Chapter 6 - Advanced Membrane-Based Desalination Systems for Water and Minerals Extracted From the Sea

Abstract

Wastes produced today mean that we have to be more and more resourceful in solving the problems of water stress, energy consumption, and the depletion of raw materials. In this chapter, seawater desalination, particularly brine residues from desalination plants, are analyzed in terms of the challenges related to mine metal ions and the recovery of potable or quasi-potable water. Membrane based operations are utilized to reach the goal. Specifically, membrane pretreatment is adopted in order to minimize membrane fouling, thereby reducing operating costs; in the posttreatment stages, membrane crystallizer is considered for the production of fresh water and minerals, thus reducing the volume of concentrated streams usually discharged by the desalination plants and recovering the dissolved salts in the form of high-quality crystals. The strategy proposed will consider future desalination processes as a system for extracting minerals from the sea, rather than via traditional mining methods and desalted water production. With the strategy proposed here, the cost of desalination plants and of the water produced must be calculated with particular attention given to the raw materials produced.