Study, Design, and Deployment of a Management Support Tool to Control the Effluents of the SIAAP in Paris

The “Syndicat interdépartemental pour l’assainissement de l’aglomération parisienne” or SIAAP (the Greater Paris inter-departmental sanitation consortium) manages a complex and extensive combined sewer network that serves a population of eight million distributed over a 1,900 km² area. The operators require decision support in real-time for both dry and wet weather to operate the numerous flow regulation, diversion and pumping facilities, as well as five treatment plants.

In partnership with Eau & Force and Satelec, Tetra Tech CSO conducted a study to develop the prototype of a decision support system called MAGES (“Modèle d'Aide à la Gestion des Effluents du SIAAP”), followed by the design, to provide real time operational support for the flow and effluent management of the Greater Paris wastewater network. It consists of:

  • A dry weather management strategy that attenuates the flow to five treatment plants;
  • A wet weather pollution control strategy that aims to reduce untreated discharges to the receiving water bodies (the Marne and Seine rivers);
  • A flood control strategy to reduce street overflows.

The MAGES decision support system proposes an optimized management strategy to the operator, which consists of operation set points for 57 regulation structures at 15-minute time steps for a control horizon of six hours, through customized human-machine interfaces (HMI). The decision support system optimizes the use of available conveyance, storage, and treatment capacities based on real-time field conditions, as well as future predicted conditions based on weather forecasting and real-time modeling. During certain wet weather events when overflows cannot be avoided, the decision support system prioritizes the overflow discharge sites based on the water quality of the receiving water bodies (the Marne and Seine rivers).

The system has been operating successfully since mid-2008. The rainfall events are being monitored by the partnership (Eau & Force, Satelec, Tetra Tech CSO) under an on-going maintenance contract. Performance reports are produced on a regular basis and used for preventive and corrective maintenance purposes.


6-month event % of CSO reduction:        100%

% reduction total storage needs:              30%

Capital investment savings:                  $800M

“The results of the study indicate that the condition of the Marne and Seine rivers has improved greatly and show a 50% improvement in water quality during wet weather. By using real time control, the cost of the overall sanitation program will be reduced by 30% thanks to the maximum use of new and existing facilities.”

Daniel Méraud – Region of Paris Metropolitan Sanitary District


Key Contact

Diana Tao

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