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Pelham Wastewater Treatment Plant
$88 million project will triple
capacity of Greenville facility
By Debra Wood
The Western Carolina Regional Sewer Authority's expanded
and upgraded Pelham Wastewater Treatment plant will enable
the agency to consolidate operations at two plants and upgrade
facilities to meet all environmental regulations.
"It's increasing the permitted capacity from 7.5 million
gallons a day to 22.5 million gallons a day," said John
Langley, the authority's project manager. "Growth in
the area is the main reason."
At the Pelham plant, crews from Pizzagalli Construction Co.
of South Burlington, Vt., are adding influent pumping capacity,
new headworks and screening facilities, primary clarification
and anaerobic digestion equipment, a 15-million-gallon holding
basin, effluent filters and ultraviolet disinfection, and
odor-control systems.
The company also will modify the aeration basins, transitioning
from a mechanical oxidation ditch to a diffused-air system.
And it is moving the plant outfall downstream to eliminate
the need to pump effluent during high-water conditions. The
former Taylor wastewater facility will be converted to a pump
station and holding facility.
Black & Veatch Corp. of Shawnee Mission, Kan., designed
and engineered the $88 million expansion. The company also
serves as the owner's representative during construction.
All work takes place on an existing wastewater-treatment
site and has required extensive sequencing, with four main
phases, each dependent on elements in prior phases. The plant
must maintain operations and meet government standards.
"It is a very complicated sequence," said Jeff
Wells, project manager for Black and Veatch. "It is online
and has to meet limits every day, and we are in the middle
of that plant. We're not off to the side."
Pizzagalli broke ground in June 2003 and expects to complete
the work in June 2007. At the beginning of September, the
project was six months ahead of schedule. Art Seymour, project
manager for Pizzagalli, said the schedule has been aggressive
and crews have worked five to six 10-hour days. Wells estimates
the schedule has about a year of time built in to handle the
sequencing.
"This job is incredibly complex," Seymour said.
"We have every inch of ground destroyed here."
Pizzagalli shaved some time off the schedule through innovative
techniques. Rather than pouring the seven, concrete clarifier
holding tanks and troughs around tank perimeters separately,
as is customary, Pizzagalli purchased a proprietary forming
system to pour the trough with the wall.
"It was a whiz-bang neat thing," Seymour said.
"It saved us about a month on each one of them. It worked
out really good for us."
Western Carolina has moved into the new operations building.
The balance of the first phase, influent pumping facilities,
was scheduled to go online at the end of October. Crews also
dug 37-ft. deep between the river and an existing pump station
for the new influent pump station. Pizzagalli put in some
taps and plugs and bypassed to the existing lines.
"The influent is deep because it is the low spot in
the system," Seymour said. "At one time, we thought
we might have to pump across the river, but we worked out
a way not to do that. That would have been risky with temporary
lines."
Pizzagalli self-performed the grading, excavating, backfill,
concrete and piping. It subcontracted electrical, instrumentation
and specialty work.
Crews are converting aeration basins, one at a time, to a
time-bubbled, diffused air process. Once that is completed,
all the sewage can flow through the new basin and contractors
can work on the old basins.
Crom Corp. of Gainesville, Fla., is building the 15-million
gallon, prestressed-concrete holding tank. It is 250 ft. in
diameter with 40-ft. sidewalls. The company will build the
tank onsite and attach it to 688 rock anchors Pizzagalli has
installed.
This will be the first Western Carolina plant to incorporate
odor-control systems, which were added because the plant is
near residential areas. The headworks and primary clarification
areas will be covered and any fumes coming off will pass through
a scrubber device.
WEDECO Ideal Horizons of Charlotte, N.C., will manufacture
and install the UV-light disinfection system, which will take
the place of chlorine. The water will flow through a channel
and pass special UV bulbs encased in sleeves. The Pelham facility
will be one of the largest UV installations in the Southeast.
"Part of the reason we are going to UV disinfection
is the state regulatory agency is adding to our permit limitations
on chlorine byproducts," project manager Langley said.
"These limits are low enough that it's not practical
for us to use chlorine anymore."
Western Carolina moved its outfall defuser down river, below
a rock dam listed on the National Register of Historic Places.
The work required digging a ditch and placing the line through
an area that included riverbed and an 1800s textile mill.
"We were between a new bridge pier and an old historical
monument," Seymour said. "It was all rock in the
river."
Pizzagalli built a berm, pumped the water out and completed
the job in sections. It hammered the rock to avoid blasting,
which could have damaged the historic structures. It took
the crew about two weeks to put in the 80-ft. header in the
river.
Throughout it all, there have been no spills, and state inspections
have turned up no leaks or permit violations.
Project Team:
Owner: Western Carolina
Regional Sewer Authority, Greenville, S.C.
General Contractor: Pizzagalli
Construction Co., South Burlington, Vt.
Engineer: Black & Veatch
Corp., Shawnee Mission, Kan.
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