The impact of seaborne trade

Global shipping continues to grow with annual growth measured at 4% in 2017 (Review of Maritime Transport 2018 - UNCTAD). This growth  benefits from several factors favorable to its future strengthening: the increase in South-South trade, the One Belt - One Road Initiative, the Partnership for Quality Infrastructures as well as extensions of the Suez Canal and the Panama Canal.

The very strong development of the maritime industry since the twentieth century has led to a sharp increase in the pollution of the seas and oceans. During their operation, the ships produce various oil wastes called slops e.g. a 50,000 horsepower container ship generates 1.6 tonnes of petroleum waste a day, or almost 1% of its fuel consumption. This waste was previously discharged at sea.

Maritime trade then required specific regulation, a first international text was born in 1954: the Convention OILPOL (International Convention for the Prevention of Pollution of the Sea by Oil). But it was neither sufficiently restrictive nor repressive enough. A new text - still in force - will then be adopted in 1973, then amended in 78. Aimed in particular at limiting all forms of pollution by ships (sea, land, air), the International Convention for the Prevention of Pollution from Ships called MARPOL 73/78 was born. It allowed for the collection and treatment of waste on land.


Oil residues can be of terrestrial origin (cleaning tanks, pipelines), but the great majority comes from the maritime trade. The generic name Slops include various hydrocarbon residues produced by maritime activity, such as sludges, bilge waters and ballast waters. They are composed, in variable proportions, of water, hydrocarbons, sediments and various pollutants.

They are produced in the engine rooms during the purification of fuels used by the ships. They contain 80% of hydrocarbons.


These polluted bilge waters contain a mixture of fuel oil, seawater, freshwater, cooling water, oil leaks and lube oils. They contain 10% of hydrocarbons.


Also called slops, ballast waters are used in older tankers to stabilize the ship by replacing the oil when they navigate with no payload. By extension ballast waters also include tank-cleaning waters. They contain 20% of hydrocarbons.


Categorized as industrial waste, slops are collected in ports and typically dealt with by ship owners. Their variable composition and the nature of the pollutants (sediments, heavy metals) make them particularly hard to treat and recycle. Therefore, more often than not, they are incinerated.

Thanks to its treatment process, which enables slops to be recycled, Ecoslops offers port infrastructures, waste collectors and ship-owners an economical and ecological solution, in accordance with regulation regarding the collection and the treatment of this kind of waste.