a study on the performance of limestone roughing filter - ePrints@USM

water in designing a roughing filter. Wegelin (1996) revealed that roughing filters were
good for removal of major solid particles and for highly turbid waters. Clark (1997)
described filtration performance depends on the source of water quality (types and
concentration of natural organic matter and suspended particles) and viscosity changes
in raw water would affect filter’s performance.
Beside, the particle sizes and nature (organic and inorganic) also have a
significant influence on its removal in roughing filter (Wegelin, 1996). Figure 2.8
(Wegener, 2003) strongly supported that suspended solid removal was less than 50%
at the particle size of 5-10 μm and almost 100 % at particle size of 50-100 μm in the
trickling filter using low density plastic filter media.
Figure 2.8: Percentage Removal Versus Particle Size (Source : Wegener, 2003)
In summary, performance of roughing filter depends on influent solids
concentration, particle size, filter media size, bed depth and filtration rate. Roughing
filter design becomes more of an art than science when attempting to determine the
optimal combination of media size and bed depth for particular source of water (Clark
et al., 1997; Wegelin, 1996).
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