Rehabilitation of accessible galleries and main drains Marceau collector Rehabilitation Nouvetra, a major domestic player for the building and rehabilitation of accessible galleries and main drains, is greatly concerned for the safety of workers in confined environments. It takes pains to create appropriate environments by its mastery of waste water deviation techniques, inside or outside of structures, so as not to interfere with the running of the network. Mastered techniques : underpinning ; hydro-stripping / hydro-demolition (HPT) ; coatings with fibre content, shotcrete ; injection of bonding material and re-activation ; treatment of cracks ; prefabricated shells and channels ; new structures; laying pipes in trenches, accessible drains in pits and galleries ; sinking wells and building chimneys. repairing work on drinking water tanks