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Dieren en planten

Water en land

Mens en Milieu

Dumping and discharge   Dredged materials   Dredged material depots   
Footprints on the sea floor, Ecomare

Dredged materials

Dredged materials, or sludge is transported via the rivers and settles in the channels and harbour basins. This sludge is often polluted with heavy metals, pesticides or other toxins, caused by industries, agriculture and households which dump their wastes into the surface water. In order to keep the harbours accessible for the shipping industry , the accumulated sludge must be removed by dredging. It is then disposed of in special dumping-grounds. The North Sea coastal states dumped a total of 88 million cubic meters of dredged material into the North Sea in 1996.

  • Pollution

    Polluted sludge can have serious consequences for the environment. Effects on plants and animals are already perceptible with lightly polluted sludge. Turbulence can easily shift the polluted material from one spot to the other, thereby causing damage to other areas. Over a longer period of time, the groundwater will become polluted. For these reasons, recycling dredged materials from harbours is under study.

  • Pollution

    Polluted sludge can have serious consequences for the environment. Effects on plants and animals are already perceptible with lightly polluted sludge. Turbulence can easily shift the polluted material from one spot to the other, thereby causing damage to other areas. Over a longer period of time, the groundwater will become polluted. For these reasons, recycling dredged materials from harbours is under study.

  • Recycling dredged materials in the Netherlands

    Up till the 1990s, dredged materials from harbours were sometimes used as landfill for terrains destined for housing developments. Now everyone agrees that this material cannot simply be dumped. Unfortunately, good alternatives are scarce.
    The best solution would be to cleanse the dredged materials, though techniques for doing so are still under development. The Ministry for Public Works and the Water Boards are most in favour of dumping under water, into pits and lakes where sand extraction has taken place.