Stricter legislation with regard to pollution of the sea limits and, in some instances, completely bans the discharge of untreated wastewater, sewage, waste oil and sludge. The ultimate situation of no discharge can be achieved by the use of a suitable incinerator.
What is an incinerator?
A shipboard facility designed for the incineration of wastes or other matter on board, generated during the normal operation of the ship. Incinerators are predominantly designed for intermittent operation, hand fired and fed by hand. The ash or vapour can be hazardous.
When used in conjunction with a sewage plant and with facilities for burning oil sludges, the incinerator forms a complete waste disposal package.The combustion chamber is a vertical cylinder lined with refractory material. An auxiliary oil-fired burner is used to ignite the refuse and oil sludge and is thermostatically controlled to minimise fuel consumption. A sludge burner is used to dispose of oil sludge, water and sewage sludge and works in conjunction with the auxiliary burner.
Combustion air is provided by a forced draught fan and swirls upwards from tangential ports in the base. A rotating-arm device accelerates combustion and also clears ash and non-combustible matter into an ash hopper. The loading door is interlocked to stop the fan and burner when opened.
Fortunately, there are Marine Service companies that provide incinerator maintenance and repairs.
Solid material, usually in sacks, is burnt by an automatic cycle of operation. Liquid waste is stored in a tank, heated and then pumped to the sludge burner where it is burnt in an automatic cycle. After use the ash box can be emptied overboard.
Procedure For Ships Waste Via Marine Incinerator
Shipboard generated wastes can only be disposed of legally by the following two methods –
- Disposal by onboard Incineration
- Disposal to a shore based facility
The availability and cost of disposal to shore based facilities and the trading constraints such as time in port, access at tanker terminals and other restrictions have made option “b” less attractive. Oil and sewage sludge incineration may take place in main or auxiliary power plants or boilers, but not whilst in ports or enclosed water.
Waste incineration onboard sea going ships is regulated by IMO MARPOL 73/78 Resolution MEPC.176(40), adopted 10 October 2008 and IMO MARPOL Annex VI, Chapter III Regulation 16 and Appendix IV – Requirements for Control of Emissions from Ships – Shipboard Incineration.
All new Incinerators installed onboard a ship on or after 1st January 2000 require compliance with the above regulations and shall have IMO Type Approved Certificate.
It is prohibited to incinerate:
- Residues of cargoes subject MARPOL Annex I, II, III
- Polychlorinated biphenyls (PCB)
- Garbage containing heavy metals, defined in Annex V
- Refined petroleum products containing halogens
- Sewage sludge and sludge oil either of which are not generated onboard the ship
- Exhaust gas cleaning system residues.
Polyvinyl chlorides (PVCs) can only be incinerated in IMO type approved incinerators. In accordance with the Helsinki Convention, all ships are prohibited to use their incinerators whilst in the Baltic Sea area. See Attached “Clean Seas Guide Baltic States” for an overview of the regulations governing this area.
The following conditions must also be met:
- Personnel responsible for operation of any incinerator shall be trained.
- Manufacturer’s manual for the incinerator shall be available onboard.
- Minimum flue gas temperature is 850 degrees Centigrade.
- The unit shall reach 600 degrees Centigrade within 5 minutes after start up.
- Monitoring of flue gas outlet temperature required.
Incinerators without IMO type approval Certificate or installed before 1st January 2000 can still be used for burning SLUDGE OIL and solid waste provided this does not contain any plastic or synthetic materials. In addition to the above, the following criteria must be established.
- Quantify and designate Sludge preparation tanks for ships using heavy fuels: 2% of daily consumption.
- Quantify Incinerator use: 1% of the bunker consumption plus 2-3 hours for solid waste incineration.
- Owners must decide on the number of hours per day that the Incinerator should be allowed to work. Generally 8-12 hours per day.
- Consideration should be made for ships trading in ECA areas (e.g. Baltic Sea) where incineration is not allowed. Put up suitable notices.
- Please confirm that your vessel has a manual for the Incinerator.
- The Operator must be trained in the use of the Incinerator by the Chief Engineer and records of this training must be maintained.
Marine Service companies also provide repair and maintenance services for incinerators.