New WWTP Lausanne-Vidy

Lausanne-Vidy Wastewater Treatment Plant, Switzerland / New WWTP

Client / Owner

Epuras SA - Lausanne City


2011 - 2020


Holinger AG, within the CREAL Association, lead by BG

Total costs

315 million EUR

Project description

The Lausanne-Vidy WWTP was built in the 50s and was commissioned in 1964. Since then, it only benefited from minor upgrades.


New treatment requirements lead to designing a new plant with an extended capacity of 240'000 m3/d, allowing:

  • a full nitrification of the wastewater (down to 2 mg NH4/l),
  • an advanced treatment of the TSS (0.3 mg/l),
  • the treatment of the micro-pollutants (80% yield on the selected indicators)
  • the disinfection of the treated water.
  • sludge digestion
  • biogas purification and reinjection
  • energetical optimisation

Such requirements implied a complete renewal of the wastewater treatment process. Besides, the preliminary design foresees the addition of a digestor in the sludge treatment, with the reuse of the biogas.

The proposed site is affected by numerouos constraints, the project plans to build the works inside a compact and closed building, which roof can be used for recreational activities, within the framework of the urban transformation project of the City of Lausanne.

Key project caracteristics

  • Design flow 2.4 m3/s for biological treatment, 12 m3/s mechanical
  • Preatreatment 3 lignes
  • 3 compact high-rate DENSADEG Clarifier/Thickener
  • 5 BIOFOR pre-DN filters (140 m2 p. unit)
  • 12 BIOFOR N filters (140 m2 p.unit)
  • Micropollutant treatment through ozonation, PAC, sand filters
  • UV Desinfection
  • 2 digesters volume 5000 m3 p. unit
  • 3 centrifuges 900 kg MS/h
  • Biogas treatment + reinjection


  • Project Design and Works for electromechanical equipments for wastewater and sludge treatment.
  • Energy planning WWTP and surroundings with LCA (Life-Cycle Analysis)
  • Process and hydraulical engineering
  • Interdisciplinary and technical coordination
  • Works supervision and direction
  • Start-up and commissionning

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