I'm always being pinged about Google's mysterious and secretive data centers. Well, see above...enjoy! Btw: Google recently hosted a "Effecient Data Center Summit" - loads of videos, presentations and best practice material re data center design, build, maintenance and overall operations ;-)
Excerpt from James's blog; "River water cooling: The Belgium river water cooled data center caught my interest when it was first discussed a year ago. The Google team went through the design in detail. Overall, it’s beautiful work but included a full water treatment plant to treat the water before using it. I like the design in that its 100% better both economically and environmentally to clean and use river water rather than to take fresh water from the local utility. But, the treatment plant itself represents a substantial capital expense and requires energy for operation. It’s clearly an innovative way to reduce fresh water consumption. However, I slightly prefer designs that depend more deeply on free air cooling and avoid the capital and operational expense of the water treatment plant."