The CV Division organised the captioned site visit on 30 July 2022.
The aim of the project was to cater for the growing traffic needs in the proposed Fanling North New Development Area (FLN NDA). The bypass is a 4-km-long dual two-lane carriageway comprising viaducts, at-grade road and underpasses which will provide a direct link to the existing Fanling Highway. The site visit included the excavation and lateral support (ELS) works for the underpass and depressed roads, rotary drilling for bored piles, and the erection of bridge segments with a launching girder.
The 30-m-wide ELS temporary works at the intersection between the underpass and the depressed road at Sha Tau Kok Road were the first visiting point. The challenges included stakeholder management on land use issues as well as temporary traffic arrangements at Sha Tau Kok Road. The site logistics were carefully planned for the construction works to minimise the impact on traffic and disturbance to the nearby residences.
The second visiting point was the construction of a bridge near Ma Wat River. The bored pile foundation of the bridge section adopted the rotary drilling method due to its proximity to the nearby villages and access constraints. Rotary bored piling reduced the impact to the public with the use of protective casings. A temporary over-deck steel bridge was also constructed to allow transportation of machinery and access of construction vehicles.
Lastly, the fabrication yard of the launching girder was visited. The working area was demarcated clearly to facilitate the construction of the precast post-tensioned bridge. The storage of precast bridge girders, main trusses and lifting devices were arranged in an orderly manner to enable safe lifting and assembly. For ease of construction, the project team adopted Building Information Modelling (BIM) technology with the use of tablet devices. This allowed better process control in terms of design and constructability reviews.
On behalf of the CV Division and the participants, we thank the Civil Engineering and Development Department (CEDD), AECOM RSS, as well as the contractor’s representatives from Daewoo-Chun Wo-Kwan Lee Joint Venture and CRCC-Paul Y. Joint Venture for their invaluable support for the site visit.
Following the publication of the Cover Story on Yuen Long Effluent Polishing Plant (YLEPP) in the Journal’s January 2022 issue, the CV Division successfully organised the captioned visit on 13 August 2022.
YLEPP is one of the latest sewage enhancement projects in the HKSAR development plan to serve the rapid population growth and development needs of the city. The aim of the project is to increase the treatment capacity of the plant from 70,000 to 100,000 m3 per day in Stage 1 and to 150,000 m3 per day in Stage 2.
Since the construction of YLEPP encountered critical environmental challenges due to the need to protect the adjacent ecologically sensitive area, percussive piling and demolition works by excavator mounted breakers were adopted in order not to disrupt the breeding season of the nearby migratory birds. A series of mitigation measures, comprising soundproof curtains, noise barriers and bird curtains, were also extensively used. A public co-use area will also be constructed to serve as an education area to promote ecological and sustainability values. Demolished trees would also be re-used to build benches.
YLEPP works adopted Aerobic Granular Sludge (AGS), an innovative wastewater treatment technology, for the first time in Hong Kong. This technology delivers a high-efficiency solution with lower energy consumption. In line with the sustainability design, the AGS treatment plant only occupies one-third of the space of the original secondary sewage treatment plant. The simple process configuration, automation and resilience function enable a higher reactor biomass concentration and faster settling, which results in better energy efficiency. These lead to both capital and operational cost savings.
In the last part of the visit, we were introduced to several temporary measures to safeguard the original functionality of YLEPP as it is a requirement to maintain its operation uninterruptedly.
On behalf of the CV Division and participants, we thank AECOM RSS and the contractor representative, Paul Y – CREC Joint Venture, for presenting the complex works to us and demonstrating the efficient use of resources, whilst implementing optimised engineering measures for protecting the environment.