Randleman Water Treatment Plant
Water Treatment Plant Design and "Zero Discharge" Waste Handling System
The Piedmont Triad
Regional Water Authority (PTRWA) is nearing completion on the Randleman Dam and
Lake in Randolph and Guilford Counties, North Carolina. The purpose of this
project is to develop a safe and dependable water supply for North Carolina's
Piedmont Triad region that will satisfy the projected water demand for a period
of 50 years. Hobbs, Upchurch & Associates is currently completing design of the
water treatment plant and completing the environmental assessment update that
will meet these needs.
Hobbs, Upchurch and Associates is
providing:
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Design of 12 MGD water treatment plant utilizing coagulation, flocculation,
sedimentation and granular filtration. These processes will be followed by
ultra filtration membranes and GAC. The plant will be expandable to 72 MGD.
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Completion of Environmental Assessment update.
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The project is currently designed with zero discharge from residuals treatment
system.
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Plans currently under review by DENR.
Water Treatment Plant Design
The process design
for the Randleman Lake Water Treatment Plant will address the concerns of
treating water from the new impoundment. The treatment process will consist of
a conventional water treatment plant, including coagulation, flocculation,
sedimentation, and dual media filtration, which will be followed by
Ultrafiltration (UF) Membranes and Granular Activated Carbon (GAC) contactors.
Waste Handling System
The waste handling
system for the water treatment plant is designed as a "zero" discharge system.
Calculations have been prepared that demonstrate the return will be less than
10% of the plant capacity. Using a UF membrane system, the decant will be
filtered and recycled to the head of the plant.
Raw Water Intake
As part of the
project, has completed the design of the raw water intake and pump station. The
intake is currently under construction. The raw water intake wet well will be
constructed within the boundaries of Randleman Lake and will allow the
withdrawal of raw water from three separate levels.
Treatment Process
The water
treatment plant process selection included pretreatment of the raw water with
potassium permanganate, the utilization of enhanced coagulation for organic
removal, ultrafiltration membranes as a positive barrier against
cryptosporidium and GAC contactors for taste and odor treatment. The GAC also
serves to remove additional organic compounds to reduce THMFP in the system.
Post disinfection will include the ability to use ammonia in the formation of
chloramines to further reduce THMFP.
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