Take a Closer Look at Sand Filters

Grate (Fabric Wrapped Over Entire Grate Opening) 

Pollutant Percent Removal Pollutant Percent Removal 

Total Suspended Solids (TSS) 70 Iron, Lead, Zinc 45 

Note that flocculation is a purely physical process in which the treated water is gently stirred to increase interparticle collisions and, thus, promote the formation of large particles. After adequate flocculation, most of the aggregates will settle out during the 1 to 2 hours of sedimentation. 

We will be examining these subjects in a little more detail in the next chapter. But for now, we should cover some of the basics because of their importance to sand filtration. The process of flocculation is applicable to aqueous waste streams where 

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