Environmental Technology

Categorising sources of pollution

Paul Gunton
Paul Gunton

09 November 2018

Categorising sources of pollution

IMO says of MARPOL that it includes regulations aimed at preventing and minimising pollution from ships - both accidental pollution and that from routine operations - and currently includes six technical Annexes. Special Areas with strict controls on operational discharges are included in most Annexes.

The Annex I Regulations for the Prevention of Pollution by Oil (entered into force 2 October 1983) covers prevention of pollution by oil from operational measures as well as from accidental discharges; the 1992 amendments to Annex I made it mandatory for new oil tankers to have double hulls and brought in a phase-in schedule for existing tankers to fit double hulls, which was subsequently revised in 2001 and 2003.

Annex II Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk entered into force 2 October 1983) details the discharge criteria and measures for the control of pollution by noxious liquid substances carried in bulk; some 250 substances were evaluated and included in the list appended to the Convention; the discharge of their residues is allowed only to reception facilities until certain concentrations and conditions (which vary with the category of substances) are complied with. In any case, no discharge of residues containing noxious substances is permitted within 12 miles of the nearest land.

Annex III Prevention of Pollution by Harmful Substances Carried by Sea in Packaged Form (entered into force 1 July 1992) contains general requirements for the issuing of detailed standards on packing, marking, labelling, documentation, stowage, quantity limitations, exceptions and notifications. For the purpose of this Annex, “harmful substances” are those substances which are identified as marine pollutants in the International Maritime Dangerous Goods Code (IMDG Code) or which meet the criteria in the Appendix of Annex III.

Annex IV Prevention of Pollution by Sewage from Ships (entered into force 27 September 2003) contains requirements to control pollution of the sea by sewage; the discharge of sewage into the sea is prohibited, except when the ship has in operation an approved sewage treatment plant or when the ship is discharging comminuted and disinfected sewage using an approved system at a distance of more than three nautical miles from the nearest land; sewage which is not comminuted or disinfected has to be discharged at a distance of more than 12 nautical miles from the nearest land. In July 2011, IMO adopted the most recent amendments to MARPOL Annex IV which entered into force on 1 January 2013. The amendments introduce the Baltic Sea as a special area under Annex IV and add new discharge requirements for passenger ships while in a special area.

Annex V Prevention of Pollution by Garbage from Ships (entered into force 31 December 1988) deals with different types of garbage and specifies the distances from land and the manner in which they may be disposed of; the most important feature of the Annex is the complete ban imposed on the disposal into the sea of all forms of plastics. In July 2011, IMO adopted extensive amendments to Annex V which entered into force on 1 January 2013. The revised Annex V prohibits the discharge of all garbage into the sea, except as provided otherwise, under specific circumstances.

Annex VI Prevention of Air Pollution from Ships (entered into force 19 May 2005) sets limits on sulphur oxide and nitrogen oxide emissions from ship exhausts and prohibits deliberate emissions of ozone depleting substances; designated emission control areas (ECAs) set more stringent standards for SOx, NOx and particulate matter. Currently these are few in number and while more are predicted for the future there are none in the pipeline that will impact on the major trade lanes. Particulate matter or PM as it is often known are solid particles that originate from many sources mostly natural and also from an extremely diverse range of human activities including cooking, cement production and burning of fossil fuels. Shipping’s main source is of course the combustion of fuels in diesel engines. PM has been cited as a major health problem with the smallest size measuring 2.5 microns often referred to as PM2.5, being seen as the most dangerous in this regard. PM from burning fuels include sulphates which are of course partially regulated under Annex VI because of the limitation on sulphur levels in fuels. Another that is not yet regulated but which is coming under increasing attention is black carbon especially with regards to Arctic shipping. There are many who believe that the impact is insignificant but the IMO’s MEPC has decided to pursue the matter.

At MEPC 68 in May 2015, the IMO approved the Bond et al. definition as proposed by the Pollution Prevention and Response Sub-Committee and noting the need for voluntary black carbon measurement studies to be conducted in order to gain experience with the application of the definition and measurement methods, agreed that protocols for such voluntary measurement studies are needed and invited that interested parties to submit relevant proposals/information to the next meeting of Pollution Prevention and Response Sub-Committee.

Following the decision the IMO’s interpretation of what constitutes black carbon is:

‘Black Carbon’ is a distinct type of carbonaceous material, formed only in flames during combustion of carbon-based fuels. It is distinguishable from other forms of carbon and carbon compounds contained in atmospheric aerosol because it has a unique combination of physical properties. With respect to this issue, it was also noted that at this stage measures to reduce the impact on the Arctic of emissions of black carbon from international shipping is not possible.

MARPOL with its six annexes and SOLAS between them regulate many aspects of ship construction aimed at minimising the environmental aspects of ships. Similarly MARPOL has influenced many operational practices onboard tankers and every other type of ship. These areas will not be covered by this guide which is focussed on describing the technology and equipment designed to aid compliance with those areas of regulation that can only be met using equipment.

In the main these are regulated by Annexes I, IV, V and VI of MARPOL but there are other areas outside of these where shipping has to meet regulatory demands. As examples, the International Convention on the Control of Harmful Anti Fouling Substances on Ships, 2001 and the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, 2004 (not yet in force) are being addressed by a new generation of coatings and a growing number of ballast water treatment systems. Ironically the coatings convention was designed to reduce the impact of biocides on marine life but there are now discussions on imposing new controls on bio-fouling of ships in order to prevent the transfer of species into new areas.

Both ballast water treatment and coatings are the subject of other ShipInsight Guides which deal with them more comprehensively than they are covered in this. However, there is a chapter in this guide which deals with the wider subject of water waste and another covering the topic of coatings.

So far all of the regulation mentioned has been promulgated by the IMO but there are also local regulations in some parts of the world that affect the equipment installed on ships. Once again ballast water treatment serves an example; with the US having adopted its own rules that are already in force while the IMO convention has not yet been ratified by sufficient states.