Colleges around the country are ditching cafeteria trays to lower water and energy use and to prevent wasted food. “If a college is looking to go ‘green,’ they need to start looking in the dining facility,” said Sodexo spokeswoman Monica Zimmer; the food-service company expects 230 of the 600 colleges it serves to stop using trays. Skeptics worry about broken dishes, and some students worry about balancing their plates in bustling cafeterias, but it’s hard to argue with the savings. The 18,000-student Georgia Tech went trayless in response to last year’s drought, saving an estimated 3,000 gallons of water each day. A 25-university study by Aramark Higher Education Food Services found that students waste 25 to 30 percent less food when trays aren’t available, and cafeterias save a third- to a half-gallon of water for each tray they don’t have to wash. Some advocates also believe that getting rid of trays will help reduce obesity.