A process for dehydration of an ethanol feedstock to ethylene by: a) preheating ethanol feedstock by heat exchange with effluent from e), b) pretreating the ethanol feedstock to produce pretreated ethanol feedstock, c) vaporizing a vaporization feedstock containing pretreated ethanol feedstock and at least a portion of the flow of treated water recycled in an exchanger to produce a vaporized feedstock, d) compressing said vaporized feedstock to produce a compressed feedstock, e) dehydrating said compressed feedstock in at least one adiabatic reactor, f) separating the effluent from the last adiabatic reactor of e) into an effluent containing ethylene and an effluent containing water, g) purifying at least a portion of the effluent containing water from 0 and separating at least one flow of treated water and at least one flow of unconverted ethanol, h) recycling at least a portion of the flow of treated water from g) upstream of c).