Thursday, July 23, 2009

Sevilla Municipal Water Company

This morning (Thursday), we visited the municipal water company for Sevilla, EMASEA. A company engineer (who spoke excellent English) spent over an hour with the class in the main control center to describe the various systems.

The majority of Sevilla's water comes from man-made lakes in the mountains approximately 35 miles north of the city. If all of the lakes were full, they could provide a three year supply of water for Sevilla and several surrounding communities (slightly over 1 million people). However, southwestern Spain is prone to droughts and Sevilla is forced to draw water from the nearby river every 20-30 years. That is undesireable because the river water is much more difficult and expensive to treat. Most of the time, water is drawn from the two highest lakes which have sufficient altitude to drive a hydroelectric power plant and for gravity driven flow to the water treatment plants on the outskirts of the city.

Storm and waste water removal are also the responsibility of EMASEA. Sevilla is like Lubbock in that it is very flat and when it does rain, it pours. Flooding is , periodically, a serious problem. Rather than using playa lakes to store the storm surge as we do in Lubbock, Sevilla uses huge underground tanks.

A particularly interesting part of the presentation related to their control systems. The central control room had one wall that was completely covered (30ft x 8ft) with a single screen where the output screens from several computers could be arranged and overlapped just as if they were on a desktop computer. On those screens, the operators could check the status and control all aspects of the mountain reservoirs, hydroelectric plants, water transport lines, treatment plants, distribution systems, and waste water collection and treatment systems. All of the these major systems also have localized autonomous control systems that could continue safe operation if communication to the central control center was disrupted. Very interesting.

Unfortunately, for security reasons, we were not allowed to take any photos in the control center.

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