Use of evaporation ponds for brine disposal in desalination plants

Desalination plants are being used increasingly in inland areas of many cou ntries for supplying water for domestic purposes. If these areas are too fa r away from the sea, the opportunity to dispose the reject brine (also know n as concentrate, reject water, or wastewater) in the ocean no longer exist s, given that ocean disposal is the common practice for plants located in c oastal areas. Evaporation ponds are especially suitable to dispose of rejec t brine from inland desalination plants in arid and semi-arid areas due to the abundance of solar energy. In irrigation projects facing a soil salinit y problem due to a shallow saline groundwater table, evaporation ponds are also in use. Saline water tables are lowered by pumping or tile draining an d the drainage water is stored in evaporation ponds. While evaporation pond s have long been used for salt production in many parts of the world, the d isposal of concentrate from desalination plants in inland areas using evapo ration ponds is of much significance both economically and environmentally. Guidelines are needed for the design, construction, maintenance, and opera tion of evaporation ponds for reject brine disposal in an economical and en vironmentally-sensitive manner. This paper provides a critical review of co ncentrate disposal technology using evaporation ponds. Relevant topics are also covered including chemistry of brine, brine disposal methods, use of e vaporation ponds in agriculture, determination of evaporation rate, and eva poration enhancement methods.