Abstract
There are many design parameters affecting filtration efficiency such as filteration rate, media packing depth, size distribution, and so on. The sphericity, the ratio of the surface area of an equal volume sphere to the real surface area of the particles, is one of major physical characters of media. The effect of sphericity on the performance of anthracite filter has been investigated. Media from eight water treatment plants have been collected. The sphericity of each media has been calculated by using well known headloss equations such as Kozeny equation, Dahmarajah equation etc.. Columns packed with anthracite media having different sphericity have been used to compare headloss development, floc accumulation in the bed, particles in bed water, filtrate turbidities after backwash and so on. The repeated experiments have indicated that the sphericity of anthracite media may not have remarkable influence on the filter performance as it has been suspected. It also has been prospected in the experiment that the media of higher sphericity would store more particles in the bed and give better filtrate quality, if provided that the effective size and the size distribution of media would be the same.