The Atlanta Google data center is utilizing a "sidestream" treatment plant that uses grey water rather than potable water for cooling.
Originally built in 1997, the Google data center uses an innovative evaporative cooling process which is 50 percent more efficient than standard mechanical chillers. Initially using potable water for the data center, Google decided to greatly reduce it's impact on the environment by recycling grey water rather than wasting drinkable water. Recently local media and officials were provided a tour of the Douglas County Google treatment plant.
The Google sidestream plant uses 30 percent of the grey water that would otherwise head back to the Chattahoochee River. The plant cleans the water to a level appropriate for the cooling process. Any water that is not evaporated in the process is then sent to a second, effluent plant before being sent back to the Chattahoochee, ensuring clean and safe water is being returned to the ecosystem after being used for the cooling process.
A typical data center can use hundreds of thousands of gallons of water per day as part of the evaporative cooling process. As a former resident of Atlanta, GA I'm all too familiar with the recent droughts, population growth and battles over water resources. This new approach alleviates strain on the municipal reservoir and does provide some benefits, but it should be noted that their is still an impact on the river's flow and ecosystem.
Source: Sustainable Brands