What are the new technologies for ship pollution control nowadays?

The main conventions for the prevention of marine pollution from ships are MARPOL 73/78 for oil substances, noxious liquid substances, hazardous substances in packaging, sewage, garbage and air pollutants emitted from ships. This convention has been applied to ships that account for 99% of the world's merchant shipping gross tonnage. In addition to MARPOL 73/78, there is also the International Convention on the Control of Harmful Anti-fouling Substrate Systems on Ships, 2001 (hereinafter referred to as the Anti-fouling Substrate Convention) for hazardous anti-fouling paints on ships, the International Convention for the Control and Management of Ships' Ballast Water and its Sediments, 2004 (hereinafter referred to as the Ballast Water Convention) for ships' ballast water carrying alien organisms and pathogens, and the Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships (hereinafter referred to as the Shipbreaking Convention) deals with safety, environmental protection and health issues in the dismantling of ships after their decommissioning. In the relevant conventions on the prevention of marine pollution from ships, science and technology serve as the technical support for the formulation of the conventions and their fulfillment, so that the technical standards in the conventions are clear and feasible; the formulation and revision of the conventions in turn provide opportunities and impetus for the development of science and technology. First of all, the achievements of science and technology are adopted by the shipping industry, promote the technical progress of the shipping industry, and become a strong technical basis for the formulation and amendment of the convention, without science and technology, it is difficult to control the pollution of the ship, for example: the anti-fouling bottom convention was formulated to restrict the use of anti-fouling paints which are very hazardous to the environment, but to prohibit the use of anti-fouling paints containing TBT, there should be an alternative measure as a precursor; the MARPOL 73/78 Bylaws which came into effect in 2007, are the first to be adopted by the shipping industry. MARPOL 73/78 Annex II amendment on cargo hold residue requirements than the original provisions of the original much lower, which is in the pumping and suction equipment and piping arrangement on the basis of improved technical performance can be realized; MARPOL 73/78 Annex VI for the fuel oil sulfur content of the gradual reduction of the requirements of the marine fuel oil according to the technological development. Sometimes the formulation of international maritime conventions is ahead of technological development, for example, when the Ballast Water Convention was formulated in 2004 and ships were required to install ballast water management systems, there was no mature ballast water treatment technology and commercial equipment available to ships. Following the introduction of the Ballast Water Convention, the international community quickly invested in research and development to address the threat of invasive alien organisms and pathogens. So far, several manufacturers have launched type-approved ballast water management systems, which IMO believes can basically meet the needs of ships applicable in 2010. When formulating and proposing relevant technical requirements for the anti-pollution convention, IMO not only relies on its own technical force, but also utilizes the United Nations Group of Experts on Marine Pollution (GESAMP) to solve technical problems in formulating and reviewing the convention and its implementation. For example, the GESAMP-BWWG Joint Technical Group (JTG) is responsible for considering the technical aspects of ballast water management systems using reactive substances and making recommendations to the Committee for approval and/or disapproval; the GESAMP-EHS JTG is responsible for the assessment of the hazards of hazardous substances carried on board ships.2 Basic Principles of Conventions and Technologies for the Prevention of Pollution from Ships Pollution from Ships Pollutants from ships are generated in two ways: operational pollution arising from normal ship operations; and pollution arising from ship accidents. There are two ways of generating pollutants from ships: operational pollution from normal ship operations; and accidental pollution from various ship accidents. There is also pollution caused by the dismantling of ships after they have been decommissioned. Operational pollution refers to some pollutants generated by the ship itself in normal operation, part of which is caused by cargo residues, such as: wash water and ballast water in the cargo hold of oil tankers and chemical tankers; part of which is generated by the ship itself, such as: oily sewage in the engine room, oily residue of fuel oil, domestic sewage, ship's garbage, and atmospheric pollutants generated by the ship; due to the operation of the ship in different water areas, ballast water as a medium for causing foreign aquatic organisms and pathogens. The transfer of foreign aquatic organisms and pathogens; the use of anti-fouling paint containing organic tin and other damage to the marine environment. Accidental pollution from ships refers to accidents such as collision, grounding, grounding, fire, explosion, etc., as well as damage to loading and unloading equipment, human factors and other accidents, which will result in a large amount of pollutants being discharged in a short period of time, thus causing significant or even catastrophic pollution damage to the local sea area. The basic principles of MARPOL are: to reduce the generation of pollutants on board; to control the discharge of pollutants from ships; to minimize the impact on the marine environment after the discharge of pollutants; and to limit the accidental discharge of pollutants from ships to the maximum extent possible. 2.1 Reduction of pollutants on board Obviously, pollutants do not come on board or reducing the amount of pollutants generated on board is an effective way to reduce the pollution of ships, and the prevention of ship pollution is to reduce the amount of pollutants generated on board. A number of provisions in the Convention have been proposed to reduce the generation of pollutants. For example: MARPOL 73/78 Annex I Rules for Prevention of Oil Pollution in order to reduce the generation of oily sewage from ships, it is stipulated that crude oil tankers with a deadweight of more than 20,000 tons should be equipped with special ballast tanks; MARPOL 73/78 Annex II Control of Bulk Noxious Liquid Substances Pollution Rules in order to reduce the residue of the cargo hold, put forward the mandatory pre-wash, effective sweeping and ventilation procedures and other technical measures; MARPOL73/78 Annex VI stipulates that the use of controlled ozone depleting substances is not allowed on board, and the emission limits for NOx from diesel engines installed on board after 2000; the anti-fouling bottom convention stipulates that anti-fouling paints containing TBT can not be applied to ships; Annex 1 of the shipbreaking convention lists the list of hazardous materials whose use is prohibited or restricted, and stipulates that the ships should try to minimize the amount of residues of cargoes, residual oils and other pollutants prior to ship dismantling. 2.2 Controlling the discharge of pollutants from ships Where the generation of pollutants is unavoidable, technical measures to minimize the pollution caused by ships include the treatment of pollutants generated on board ships or the discharge of pollutants to onshore reception facilities. Treatment of pollutants on board reduces their quantity or concentration, e.g. MARPOL 73/78 Annex I requires that engine room sewage must be treated by 15 ppm oil-water separation equipment before discharge, and oily sewage from cargo tanks must be discharged through an oil discharge monitoring system; MARPOL 73/78 Annex IV requires ships to be equipped with domestic sewage treatment plants, domestic sewage MARPOL 73/78 By-law IV requires ships to be equipped with domestic sewage treatment plants, domestic sewage shredding and disinfection systems; MARPOL 73/78 By-law VI requires that in SOx control areas, the alternative to 1.5% m/m fuel oil is the installation of exhaust gas filtration systems to reduce SOx emissions below the permitted values; and the Ballast Water Convention requires ships to install ballast water treatment systems to remove foreign organisms and pathogens carried in ballast water. Another effective technical measure to reduce pollutant emissions is the discharge of pollutants generated on board ships to onshore reception facilities. In some cases, the need for reception facilities arises from conventions that prohibit the discharge of highly toxic or environmentally non-degradable substances altogether, e.g., any plastics are banned from entering the sea; anti-fouling paints containing TBT are banned; and discharges of toxic liquid substances of Class X are prohibited. Other cases are mainly limited by treatment technologies, some of which are easy to implement on shore but difficult on board ships. For example: MARPOL 73/78 Annex I stipulates that the residues in the bilge and sludge tanks of ships can be discharged to onshore reception facilities through standard discharge connections; MARPOL 73/78 Annex II stipulates that chemical-containing effluents generated by mandatory pre-washing should be discharged to onshore reception facilities; in addition, MARPOL 73/78 Annexes IV, V and VI have the requirement of onshore reception facilities; ballast water The Convention requires that ship repair and cleaning ports should be equipped with ballast tank sediment reception facilities.2.3 Minimize the impact on the marine environment after the discharge of pollutantsAccording to the current level of science and technology, it is inevitable that some pollutants will be generated and discharged in the course of the ship's operation, and this is also the reason why the Pollution Prevention Convention does not require that all pollutants are discharged to "zero", but of course such discharges are not required. This is why the Pollution Prevention Convention does not require all pollutants to be discharged "zero", but of course such discharge is within the "environmental capacity". Examples include: oily sewage with an oil content of 15 ppm or less; sewage containing a certain concentration of toxic liquid substances; some types of ship's garbage; and NOx and SOx gases below a certain limit. In order to ensure that the pollutants allowed to be discharged can be mixed with seawater as soon as possible and do not have any obvious impact on the environment, the Convention also stipulates the corresponding discharge conditions, for example: oily sewage with a content of 15 ppm or less is discharged at the waterline; sewage containing poisonous liquid substances that are allowed to be discharged must meet the conditions of discharging below the waterline, the speed of self-navigating ships is 7 knots, and the speed of non-self-navigating ships is 4 knots, and it is 12 nautical miles away from the nearest land, and the depth of water is 25 meters, and so on; Domestic sewage is permitted to be discharged under the conditions that it is 3 nautical miles away from the nearest land, that the discharge is pulverized and disinfected, that the vessel travels at a speed of 4 knots or more, and that it is discharged at a moderate rate, among others. In order to protect the more sensitive sea areas, the Convention stipulates more stringent pollutant discharge standards for "special areas", "particularly sensitive sea areas" and "SOx emission control areas". For example, when a tanker is in a Special Area, it is prohibited to discharge oil or oily mixtures from the cargo oil area of the ship into the sea; the Antarctic region is a Special Area under MARPOL 73/78 Annex II, and it is prohibited to discharge any noxious liquid substances or mixtures of such substances into Antarctic waters; and in the Baltic and North Seas, as an SOx Emission Control Area, the sulphur content of the fuel oil is restricted to 1.5% m/m or the installation of an exhaust gas filtration system is prohibited. exhaust gas filtering systems to reduce total SOx emissions from ships, including main and auxiliary propellers, to 6.0 g /kW-h or less.2.4 Maximizing Control of Accidental Discharges of Pollutants from ShipsAccidental discharges of pollutants from ships are a major risk for significant localized pollution damage, and successive major oil spills from tanker vessels have resulted in prolonged ecological damage or catastrophes in a number of marine areas. In order to prevent such accidents from occurring, MARPOL 73/78 Annex I proposes targeted technical measures. For example: in order to limit the volume of oil spilled after the breakage of a single tank, the capacity of a single tank is limited: the maximum capacity of each tank of any tanker shall not exceed 40,000m3; for the specialized ballast tanks of oil tankers, in addition to the capacity requirement, they are also required to be arranged in the most vulnerable part of the ship to provide a protective measure to prevent oil from escaping in the event of stranding or collision; in response to the major oil spill incidents of single-hulled tankers, the MARPOL 73/78 By-law I has put forward specific technical measures. MARPOL 73/78 Annex I adds double-hull requirements for oil tankers delivered after 1996 and progressively for oil tankers delivered before 1996; in order to provide adequate protection against oil pollution in the event of a collision or grounding, MARPOL 73/78 Annex I requires that oil tankers delivered on or after January 1, 2010 shall be structurally designed to ensure that the amount of oil spilled in an accident is within certain limits; there is also a requirement for oil tankers to be arranged in the most vulnerable parts of the ship to provide a measure to prevent oil from escaping in the event of a collision or grounding. within certain limits; and there is also a requirement for each tanker of 150 GT and above and each non-tanker of 400 GT and above that a Shipboard Oil Pollution Contingency Plan endorsed by the competent authority should be available to ensure that the correct and effective methods are adopted in the event of an emergency response to a pollution incident.3 Trends in the development of new technologies for preventing ship-source pollutionWith people's environmental awareness increasing, both in terms of legislation and technology as well as in management, there is a need for more Further developments are needed in terms of legislation, technology and management. The shipping industry has also adopted more new technologies to prevent pollution from ships under the promotion of the IMO Convention, and these new technologies play a great role in better protecting the marine environment.