AWWA JAW60509

Oxidation of ferrous iron, Fe(II), to ferric iron, Fe(III), is an important reaction in drinking watertreatment and distribution systems, and the ferric particles that form are a major source ofconsumer complaints about colored water. Ferrous iron is found naturally in many groundwatersand can be released from distribution system materials. Bench-scale experiments wereconducted to study the effects of pH, oxidant type (oxygen, chlorine, and chlorine dioxide), andoxidant concentration on the properties of Fe(III) particles and suspensions formed from Fe(II)oxidation. The color and turbidity per unit mass of iron of suspensions formed from oxygen weremore than twice those of suspensions formed from chlorine and chlorine dioxide at all pHvalues. Similar observations were made during tests with oxygen and chlorine using naturalgroundwaters at two field locations. Particles formed from chlorine and chlorine dioxide wereless dense and had a greater capacity to adsorb orthophosphate. Experimental observationswere explained using a model that considers differences in Fe(III) particle formation andgrowth pathways. These research findings have practical implications related to both watertreatment (iron removal) and distribution system issues. Includes 39 references, tables, figures.

Product Details

Edition:

Vol. 96 - No. 8

Published:

08/01/2004

Number of Pages:

13

File Size:

1 file , 1.5 MB