ABSTRACT
Membrane technology is a novel and emerging separation technology. The technique of osmosis, transport of water or solvent through a semipermeable membrane has been known since 1784. The first commercial cellulose nitrate or cellulose nitrate-cellulose acetate membrane used for practical applications were manufactured by Sortorius in Germany after World War I. Asymmetric membranes are thin film composite membranes. They have a dense skin layer on top of a spongy support layer underneath. Semipermeable membranes are those which permit passage of certain components in a solution and retain others based on molecular weight/size. Membrane processing is based on selective permeability of a porous membrane. The membrane permits passage of certain components known as “permeate” and retains/rejects other components known as “retentate.” Applications of membrane bioreactors include: production of ethanol, production of acetone-butanol, production of lactic acid from glucose and from cheese whey, production of citric acid from glucose.
