Analysis of the characteristics of corrosion scale in drinking water distribution systems

Scanning electron microscopy,X-ray fluorescence spectroscopy,X-ray diffraction and X-ray photoelectron spectroscopy were used to analyze the microstructure,chemical composition,crystalline structure and compound constitute of the corrosion scale from cast iron pipe and galvanized steel pipe in drinking water distribution systems.The outer of the corrosion scale was compact,while the inner was porous.Iron was the primary chemical element of the corrosion scale,and the composition of the scale was iron compounds.The outer scale were ferric compounds such as α-FeOOH,γ-FeOOH,α-Fe_2O_3,γ-Fe_2O_3,FeCl_3,while the inner were ferrous compounds such as Fe_3O_4,FeCl_2,FeCO_3.The characteristics of the corrosion scale was lying on hydraulic conditions and water quality in distribution systems,and the characteristics of iron pipe materials.