The ion-exchange membrane bioreactor: developments and perspectives in drinking water treatment

Until recently, membranes in bioreactors were essentially regarded as micro/ultra porous barriers to promote high cell concentrations for process intensification and to avoid contamination of the treated water with the biocatalyst. This chapter will discuss in particular the use of membrane bioreactors for treatment of water supplies contaminated with micro-polluting ions. The contamination of drinking water sources with inorganic compounds is a matter of concern, because of their harmful effect on human health. Some of these compounds are highly soluble in water and dissociate completely, resulting in ions that are chemically stable under normal water conditions. Examples of polluting ions include nitrate, nitrite, perchlorate, bromate, arsenate and ionic mercury, for which the proposed guideline values for drinking water quality are quite low (in the range of mu g/L to a few mg/L) owing to their carcinogenic effects or other risk factors to public health.