Chemical industry waste treatment, membrane application

Generally, a distinction can be made between membrane bioreactors based on cells performing a desired conversion and processes based on enzymes. In ceU-based processes, bacteria, plant and mammalian cells are used for the production of (fine) chemicals, pharmaceuticals and food additives or for the treatment of waste streams. Enzyme-based membrane bioreactors are typically used for the degradation of natural polymeric materials Hke starch, cellulose or proteins or for the resolution of optically active components in the pharmaceutical, agrochemical, food and chemical industry [50, 51]. In general, only ultrafiltration (UF) or microfiltration (MF)-based processes have been reported and little is known on the application of reverse osmosis (RO) or nanofiltration (NF) in membrane bioreactors. Additionally, membrane contactor systems have been developed, based on micro-porous polyolefin or teflon membranes [52-55]. 

This section deals with the application of membranes in the treatment of industrial effluent generated by the chemical industries and waste generated by the nuclear industries. Also, this section focuses on important perspectives on environmental engineering with respect to chemical and nuclear waste processing. Before going into the details of the processes used for this purpose, one should understand the background of these types of waste. 

R.O. systems utilizing externally wound tubular membrane element in modular assemblies have been used in the desalination of brackish and sea waters, the treatment and/or concentration of industrial waste waters, the separation/concentration of fluid food, pharmaceuticals and chemical solutions, and the manufacture of water purifiers for domestic use. Generally, externally wound tubular membrane systems have been found to be highly suitable for ultrafiltration applications in the processing Industry and in water pollution control applications. 

Membrane processes are very important in our everyday life, but also in industry, for example, for water and waste water treatment, in medical applications, or separation of petrochemicals. Membrane processes are an energy saving method for the separation of mixtures, which occur in nearly all production processes in the chemical industry. Membrane-based devices are much smaller and work at lower temperatures compared to conventional separation facilities with distillation, extraction, or adsorption processes. Classical separation methods used for purification of chemical products, notably distillation, extraction, and crystallization are energy and cost intensive. Over 50% of the energy costs in the chemical industry are used for the separation of gaseous or liquid mixtures. With membrane technology, the costs for difficult separations, for example, of azeotropic mixtures. 

M. Sancho, J.M. Amal, G. Veidu, J. Lora, Reverse osmosis-based treatment of radioactive liquid wastes generated in hospital facility and steel industry Case studies, in A.K. Pabby, S.S.H. Rizvi, A.M. Sastre (eds.). Handbook of Membrane Separations Chemical, Pharmaceutical, and Biotechnological Applications, CRC Press, Boca Raton, EL, 2008, Chapter 32, pp. 919-931. 

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