Siu Ho Wan Water Treatment Works extension, Hong Kong

The Water Supplies Department (WSD) of the Government of the Hong Kong Special Administrative Region awarded the HK$2,065 million (£216 million) project to the China Road and Bridge Corporation in March 2022 using an NEC4 Engineering and Construction Contract (ECC) Option C contract. The project is set to be completed in stages from mid-2025.

Opened in 1996, the existing Siu Ho Wan Water Treatment Works in north Lantau supplies fresh water to Tung Chung New Town and Hong Kong International Airport. According to the planned population intake for Tung Chung New Town Extension and other proposed developments in the area, the existing treatment capacity at Siu Ho Wan has to be doubled from 150,000 m³/day to 300,000 m³/day by 2028. The project involves construction of a new innovative multi-level water treatment building, a new office and laboratory building, modification of existing treatment facilities and provision of a new raw water booster pumping station to increase the supply of raw water from a nearby reservoir.

Advanced treatment technology has been adopted for the uprated works, with pre-ozonation ahead of dissolved air flotation clarification, followed by intermediate ozonation, two-stage filtration and disinfection with chlorine. The project also features environmentally friendly measures such as treatment and recycling of all process wastewater to achieve zero discharge, provision of photovoltaic system to supplement electricity supply, variable speed pumps to reduce energy consumption and a digital twin for optimising operation. 

The chief engineer of WSD Consultants Management Division is the NEC project manager and the client’s designer and NEC supervisor is Binnies Hong Kong Limited. At the Chartered Institution of Water and Environmental Management (CIWEM) Hong Kong’s 2024 Innovation and Sustainability Awards, the project won the Chairman's Commendation Award for Excellence in Both Innovation and Sustainability, the Gold Award for Innovation and the Silver Award for Sustainability.

Collaborative environment

WSD Consultants Management Division chief engineer Percy Hau says creating a collaborative environment among the client, project manager and contractor was in line with the NEC’s ‘spirit of mutual trust and co-operation’, which was of critical importance for the successful delivery of the project. ‘The project team has made a concerted effort, which includes working in a joint site office, wearing site uniforms with the same project logo, and holding weekly partnering meetings, regular team-building events and partnering workshops so as to promote collaborative spirit.’

He says the project team had endeavoured to manage all project risks effectively via the NEC early warning process. ‘This includes the identification of potential risks and sharing ideas on possible solutions at the earliest stage.’ 

Hau says that limited working space was one of the challenges to complete the project while keeping existing plant in operation. ‘For example, two new 1.2 m diameter water mains had to be constructed adjacent to an existing barrack, and safety and accessibility issues were raised in an early warning meeting. As there was no alternative alignment for the water mains, the project team proactively liaised with the plant operator for temporarily relocating the barrack elsewhere. This idea was acceptable to all stakeholders, enabling construction activities and plant operations to run in parallel, while the contractor was fairly remunerated for the arrangement through a compensation event.’ 

He adds that lack of storage space for construction materials was another challenge. ‘Despite the client having no contractual obligation to provide temporary storage area, the project manager liaised with stakeholders of government installations nearby so that a parcel of land of about 1370 m2 could be released for temporary storage.’

Innovative technology

Hau says that to enhance efficiency and safety on site, the project team adopted a digital works supervision system (DWSS) as required by the contract. ‘The DWSS provides a centralised platform for collecting project information and managing workflow of site activities, ensuring that everyone is on the same page.’

He adds that the DWSS was also integrated with various smart safety devices to improve site safety. ‘This includes smart watches to provide continuous monitoring of workers' health and enable immediate rescue in case of an accident, and closed-circuit television with artificial intelligence to monitor site safety behaviour.’ 

In addition to the DWSS, Hau says a digital twin will be used to simulate the entire treatment process. ‘An accurate and real-time prediction allows us to operate the treatment plant in a cost-effective manner through optimising supply and demand management, pumps configuration, treatment processes and chemical dosage.’   

In summary he says, ‘We have endeavoured to foster a collaborative environment, comply with NEC requirements and encourage the use of innovative technology. These efforts are critical in ensuring successful completion of the project within the agreed programme and budget.’ 

Benefits of using NEC

• NEC encouraged stakeholders to act in a ‘spirit of mutual trust and co-operation’, which is crucial to success. 
• NEC early warning process enabled the project team to identify and collaboratively manage all project risks effectively.
• NEC compensation event process ensured fair valuation of works due to changes of scope.