Total chromium-Cr(III) and hexavalent chromium [Cr(VI)]-
have been regulated by national drinking water regulations since
1975. The federal maximum contaminant level (MCL) for total Cr is
set at 100 µg/L, and the California MCL is 50 µg/L. Increasing
public concern about Cr(VI) in drinking water supplies, a California
state mandate to establish a Cr(VI)-specific MCL, and the potential
for stricter regulations at both the federal and California levels
have sparked interest in cost-effective treatment technologies
that can remove Cr(VI) to low µg/L concentrations.
This research evaluated the performance of five vendor-provided
technologies to identify an effective treatment option for
demonstration-scale testing. The systems included strong-base
anion and weak-base anion exchange columns, strong-base anion
exchange and granular activated carbon columns, magnetized ion
exchange using a continuous reactor, zeolite adsorptive media,
and reduction with sodium bisulfite or sodium sulfite followed by
filtration. The pilot testing identified several effective treatment
options, all of which have the potential for removing Cr(VI) from
drinking water to concentrations below or even far below the 5-
µg/L goal of this research.
Previous studies focused on reduction of Cr(VI) to levels
10-1,000 times greater than those targeted by this testing. If a
low MCL is promulgated for Cr(VI) or consumers become concerned
about drinking water with elevated concentrations, water
utility managers now have treatment options to consider that
effectively reduce Cr(VI) to low levels. Includes 21 references, tables, figures.
| Edition : | Vol. 98 - No. 2 |
| File Size : | 1
file
, 380 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 02/01/2006 |
