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Plant in the Park
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“Aggressive” Schedule has the Bronx’s Biggest Project Looking at 2011 Finish
By Deb Wood
The borough’s biggest construction project is not that baseball stadium on River Avenue you’ve been hearing so much about.
But it’s generating just as much controversy.
Aiming
to meet the requirements of the Safe Drinking Water Act, the New York
City Department of Environmental Protection is building the $2.2
billion Croton Water Filtration Plant in the Bronx to process potable
water from the Croton watershed.
“Not
only will the plant ensure that the water meets all current and
upcoming state and federal standards, but it will also have the ability
to meet New York City’s ever-growing demands,” says Don Fusco, project
manager for Skanska USA Civil of Whitestone, N.Y., which is building
the plant as part of a joint venture with Tully Construction of
Flushing, N.Y.
The Croton plant will supply
about 10% of New York City’s drinking water during normal times and
upwards of 30% during droughts. The plant – which many feel the city
should have built in neighboring Westchester County – will have the
capacity to treat 290 million gallons of water daily.
“New
York City already has what many drinking water utilities around the
country are seeking a diversity of water supply options,” says Anne
Canty, deputy commissioner of the Bureau of Communications and
Intergovernmental Affairs at DEP. “Construction of the Croton
Filtration Plant will ensure that this remains true, even as New York
City incorporates a projected million more people over the next 20
years and as DEP plans to repair critical infrastructure.”
AECOM
Water and Hazen and Sawyer, both of New York, designed the plant,
completed environmental permitting and are providing design services
during construction.
A joint venture
between Skanska USA Civil of Whitestone, N.Y., and Tully Construction
of Flushing, N.Y., received a $1.3 billion contract to construct the
400,000-sq-ft plant beneath the Mosholu Golf Course driving range in
Van Cortlandt Park. A smal
l aboveground structure will provide access
for workers and deliveries.
“It’s a very large project and very aggressive, with 51 months construction,” Fusco says.
Skanska
elevated its offices on structural steel, above subcontractor trailers,
to maximize limited space. Equipment is stored at the vendors’
locations due to the tight site, which is surrounded on three sides by
the golf course and the fourth by a road and an elevated four-line
subway.
Schiavone’s work
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| The
400,000-sq-ft Croton Water Filtration Plant being built at Van Cortland
Park in the Bronx will supply
about 10% of New York City’s drinking
water with a capacity to treat nearly 300 million gallons of water per
day. (Photo courtesy of Skanska USA Civil.) |
Schiavone
Construction of Secaucus, N.J., under a separate $126 million contract
let before design finished, excavated more than 1 million cu yds of
soil and rock to make way for the project, which is rising from the
300,000-sq-ft pit. Schiavone completed the earthwork two months ahead
of schedule in mid-2007.
“It was 90 ft deep, and 75% of it was rock,” says Paul Scagnelli, Schiavone’s executive vice president and chief engineer.
The
company holds other contracts with DEP on the Croton project. In a
joint venture with John P. Picone Inc. of Lawrence, N.Y., Schiavone is
constructing three tunnels to carry the water to and from the Croton
aqueduct. The boring and blasting on the $212 million contract was
completed by yearend, and the team is now lining the 12- and
13-ft-diameter tunnels. The shafts range from 55 to 80 ft deep.
“Three
existing water tunnels are within a quarter mile of the site,”
Scagnelli says. “When we were constructing one tunnel, we had to cross
an exis
ting tunnel and blast carefully to make sure we didn’t interfere
with the water supply. We measured vibrations.”
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| The
entire Croton Water Filtration Plant is being built below grade and
will be covered with a concrete roof and grass for a driving range.
(Photo courtesy of Skanska USA Civil.) |
Schiavone
in a joint venture with Frontier-Kemper of Pelham, N.Y., received a
$100 million contract to rehabilitate the 100-year-old, brick-lined
Croton aqueduct and at yearend was waiting for the notice to proceed.
The job requires repointing, regrouting and replacing bricks as needed.
“Everybody was impressed with the quality of
construction that took
place 100 years ago,” says Bob Jarnis, project
director for AECOM Water and project manager for Croton design services
during construction. “It will bring its useful life up to the same
useful life of the new plant.”
Skanska-Tully’s work
Skanska-Tully
is self-performing 95% of the construction; cast-in-place concrete;
process piping; process equipment purchases; and installation,
instrumentation and plant start-up. Skanska has an 80% share of the
joint venture.
“It’s a joint venture, with no division of responsibility,” says Fusco about the partnership. “It’s a sharing of resources.”
Skanska
and Tully employees work side-by-side and step up when someone has a
special expertise. At peak, this summer, Fusco expects 600 tradespeople
and 100 administrative personnel onsite.
Skanska-Tully
began placing the 4.5-ft-thick, reinforced-concrete mat foundation in
August 2007 and is now going vertical on the three- and four-story
reinforced cast-in-place concrete structure.
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| (Photo courtesy of Skanska USA Civil.) |
The
building required a “beefed-up structural design to account for the
underground facilities,” Jarnis says. “The most impact of being below
grade was worker access and ventilation.”
The team is installing shafts for air exchange and created an aboveground point of entry.
“As
we are building the structure, we have the mechanical work sequenced,
so it is going in as openings are left in the structure,” Fusco says.
“We are putting in the equipment, closing it up and moving on to the
next floor.”
Mechanical and civil proceed simultaneously, with a slight lag to mechanical.
“The schedule doesn’t allow us to come back later with the mechanical; it has to be parallel,” Fusco says.
Fusco
anticipates the plant will consume 250,000 cu yds of concrete, 27,000
tons of reinforcing steel and 200,000 ft of piping. Grass for the
driving range will top a concrete roof.
“Over the course of three years, we are bringing 25,000 concrete trucks out to the job,” Fusco says.
Skanska-Tully’s
project was 28% complete at the end of 2008 and on schedule for an
October 2011 finish. Start-up and commissioning will take an additional
six months.
Plant operations
The
plant is divided and can be run as separate facilities, each capable of
filtering 145 million gallons per day. Untreated water arrives through
an 800-ft, 12-in.-diameter tunnel being built by Schiavone and Picone.
The water comes in and is pumped to the top level of the structure by
large 1,000-hp pumps. It flows by gravity through multiple processes.
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| (Photo courtesy of Skanska USA Civil.) |
“To
minimize the footprint, we stacked the dissolved air floatation
filtration system,” Jarnis says. “The dissolved air floatation is a
pretreatment system that makes it easier to filter the water. By
putting it above the filter, we get effective treatment with a smaller
footprint. That was one of the innovations.”
Chemicals
are added to make particles stick together for easier filtering. Then,
air is added to force particles, such as tree bark, to float to the
surface so they can be skimmed off. The water then passes through sand
and anthracite, a pulverized coal product, to remove more particulates.
Solids removed from the water will be pumped to the Hunts Point Water
Pollution Control Plant for processing and disposal.
“The
real heart of the process is when the water goes through ultraviolet
light,” Fusco says. “It runs through 20 ultraviolet chambers. The light
bombards the water and kills off any bacteria in the water system.”
From
there,20after treatment, water is pumped by a 2,500-hp pump into two
102-in.-diameter discharge pipes to the Jerome Park Reservoir, about a
mile away, where it is stored before distribution. The two lines
interconnect and link with the city’s water system.
Team Box:
Owner: New York City Department of Environmental Protection
General Contractor: Skanska-Tully, a joint venture between Skanska USA Civil, Whitestone, N.Y., and Tully Construction, Flushing, N.Y.
Sitework and Excavation: Schiavone Construction, Secaucus, N.J.
Tunnels:
Schiavone Construction, Secaucus, N.J., and John P. Picone Inc,
Lawrence, N.Y. Aqueduct Rehabilitation: Schiavone Construction,
Secaucus, N.J., and Frontier-Kemper, Pelham, N.Y.
Construction Management: A joint venture of URS Corp., San Francisco, and Malcom Pirnie, White Plains, N.Y.
Design/Engineering: AECOM Water, New York, and Hazen and Sawyer, New York
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