Partial view of the Metro construction site in Saint Quen: Two temporary basins containing contaminated groundwater in the foreground. (©Tsurumi)
Partial view of the Metro construction site in Saint Quen: Two temporary basins containing contaminated groundwater in the foreground. (©Tsurumi)
The Metro network is currently being extended in the north-west of the French capital and work is underway to expand the underground station Mairie de Saint-Quen on line 13 into an interchange. Line 14 is being extended to the station at the same time. The new sections should be in operation in 2017.
 
One section of the site previously housed a rail yard and following its demolition, the 2000 m² site had to be cleared of harmful substances. The soil is infiltrated with crude oil residues and the contaminated water produced during the work on this soil. Wells were set up to drain the ground. The water from these wells is gradually pumped into specially-erected basins for intermediate storage.
 
After the sedimentation stage, Tsurumi 8-FSP submersible scum skimmers draw off the film of harmful substances. They are clearly identifiable by their three red ball floats. Each skimmer extracts around 250 l/min.
 
The company in charge of construction also uses products from the Japanese manufacturer for the well – specifically the KTZ series, a construction site pump for contaminated water.