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Removing particles and THM precursors by enhanced coagulation
Author(s) -
Vrijenhoek Eric M.,
Childress Amy E.,
Elimelech Menachem,
Tanaka Theodore S.,
Beuhler Mark D.
Publication year - 1998
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.1551-8833.1998.tb08417.x
Subject(s) - trihalomethane , turbidity , alum , coagulation , chemistry , effluent , particle (ecology) , particle size , water treatment , environmental chemistry , particle counter , chromatography , pulp and paper industry , environmental engineering , environmental science , aerosol , organic chemistry , psychology , oceanography , psychiatry , engineering , geology
A pilot‐scale study shows that enhanced coagulation removes both particles and THM precursors. The effectiveness of enhanced coagulation for removing particles and trihalomethane (THM) precursors at various alum dosages and coagulation pH values was assessed. Samples of both source water and filter effluent were examined by counting particles and measuring particle size distribution, turbidity, total organic carbon, ultraviolet light absorbance at 254 nm (UV 254 ), and THM formation potential. Removal of particles and turbidity increased substantially at alum dosages above 20 mg/L. Particle removal was not significantly different at adjusted pH (5.5) compared with ambient pH. Filter effluent particle counts were consistent with residual turbidity data; however, particle counting provided more information on the efficiency of the solid‐liquid separation. Significantly more THM precursors were removed by enhanced coagulation at pH 5.5 than at ambient pH. Higher dosages were needed to achieve acceptable removal of THM precursors than were needed for removal of particles.