MANAGING WASTE
FROM COMMERCIAL SHIPS

Waste produced by passengers and crew

Waste produced by ships

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?

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?

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?

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.

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?

Local seawater is used to rinse mud and debris from anchors and anchor chains to prevent the transport of invasive species.

How is the waste produced?

The seawater, mud and debris remain in local waters.

How is it treated and disposed?

There are no regulations in effect for anchor wash water.

What restrictions are in effect?

Propeller shaft oil

Propeller shafts are treated with lubricating oil, which can leak into the ocean if the propeller shaft seal is damaged from aging, fishing nets getting caught or the propeller contacting the seabed or ice. Worldwide, up to 240 million litres of propeller shaft oil are estimated to leak into the ocean every year.

How is the waste produced?

Regular inspections and maintenance of the propeller shaft seal minimizes the oil entering the environment. Some newer ships are designed with sea water lubrication rather than oil to prevent this problem.

How is it treated and disposed?

Canadian and U.S. regulations prohibit ships from discharging harmful levels of lubricants or oils.

What restrictions are in effect?

Hull coatings and microplastics

Anti-fouling coatings are applied to ship hulls to prevent marine life from attaching, called biofouling, as invasive species can cause enormous and irreversible environmental damage. A clean hull is also more fuel efficient. However, these coatings can leach heavy metal contaminants and flake off over time, creating microplastic pollution in the ocean.

How is the waste produced?

Regular in-water cleaning using divers or robots can help extend the useful life of the coating by removing biofouling without damaging the coating.

How is it treated and disposed?

Recognizing that both biofouling and treatments to prevent biofouling can harm the environment, the International Maritime Organization (IMO) has established an anti-fouling convention and guidelines to control biofouling, while committing to further research on these topics.

The International Convention on the Control of Harmful Anti-fouling Systems on Ships, in force since 2008, prohibits the use of harmful organotin compounds in anti-fouling paints used on ships and prevents the future use of other harmful substances in anti-fouling systems.

In 2011, the IMO published Guidelines for the control and management of ships' biofouling to minimize the transfer of invasive aquatic species (resolution MEPC.207(62)). The importance of this issue is recognized by the IMO and many other organizations.

In 2019, microplastic pollution from hull coatings was assessed by the IMO; further research is required to understand microplastics contributions from the cleaning and maintenance of coatings.

What restrictions are in effect?

Sewage (black water)

Waste drained from toilets, urinals, hospitals, and animal spaces on ships is called black water. It is highly concentrated and contains harmful levels of bacteria.

How is the waste produced?

Sewage is soaked and filtered and sometimes treated before being disposed of into the ocean where permitted. Black water can be treated by filtering using UV light, hypo-chlorination or biologic methods using bacteria to break down sewage. Sewage is then passed through a screen to filter out non-organic waste.
Liquid is chlorinated and treated in grey water tanks. Treated water can be pumped overboard. Remaining sludge is further filtered and broken down in an aeration chamber for disposal ashore. For more information.

How is it treated and disposed?

Sewage may not be discharged in Canada’s inland waters. Raw sewage may be discharged more than 12 nautical miles from land while the ship is underway.

In Canadian waters south of 60°N:

What restrictions are in effect?

Within 3 nautical miles of land, disposing of untreated sewage is prohibited
Within 12 nautical miles of land, ships over 400 gross tonnes are prohibited from disposing untreated sewage; however, treated sewage may be discharged if it meets fecal coliform limits

Grey water is the drainage from dishwashers, galley sinks, showers, baths, laundry, and washbasins. It can contain grease, oil, fat, food particles, detergents, flame retardants, pharmaceuticals and personal care products, disinfectants, microplastics, and also bacteria (such as fecal coliform), pathogens, metals, and chemicals, which can harm marine ecosystems.

How is the waste produced?

Grey water is discharged overboard, either treated or untreated. Some ships have treatment systems to treat grey and black water in the same tanks.

How is it treated and disposed?

Ships operating in Canadian waters south of 60°N:

What restrictions are in effect?

May discharge greywater if there are no solids in or sheen on the water

Ships carrying more than 500 people south of 60°N:

May discharge greywater if it is treated with an approved marine sanitation device or if at least 3 nautical miles from shore

Ships operating in Canadian waters north of 60°N:

May not discharge any waste in Arctic waters unless of a type permitted by the Canada Water Act

There are no International Maritime Organization requirements for the treatment of greywater from ships; any regulations in place are at a national or regional level.

Food

Food waste from cargo and passenger vessels such as waste scraps and organic material.

How is the waste produced?

Three permissible means of food disposal:

How is it treated and disposed?

In Canadian waters, minced food waste may be discharged if the ship is underway and more than 3 nautical miles from land. Non-ground food waste may be discharged if the ship is underway and more than 12 nautical miles from land.Offloading food waste in ports may be restricted due to biosecurity risks.

All ships must carry a garbage record book for food wastes [MEPC. 201(62)]. Food disposal must be signed by the ship’s captain citing time, date, amount, content, and location of disposal.

What restrictions are in effect?

incineration at sea
disposal at port reception facilities (subject to biosecurity regulations)
discharge at sea

Garbage

Garbage is a broad category similar to household waste. It includes food waste, plastics, packaging, synthetic rope, incinerator ash and e-waste.

How is the waste produced?

Garbage may not be disposed of at sea with minor exceptions such as shredded food waste and animal carcasses. Ships are required to separate and safely store waste. This waste is then disposed at an approved shore disposal centre.

How is it treated and disposed?

Garbage discharge requirements under MARPOL Annex V apply to all ships with guidelines for specified waste. All ships over 400 gross tonnes or capable of carrying at least 15 people must have a garbage management plan which includes publicly displayed graphics explaining garbage processing, discharge requirements and a garbage record book.

Garbage may not be disposed:

What restrictions are in effect?

Within 0.5 nautical mile of a marine mammal
In designated special protection areas of Lake Superior and Lake Huron

Sources & Citations

Burnaby Now. (2021). Pollution Expert Aims to Create ‘Water Champions’.

Statista. (2021). Number of Ships in the World Merchant Fleet as of January 1, 2020, by Type.

Clear Seas’ work is focused on commercial marine shipping and does not generally include cruise ships or fishing vessels. They are subject to the same regulations governing waste disposal.

International Convention for the Prevention of Pollution from Ships (MARPOL 73/78). (2015). Practical Guide. P. 19.

Government of Canada. (2012). Vessel Pollution and Dangerous Chemical Regulations.

Marine Insights. (2021). MARPOL Annex 1 Explained: How to Prevent Pollution from Oil at Sea.

Barbara Werschkun, Sangeeta Banerji, Oihane C. Basurko, Matej David, Frank Fuhr, Stephan Gollasch, Tamara Grummt, Michael Haarich, Awadhesh N. Jha, Stefan Kacan, Anja Kehrer, Jan Linders, Ehsan Mesbahi, Dandu Pughiuc, Susan D. Richardson, Beatrice Schwarz-Schulz, Amisha Shah, Norbert Theobald, Urs von Gunten, Stefanie Wieck, Thomas Höfer. (2014). Emerging risks from ballast water treatment: The run-up to the International Ballast Water Management Convention, in Chemosphere, volume 112, p. 256-266.

Restrictions are based on rules established by the International Maritime Organization, Canadian laws and regulations applied by individual Canadian ports.

World Wildlife Fund. (2020). Grey Water Dumping Threatens Ocean Health and People.

Nuka Research and Planning Group, LLC. (2019). Bilateral Workshop: Grey Water Discharges from Vessels – Summary Report.

Government of Canada. (2021). Vessel Pollution and Dangerous Chemicals Regulations. Subdivision 5 – Discharge of Sewage or Sewage Sludge.

Canadian Food Inspection Agency. (2018). International Waste Directive. Appendix 2: Requirements for the handling, removal, and disposition of international waste at points of entry into Canada (airports and marine terminal, and land crossing). Government of Canada.

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