We secure contaminated dredged material on land

All sediments that we dredge in Hamburg from the Tideelbe are subjected to detailed analysis by us. If they are clean enough – that is, if all legal requirements are met – we return them to the water as an important natural component. Today, we are able to return over 95 per cent of the dredged material to the River Elbe or the North Sea. This is not only much more cost-effective and in line with international best practice, but also environmentally sound.

However, if analyses by certified laboratories show that the dredged material is too contaminated, we responsibly bring it ashore, where we treat it and dispose of it safely at our landfill sites.

Since 1993, processing has taken place at our METHA, an innovative industrial facility that separates the dredged material into clean sand and contaminated fine-grained material, known as METHA material. The clean sand can be used without restriction as a building material. The very dense, clay-like METHA material is either safely disposed of at our dredged material landfills or used there as certified sealing material. We are also exploring other potential uses, such as a substitute building material in the ceramics industry or as a replacement for clay in dyke construction.

For emergencies, such as accidents, and for foreign material that may not be stored at our disposal sites, we maintain special areas where large quantities of contaminated dredged material can be deposited at short notice and subsequently dewatered. Some of these dewatering fields are separately sealed and are used for oil-contaminated material that cannot be treated in the METHA facility. The effluent is collected and treated at our SARA wastewater treatment plant.

Each year, we remove around 200,000 tonnes of heavily contaminated sediments from the tidal waters in Hamburg, thereby making the Elbe and the North Sea a little cleaner each time. These are almost always old sediments containing industrial pollutants from the Elbe catchment area upstream of Hamburg.  

The purpose of a landfill is to accommodate contaminated material in such a way that it no longer comes into contact with the environment in the long term. We achieve this at our dredged material landfills by encapsulating the contaminated METHA material on all sides with a seal to prevent rainwater from penetrating or leachate from entering the groundwater. We also use specially prepared METHA material as a seal, which, like loam or clay, allows almost no water to pass through. The little water that does escape is completely drained off via coarse-grained layers, so-called drainage, and cleaned in our SARA wastewater treatment plant. It is then so clean that it can be safely channelled back into the Elbe.

We operate two dredged material landfills in Hamburg: The Francop landfill in the fruit-growing area of Süderelbmarsch - where our METHA is also located - and one in the east of Hamburg, the Feldhofe landfill. The older Francop landfill has now been completely filled and is being secured and landscaped. The final design, e.g. as a public green space or for other uses, is still being discussed. The Feldhofe landfill, on the other hand, still has capacity for many years to come, so that the needs-based disposal of contaminated dredged material will continue to be ensured.

Even if we can continue to safely accommodate contaminated dredged material, our goal is that the sediments of the Elbe will one day be so clean that they can remain in the Elbe without restriction. After all, they are an important natural resource - not least for coastal protection, so that forelands, salt marshes and mudflats can grow in line with rising sea levels.

We will therefore continue to campaign for the greatest possible reduction in pollution through targeted remediation measures in the entire Elbe region up to the Czech Republic. This is because it is fundamentally more efficient to tackle pollution at source than to remove it from the water in the tidal Elbe, where it has already mixed with clean sediments.