Hardened Ethernet switches serving the environment

The Lynx range of Westermo Ethernet switches has been selected to manage the monitoring and SCADA systems of the Seine Grésillons wastewater treatment plant of SIAAP (Syndicat Interdépartemental pour l’Assainissement de l’Agglomération Parisienne – the Paris regional sanitation agency) plant in Yve lines, to the west of Paris. This is a wastewater treatment plant inaugurated in February 2007 capable of operating with a small number of personnel. The Westermo switches have made the difference, thanks to their performance in severe environments, their reliability and their recovery time of less than 20 months.

Process equipment

The Seine Grésillons plant is one of the world’s most modern. In the event of an alarm, technicians can connect locally at any point in the network by wire or WiFi link 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, it operates with on-call personnel only.

The Seine Grésillons treats effluents from 18 municipalities in Yvelines and Val d’Oise, covering 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, automatic control and supervision work packages. The first construction phase was completed in October 2006, providing a treatment capacity of 1.16 cubic meters per second (m³/sec), or 100,000 cubic meters per day (m³/d). Capacity will be increased to 300,000 m³/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. Resulting sludges are dried, substantially reducing their volume. The plant doesn’t emit any odour: all the steps in the process are contained hermetically, and the air is fully treated before being released odour free.

Water treatment is among the most demanding processes. It requires real-time monitoring of a very large number of equipment units. The first part of the plant already involves over 4,500 physical inputs/outputs and 25,000 variables, all handled on industrial Ethernet networks from the control room to the inputs/outputs. All plant management operations are controlled through 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, making the reliability of the switches used of prime importance.

Process equipment.

“At the time of the call for tenders in 2002, the hardware and automatic control systems weren’t specified, so we examined the best solutions on the market. For the switches, we needed proven, highly–resistant units with short recovery times. After evaluation, we selected Westermo”, said Louis Claire, ETDE Automatic Control and Supervision project manager. Eighteen Westermo Lynx redundant-ring switches were chosen. This range has the switch with the shortest recovery time on the market. The switches manage the monitoring, control and supervision data of the plant and are linked directly to six controllers. Their reliability and rapid reconfiguration are crucial to ensuring the plant’s optimum operation.

The Westermo Lynx Ethernet switch family is certified for all demanding environments, including industrial, process, marine, railway, military (M12 connector) and electricity substation, for all network topologies and management modes: simple, redundant ring with recovery time less than 20 ms, SNMP, IGMP, VLAN. The switch range includes over 90 products with unrivalled technical characteristics: redundant 19-60 VDC power supply, working temperature from –40 to +70°C, IP40 protection, 150-metre long cable specification (Cat5e), reconfiguration in 20 ms after ring break (recovery), support for up to 200 switches per ring, management of four priority queues, auto-negotiation for each port, watch-dog; all implemented in a very robust, reliable 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. It’s the only product on the market to feature such specifications at an extremely competitive price given its performance.

Westermo Teleindustri AB
Stora Sundby, Sweden
www.westermo.com
Enquiry No. 205