Greenpeace really likes Google and their commitment to using more efficient ways to power their data centers across the country. I’m sure the conservation group would also be delighted by Google’s recycled water cooling system.

Jim Brown, Google’s Data Center Facilities Manager, posted today on the company’s blog about how they use water from the Chattanoochee River in Georgia to cool their data center in a unique way. The Chattanoochee River is a large river that begins in the northern part of Georgia, runs through Atlanta and then empties out into the Gulf of Mexico.

Anyway, Brown says that Google cools their data centers with half the energy normally required by using a technique called free cooling. They do this by bringing cold water into the data center to cool their servers then release it as water vapor through cooling towers.

Google used to make use of Douglas County’s clean drinking water to cool their servers when the data center first opened in 2007. Soon after, they struck a deal with the county to let them use reuse water instead. This allowed them to use 100 percent recycled water for all of their cooling needs.

It’s get way cooler than that though. Google and the county built a side-stream water plant about five miles west of the county’s main water plant. This allows them to divert up to 30 percent of reuse water to their data center for cooling. What’s left of the water after cooling their servers is treated onsite and released back into the river as clean water.

Google also released a video showing the inner workings of their Douglas County cooling facility.