Occurrence and composition of particulates in filter process streams

The objective of this work was to provide an in-depth analysis of the particulate composition of influent and effluent streams for granular media filters at full-scale water treatment plants. Findings from these analyses were evaluated with respect to the design and operation of the treatment system and the water qualities involved. On a mass basis, inorganic and organic materials in the filter influent and effluent streams were predominantly present in the submicron-size fraction (defined here as particles with diameters between 30 and 450 nm), regardless of whether direct or conventional filtration was used. However, variability in results from the different facilities indicated that water quality and treatment type significantly influenced the size distribution of organic and inorganic materials. On the basis of a mass concentration, the inorganic composition of the particulate-size fractions was largely hardness cations, silica, and organics, plus residual amounts of iron and/or aluminum. 2011