REVISED GUIDELINES FOR SYSTEMS FOR HANDLING OILY WASTES IN MACHINERY SPACES OF SHIPS
1 The revised Annex I of MARPOL 73/78 contains certain regulations and unified interpretationsrelatedtoequipmentforthestorage,handlinganddisposalofoilyresiduesand engine-room oily bilge water.
2 InthecontinuousreviewbytheMarineEnvironmentProtectionCommittee(MEPC)of appropriate technology for fulfilment of the Convention requirements, substantial information has been collected which is valuable in the design, approval and surveying of installations in engine-roomsforsystemshandlingoilybilgewater,andoilyresidues,butthisdoesnotform part
of the Convention regulations orthe related interpretations.
3 The MEPC had decided that this information is, nevertheless, of substantial value to Administrations,shipownersandshipbuildersand,accordingly,decidedthatdisseminationofthe information should be in the format of an MEPC circular.
4 The information contained in these Guidelines should be regarded as guidance in achievinganefficientandeffectivesystemforthehandlingofoilybilgewaterandoilyresidues
for new buildings and, where applicable and reasonable, for ships which are in service. The information should be considered in conjunction with specific conditions and circumstances, shipownersíandshipbuildersípractices,classificationsocietyrules,Administrationrequirements, etc., applicable to specific ships.
5 Definitions for the purpose of the Guidelines
5.1 Oily waste means oil residues (sludge) and oily bilge water.
5.2 Oil residue (sludge) means:
.1 separated sludge, which means sludge resulting from purification of fuel and lubricating oil;
.2 drainandleakageoil,whichmeansoilresultingfromdrainagesandleakagesin machinery spaces; and
.3 exhausted oils, which means exhausted lubricating oil, hydraulic oil or other hydrocarbon-based liquids which are not suitable for use in machinery due to deterioration and contamination.
5.3 Sludge tanks mean:
.1 tanks for separated sludge;
.2 drain and leakage oil tanks; and
.3 exhausted oil tanks.
5.4 Bilge water holding tanks mean tanks for oily bilge water.
MARPOL 73/78 adopted by resolution MEPC.117(52).
5.6 Oilsludgeincineratorsaresystemsprovingincinerationofoilsludgegeneratedonboard seagoing ships.
Sludge incinerators could be:
- main and auxiliary steam boilers with appropriate oil sludge processing systems;
- heaters of thermal fluid systems withappropriate oil sludge processing systems;
- incinerators with appropriate oil sludge processing systems designed for sludge incineration; or
- inert gas systems with appropriate oil sludge processing systems.
6 Collection and storage of oily wastes
6.1 A sludge tank or tanks are mandatory under regulation 12.
6.2 A bilge water holding tank is arranged to receive the daily generation of bilge water beforethiswaterisdischargedashoreordischargedthroughthe15ppmequipmentoverboard.
A bilgewaterholdingtankisnotmandatory,butwillenableshipstooperatesafelyduringport visits,duringoperationinspecialareasandcoastalwatersandduringperiodsofmaintenanceof
the 15 ppmequipment.
6.3 Abilgewaterholdingtankwillalsoprovideadditionalsafeguardsinthepurificationof oily bilge water should quick-separating detergents be used for cleaning purposes.
7 Arrangements for oily waste tanks
7.1 Tanks for the purposes mentioned above should be arranged to satisfy the intended service of the ship.
7.2 Sludge tanks may be separate and independent but may also be combined, as suitable, depending on the size and the service of the ship.
beconsidered,havingregardtothesmallertankvolumethatneedstohavecleaningandheating arrangements and the reduced space requirement for tank capacity that should preferably be arranged above the tank top.
7.4 Ifabilgewaterholdingtankisarranged,itshouldbeseparateandindependentfrom other tanks for the collection of sludge.
7.5 Ships operating with residual fuel oil of a relative density greater than 0.94 at 15°C shouldbeprovidedwithabilgewaterholdingtankofadequatecapacityandfittedwithheating facilities to preheat the oily mixture prior to the discharge of the tankís contents into the sea through 15 ppmequipment.
8 Size of oily waste tanks
8.1 Tanksforcollectionofoilywastefromvariousfunctionsintheengine-roomshouldhave adequate capacity, having regard to the intended type of service of the ship. The information givenbelowwillprovideguidanceinthisrespect,butallotheraspectsapplicabletothespecific vessel trading pattern and time in port should additionally betaken into account.
8.2 The recommended capacity for oil residue (sludge) tanks is specified in the interpretations
to regulation 12.
8.3 Ifanexhaustedoiltankisinstalled,inadditiontotherequirementunderregulation 12,it should be of sufficient capacity to receive lubricating oil or other oils and hydrocarbon-based liquidsfromengine-roomsystemsbeingexhaustedduetodeterioration,contaminationordueto maintenance activities. The oil being discharged from the 15 ppm equipment may also be dischargedtothistank. Formainandauxiliaryengines,whichrequireacompletechangeofthe lubricatingoilatsea,thecapacityofthetankshouldbedeterminedas1.5m¹foreach1,000kW engine rating.
8.4 If a drain and leakage oil tank is installed, in addition to the requirement under regulation 12, it may be arranged at several locations in the engine-room. The oil being dischargedfromthe15ppmequipmentmayalsobedischargedtothistank. Therecommended capacity should be as follows:
Main engine rating (kW)
up to 10,000
20 x D x p/106
D x (0.2 + 7 x (P-10,000)/106)
where, D = days; the same length of the voyage as used in the interpretation to
P = main engine rating in kW.
8.5 Bilgewaterholdingtanks,iffitted,shouldhaveacapacitythatprovidestotheshipthe flexibilityofoperationinports,coastalwatersandspecialareas,withouttheneedtodischarge
de-oiledwateroverboard. Theoperationalmeritofnothavingtooperatethe15ppmequipment frequently should also be considered. The capacityofbilgewaterholdingtanksshouldbeas follows:
Main engine rating (kW)
up to 1,000
Above 1,000 up to 20,000
1.5 + (P-1,000)/1,500
14.2 + 0.2 (P-20,000)/1,500
where, P = main engine rating in kW.
9 Pumping, piping and discharge systems in machinery spaces
9.1 On board ships, the propulsion systems of which are operated by heavy fuel oil, the followingguidelinesareprovidedforthepipingsystemcomprisingtheplantcomponentsforthe treatmentandstorageofoilybilgewater,separatedsludge,drainandleakageoilandexhaustedoil.
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or bilge water holding tank.
9.3 If an integral pump is fitted, the discharge should not bypassthe 15 ppmequipment.
9.4 The discharge piping system of the 15 ppm equipment should be completely separate from the bilge pumping and ballast water system except the recycling line referred to in paragraph 9.2.
be separated fromthe bunker fuel oil.
9.6 The separated dirty water and exhausted control water of fuel oil purifiers should be dischargedintoaparticulartankforthispurposeinordertominimizetheinfluxtothetankfor separatedsludge. Thisparticulartankshouldbelocatedabovethedoublebottomforthepurpose
offacilitatingitsdrainwithouttheneedforadrainpump. Ifdirtywaterandexhaustedcontrol water from purifiers is not discharged to a particular tank, and in lieu of this to a tank for separated sludge, the tank should be located above the double bottom for the purpose of the aforementioned draining facilities.
9.7 Pipingtoandfromsludgetanksshallhavenodirectconnectionoverboard,otherthanthe standard discharge connection required by regulation 13.
10 Systems for separated sludge
10.1 Tanks for separated sludge and their pipework
Tanks for separated sludge, their pipeworkand pumps should be designed as follows:
10.1.1 Size of tanks
See paragraph 8.
10.1.2 Design of tanks and tank heating systems
The tanks and tank heating systems should be designedtothesatisfaction of the Administration.
10.1.3 Tank heating system
Tanks for separated sludge should be equipped with tank heating systems. The heating pipes should be arranged so that, seen from the heating inlet, they are arranged away from the boundaries and then, across the whole bottom area, sufficiently high to avoid being covered totally by sediments in the tank.
The tank heating systemshould be designed so as toenable heating of the oil sludge up to 60°C. The suction line fromthe sludge tank to the pump should be provided with heat tracing.
10.1.4 Pipelines from the heavy fuel oil purifier to the tank
Wheneverpossible,thesludgetankshouldbelocatedbelowtheheavyfueloilpurifier. Ifthisis notpossible,thesludgetankshouldbesituatedclosetotheheavyfueloilpurifierinsuchaway that the discharge line to the tank can be installed at the maximum gradient. The pipelines should, wherever possible, be straight or fitted with large radius elbows.
10.1.5 Thesubmersiblepumporopeningofthesuctionlineshouldbearrangedsothattheoil sludge'spathtothesuctionopeningisasshortaspossible,orthesludgetankshouldbemounted or designed, so that the oil sludge moves down a slope towards the suction opening The openingsshouldbeplacedaswideaspossibleintheframesabovethetankbottom insuchaway that the oil sludge has freeaccess to the suction line.
10.1.6 Pump and pressure lines
The pump should be suitable for use with high viscosity oil sludge e.g., “self-priming displacement pump”, with suitable means for protection against dry running.It should have total head of at least 4 bar, and the delivery rate should be determined by applying the formula:
Q = v /t (m¹/h)
where V is the volume of the sludge tank as calculated by the interpretation to regulation 12. Fourhoursshouldbesubstitutedforthetimet. However,thepumping capacity should be not less than 2.0 m¹/h.
Thegeodeticsuctionheadofthepumpshouldnotexceed3.0mforshipswithamainengine rating up to 15,000 kWand 3.5 mfor ships greater than 15,000 kW.
Thepressuresideofthepumpshouldonlybeconnectedtothetransferlineondeck,tosludge tanks and to the incineration equipment, if provided.
10.1.7 Sludge tank design to facilitate cleaning
Access holes should bearranged so that all areasofthetankcanbe cleaned. Anaccesshole should be sited on top of the tank to facilitatetheuse of a portable pump.
10.1.8 Steaming-out lines
The top of sludge tanks should be fittedwith steaming-out lines for cleaning.
11 Example of an on-board systemfor oil sludge incineration
are oil sludge incinerators.
11.2 Oil sludgeincinerators
An oil sludge incinerator systemis composed of:
- steamboiler or heater of thermal fluid systems or an incinerator;
- oil burner;
- oil sludge processing system; and
- tanks for separated sludge.
11.3 Oil sludge processing systems
The oil sludge processing systemconsists of:
- tank for mixing oil residues with fuel oil (mixing tank);
- oil sludge preheating system;
- filter; and
- homogenization system.
11.4 Mixing tank
Themixingtankshouldbeprovidedinadditiontothetankforseparatedsludge. Itshouldbe equippedwithsuitabledrainagefacilities. Withaviewtoimprovingcombustibilityandcalorific value, a fuel oil supply connection should be provided.
11.5 Homogenization system
Thehomogenizationsystemshouldassurethattheentirecontentsofthemixingtankshouldbe processedintoahomogenousandcombustiblemixture. Thissystemshouldbeputintooperation followingadequatedrainingofthetank. Adeviceforcontinuousindicationandmonitoringof
the water content ofthe oil sludge should be provided.