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8. GRANULAR MEDIA FILTRATION
FIGURE 8.3
Single-stage gravity filters of the Carlsbad desalination plant, California.
FIGURE 8.4
Single-stage gravity filters of the Sorek desalination plant, Israel.
Two practical approaches to address this type of problems are: (1) use of dissolved air flotation facility ahead of the pretreatment filters to gently remove algal cells and prevent their breakage (which is preferable); (2) installation of GAC media layer (“activated carbon cap”) on the surface of the filters to remove some of the polysaccharides and other organics in the source water.
Pressure filters usually operate at several times higher filtration pressure than gravity filters. Because the operating pressure of these filters is often higher than the algal cell break-pressure
