Application of Freezing to the Desalination of Saline Water

Freezing is one of the methods used for desalination. Although different methods, like reverse osmosis and distillation, are used commercially, freezing can be used for remote areas, cold regions and for small and remote societies. We have investigated the method of crystallization by external cooling via non-direct contact for desalination of seawater. The steps used for the freezing-melting (FM) process included: crystallization (at –20°C), separation, surface washing and melting of the samples. Three samples were taken from Boshehr beach. After three cycles of FM, the total dissolved solid (TDS) of the first sample reduced from 37,650 to 15,200, 5,059 and 1,403 mg/L, for cycles one, two and three respectively. For the second sample the TDS reduced from 40,750 to 17,884, 5,584 and 1,487 mg/L and for the third sample with from 33,351 to 15,885, 4,850 and 1,345 mg/L. This showed that after three cycles of FM, potable water can be produced.