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Project overview


The Beggen treatment plant collects wastewater from Luxembourg City and the municipalities of Strassen, Bertrange and Leudelange, the locality of Roedgen, and the area to the west of the airport. As all of these are high-growth areas, in terms both of the number of residents and the volume of economic activity, the Beggen water treatment plant has reached its maximum capacity of 210,000 population equivalen.t
The capacity of the plant will be upgraded to satisfy a requirement of 450,000 population equivalent by 2047.

The project

As the plant’s operation cannot be suspended and all standards must be adhered to at all times, the plant will remain operational while the extension works are carried out.

These works include the addition of a new primary sedimentation stage, with four parallel channels, downstream of the existing mechanical treatment stage. After this stage of the treatment process, the City of Luxembourg has opted to add a biological treatment, using sequencing batch reactor (SBR) technology, which is both highly effective and compact. This will be followed by a fourth decontamination stage in which the water is treated using ozone and granular activated carbon. This technique has been tried and tested, especially in purifying drinking water from natural springs.

On account of the growth of the municipalities in the plant's catchment area, initial construction work – referred to as the "DELTA extension" phase – will be needed to ease pressure on the existing biological treatment facility. The reason for partially extending the biological treatment stage is to relieve pressure on the existing installations until the extension works are completed, ensuring the plant can continue to meet all currently applicable legal standards until 2030.

Works schedule

Summer 2021 – Summer 2022: Detailed design, invitations to tender and public tenders

2022–2023: Awarding of contracts


  • Construction of the office building and the new primary clarifier with workshops and storage areas
  • Construction of the 3 SBR basins along the banks of the Alzette
  • Construction of the mechanical sludge-dehydration treatment facility


  • Construction of digester no. 3 and conversion of the two existing digesters


  • Demolition of the existing office building
  • Construction of the 3 SBR basins in the middle of the site


  • Construction of the 3 SBR basins on the Beggen side of the site
  • Commissioning of the biological and mechanical treatment facilities


  • Construction of infrastructure for the fourth stage of treatment


  • Completion of works and final commissioning of all new infrastructure

Progress on the site

Actualisé chaque heure.

Travaux de décembre 2022

Travaux d'octobre 2022

Timelapse de février 2021.

Travaux de janvier 2022.

Travaux de novembre 2021.

Travaux d'octobre 2021.

How it works

One project, with many parties involved

The extension of the Beggen water treatment plant is a challenging undertaking that requires close cooperation between the City of Luxembourg and its external partners, as well as compromise between all of the parties involved.

Project owner
The City of Luxembourg
The Ministry of the Environment, Climate and Sustainable Development (Ministère de l'Environnement, du Climat et du Développement durable) – Water Management Fund (Fonds pour la gestion de l’eau).
Project management
Paul Wurth Geprolux S.A
BG Ingénieurs Conseils S.A.
TR-Engineering ingénieurs-conseils
Hydro-Ingenieure Planungsgesellschaft für Siedlungswasserwirtschaft mbH
LUXauTEC ingénieurs-conseils
Holinger S.A.
Building experts
ProSolut S.A.
Secolux S.A.
Grundbaulabor Trier Ingenieur GmbH

More information

For more detailed information, including specifics on the water treatment process and its impact on the environment, read our brochure.

the department

Contact details

3, rue du Laboratoire
L-1911 Luxembourg

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