The 15km underground sewer line of the Yen Xa Wastewater Treatment Plant project has been completed, preparing to rescue the polluted To Lich River. Special technology is also being applied for the first time to a project in Hanoi .
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Eight years after construction began, the Yen Xa Wastewater Treatment Plant project (Thanh Tri District, Hanoi) is rushing to complete many important components in order to begin trial operation at the end of this year.
The project is divided into four packages, of which package number 2 is the construction of a wastewater collection system for the To Lich River, undertaken by Tekken Company (Japan). This package started on March 16, 2020, and has now reached 93% completion.
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Under this contract, the contractor will construct and install an underground sewer system running along the To Lich River, starting from the Hoang Quoc Viet intersection and ending at the confluence of the To Lich and Lu rivers in Hoang Mai district (location shown in the image).
The unit used the open trench method for a small portion of the route, while the rest employed the new technology of robotic underground jacking.
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With the jacking system, the contractor will initially drill vertical wells, reinforcing them with piles, then send robots down to the bottom of the wells and drill horizontally to connect the wells together.
The underground culvert connecting the two manholes at the confluence of the To Lich and Lu rivers has the longest distance (550m) and is located at a depth of 13.44m below the road surface. The culvert shell is made of concrete coated with epoxy paint for waterproofing and corrosion resistance.
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Along the route running along the To Lich River, the sewer line will change depth at different locations and will have many points that run beneath the riverbed.
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Mr. Chong Jiun Yiat, Project Director of Package 2, stated that this is the first time the pipe jacking technology has been applied to a project in Hanoi. For this package, Tekken has completed 100% of the open excavation and pipe jacking work, with 87% of the manhole construction and 85% of the branch sewer line installation work remaining.
The contractor is racing against time to complete the work by the end of this year. The biggest obstacle currently is that Hanoi has terminated the contract with the contractor for package 3 (installation of the main sewer system on the Lu River). Therefore, Tekken stated that the installation of manholes at the confluence of the Lu River and the To Lich River has not yet been carried out.
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At the location of the underground well, the contractor also designed access ramps to the sewer system to facilitate construction. Mr. Chong assessed that well construction was the most difficult item in this contract, as the contractor had to relocate many above-ground utilities such as water pipes, drainage pipes, telecommunication cables, and electrical wires during the implementation process.
The construction team is simultaneously carrying out the work and monitoring to see if the jacking affects the infrastructure above ground.
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On April 16th, Hanoi Party Secretary Dinh Tien Dung and his delegation conducted a site inspection of package 2, directly checking the underground drainage system beneath the To Lich River at the confluence of the Lu and To Lich rivers (Photo: Hanoi Moi).
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After passing through the collection sewer system, wastewater will be channeled to the Yen Xa Wastewater Treatment Plant. Construction of this plant (package 1) is 96% complete, awaiting synchronous connection with packages 2 and 4 (construction of sewer systems for part of the Ha Dong area and the new urban area) for trial operation this year.
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The Hanoi City Infrastructure and Agricultural Construction Investment Project Management Board (the investor) is also requesting the Hanoi Department of Construction to provide its opinion soon on the policy of continuing to invest in 9 primary sedimentation tanks and 6 gravity sludge compression tanks using city funds.
This is to ensure the completion of the plant's processing procedures, water replenishment solutions, and sludge treatment technology as directed by the city.
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Diagram of the wastewater drainage system from the To Lich River to the Yen Xa Wastewater Treatment Plant (Graphic: Ngoc Tan).
Once operational, the project will contribute to treating domestic wastewater in seven districts: Hai Ba Trung, Dong Da, Ba Dinh, Tay Ho, Cau Giay, Ha Dong, and Thanh Tri. Hanoi also hopes the project will "rescue" the capital's polluted rivers, including the To Lich River, Lu River, Set River, and a portion of the Nhue River.
The Yen Xa wastewater treatment system project includes the construction of a wastewater treatment plant with a capacity of 270,000 m3/day; the construction of a collection sewer system, main sewers, and connection systems (along both sides of the To Lich and Lu rivers) in the Ha Dong new urban area. The total length is approximately 52.62 km.
The factory, located in Thanh Liet commune, Thanh Tri district, covers an area of approximately 13.8 hectares.
The total investment for the project is VND 16,293 billion, with over 84% being ODA loans from the Japanese government .
The project, launched in 2016 with a target completion date of 2020, was later delayed to 2022 but has yet to become operational. Hanoi has set a new target for the system's operation by 2025.
According to Dan Tri
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