By converting one of its ethanol plants to a zero-discharge facility, one renewable-fuels manufacturer is saving 100 million gal/yr of water. Water-supply issues are emerging as a national concern with certain sectors coming under increasing scrutiny. This is certainly the case with the ethanol industry. State discharge regulations dictate that plant designs incorporate technological solutions to minimize water use. These designs give operators increased flexibility in terms of enabling the reuse of water streams internally, with the goal to discharge no water to the environment. When this can be accomplished, the plant operates as a zero liquid discharge (ZLD) facility.