en maintenant le traitement

14:33 Dec 22, 2013 

@Robinson09: Your suggested translation is simply not coherent English.

@Asker: You are not supposed to piggyback a supplementary question onto the question posted, but you really do need to rethink your proposed translation of "tâches de son lot". Check out the translation of "lot".

12:20 Dec 22, 2013 

Can be translated as 'work of his is in just running or currently processing.'

11:30 Dec 22, 2013 

That would make sense, as often you can't simply shut down an ongoing operation.
The translation would still be something along the lines of "keeping the operation running", it's more a question of making it clear what "operation/treatment" is being referred to.

06:36 Dec 22, 2013 

You could be right. In a separate document the principal contract is specified as being the building of a "unité de dépollution" and the work being subcontracted is described as a "procédé de traitement biologique SBR", which is a kind of biological waste water treatment. So presumably it means that the subcontractors must carry out their work in parallel with the treatment system already in place and ensure its ongoing quality.

23:25 Dec 21, 2013 

"en maintenant le traitement et en veillant à la préservation de la qualité de ce dernier": I'm pretty sure that "le traitement" doesn't refer any work done by contractors or subcontractors, but to some ongoing "preservation treatment" aimed at keeping the existing structure in good shape.
What this clause says is that whoever is doing any work on this site must not interfere with this "ongoing preservation treatment".
"... En tenant compte des sujétions inhérentes aux infrastructures existantes et conservées pendant la durée des travaux" is only the end of the sentence; what's at the beginning? this "treatment" must have been defined or at least mentioned in previous parts of the ST? Any clues?