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Protection of the Environment
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To comply with the MARPOL regulations on the environmental protection every ship must have an International Oil Pollution Prevention Certificate (IOPP). In order to obtain this certificate a vessel must first of all carry oily water separating and filtering system with oil discharge monitoring and control system, slop tanks, sludge tanks, piping and pumping arrangements. Any vessel is to be also equipped with an incinerator and sewage and waste water treatment system.
Oily or bilge waters shall pass through separating equipment first and the oil filtering system shall be such that it will accept the discharge from the separating system and produce an effluent the oil content of which doesn’t exceed 15 parts per million. It shall be provided with alarm arrangements to indicate when this level cannot be maintained. No discharge of effluent (residues) is permitted within12 miles of the nearest land. More stringent restrictions applied to the Baltic and Black Sea areas.
The discharge of sewage into the sea is prohibited, except when the ship is discharging comminuted and disinfected sewage using a system, approved by the regulations, at a distance of more than four 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, provided that in any case, the sewage that has been stored in holding tanks shall not be discharged instantaneously but at a moderate rate when the ship is proceeding at not less than 4 knots.
Unrestricted disposal of oil-contaminated mixtures, such as sludge from fuel treatment, into the sea is forbidden by international law, except under well defined conditions laid down in MARPOL, Annex 1. In practical terms there are two ways of disposing of fuel oil sludge; by on board incineration, or by storage on board for discharge to shore reception facilities. Some vessels have an incinerator which, besides being designed to burn sludge, can also deal with other ship generated wastes (garbage). On other vessels there may be arrangements by which the sludge can be burnt in an auxiliary boiler.
Upon entry into force of Annex VI to MARPOL on the 19 May 2005 the rules set limits on sulphur oxide (SOx) and nitrogen oxide (NOx) emissions from ship exhausts and prohibit deliberate emissions of ozone depleting substances. Another amendment (2008) specifies a global cap of 3.5% m/m on the sulphur content of fuel oil. Annex VI contains provisions allowing for special “SO Emission Control Areas” (SECAs) to be designated with more stringent control on sulphur emissions. In these areas the sulphur content of fuel oil used on board ships must not exceed 1% m/m. In order to meet these requirements it is often necessary for vessels trading to such areas to have an additional fuel oil storage tank with a fuel of the defined maximum level of sulphur.
Another environmental aspect relating to emissions resulting from the combustion of fuel oil is the nitrogen oxides (NOx) level of the exhaust gas. The level of NOx formed depends mainly on the combustion process, and for a diesel engine can be as high as 1500 ppm. This level can be reduced slightly, either by adjustment of the engine, usually with a slight rise in specific combustion, or by burning a fuel oil emulsion (a mixture of fuel finely dispersed with water). These methods alone, or in combination, are capable of giving the levels of reduction which are being discussed for future regulations. However, at present a few ports have local regulations which require much higher reductions; to meet these the exhaust gas has to be treated chemically. The plant required for this is large and expensive.
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- Using the information of the text discuss the following:
a) what is IOPP? Under what condition is it issued?
b) what is the purpose of the following equipment using: bilge water separator, filtering system, oil content meter, alarm arrangement, slop tanks, incinerator, sewage and waste water treatment system?
c) what do you know about SECAs? What for were they organized?
d) How is the nitrogen oxides level of the exhaust gases contained?
- Using the information of the text discuss what equipment must a ship carry to comply with:
- Annex I;
- Annex IV;
- Annex V;
- Annex VI.
- You are going to have your ship surveyed and a talk with the Inspector of the Port State Control. Can you foresee the inspector’s possible questions relating to the equipment used to prevent marine pollution by oil? (the following expressions will help you)
International Oil Pollution Prevention Certificate; to be fitted with; to comply with; to carry; residue or sludge tanks; capacity; a pipeline for the discharge of residues to reception facilities; separating and filtering equipment; oil content meter; to be in good operating condition (in order, in good repair); last discharge; entries in the Oil Record Book; bilge water separator certificate; take samples before and after the separator; dispose of fuel oil sludge.
- The Inspector of the Marine Pollution Control is going to extract penalty from your ship for the discharge of sewage into the sea. Give arguments that you are not to blame for that because you have done everything in accordance with the rules (see information in the text).
- During the ship’s survey explain to the Inspector what measures you take to avoid overfilling the sludge tanks (what operation is carried out and what equipment is used).
- Your ship is going to cross the SECAs and you have an inspection on board. What possible conversation will you have with the Inspector? Complete the dialogue and act it.
Inspector: As far as I understand, your ship is bound for Antwerp.
Chief Engineer:
Inspector: And do you know the new rules concerning marine pollution while sailing
in SECAs?
Ch. Engineer: (to cross; sulphur content; to exceed; additional fuel oil storage tank; to transfer)
Inspector: In this case I must check oil certificates.
Ch. Engineer: (sulphur content; meet the requirements)
Inspector: And if you don’t mind I’ll take samples of the fuel just to be sure that required fuel is on board.
Ch. Engineer:
Inspector: And by the waywhat is the capacity of the tank? Is it enough fuel for your voyage?
Ch. Engineer:
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- Your ship is going to leave the port and head for the SECAs. But she is forbidden to leave the port until the deficiency is eliminated. Think of a possible reason of your ship’s arrest (delay).
- Explain why regulations on the reduction of the nitrogen oxides level of the exhaust gas
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