Frank, i found a French site that claims there are already telecom cables in the sewer lines of Paris:
paris-france.org
Treating wastewater
What happens to this drinking water, which arrives in our kitchens, bathrooms and toilets, after we have flushed the toilet or
emptied our sinks and baths ?
The dirty or so-called waste water leaves our buildings via drain pipes and enters the sewers. Paris has a total of 2,300 km of
sewers which follow the route of the capital?s streets, a veritable city below a city. This vast network has three characteristics :
Firstly it is gravitational which means the sewers use the natural slope of the Parisian basin to drain the wastewater.
Secondly it is inspectionable, which largely facilitates its upkeep and the maintenance of the drinking water pipe systems , in
addition to the telephone cables which use the sewer network for their own system. As a result of these ground level access
inspection points, operatives can enter the system without having to break up the road surface.
Finally, the Paris sewer network is unitary which means it collects both our waste water and rainwater.
The sewer pipe systems which receive the dirty water come in various sizes. The wastewater is initially discharged into branch
sewers. These sewers flow into larger sewers, the collectors. The collectors, in turn, flow into even larger sewers, the outfalls.
These are enormous pipe systems, over 4 metres in diameter, which convey the wastewater to the sewage treatment plants.
Since the dirty water is not simply discharged in this form into the Seine, where it would cause enormous pollution to the river and
be a danger to fish and plant life, the wastewater must be treated.
There are four sewage treatment plants located in the Paris urban area at AchŠres, Valenton, Noisy-le-Grand and Colombes which
are responsible for "washing" almost 3 million m3 of dirty water a day. This does not mean converting it into drinking water but
simply cleaning it so that it can be discharged into the Seine.
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I also found a company called SITA that might be involved in sewer cleaning. I emailed them about the "huge wooden balls" and danger to cables. |
