Dredging project will remove deadly pollutant from Antwerp waters

Dredging project will remove deadly pollutant from Antwerp waters
Dredgers at work in the port of Antwerp. © Port Authority

A new project is due to start this month in the port of Antwerp, designed to clean the river of a deadly toxic pollutant and improve the quality of river water for marine life.

The project is titled AMORAS, and involves cooperation between the Flemish government, the Antwerp Port Authority and a consortium of two of Belgium’s – and indeed the world’s – major dredging companies, Jan De Nul and Deme.

Between them they have developed technology to remove a chemical known as tributyltin from the silt on the river bottom.

Tributyltin (TBT) is a compound widely used from the 1970s in paint used to protect the hulls of ships and boats from living organisms like barnacles from growing there. However although effective for purpose and therefore popular, it was later found to be highly toxic to all marine species, not just the ones targetted.

The product is extremely harmful to the environment and is also difficult to break down,” said Yi-Bin Shan, the head of maritime access at the public works ministry.

All these years, TBT has been building up in the sludge and gradually. It disrupts the metabolism and hormone action of mainly molluscs, such as snails and mussels.”

If it enters the food chain, it can also be hazardous to humans. Starting in the 1980s it was progressively restricted until the International Maritime Organisation banned it entirely in 2001.

However while TBT is no longer used, it persists as a pollutant in the seabed, and in the case of Antwerp in the silt that lies at the bottom of the river and its estuary.

After years of research, there is now finally a solution for this historic pollution,” said Lydia Peeters (Open VLD), Flemish minister for public works.

This is a worldwide first and a milestone for Flanders and the port of Antwerp. We will be able to remove the most contaminated sludge from the port. As a result, the water quality will improve substantially.”

To keep the access to the port open to shipping, dredgers work non-stop to dredge silt from the estuary, which is then taken to land and treated. Until now, silt polluted with TBT could not be cleaned, and had to be taken to the bordering Netherlands to be disposed of.

Together with the university of Antwerp, we have been investigating for several years now how to remove TBT from the port,” said Port Authority CEO Jacques Vandermeiren.

We are proud to finally be able to tackle this historic pollution. Currently, the water quality in the port scores below the European standard. This will improve considerably with this project. As a port authority, we think it is important to take our responsibility towards society. We are the only port in the world that not only removes contaminated sludge, but also processes it sustainably.”

The project, which aims ultimately to remove 800,000 cubic metres of contaminated silt from the river, is jointly financed by the Flemish region and the port authority.

“Flanders is providing €25 million annually for the operation of AMORAS,” Peeters said.

We are now making an additional investment of €700,000 a year to dispose of TBT in an ecologically responsible manner.”

The Port of Antwerp has invested €1 million in the preliminary phase of this project and will release €1.5 million euros annually for the effective processing of TBT sludge,” said city councillor for the port, Annick De Ridder (N-VA).

The Port of Antwerp wants to be an inspiration for other ports, and to take on a pioneering role in the field of sustainability.”

Alan Hope

The Brussels Times

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