Overview of the project

Objectives of the City of Luxembourg

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


  • Awarding of contracts


  • Construction of the new office building and demolition of the existing office building


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


  • Construction of the 3 SBR basins along the banks of the Alzette


  • Construction of the 3 SBR basins on the Beggen side of the site
  • Commissioning of the biological and dehydration treatment facilities, as well as the primary clarifier


  • Construction of a new storage basin for the SBR and a treated water balancing tank


  • Construction of infrastructure for the fourth stage of treatment


  • Completion of works and final commissioning of all new infrastructure

Progress on the site

Updated every hour.

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Works in February 2024

Works in March 2024

Works in April 2024


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
  • 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).
  • 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.
  • ProSolut S.A.
  • Secolux S.A.
  • Grundbaulabor Trier Ingenieur GmbH
  • OBG Lux S.A.  
  • Zahnen Technik GmbH
  • Soludec S.A.
  • Tralux SARL
  • G4S Security Solutions SARL
  • Entrapaulus Construction S.A.
  • AUTEC GmbH
  • Kautz Starkstrom-Anlagen Luxembourg SARL

More information

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