Google reusing municipal effluent for cooling

Information giant Google is reusing municipal wastewater to cool its data centre in Douglas County, Georgia, USA.

A typical data center can use hundreds of thousands of gallons of water a day. Google says its data centers use half the energy of a typical data-center, in part because they rely on evaporative cooling rather than energy-hungry mechanical chillers.

When Google first built its Georgia facility in 2007, the water it used came from the local potable supply, but the company soon realized that the water did not need to be clean enough to drink. After discussion with the Douglasville-Douglas County Water & Sewer Authority (WSA) about setting up a system that uses grey or recycled water in its cooling infrastructure.

Google worked with the WSA to build the Sweetwater Creek Side-Stream Plant, about five miles (8 km) west of the data center, which receives up to 30% of the water that would have gone back into the Chattahoochee river. Instead, it is sent through the plant for treatment and then on to the data center.

Any water that does not evaporate during the cooling process then goes to an effluent treatment plant located on-site. There it is disinfected, mineral solids are removed and the effluent is sent it back out to the receiving river.

With this system in place, the company is able to use recycled water for 100% of its cooling needs.