Indicators Water

Since December 2005, Cannes-Mandelieu airport has implemented a water collector and sludge trap at the end of the runway which enables it to treat 100% of rain water and thus avoid pollution of bathing waters.
The total cost of this equipment is one million Euros. The construction site required the coordination of several trade associations, including experts in soil studies and geotechnics, civil engineering and electricity companies and specialists in tanks and pumps…

What does it involve ?
This hydrocarbon settling and separation tank, also called a sludge trap, is used in the treatment of rain water from the area where the airport terminal and tarmac areas are located.  It functions by collecting the sediment and separating the hydrocarbons present in the water in order to discharge unpolluted water into the Béal. It is installed at the end of the runway, on the sea side, upstream of Béal’s oxbow lake.

Does this installation meet a legal obligation?
Yes, it is laid down by the decree of additional provisions of 21st March 2001 relating to the impermeable surface areas of Cannes-Mandelieu Airport, within the scope of the Law on Water.

How does it work?
The settling tank is a cylindrical tank 12 metres in length and 3 metres in diameter, connected to the watercourse network, buried 4.75m deep under a concrete slab. A pumping station, equipped with two pumps, enables the water to be discharged after treatment.  In the event of heavy rains, a storm overflow collects the overflow and discharges it into the Béal.  A water analyser, made of up chemical and electronic components, checks the water purity and issues an alert in the event of any problems.

How long have the works lasted and did you encounter any specific difficulties?
The works started in February 2005 and finished in early 2006.  The main difficulty was digging a hole in the water table to a depth of 6 metres. We found a highly permeable, sandy area full of water which complicated the works. Other constraints were linked to the location of the work site at the end of the runway, under the gap of airplane take offs.   So as not to disrupt aviation traffic, we were limited to machines 3.5 metres tall and working at night was not always possible. Furthermore, the area was located in a restricted area so we had to arrange special access to the work site.