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THE EFFECT OF ORTHO- AND POLYPHOSPHATE ON THE PROPERTIES OF IRON PARTICLES AND SUSPENSIONS
Citation:
Lytle*, D A. AND V. L. Snoeyink. THE EFFECT OF ORTHO- AND POLYPHOSPHATE ON THE PROPERTIES OF IRON PARTICLES AND SUSPENSIONS. Lacey, M. (ed.), JOURNAL OF AMERICAN WATER WORKS ASSOCIATION. AWWA, Washington, DC, 94(10):87-99, (2002).
Description:
Orthophosphate and polyphosphates are used widely by drinking water utilities to reduce lead, copper and iron release from distribution system materials, and reduce visible iron precipitation and related discolored-water complaints. Bench-scale experiments were conducted to evaluate the effect of orthophosphate and several polyphosphates on the properties of iron particles and suspensions derived from the oxygenation of Fe(II) at a single oxygen concentration over a broad pH range. Results showed that polyphosphates, and orthophosphate to a lesser extent, reduced apparent color and turbidity of iron suspensions, decreased particle size, made the zela potential more negative, and increased iron suspension stability. A fixed mass concentration of low molecular weight polyphosphate was more effective at reducing the particle size of Fe(III) solids than high molecular weight polyphosphates.