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Treatment Options and Their Effect on NOM—Coagulant Floc Structures
Author(s) -
Jarvis Peter,
Jefferson Bruce,
Dixon David,
Parsons Simon A.
Publication year - 2008
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.2008.tb08130.x
Subject(s) - alum , ferric , settling , coagulation , chemistry , cationic polymerization , sedimentation , polymer , breakage , ion exchange , water treatment , chemical engineering , inorganic chemistry , ion , environmental engineering , materials science , polymer chemistry , composite material , organic chemistry , geology , sediment , psychology , paleontology , psychiatry , engineering
Multiple treatment options were compared for their effect on natural organic matter (NOM)–coagulant floc structure at optimum coagulant doses. The treatment options were coagulation with: ferric, ferric + polymer, alum, and polymer and magnetic ion exchange pretreatment followed by ferric coagulation. Using a range of diagnostic techniques, size, strength, breakage, and settling rate were compared. Ion exchange pretreatment resulted in significantly improved floc structure in terms of increased size, settling rate, and strength. Comparison of conventional ferric and alum coagulants suggested that ferric resulted in improved floc structure combined with better NOM removal. The cationic polymer investigated did not improve floc structure. The reasons for the observed changes were thought to be related to the type of organic material incorporated into the floc matrix.