Paris sewerage authority SIAAP therefore decided to build a second siphon. This would boost capacity to match the station’s 21 m3/s. And two siphons would make subsequent maintenance work easier to plan. Two circular shafts, 12m and 10m in diameter on either side of the track are joined by a 450m tunnel, 3.60m in diameter, 20m to 25m below ground level. The Herrenknecht tunnel boring machine began its journey early in January under the auspices of its traditional godmother Anne Le Strat, parliamentarian sitting on the SIAAP board and president of Eau de Paris (the new name for SAGEP). Total project cost is €14.496 million. Completion is scheduled for next March.More information in the next issue of Hydroplus.Pascale Peignen SéralineSyndicat Intercommunal d’Assainissement de l’Agglomération Parisienne web site : click hereTo contact the editorial team of Hydroplus, click here.