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SKYCO PLANT
WATER TREATMENT PROCESS
WELLS
The plant is supplied by 10 deep wells that are rated at 500 gallons per
minute (gpm). The wells average 170 to 220 feet deep. They are screened from
around 140 feet to 200 feet deep. They draw water from the Upper Yorktown
Aquifer. These are located on Highway 345S between Skyco and Wanchese. Six of these wells have auxiliary motors to pump water in the event of
a power outage. The plant is fed by these wells through a 16 inch pipe.
TREATMENT
The main treatment the plant employs is softening and iron removal of the
water. The plant was built as an Ion Exchange Treatment Plant. The water
plant uses four Bruner-Calgon sodium zeolite ion-exchange softening tanks
with a capacity of 875 gpm each.
When a hard water is passed through a
sodium cation resin, the calcium and magnesium in the hard water are replaced
by sodium from the resin. Calcium and magnesium are the minerals that produce
hard water. After all the sodium in the resin has been exhausted, the resin
can be regenerated with a common salt solution which restores the sodium
in the resin. The resin is then ready to process the hard water to soft
water again. A secondary treatment was added and came on-line in May of 2003. It
consists of five vessels containing a resin to remove organics. These vessels
are capable of treating five million gallons of water per day. Organics when
combined with chlorine create trihalomethanes. By removing the organics, we
reduce the trihalomethanes in the finished product. We then add a chemical called Calciquest 50/50, which is a
blend of phosphates formulated to control steel and lead corrosion. It
also prevents the precipitation of dissolved iron and manganese. We add
this at 1.0 mg/l. We then add chlorine at 1.5 to 2.0 mg/l. The last chemical
we add is hydrofluosilicic acid, which is a type of Fluoride. Fluoride
is added to prevent tooth decay in children. The fluoridation of drinking
water has been shown to reduce dental decay among children by 2/3. The
water is then stored in a two million ground storage tank behind the plant.
The water is either pumped to a 200,000 gallon elevated tank in front of
the plant or to ground storage tanks on the beach.
Page last updated July 21, 2003
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