AWWA WQTC62417

The Metropolitan Water District of Southern California initiated a study to evaluatemanganese (Mn) desorption from filter media during biological filtration start up. Mncontamination of the filter media was a byproduct of multiple years of pre-chlorinationwhile using Mn-containing ferric chloride (FeCl₃) for coagulation. During pilot- and fullscaletesting, FeCl₃ coagulation (without chlorine) released soluble Mn at nearly fourtimes the level compared to alum (105 µg/L for FeCl₃ and 27 µg/L for alum). Pilot-scaleexperiments led to the conclusion that Mn was present in the filter column in threevalance states [Mn(II), Mn(III), and Mn(IV)]. Mn in the filter effluent was hypothesizedto be first physically displaced as Mn(III) from anthracite media by ferric iron,aluminum, and hydrogen, and then catalytically oxidized to Mn(IV) by silica sand. Includes 34 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

19

File Size:

1 file , 610 KB