The Metropolitan Water District of Southern California carried out a study to evaluate
manganese (Mn) desorption from filter media during biological filtration startup. Mn
contamination of the filter media was a byproduct of prior use of ferric chloride (FeCl<sub>3</sub>), which
contains Mn, for coagulation and free chlorine exposure. During pilot- and full-scale testing
at pH 6.5, FeCl<sub>3</sub> coagulation (without chlorine) released soluble Mn at nearly four times the
level released by aluminum sulfate (alum; 105 µg/L for FeCl<sub>3</sub> and 27 µg/L for alum). Pilot-scale
experiments demonstrated that Mn was present in the filter column in three valence states
[Mn(II), Mn(III), and Mn(IV)]. Mn(II) in the filter influent was from the FeCl<sub>3</sub>. Mn on the
anthracite media was hypothesized to be Mn(II)/Mn(IV) and first physically displaced by ferric
iron, aluminum, and hydrogen, and then catalytically oxidized to Mn(IV) by silica sand. Includes 39 references, tables, figures.
| Edition : | Vol. 98 - No. 5 |
| File Size : | 1
file
, 370 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 05/01/2006 |
