At a plant that processes sewage sludge, biosolids, and other potentially malodorous materials, you might think there would be a certain smell around quasar energy group’s bio-digester in Wooster. But it’s surprising that there’s no offending aroma coming from the plant where organic waste is turned into natural gas that’s used to power about half of the Ohio State campus in Wooster. Why? quasar’s vice president of engineering, Clemens Halene, explains that the digester is anaerobic, or without air, and they work to keep the process air tight.