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The wastewater treatment plant Seine Grésillons SIAAP in the west of Paris has selected Ethernet switches from Westermo to manage the monitoring, control and supervision of its data. This aids the plant in operating with a small number of personnel.
The Seine Grésillons SIAAP (Paris conurbation inter-departmental sanitation agency) plant inYvelines, west of Paris, France, is one of the most modern treatmentplants in the world. In the event of an alarm, the technicians can connect locally at any point of the network by wire or WiFi to the same production management interface to obtain an initial diagnosis. The entire plant is managed by a redundant ring Ethernet network. All production data are fully archived and stored in real time.
At weekends the plant operates with on-call personnel only.
The Seine Grésillons treats effluents from 18 municipalities in Yvelines and Val d’Oise, for a population of more than 300,000, using the most advanced physicochemical and biological processes. Lead contractor for plant construction was Sterau, which selected ETDE for the electricity, automaticcontrol and supervision work packages. The first construction phase was completed in October 2006, providing a treatment capacity of 1.16m3/sec, or 100,000m3 per day. Capacity will be increased to 300,000m3/d in 2013.
One of the technologies employed is attached growth, in which effluents are treated by physicochemical lamellar settling followed by biological treatment in three biofiltration stages. The modularity of the biofiltration provides reliability and flexibility of operation, thus optimising reagent use.
The resulting sludges are dried, substantially reducing their volume. The plant does not emit any odour: all the steps in the process are contained hermetically, and theair is fully treated before being released odour-free.
Water treatment is among the most demanding processes. It requires real-timemonitoring of a very large number of equipment units. The first part of the plant already involves over 4500 physical inputs/outputs and 25,000 variables, all handled on industrial Ethernet networks from the control room to the I/Os. All plant management operations are controlledthrough a single production management interface, available both in the control room and to on-site operators. Procedures are guided and taken into account in real time over the entire operating system, makingthe reliability of the switches used of prime importance.
“Atthe time of the call for tenders in 2002 the hardware and automatic control systems were not specified, so we examined the best solutions onthe market. For the switches we needed proven, highly-resistant unitswith short recovery times. After evaluation, we selected Westermo”, said Louis Claire, ETDE Automatic Control and Supervision project manager, “18 Westermo Lynx redundant-ring switches were chosen. This rangehas the switch with the shortest recovery time on the market. The switches manage all the monitoring, control and supervision data of the plant and are linked directly to the six controllers. Their reliabilityand their rapid reconfiguration are crucial to ensuring optimum operation of the plant.”
The Lynx Ethernet switch family is certifiedfor all demanding environments, including industrial, process, marine, railway, military (M12 connector) and electricity substation, for all network topologies and management modes: simple, redundant ring withrecovery time less than 20ms, SNMP, IGMP, VLAN. The switch range offers: redundant 19-60VDC power supply, working temperature from -40 to 70C, IP40, 150m cable specification (Cat5e), support for up to 200 switches per ring, management of four priority queues, auto-negotiation for each port, watch-dog; all in a robust metal case. Determinism provided by layer 2 and 3 priority support enables use for real-time or voice over IP applications when latency times are critical and must be guaranteed.
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