Nuclear industry waste treatment, membrane application

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. 

It has been demonstrated that membrane separation processes can be successfully used in the removal of radioactive substances, with some distinct advantages over conventional processes. Following the development of suitable membrane materials and their long-term verification in conventional water purification, membrane processes have been adopted by the nuclear industry as a viable alternative for the treatment of radioactive liquid wastes [1]. In most applications, membrane processes are used as one or more of the treatment steps in complex waste treatment systems, which combine both conventional and membrane treatment technologies. These combined systems have proved more efficient and effective for similar tasks than conventional methods alone. 

Reverse osmosis enables complete retention of aU dissolved compounds, even small monovalent ions. To avoid the membrane blocking and scaling before reverse osmosis, microfiltration, or ultrafiltration pretreatment can be applied. Apart from preliminary treatment, ultrafiltration can be used for separation of suspensions or colloids, which are often formed by actinides or ions such as " Mg, Fe, °Co, and Sb. Microfiltration found the application for waste dewatering after precipitation. Nanofiltration (NF) that uses lower pressures than reverse osmosis is applied for separation of bivalent from monovalent ions. The most common application of NF process in nuclear industry is boric acid separation from the reactor coolant. 

Some areas of application are the nuclear industry and the treatment of radioactive liquid wastes, with two main purposes reduction in the waste volume for further disposal, and reuse of decontaminated water. Pressure-driven membrane processes (microfiltration, ultrafiltration, nanofiltration, and reverse osmosis [RO]) are widely used for the treatment of radioactive waste. 

Some research groups worldwide are currently working on the application of membrane technology to the treatment of radioactive liquid wastes with different levels of activity, from low to high activity waste. Research is mainly focused on wastes from the nuclear industry. However, the nuclear industry is not the only source of radioactive wastes medical and research applications of radioisotopes also generate radioactive wastes. 

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