On a highly technical worksite with a short lead time requiring serious SADE Group resources and wide-ranging know-how.
SMAV (Valenciennes Intermunicipal Wastewater Treatment Authority) selected SADE to extend its wastewater treatment network, including renovating 2 building complex connections.
This project is the final phase of a major overhaul of the public wastewater treatment network. Its primary aim is to stop discharging wastewater into the La Balhaut stream. And also to reroute it to the River Escaut and reduce demand on the WWTP, which has until now handled 100% of the water from the system.
2 apartment buildings, 1 complex
Here, wastewater from the Rubens and Elisabeth apartment buildings still spills into an underground, channelled stretch of the stream. SADE was selected to reroute it to with two extensions of the wastewater treatment systems via 2 lifting stations. Although the works on the Elisabeth apartment building are conventional, this is not the case for the Rubens apartment building.
What a “site”!
Rerouting wastewater from the Rubens apartment building means:
- extending the wastewater treatment system by 100m at a depth of 1.30m with a ∅160 polypropylene (PP) pipe, and creating 3 PP manholes (∅1,000);
- adding a 7m-deep concrete manhole over the upper generatrix of the stream channel;
- laying, in the ∅1,400 channel, 2 corbelled segments of ∅160 PP pipe to reroute wastewater from the 3 service pipe connections connected to the 86 apartments;
- connecting these segments to a 10m-high, ∅2,000 GRP lifting station previously set up near the channel and its new manhole.
An XXL, synergetic lifting station
Lowering then installing this kind of lifting station on a cast apron and installing this kind of manhole over the channel require safe, bespoke preliminary earthworks. As a result, nearly 250m3 of earth were excavated down to a depth of 10.5m using a long-reach excavator in a 6x4m area secured with 112 micropiles (depth: 18m, ∅300) and 3 HEB belts. With micropiles bored by our subsidiary PERRIER, which also worked on the HEBs, an apron and working drawings produced by SADE Ingénierie, equipping of the station (two 1+1 pumps) handled by our subsidiaries SET and CIEMA, and materials negotiated by TERRATECH, this facility couldn’t be any more synergetic.
A short lead time
Work began in early July and this section of the worksite is scheduled for completion by 31 August, subject to significant penalties. To meet its commitment, SADE Group successfully mobilised the right material and human resources, and some staff even agreed to postpone their leave to “enjoy the ride”. Many thanks to them all!