Rapid Small Scale Column Tests (RSSCTs) were used as a timely means to quickly verify Arsenic technology selection for a specific water matrix and to develop associated cost
projections for three municipalities in Arizona as part of their efforts to gain compliance with the
new 10 µg/L Arsenic maximum contaminant level. RSSCTs were conducted using three to five
commercially available media on six groundwaters in Arizona. Testing was done following a
protocol developed by Arizona State University. RSSCTs were originally developed to quickly
evaluate the organic removal performance of activated carbon, and similar protocols have been
developed for Arsenic removal with metal-oxide sorbents. The results from the RSSCTs allowed
comparison of run lengths (measured in bed volumes (BVs)) from each media before the Arsenic
concentration in treated water was greater than 10 µg/L or a specified target goal. These tests
simulate operation of a full-scale Arsenic adsorption treatment system.
Due to the rapidly approaching implementation of the Arsenic rule, several municipalities have
been working to expedite Arsenic treatment system selection and implementation. RSSCT
durations range from 2 to 8 weeks rather than 6-months to 12-months required for pilot testing.
RSSCTs were used at different groundwater wells to confirm the effectiveness of adsorption
media for Arsenic removal in specific water matrices. Groundwater tested covered a range of
water quality parameters. Arsenic concentrations ranged from 11 to 50 µg/L. Field pH ranged
from 7.5 to 8.6. Silica concentrations ranged from 15.4 to 47.6 mg/L. In some cases Arsenic
breakthrough curves showed notable differences based upon differing water matrices and in
other cases media performance was similar.
Based upon a fast approaching compliance deadline, bench scale testing using RSSCTs was
specified by each of three water systems in lieu of pilot testing. RSSCTs were not only utilized
to ensure that the media selected adequately removed Arsenic, but testing was also used to
prescreen vendors for bidding purposes and help establish anticipated media change-out
frequencies and associated operation and maintenance cost projections. This paper will benefit
water systems that have struggled to meet compliance by January 2006, with the introduction of
a tool that will aid in making secure decisions on technology selection. RSSCTs may also be
used in forthcoming years to test new media on specific water matrices as they become available
on the market. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 330 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 11 |
| Published : | 11/01/2005 |
