MANAGING WASTE
FROM COMMERCIAL SHIPS

#clearfacts #sustainableshipping #shipwaste
FR
Commercial ships produce waste as part of regular operations. Proper disposal prevents pollution from ships. An accidental or deliberate discharge of waste from a ship can damage ocean habitat, contaminate food chains or harm marine life.
Ship owners, mariners, regulators, and port authorities work together to safely dispose of this waste. With an increasing focus on the marine environment, Canadians and Indigenous communities want to be sure marine resources are protected from the effects of ship-generated waste.
This site’s purpose is to share objective information about the impacts of operational waste from the marine shipping industry – including the types of waste ships produce, how these wastes can be harmful, and where and how wastes are disposed of – and to encourage informed conversations about these issues.
“We used to say when the tide went out, the table was set. Now it’s full of heavy metals and contaminants.”
[1]
Waste Produced by Ships AND CREWS
More than 55,000⁽²’³⁾ commercial ships sail the world’s oceans and waters annually. As they move from port to port, they generate a range of oily waste, exhaust gas cleaning washwater, ballast water, sewage (black water), greywater, cargo residues, food waste, and other garbage similar to typical household waste.
Learn the difference between
Waste produced by passengers and crew
Waste produced by ships
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Anchor chain
wash water
Hull coatings and microplastics
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Ballast water
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Cargo residues and wash water
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Bilge water
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Propeller shaft oil
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Exhaust gas cleaning system (EGCS) or scrubber discharge water
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Food
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Sewage (black water)
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Garbage
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Greywater
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Click on the blue dots
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For a comparison of Canadian, U.S. and international regulations
FREQUENTLY ASKED QUESTIONS ABOUT SHIP-GENERATED WASTE
Waste from ships is contentious.
If you have seen a ship pumping water overboard or exhaust into the air, you might be concerned about pollution. Read on for some questions and answers about Canada’s regulations for ship waste treatment and disposal.
A ship at anchor or berth is pumping water over the side – why?
The crew could be washing the anchor chain to prevent marine species from coming along when the ship leaves (and becoming invasive elsewhere), releasing rain or seawater that has collected on deck, or adjusting ballast water levels as the ship takes on or offloads cargo. Ballast water is held in specialized tanks in the ship and allows the ship to maintain a safe bouyancy. International and Canadian regulations require ships coming to Canada to exchange ballast water taken up in a coastal area with water from the open ocean to minimize the risk of invasive species arriving in Canadian ports.
Can ships discharge sewage? Does it have to be treated?
How far from shore does the ship have to be?
The United Nations Convention on the Law of the Sea (UNCLOS) establishes the territorial sea – the ocean directly under a country’s jurisdiction – as 12 nautical miles from shore. Ships greater than 400 gross tonnes cannot discharge untreated sewage within the territorial sea. Within the territorial sea and in Canada’s inland waters such as the Great Lakes, sewage discharges from ships must be treated using UV light, hypo-chlorination or biologic methods, before discharge. Ships must be travelling at 4 knots or faster when discharging untreated sewage more than 12 nautical miles from shore.⁽¹¹⁾ Sewage is passed through a screen to filter out non-organic waste.
Can ships discharge oil? What about the discharge of oily bilge water?
Ships are only permitted to discharge liquid waste if the oil content is not from oil cargo and is less than 15 parts per million (ppm) when undiluted. The oil content must be less than 5 ppm for discharge in inland waters and in all cases, the ship must be underway. Water that collects in the lowest parts of a ship is referred to as bilge water and can accumulate oil and other wastes. Bilge water is pumped out through an oily water separator. The separator sounds an alarm if the waste exceeds 15 ppm of oil, alerting the engine room or the captain. The harmful residue is stored in a holding tank for disposal at an authorized disposal centre. The regulations around waste discharge are different in Arctic waters. See the Learn more about ship waste in Arctic waters pop-up window below for more information.
How was 15 parts per million (ppm) of oil chosen as a standard?
The standard of 15 ppm is the point where an oil sheen can be seen with the naked eye for immediate confirmation during an inspection. That is also the point that oil kills birds and marine life by breaking down their natural protective insulation. In the Great Lakes and other inland waters, which are important sources of drinking water, this limit is 5 ppm. In Arctic waters, bilge water discharges are prohibited. These standards are selected to protect the environment and enable appropriate action to be taken as quickly as possible.
Do marine inspectors require specialized training and tools to do their jobs?
The marine safety inspectors at Transport Canada who enforce the rules and regulations are experienced mariners. They are selected under Canadian law and undergo specialized training to enforce the entire maritime regime. Owing to the wide range of issues these regulations cover, inspectors need simple ways of determining if a ship is following the rules, such as knowing 15 ppm oil is a visible sheen on the water.
Why are ships allowed to dispose any of their waste into the ocean?
Ships cover long distances between ports and have limited storage space. Furthermore, retaining some types of waste onboard may pose health risk to the ships’ crew. It is contentious, but if a waste meets certain standards set by international agreements to limit harm to the environment, that waste may be permitted to be disposed at sea. The underlying assumption is that the ocean can manage untreated sewage and certain wastes if appropriately disposed of away from shore in small, diluted quantities. However, some wastes, such as plastics and harmful chemicals cannot be discharged at sea at any time.⁽⁴⁾
Who is checking to make sure ships aren’t discharging waste illegally?
Port State Control inspectors in Canada and internationally check ship records and on-board equipment to ensure compliance with regulations, and interview crews for familiarity with requirements. Regulators also rely on satellite, aerial, and water-based surveillance to monitor ship behaviour in Canada’s Exclusive Economic Zone (within 200 nautical miles from shore). If ships are in violation they can be fined, face sanctions, denied access to member ports, and face crippling increases to their insurance. Citizens, environmental groups and corporations alike are demanding that companies they work with meet a high standard of conduct and follow the law.
A ship at anchor or berth is pumping water over the side – why?
The crew could be washing the anchor chain to prevent marine species from coming along when the ship leaves (and becoming invasive elsewhere), releasing rain or seawater that has collected on deck, or adjusting ballast water levels as the ship takes on or offloads cargo. Ballast water is held in specialized tanks in the ship and allows the ship to maintain a safe bouyancy. International and Canadian regulations require ships coming to Canada to exchange ballast water taken up in a coastal area with water from the open ocean to minimize the risk of invasive species arriving in Canadian ports.
Can ships discharge sewage? Does it have to be treated?
How far from shore does the ship have to be?
The United Nations Convention on the Law of the Sea (UNCLOS) establishes the territorial sea – the ocean directly under a country’s jurisdiction – as 12 nautical miles from shore. Ships greater than 400 gross tonnes cannot discharge untreated sewage within the territorial sea. Within the territorial sea and in Canada’s inland waters such as the Great Lakes, sewage discharges from ships must be treated using UV light, hypo-chlorination or biologic methods, before discharge. Ships must be travelling at 4 knots or faster when discharging untreated sewage more than 12 nautical miles from shore.⁽¹¹⁾ Sewage is passed through a screen to filter out non-organic waste.
Can ships discharge oil? What about the discharge of oily bilge water?
Ships are only permitted to discharge liquid waste if the oil content is not from oil cargo and is less than 15 parts per million (ppm) when undiluted. The oil content must be less than 5 ppm for discharge in inland waters and in all cases, the ship must be underway. Water that collects in the lowest parts of a ship is referred to as bilge water and can accumulate oil and other wastes. Bilge water is pumped out through an oily water separator. The separator sounds an alarm if the waste exceeds 15 ppm of oil, alerting the engine room or the captain. The harmful residue is stored in a holding tank for disposal at an authorized disposal centre. The regulations around waste discharge are different in Arctic waters. See the Learn more about ship waste in Arctic waters pop-up window below for more information.
How was 15 parts per million (ppm) of oil chosen as a standard?
The standard of 15 ppm is the point where an oil sheen can be seen with the naked eye for immediate confirmation during an inspection. That is also the point that oil kills birds and marine life by breaking down their natural protective insulation. In the Great Lakes and other inland waters, which are important sources of drinking water, this limit is 5 ppm. In Arctic waters, bilge water discharges are prohibited. These standards are selected to protect the environment and enable appropriate action to be taken as quickly as possible.
Do marine inspectors require specialized training and tools to do their jobs?
The marine safety inspectors at Transport Canada who enforce the rules and regulations are experienced mariners. They are selected under Canadian law and undergo specialized training to enforce the entire maritime regime. Owing to the wide range of issues these regulations cover, inspectors need simple ways of determining if a ship is following the rules, such as knowing 15 ppm oil is a visible sheen on the water.
Why are ships allowed to dispose any of their waste into the ocean?
Ships cover long distances between ports and have limited storage space. Furthermore, retaining some types of waste onboard may pose health risk to the ships’ crew. It is contentious, but if a waste meets certain standards set by international agreements to limit harm to the environment, that waste may be permitted to be disposed at sea. The underlying assumption is that the ocean can manage untreated sewage and certain wastes if appropriately disposed of away from shore in small, diluted quantities. However, some wastes, such as plastics and harmful chemicals cannot be discharged at sea at any time.⁽⁴⁾
Who is checking to make sure ships aren’t discharging waste illegally?
Port State Control inspectors in Canada and internationally check ship records and on-board equipment to ensure compliance with regulations, and interview crews for familiarity with requirements. Regulators also rely on satellite, aerial, and water-based surveillance to monitor ship behaviour in Canada’s Exclusive Economic Zone (within 200 nautical miles from shore). If ships are in violation they can be fined, face sanctions, denied access to member ports, and face crippling increases to their insurance. Citizens, environmental groups and corporations alike are demanding that companies they work with meet a high standard of conduct and follow the law.
Ship Waste RULES and Regulations
Commercial ships sail through national and international waters and are required to observe many different regulations, restrictions, and protected areas.
Internationally, the disposal of waste from ships is governed by the International Convention for the Prevention of Pollution from Ships (MARPOL) first established in 1973 by the International Maritime Organization (IMO) and fully adopted in 1978, with protocols and annexes added and entered into force since to address oil, noxious liquids in bulk, harmful substances in packaged form, sewage, garbage, and air pollution.
Canada joined MARPOL in 1993 and has incorporated most of the Convention’s aspects into the Canada Shipping Act, 2001 under the Vessel Pollution and Dangerous Chemicals Regulations to protect Canadian waters within Canada’s exclusive economic zone up to 200 nautical miles from shore. Under the Fisheries Act, it is illegal to dispose of any deleterious substance into water, regardless of the source of the substance (person or ship) unless carried out in accordance with requirements under another Act of Parliament. A deleterious substance is anything that is likely to cause harm to fish or fish habitat. However, some harmful substances can be disposed of if the concentration is below established water quality standards.
Some additional restrictions on waste disposal in Canada exist in Marine Protected Areas, National Marine Conservation Areas, and National Wildlife Areas.
Learn more about Special Areas of pollution control
Learn more about ship waste in Arctic waters
Exclusive economic zone
(extending 200 nautical miles from the shore)
Territorial waters
(extending 12 nautical miles from the shore)
Marine Protected Areas (MPAs)
National Marine Conservation Areas
PROTECTED AREAS IN CANADIAN WATERS
Learn more about protected areas in Canada, here.
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Size in km : 1,000
Year established: 2019
Banc-des-Américains
2
Musquash Estuary
Size in km : 7
Year established: 2006
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2
St. Anns Bank
Size in km : 4,364
Year established: 2017
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2
The Gully
Size in km : 2,363
Year established: 2004
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2
Laurentian Channel
Size in km : 11,580
Year established: 2019
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2
Basin Head
Size in km : 9
Year established: 2005
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2
Eastport
Size in km : 2
Year established: 2005
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2
Gilbert Bay
Size in km : 60
Year established: 2005
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2
Tuvaijuittuq
Size in km : 319,411
Year established: 2019
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2
Tarium Niryutait
Size in km : 1,750
Year established: 2010
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2
Anguniaqvia niqiqyuam
(Ung-u-niak-via Ni-kig-e-um)
Size in km : 2,358
Year established: 2016
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2
SGaan Kinghlas-Bowie
Seamount
Size in km : 6,103
Year established: 2008
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2
Hecate Strait and
Queen Charlotte Sound Glass
Sponge Reefs
Size in km : 2,410
Year established: 2017
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2
Endeavour
Hydrothermal Vents
Size in km : 97
Year established: 2003
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2
Gwaii Haanas National Marine
Conservation Area Reserve
and Haida Heritage Site
2
Size in km : 1,500 including 200 smaller islands and islets
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Scott Islands marine
National Wildlife Area
Size in km : 11,546
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2
The Fathom Five
National Marine Park
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Size in km : 112
2
2
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Size in km : 108,000
Talluruptiup Imanga
(Lancaster Sound)
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2
Size in km : 1,246
Saguenay-St. Lawrence Marine Park
Monitoring and Enforcing Ship Waste Disposal
IMO member states, including Canada, are responsible for incorporating international regulations into national law and then enforcing ships’ adherence to those regulations.
Under the Canada Shipping Act, 2001, the Marine Transportation Security Act and through the Marine Safety and Security Oversight Program, Transport Canada monitors every ship in Canadian waters through a number of mechanisms, including:
Learn more about the National Aerial Surveillance Program
Participation in the Tokyo and Paris Memoranda of Understanding – databases of commercial ships maintained and accessed by national marine inspectors to identify ships of concern.
Requirement for ships to contact Transport Canada 96 hours before entering Canadian waters to provide details about the ship, its crew and cargo.
Regular and random Port State Control inspections conducted by experienced marine safety inspectors to assess the ship’s condition and operations, including logs of any discharges.
Surveillance of ship discharges while in Canadian waters through the National Aerial Surveillance Program.
REMOVING WASTE FROM SHIPS
Some waste produced on or by ships must be retained to be disposed of on land.
When a ship is in port, private service providers remove waste either using barges or trucks, depending on available space, regulations, and type of waste.
The waste removal services vary from port to port to meet the needs of the ships that call. For example, a port that receives cruise ships requires more capacity to handle food waste and recyclable materials than a port that receives only cargo vessels. International food, animal, plant and other organic waste can only be removed from a ship if the service provider is approved by the Canadian Food Inspection Agency.

Ports that receive international ships offer the full range of waste removal services through local port waste reception facilities. Regional ports offer a selection of waste removal services as required by the ships that call.
Initiatives Underway
Waste Management, Green Marine Environmental Certification Program
The North American voluntary environmental certification program Green Marine assesses the environmental footprint of participants using 14 performance indicators, including one related to waste management. Among others, this indicator aims to reduce operational garbage and increase recycling onboard ships. It includes five levels of performance ship owners, ports, terminals, and shipyards can achieve, from installing recycling bins to conducting a waste audit and developing a waste management strategy.

Learn more
Environmental Certifications and Incentive Programs
A number of certification programs aimed at encouraging the marine shipping industry to reduce its environmental footprint consider waste produced by ships – and how it’s being managed – as an indicator of environmental performance.

Learn more
New Ballast Water Regulations
To further reduce the environmental risks associated with the introduction of invasive species that can occur through the discharge of ballast water by ships, Canada proposed new, enhanced Ballast Water Regulations. This new set of regulations will give effect to the International Convention for the Control and Management of Ships’ Ballast Water and Sediments and require domestic and international commercial vessels to install a ballast water management system by 2024.

Learn more
Quebec Government Recycling Program
Quebec’s Ici on Recycle! – RECYC QUÉBEC recycling program recognizes organizations that are committed to improve their waste management performance through a nomination and certification process. The program, which has been adapted to vessels and their operations in recent years, includes zero-waste initiatives to reduce the use of single-use plastics on board ships.

Learn more
Waste Management, Green Marine Environmental Certification Program
The North American voluntary environmental certification program Green Marine assesses the environmental footprint of participants using 14 performance indicators, including one related to waste management. Among others, this indicator aims to reduce operational garbage and increase recycling onboard ships. It includes five levels of performance ship owners, ports, terminals, and shipyards can achieve, from installing recycling bins to conducting a waste audit and developing a waste management strategy.

Learn more
Environmental Certifications and Incentive Programs
A number of certification programs aimed at encouraging the marine shipping industry to reduce its environmental footprint consider waste produced by ships – and how it’s being managed – as an indicator of environmental performance.

Learn more
New Ballast Water Regulations
To further reduce the environmental risks associated with the introduction of invasive species that can occur through the discharge of ballast water by ships, Canada proposed new, enhanced Ballast Water Regulations. This new set of regulations will give effect to the International Convention for the Control and Management of Ships’ Ballast Water and Sediments and require domestic and international commercial vessels to install a ballast water management system by 2024.

Learn more
Quebec Government Recycling Program
Quebec’s Ici on Recycle! – RECYC QUÉBEC recycling program recognizes organizations that are committed to improve their waste management performance through a nomination and certification process. The program, which has been adapted to vessels and their operations in recent years, includes zero-waste initiatives to reduce the use of single-use plastics on board ships.

Learn more
Clear Seas was launched in 2015 after extensive discussions among government, industry, environmental organizations, Indigenous Peoples and coastal communities revealed a need for impartial information about the Canadian marine shipping industry. Learn more about the organization’s research, team and funders, here.
ABOUT
Clear Seas Centre for Responsible Marine Shipping is an independent not-for-profit research centre that supports safe and sustainable marine shipping in Canada.
Sources & Citations
A comparison of Canadian, U.S. and international regulations
International regulations to prevent and minimize pollution from ships came into effect in the early 1970s in response to several major oil spills. The International Maritime Organization (IMO) adopted a set of rules under the International Convention for the Prevention of Pollution from Ships (MARPOL). Since then, it has been expanded to include noxious liquid substances, harmful materials carried in package form, sewage, garbage, and air pollution.

Many of these rules have been incorporated into national regulations and laws. In Canada, most aspects of MARPOL have been adopted under the Canada Shipping Act, 2001. In addition, the International Code for Ships Operating in Polar Waters (Polar Code), developed by the IMO, has been incorporated into Canada’s Arctic Waters Pollution Prevention Act (AWPPA). To compare, some Canadian regulations such as those for sewage discharge are stricter than MARPOL.

While the two countries work together in shared waters, there are some differences between the U.S. and Canada, notably in the Great Lakes region.

In general, Canada and the U.S. try to coordinate actions under the Great Lakes Water Quality Agreement for joint emergency pollution response and work together on ballast water management in the Great Lakes. However, the two countries are not in agreement for new ballast water rules taking effect in 2024 and requiring vessels of at least 400 gross tonnes to be equipped with a ballast water management system. The U.S., which has not ratified the IMO’s International Convention for the Control and Management of Ships’ Ballast Water and Sediments and has exempted its fleet of commercial vessels operating on the Great Lakes from having to install onboard ballast water management systems, believes that this rule should not be applied to ships that only use the Great Lakes-St. Lawrence River region. Conversely, Canada has ratified the Convention, and says ships must have onboard systems. Both countries are in negotiations to resolve the matter.

When the two nations are parties to the same conventions, they do not necessarily apply the same standards because some conventions provide a minimum requirement and some American states may regulate higher standards or adopt their own standards, as in the case of California regarding ballast water management.

For example, the U.S. is not a signatory to MARPOL IV (regulations on sewage) but they have equivalent laws to protect against pollution from sewage, found in the Section 312 of the Clean Water Act.
Section 312 of the Clean Water Act requires the use of operable, U.S. Coast Guard-certified marine sanitation devices onboard vessels that are equipped with toilets and operating on U.S. navigable waters

Untreated sewage discharges are prohibited within 3 nautical miles from shore

Some areas are designated as “No Discharge Zones”
The U.S. and Canada are signatory to MARPOL V (regulations on garbage). Certain U.S. states such as Alaska and Washington often apply stricter standards.

The role of port authorities in managing ship waste:
Canada’s port authorities play a crucial role in managing ship-source waste. They publish rules and regulations for their jurisdiction describing how all types of ship waste are managed and disposed. Overall, port rules meet and often exceed national regulations. The ship operator must seek the necessary approvals from the appropriate regulator, harbour master or operations centre before discharging waste. The Port of Halifax offers a typical example of a guide and its requirements.
Regulations in Arctic waters
In Arctic waters, bilge water cannot be discharged. For ships greater than 400 gross tonnes or certified to carry more than 15 people, treated sewage may be discharged more than 3 nautical miles or as far as practicable from land, ice-shelf, or land-fast ice while underway. Untreated sewage may be discharged at least 12 nautical miles from land or ice and while underway. There are no specific regulations on the discharge of grey water north of 60°N. Vessel operators are asked to avoid discharging untreated grey water under any circumstance when operating in these waters, but this recommendation is not enforced.
Special Areas of pollution control
A Special Area can be designated under MARPOL to create further measures to prevent ocean pollution by oil, noxious liquid substances, sewage, garbage or air pollution due to the area’s recognized ecological conditions and the nature of traffic in the area. Designated areas are provided with a higher level of protection, for example, the four Emission Control Areas located in the Baltic Sea, the North Sea, North America, and the U.S. Caribbean Sea to restrict sulphur oxides (SOx) and nitrogen oxides (NOx) emissions. A list of the Special Areas under MARPOL can be found here.
Ship waste in Arctic waters
As Arctic shipping increases, so do the risks associated with ship-source waste. Waste generated and transported onboard ships navigating Arctic waters poses risks to the region's marine and coastal environments due to its limited port infrastructure and reliance on the Arctic Ocean as a food source by the Inuit and other Indigenous inhabitants.

As a form of marine litter, plastics have direct effects within the Arctic ecosystem. Some plastics and microplastics accumulate on the ice and re-release into the ocean upon melt, leaching toxins.

The Arctic Shipping Safety and Pollution Prevention Regulations, which incorporate the Polar Code into Canada’s regulatory framework, prohibit the discharge of waste of any type in Arctic waters, with the exception of sewage and food waste, under certain conditions. Waste means any substance, including water containing such substance, that, if discharged in the marine environment, would degrade the water quality to be harmful to people, animals, fish, and plants useful to people, and further includes anything deemed to be waste under the Canada Water Act.

The discharge of oil or mixtures that contain oil is also strictly prohibited with few exceptions, notably if the discharge is the result of an accident or damage to the ship while reasonable precautions were taken, and if the discharge is necessary to save lives or prevent the loss of the ship.

Depositing waste in Arctic waters is considered an offence. A person or a ship convicted under the AWPPA may be fined $5,000 or $100,000, respectively. For ships greater than 400 gross tonnes or certified to carry more than 15 people, the Arctic Shipping Safety and Pollution Prevention Regulations allow the discharge of treated (disinfected and ground-up) sewage more than three nautical miles from land, ice-shelf, or land-fast ice while the ship is underway. Any treated sewage discharges must be as far as practicable from land or ice. To discharge untreated sewage, the ship must be underway and at least 12 nautical miles from land or ice.
The National Aerial Surveillance Program
The National Aerial Surveillance Program is run by Transport Canada and Environment and Climate Change Canada to patrol Canada’s coastlines for ship-source pollution like oil spills. Distinctive, red-painted Dash-8 aeroplanes and a drone equipped with remote sensing equipment keep watch over Canada’s coastlines. Watch this video to learn more.

If ships are identified as illegally discharging waste, Transport Canada may employ different measures under the Canada Shipping Act, 2001. Penalties range from letters of non-compliance and fines of up to $25,000 per day for the duration of the offence. This can mean loss of business, increased rates of insurance and ultimately banning from Canadian waters.
Cargo residues and wash water
Cargo ships can carry anything from grains to minerals and may carry noxious liquid substances and hazardous chemicals. Oil tankers carry different grades and types of oil. To avoid cross-contamination, ships holds have to be cleaned between loads. Hold washing can happen while in port or at sea during a voyage.
How is the waste produced?
Cargo hold wash water contains cargo residues and cleaning agents. Some wash water can be discharged into the ocean when the ship is underway and far enough from shore. More harmful cargo residues must be disposed of on land.
How is it treated and disposed?
Cargo residues may only be discharged at sea >12 nautical miles from land if all reasonable efforts have been made to empty the cargo hold and reclaim as much cargo residue as possible. Specific materials and exceptions are detailed here.

Cleaning agents and wash water may also be disposed at sea if not harmful to the marine environment, in accordance with Canadian discharge standards and procedures.

Noxious substances and dangerous chemicals including cargo wash water from these substances must be disposed of on land. Discharges of oily waste water under 15 parts per million are allowed below the surface of the water >12 nautical miles from land.
The disposal of all cargo residues and wash water are subject to MARPOL Annex V. This is a simple guide.
What restrictions are in effect?
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Ballast water
To maintain stability, ships need to take on or discharge ballast water when they unload and load cargo. About 10 billion tonnes of ballast water are transported globally by ship each year. Ballast water can harm local environments by transporting and discharging non-native and potentially invasive marine species.
How is the waste produced?
Ships exchange ballast water while in the open ocean to dump non-native species far from coastal waters. Ships can be fitted with ballast water treatment system that use ultraviolet light, electro-chlorination or chemical injection to treat ballast water before discharge to kill marine organisms.
How is it treated and disposed?
Current regulation (D-1) requires that ships exchange ballast water at least 200 nautical miles from shore at a minimum depth of 200 m and have a ballast water plan which includes a log and checklist to demonstrate compliance with the Ballast Water Management Convention. Ships equipped with an approved ballast water management system – that treats ballast water onboard before its discharge – may be exempted from conducting a ballast water exchange before entering coastal waters.

As of September 2024, additional regulations (D-2) are in force for all ships above 400 gross tonnes requiring use of a ballast water management system to reduce the number of viable organisms below maximum limits.
What restrictions are in effect?
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Bilge water
The bilge is the lowest point on a ship. Bilge water, the waste that collects there, contains a mixture of oil, sludge, chemicals, detergents, and other pollutants generated from ship operations. Bilge can also accumulate in cargo holds (hold bilge). This type of bilge water can be generated by the moisture contained in cargoes, by the decay of cargo debris left in the holds, and by rainwater that collects in the holds.
How is the waste produced?
Bilge water is treated using an oil/water separator. The oil content is monitored by a sensor that shuts down the unit if limits are exceeded. The separated oil is disposed of at an approved site on shore. Only the oil content of bilge water is regulated, so treated water may contain other pollutants.

Hold bilge, which generally contains only water, is normally pumped overboard through the cargo hold pumping system. If it contains oil, the hold bilge is pumped to a designated collecting tank instead, where the oil is separated from the water to be discharged ashore later.
How is it treated and disposed?
Bilge water must be treated to reduce oil content to:
What restrictions are in effect?
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Less than 15 parts per million (ppm) for disposal at sea
Less than 5 ppm for disposal in inland waters
Sludge remaining in bilge tanks cannot be disposed of at sea. All oil tankers >150 gross tonnes and all commercial vessels >400 gross tonnes are required to have oil/water separators and oil discharge monitoring systems.4 Ships must document all oil discharge.
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Exhaust gas cleaning system (EGCS) or scrubber discharge water
EGCSs, or scrubbers, treat air pollution to remove sulphur oxides (SO­x) from ship engine exhaust by “washing” it.

Open-loop systems use the natural alkalinity of seawater to neutralize SOx and continuously release discharge waters.

Closed-loop systems use freshwater with caustic soda to neutralize SOx, then recirculate the wash water and separate out remaining particulates as sludge. A small amount of wash-water is discharged.
How is the waste produced?
Open-loop scrubber water is tested for acidity and the presence of other chemicals to meet minimum standards before discharge. Water from the engine cooling system is used to dilute the waste stream and neutralize its acidity so it can be discharged into the ocean while the ship is underway.

Closed-loop scrubber waste-water is tested and if too contaminated for discharge into the ocean, it must be held for disposal on land.
How is it treated and disposed?
The IMO established guidelines for EGCS waste disposal including limits on water pH and polycyclic aromatic hydrocarbons (found in soot, coal and tar) as set out in MEPC.259(68).

Internationally, some ports have prohibited scrubber water discharge within their jurisdiction; the Port of Vancouver is the first Canadian port to restrict scrubber discharge.
What restrictions are in effect?
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