Unconventional desalination: The use of cyclone separators in HDH desalination to achieve zero liquid discharge

Research in water desalination technologies is constantly growing to meet global demands for freshwater. Though acting to meet these demands, the rapid growth and spread of desalination technologies poses envi-ronmental issues due to the increasing brine concentrates that are ultimately discharged back to nature. This article presents a cyclone separator to transform a humidification-dehumidification (HDH) cycle to a dual -product cycle to produce freshwater and solid salt crystals for highly saline streams. A desalination cycle equipped with a cyclone separator is used to treat water with 3.5 %-81 % salinity. The separation efficiency is well above 99 % and can produce potable water from hyper saline feed in a once-through process. The cyclone separator performance was tested under different conditions including humidity ratios, relative humidities, and feed stream's salinities. The cyclone separator is self-cleaning and overcomes salt scaling. This behavior is a direct function of the walls' temperature and the carrier air dew point. Self-cleaning capability allows the cyclone separator to treat feed water of extreme salinities (up to 810,000 ppm) down to freshwater salinity with zero liquid discharge. The cyclone separator was utilized in a novel HDH desalination technology to treat different salinities. The product was freshwater of salinity < 500 ppm.