Pentek RO-3000 Installation And Operating Instructions Manual page 14

Performance Data
Arsenic Fact Sheet
Arsenic (abbreviated As) is found naturally in some well water. Arsenic in water
has no color, taste or odor. It must be measured by a lab test. Public water
utilities must have their water tested for arsenic. You can get the results from
your water utility. If you have your own well, you can have the water tested. The
local health department or state environmental health agency can provide a list
of certified labs. The cost is typically $15 to $30. Information about arsenic in
water can be found on the Internet at the US Environmental Protection Agency
website: www.epa.gov/safewater/arsenic.html.
There are two forms of arsenic: pentavalent arsenic [also called As(V), As(+5),
and arsenate] and trivalent arsenic [also called As(III), As(+3) and arsenite]. In
well water, arsenic may be pentavalent, trivalent, or a combination of both.
Special sampling procedures are needed for a lab to determine what type and
how much of each type of arsenic is in the water. Check with the labs in your
area to see if they can provide this type of service.
Reverse osmosis (RO) water treatment systems do not remove trivalent arsenic
from water very well. RO systems are very effective at removing pentavalent
arsenic. A free chlorine residual will rapidly convert trivalent arsenic to
pentavalent arsenic. Other water treatment chemicals such as ozone and
potassium permanganate will also change trivalent arsenic to pentavalent
arsenic. A combined chlorine residual (also called chloramine) may not convert
all the trivalent arsenic. If you get your water from a public water utility, contact
the utility to find out if free chlorine or combined chlorine is used in the water
system.
The RO-3500 system is designed to remove pentavalent arsenic. It will not
convert trivalent arsenic to pentavalent arsenic. The system was tested in a lab.
Under those conditions, the system reduced 0.30 mg/L (ppm) pentavalent arsenic
to 0.010 mg/L (ppm)(the USEPA standard for drinking water) or less. The
performance of the system may be different at your installation. Have the treated
water tested for arsenic to check if the system is working properly.
The RO component of the RO-3500 system must be replaced every 12-24 months
to ensure the system will continue to remove pentavalent arsenic. The
component identification and locations where you can purchase the component
are listed in the installation/operation manual.
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