ship staff by Master/ CE on this Alert/ circular for clear guidance
on Bilge Holding Tank Management, its recording and reporting requirements. Training to be
recorded in TSM 162 and reverted to:
TO:
Vessel manager of your vessel/ Fleet group Manager
CC:
environmental.compliance@thome.com.sg
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