It takes around three to seven barrels of water to make one barrel of beer. Craft brewers in California use around 558 million gallons of water to process beer and another 93 million gallons to make the beer each year. Engineers from the Department of Civil, Environmental and Architectural Engineering at the University of Colorado, Boulder created a new bio-manufacturing process that turns brewery wastewater into the carbon-based material needed to create energy storage cells.
Article source: http://www.forbes.com/sites/jenniferhicks/2016/10/12/engineers-convert-brewery-wastewater-into-energy-cells-for-biobatteries/#150a36881d75
Photo source: By Distelhäuser Brauerei (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons