RC115 NovDec 2024 - Magazine - Page 14
INTERNATIONAL PROJECTS
CALIFORNIA, U.S.
DISTRICT OF COLUMBIA, U.S.
POTOMAC RIVER TUNNEL PROJECT
THE POTOMAC RIVER TUNNEL PROJECT, a landmark initiative under the Clean Rivers Project,
has commenced with the combined expertise of CBNA, Halmar, COWI, and Hatch. This
formidable partnership has secured an $819 million design-build contract from DC
Water, marking the largest contract ever awarded by the authority.
The project aims to construct a nearly nine-kilometre-long tunnel beneath the Potomac
River, serving as a critical infrastructure element to control combined sewer overflows
(CSOs). This effort will significantly enhance the water quality of the Potomac River, aligning
with broader goals to improve the Anacostia and Potomac Rivers and Rock Creek while
bolstering the sewer system’s capacity.
“COWI will lead the design of the tunnel and adits and provide geotechnical support for
the entire project. We leverage our domestic and global personnel to bring experts in multiple disciplines,” said Steven Kramer, COWI’s senior project director.
“Our team began working in late 2023 and has already delivered several key early
lead items which has enabled the design and build team to begin construction. Working
with CBNA-Halmar through the tender process and now the actual project has been
very exciting and gratifying for our engineers. In a design and build project, it is always
rewarding to see our design being implemented especially on such a critical project as
the Potomac River Tunnel.”
As the co-designer, Hatch is responsible for design management of all underground engineering work and design of tunnel access shafts, drop shafts, and near surface structures
including flow diversion structures, intakes, emergency overflow structures, and associated
support of excavation. Traversing beneath iconic landmarks such as the Georgetown waterfront, West Potomac Park, and the National Mall, the 5.5-metre-diameter tunnel will extend
to Hains Point, ultimately linking with the existing Anacostia River Tunnel. The construction
process has begun and will utilize advanced tunnel boring machines to navigate diverse
ground conditions, requiring innovative engineering and construction solutions from all
partners involved.
Once operational, the Potomac River Tunnel is expected to reduce CSOs into the Potomac River by an impressive 93 per cent during typical rainfall years, underscoring its significance in promoting environmental sustainability in the District of Columbia.
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RENEW CANADA – NOVEMBER/DECEMBER 2024
PCL CONSTRUCTION is building the new Treasure Island Water
Resource Recovery Facility design-build project in San
Francisco, California which replaces aging infrastructure and
meets the island’s wastewater and recycled water needs of
the future. Originally constructed in 1961, the existing plant
has become outdated and undersized. The new facility will
have an annual average wastewater treatment capacity of
1.3 million gallons per day for Treasure Island and adjacent
Yerba Buena Island, California. It will also have an annual
average recycled water treatment capacity of 0.4 million
gallons per day for Treasure Island.
The significance of this San Francisco Public Utilities
Commission project extends beyond the immediate need
for upgraded infrastructure. The island is projected to
gain 20,000 residents by 2036—eight times its current
population, and this new facility will play a crucial role
in meeting the wastewater treatment demands of this
expanded community. Half of the treated wastewater
produced by the facility will be recycled for irrigation, lawns,
landscaping and community parks.
This state-of-the-art facility will replace the existing plant
and include a range of advanced processes to ensure efficient
and effective treatment. Project scope elements for the new
treatment facility include a liquid and solid stream comprised
of coarse screens, grit removal, fine screens, biological nutrient feed, a membrane bioreactor and ultraviolet disinfection.
Additional features in support of the facility include recycled
water pumping, wetlands, stormwater pipe discharge, aerated
solids holding tank, solids thickening, an onsite recycled water
dispenser and an administration and maintenance building.
Emphasizing both functionality and security, the project also
features a perimeter security fence, stormwater handling measures and site security enhancements.
Aligned with the Envision Sustainable Infrastructure
Framework, this project sets ambitious goals related to
neighborhood outreach, waste reduction, habitat restoration,
and emissions and energy reduction. The San Francisco Public
Utilities Commission aims to achieve Envision Gold Verification for the new facility, demonstrating a commitment to
sustainable practices and community stewardship.
“The Treasure Island Water Resource Recovery Facility
represents a significant stride towards a greener future, with
improved aesthetics, increased capacity and advanced treatment processes,” said Richard Hewitt, vice president and district
manager of PCL’s Civil Infrastructure division. “The upgraded
facility will offer reliable, high-quality service to all who live, work,
and play on Treasure Island and Yerba Buena Island, ensuring a
sustainable water future for generations to come.”
RENEWCANADA.NET
PCL, COWI
TREASURE ISLAND WATER
RESOURCE RECOVERY FACILITY
