Figure 1. EPDM degradation (60x). Upper half was exposed to reclaimed water, lower
half was protected.
Figure 2. Cracking and pitting (200x) of EPDM exposed to reclaimed water.
Figure 3 (above).
Cracking and pitting
(60x) of EPDM exposed
to reclaimed water.
Closeup area in red
outline shown in
Figure 4 (right).
shaft shown before and
after exposure to
happen, for example, when any type of
chloride was present. An example of
accelerated corrosion of stainless-steel
exposed to reclaimed water is shown in
Figure 4. The selection of the specific
type of stainless, and in some cases pas-sivation, becomes critical, and applications may vary with the chemicals present in the reclaimed water.
A NEW MARKET IN
As the irrigation world continues to
move increasingly from potable water to
reclaimed water, the valves traditionally
used are being recreated to new levels to
endure the chemical barrage. Initial
response solutions were fragmented and
often specific to a particular end-user
environment. While often effective,
these solutions were usually expensive
and not well adapted to a more univer-
sal variety of application. The valve
modification that does well in high-
chlorine water, for example, will not
necessarily endure in water treated with
chloramines, and an add-on system that
injects hydrogen peroxide to control
odors sometimes present in reclaimed
water presents entirely new challenges.
As the reclaimed water industry evolves
and grows, so, too, will its regulation
and standardization. This reality will be
welcomed by the providers of irrigation
valves as well as the end users of this
water resource. During the transition,
several things can be done by valve end
users to mitigate potential issues and
push forward the evolutionary process.
When first converting a traditional
potable water irrigation system to
reclaimed water, for example, users
should watch carefully for any signs of
corrosion, leaks or changes in valve performance. They should know what treatment the reclaimed water is using and
be aware of any changes in that treatment. This knowledge can be used for
good coordination between end users
and valve manufacturers during valve