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98 5. PRETREATMENT BY SCREENING
FIGURE 5.2 Coarse screens of onshore intake.
Two types of rotating fine screens that have found the widest application in desalination plants are band and drum screens. Typically, band screens are installed at smaller and medium-size plants with intake capacity, while drum screens have found wider implemen- tation for some of the largest size desalination facilities worldwide. Fine bar screens are some- times also used in open intakes but they are not as common and band and drum screens.
5.2.2.2 Band Screens
These vertical traveling screens consist of individual screening panels with fine mesh open- ings, which are attached on support roller chains, and which in turn are installed on metal- framed guide tracks (see Fig. 5.3).
As the intake source water travels through the screens, the debris contained in the water are removed and accumulated on the screen panels. The screen panel mesh is typically made
FIGURE 5.3 Intake structure with bar rack followed by band screen.
