2.5 million m3 of waste water: this is the volume of waste water which passes, each day, through the water treatment network managed by the interdepartmental syndicate for sanitation of the Parisian conurbation - SIAAP. The territory covered by the SIAAP is made up of the Paris conurbation (Paris departments, Hauts-de-Seine, Val-de-Marne and Seine-Saint-Denis comprised of 124 communes, 6.6 million inhabitants as well as some communes of Seine-et-Marne, Yvelines, Essonne and Val-d’Oise (162 communes, 2.3 million inhabitants).
This waste water is conducted to 6 SIAAP water treatment plants which cleanse three quarters of the waste water produced by the whole of the Île-de-France region. Once purified it is then released into the Seine or its tributary the Marne.
