AWWA ACE56286

Colored water problems can be reduced by removing source water iron, controlling corrosion and iron release from corrosion scales, and controlling the form of iron precipitates. Chemicals such as silicate or polyphosphate may be used to reduce the amount of noticeable iron precipitate. This approach may be used to reduce the impacts of both source water iron and iron released from distribution system materials. Corrosion may be controlled by proper control of pH, alkalinity and hardness, as well as through the use of corrosion inhibitors such as orthophosphate. The objective of this research was to evaluate the effect of orthophosphate and several polyphosphates on the properties of iron particles and aqueous iron suspensions formed from the oxygenation of Fe(II). Details are given of the materials and methods used, which include: reaction cell; water; chemicals; analytical methods; experimental procedure; and, particle analysis. Includes 23 references.