Engineering process of membrane technology in power generation industry is demonstrated in Fig. 15. RO technology is used in all the membrane plants in this industry and sometimes double RO technology is used. Single or double RO are often employed with UF, PF or RF. 74% of the membrane plants use single RO and 26% of them use double RO. 42% of the membrane plants uses single RO coupled with rapid filtration. This may be due to the fact that single RO coupled rapid filtration is the most cost efficient treatment method and still generate water of acceptable quality.
Applications in steel industry also focuses on RO. RO is either coupled with UF, MMF, or both. 46% of membrane plants use RO coupled with UF. 45% of membrane plants use RO coupled with MMF. Only 9% of the membrane plants use RO coupled with both UF and MMF. It is easy to see from Figs. 14–16 that the engineering process in different industries are varying. This is due to the following facts. The wastewater originating from different industries have a broad range of different contaminants and thus have different features. The purpose of the wastewater treatment is varying for different industries. For example, water treated by RO is often aimed to be recycled and reused as makeup water or cooling water.