Apr 25, 2003

Arsenic Removal System Keeps Village in Compliance

At Work on Arsenic Removal

The town of Camp Verde, Ariz., historically has had an
arsenic problem, which led to the development of a new well approximately seven
miles from the town. Initial arsenic testing indicated that the new well had
low arsenic content, but arsenic levels had increased since pumping began. This
increase along with the U.S. Environmental Protection Agency?s lowering
of the Maximum Contaminant Level (MCL) to 10 ppb has the water company
concerned about meeting the new arsenic standards.

Water Remediation Technology (WRT) contacted the managers of
the water system and the Arizona Department of Environmental Quality and
proposed to install a small arsenic removal system on one of the satellite
water systems that was consuming 7,000 to 10,000 gallons a day (6 to 8 gpm on
demand) with arsenic levels around 25 ppb. The goal for the project was to
consistently produce water with less than 10 ppb arsenic. It also was important
that the installation operate with a minimum of attention from Camp Verde
personnel.

The Camp Verde System was designed to handle 6 to 8 gallons
per minute in four 16"-diameter by 10¢-tall pressure vessels. Each
vessel contained 6.5 feet of 20 ¥ 40 mesh Z-33 arsenic removal media. This
media depth was chosen to enable the monitoring of loading over a shorter
period of time than would be the case in a full size system that would contain
about 15 feet of media per tank in larger tanks. The vessels were plumbed and
valved to allow any tank to be the number one tank and to allow any tank to be
taken off line without shutting down the system.

The plant was placed in operation on December 22, 2001 and
has operated continuously since that time. pH analysis conducted in the field
by Camp Verde staff has shown no significant change in the pH between feed and
discharge. Rechecks of the iron assay have shown only modest iron increase in
the discharge over the feed. (Feed = 0.2 ppm, Discharge = 0.7 ppm.) Arsenic
levels in the feed have been consistent at 24 to 27 ppb. (See Figure 1.) All
columns are continuing to remove arsenic. As of February 24, 2002, more than
363,000 gallons have been treated during seven weeks with no media change and
no discharges over the MCL of 10 ppb. The test continues to run smoothly.

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