ENGINEERING CHALLENGES FOR FLOW CONTROL OF
RECLAIMED WATER
In the valve world, the turf and landscape irrigation realm is seeing significant new opportunity, and
along with this application have come
numerous growing pains, especially
with respect to the effect of chemicals
used in water treatment on various
valve component materials.
Water that is recycled from earlier uses is a
tremendous resource in irrigation these days, and
valves play a vital role in the process. However,
the practice has brought both new opportunity
and new challenges.
BY ROLF STRUTZENBERG
WHAT IS RECLAIMED
WATER?
As the direct byproduct of extensive
wastewater treatment, reclaimed
water—also referred to as recycled,
secondary or tertiary water—is fil-
tered and chemically treated to strin-
gent standards. With the right treat-
ment, this reused water may be
better quality than potable water
from a typical water district. The
wastewater is treated to different
levels depending on the application
for which it is intended as well as the
potential for human exposure. The
general level of treatment for non-
potable and indirect potable uses is
outlined in Table 1 (see page 35).
Despite the fact wastewater can now
be processed to a fully potable level,
society is not yet ready to embrace
the thought of drinking water that
came directly from a sewage treat-
ment plant. Also, the cost of treat-
ment levels acceptable for direct
human consumption remains high,
and a method for complete elimina-
tion of hormones and synthetic com-
pounds (such as drug residues) found
in wastewater has not yet been
proven. However, this has created a
golden opportunity for direct appli-
cation in the turf and landscape irri-
gation world. With the purchase cost
of reclaimed water typically about
one-third the cost of potable water
and numerous financial subsidies
available to encourage irrigation sys-
tems using reclaimed water, this
market is expanding rapidly.
