Tailored granular activated carbon (GAC) can reduce groundwater perchlorate levels from 60-80
ug/L to below detection. Specifically, rapid small-scale column tests, also called RSSCTs,
showed that by preloading GAC with iron-oxalic acid, the GAC adsorption capacity could be
improved up to 42%. When the preloaded GAC became saturated with perchlorate, 65-74%
of the GAC's original adsorption capacity could be restored by chemically regenerating the GAC
with sodium borohydride. This chemical regeneration could be achieved with the use of a
small fraction of the water that had been processed during the water treatment cycle. The waste
stream from chemical regeneration contained concentrated perchlorate levels as high as
7,000-15,000 ug/L. With this approach, the simulations described in this article indicated that
when two tailored GAC beds were operated in series with a 40-min empty-bed contact time,
they could provide water treatment service for 60-75 days during the first operations cycle;
following chemical regeneration, the GAC beds could provide about an additional 30-40 days
of water service for several successive treatment and regeneration cycles.
Includes 29 references, tables, figures.
| Edition : | Vol. 94 - No. 11 |
| File Size : | 1
file
, 310 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 13 |
| Published : | 11/01/2002 |
