Annet-sur-Marne : Drinking water production plant

Sludge treatment

A treatment unit for settled sludge came into service on the Annet site in 2004.

Iron chloride is added to the material recovered throughout the water treatment process (draining of sedimentation tanks, washing of filters), to facilitate gravity separation of the sludge and water in a lamella thickener. The resulting sludge is stabilised with lime then compressed in two filter presses that squeeze out the remaining water. The dry sludge is then removed by lorry and may be used as capping layers on technical landfill sites or as soil improvers. This unit can recover 16 tonnes per day of material in suspension.

Automatic Control System

The plant is fully automated, allowing for quality management and treatment control 24 hours a day. A front-end logic controller receives information from remote stations and assembles it in the control room, where it is displayed as mimic diagrams.

In the event of a malfunction, an alarm is transmitted to the control room or to the on-call technicians outside working hours.

Laboratory

The Annet-sur-Marne plant has its own chemical and bacteriological laboratory.
Automatic analysers provide continuous monitoring of quality in the system.
They also serve to optimise the various treatment stages by integrating results into the automated control chain.
The plant also provides automatic bacteriological monitoring of the water distributed in the network managed by the Ile de France-Centre region.