Membrane Distillation in Desalination and Water Treatment

Abstract

Membrane distillation (MD) is a thermally driven separation process. There are four types of MD: direct contact membrane distillation (DCMD), vacuum membrane distillation (VMD), air gap membrane distillation (AGMD) and sweep gas membrane distillation (SGMD). MD process has a number of potential advantages, namely, low operating temperature and hydraulic pressure, very high rejection of nonvolatile solutes, smaller footprint and potentially high water vapor flux for example in DCMD compared to conventional thermal distillation processes. For such reasons, MD has been considered as an emerging new technology in desalination and wastewater treatment. This chapter addresses a variety of applications of MD employing primarily the techniques of DCMD, VMD, and AGMD. State-of-the-art research results in different areas such as, desalination of seawater and brackish water, produced water treatment from oil exploration and coal seam gas production, high temperature DCMD, water treatment in bioreactors and oily wastewaters, treatment of processing streams from dairy, food, beverage industries and animal husbandry, concentration of acids, membrane distillation in biorefineries, mineral recovery and radioactive water treatment, are briefly presented and discussed in this chapter.