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Sito Rakennuttajat won its largest ever dredging contract in Klaipeda, Lithuania

The port dredging project is not only extensive, but also very challenging. The highly polluted sediment will be treated using the Geotube® method. The work will be carried out without suspending activities at the port.

The busy Port of Klaipeda. The dry dock will also be operational throughout the dredging. Photo: Livinus Ven.

“This is a very significant project, especially for an operator of our size”, says Livinus Ven, expert of large-scale marine dredging who works as an environmental solutions project manager at Sito Rakennuttajat.

The project is indeed very significant in a number of ways, as its value is EUR 9 million.

Incidentally, based on the amount of sediment to be filtered, the treatment of the Port of Klaipeda’s polluted sediment is the largest project utilising the Geotube method implemented in Europe to date. A total of 257,300 m³ of polluted sediment will be dredged in the Port of Klaipeda.

Livinus Ven is excited and looking forward to starting the project. Winning the competitive bidding felt good. According to Livinus, large marine dredging projects around the world tend to go to a few giant corporations operating in the dredging industry.

However, the people at Sito Rakennuttajat are accustomed to facing big challenges with an open mind. In August 2016, Business Area Director Anton Palolahti, the developer of Sito’s Geotube method, and Livinus Ven started working on the Klaipeda project. Receiving a formal invitation to tender already felt like a partial victory and, in late July 2017, it was finally time to officially sign the contracts.

A busy and versatile port

Klaipeda is the third largest city in Lithuania and a popular holiday destination. Its only deep-water harbour in the Baltic Sea was established during the Soviet era in 1991. The busy port has both passenger and freight traffic as well as an LNG terminal. The dry dock includes three basins.

The port is located in the Neman River delta. Over the years, a large amount of soil has accumulated in the basins, hindering their use.

Due to the dry dock activities, the bottom of the port is highly polluted. Both heavy metals and waste oil have been found in the sediment. The depth of the polluted sediment is 1–1.5 metres.

The port of Klaipeda has received a significant EU investment to expand and deepen the port to about 14–17 metres, but before that can be achieved, the polluted sediment must be removed safely.

The right price and a top team

According to Livinus Ven, Sito Rakennuttajat won the Port of Klaipeda sediment dredging project with the most affordable tender that met the terms exactly. It all comes together in the Geotube method developed by Anton Palolahti at Sito and Livinus Ven’s harbour dredging expertise that has been honed around the world. The project organisation is light, competent and full of local knowledge. Sito Rakennuttajat is responsible for project management and Tech Service Oy, Vesirakennus Ojanen Oy and Suomen Vesityö Oy for the operational portion of the project.

All in all, dredging of the polluted sediment in the Port of Klaipeda is very challenging because it must be carried out without disturbing the operations of the port and dry dock. This is achieved by combining environmental dredging with the Geotube method.

Safe cleaning

The Geotube method used in the cleaning of the Port of Klaipeda’s polluted sediments has been successfully utilised, for example, in the treatment of sludge from pulp mills. The sludge to be treated is pumped into a geotube made of special textile. The filtered clean water can be run back into a waterway, for example. In a full geotube, the sludge continues to dry until it can be utilized, for example, as artificial fill, depending on its properties.

Geotubes in Klaipeda during the first work stage. Photo: Livinus Ven.

“A geotube, which is 50 metres long and three metres high in total, actually works like a coffee filter. In Klaipeda, polluted sediment sludge is fed through pipes into a polymer container where it is mixed with a carefully selected compound of powder-like polymer that binds the sediment and any toxins it contains. The separated water, in turn, pours out from the top”, Livinus describes.

There will be about 166 geotubes in Klaipeda with their own reserved field that will eventually be landscaped.

The mobile polymer apparatus equipped by Sito Rakennuttajat for the Klaipeda project is ready to go. Incidentally, it is one of the largest polymer apparatuses in the world and the most modern in its field.

The two-year project starts in late summer.