Economics of desalination for three plant sizes

Abstract Economic comparison is made for three different plant sizes. Small plants with a capacity below 100 m3/d; medium-scale plants with a capacity between 100 and 200 m3/d, and large plants with a capacity above 200 m3/d. Compared are solar stills, solar-assisted desalination, reverse osmosis for small plants. Published comparisons of medium and large commercially available plants are reviewed. The economics of two new and one as yet undeveloped processes are compared. Dehumidification of air and a direct contact freezing process are new. Development of the butane freezing process for large plants can reduce water-cost by over 30%.