Facebook's Arctic data centers and Google's seawater server farms both tried to check the massive energy costs needed to keep their servers sufficiently cooled. Google's Douglas County data center has a similar idea—it just involves raw sewage.
When the data center went online in 2007, it was fed with the same fresh-water supply as the rest of Douglas County. But Google's heat sinks can't tell the difference between Dom Perignon and rotgut so Google switched to a 100-percent recycled water supply.
Upstream from the data center—literally further up the Chattahoochee River—lies the Douglas County Water Authority plant. It cleans the grey water from nearby towns and releases it into the river. Google's data center siphons 30 percent of that outflow before it hits the river and pumps it through its heat exchange system. Any water that doesn't evaporate from the center's massive cooling towers flows from the data center and into a specially-built effluent treatment plant that Google constructed. This plant further cleans the water before flushing the clean water into the Chattahoochee.
According to Michael Patton, the deputy director of water and waste water operations for the WSA, "It's a win-win for both us and for the community too." Google gets free cooling while reducing its potable water consumption which frees up more for the rest of Douglas County during the hotter months. [Wired via ZDnet]