Full Description

Total chromium-Cr(III) and hexavalent chromium [Cr(VI)]-have been regulated by national drinking water regulations since1975. The federal maximum contaminant level (MCL) for total Cr isset at 100 g/L, and the California MCL is 50 g/L. Increasingpublic concern about Cr(VI) in drinking water supplies, a Californiastate mandate to establish a Cr(VI)-specific MCL, and the potentialfor stricter regulations at both the federal and California levelshave sparked interest in cost-effective treatment technologiesthat can remove Cr(VI) to low g/L concentrations.This research evaluated the performance of five vendor-providedtechnologies to identify an effective treatment option fordemonstration-scale testing. The systems included strong-baseanion and weak-base anion exchange columns, strong-base anionexchange and granular activated carbon columns, magnetized ionexchange using a continuous reactor, zeolite adsorptive media,and reduction with sodium bisulfite or sodium sulfite followed byfiltration. The pilot testing identified several effective treatmentoptions, all of which have the potential for removing Cr(VI) fromdrinking water to concentrations below or even far below the 5-g/L goal of this research.Previous studies focused on reduction of Cr(VI) to levels10-1,000 times greater than those targeted by this testing. If alow MCL is promulgated for Cr(VI) or consumers become concernedabout drinking water with elevated concentrations, waterutility managers now have treatment options to consider thateffectively reduce Cr(VI) to low levels. Includes 21 references, tables, figures.

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Edition: Vol. 98 - No. 2 Published: 02/01/2006 Number of Pages: 10 File Size: 1 file , 380 KB