Hong Kong landfill is the world’s largest and longest NEC contract

The Hong Kong government has awarded a HK$61.1 billion (£6.2 billion) NEC4 Design Build and Operate Contract (DBOC) for a landfill site extension lasting nearly 60 years. It is the world’s largest and longest single NEC contract to date.

The Environmental Protection Department (EPD) of the Government of the Hong Kong Special Administrative Region of China awarded the contract for the West New Territories Landfill Extension (WENTX) to Hong Kong Resources Recovery Park, a joint venture of China State Construction and Veolia, in August 2023.

After three years of design and initial works phases, the roughly 100 ha site next to the existing West New Territories (WENT) Landfill at Nim Wan, Tuen Mun will be filled with up to 76 million m³ of waste over the following 25 years or so, subject to actual waste intake. The contract includes further 2 years for final restoration works and then another 30 years for aftercare.

Biggest NEC contract

The previous largest value NEC contract was the €3.25 billion (£2.8 billion) NEC4 Engineering and Construction Contract (ECC) Option C (target contract with activity schedule) for section 3B of the Oosterweel ring road project in Belgium. Let in 2021, the work is due for completion in 2027.

The previous biggest NEC award in Hong Kong was the Civil Engineering and Development Department’s HK$12 billion (£1.2 billion) ECC Option B (priced contract with bill of quantities) contract for Tung Chung New Town Extension reclamation works, which was completed in January 2023.

DBOC is also being used by Hong Kong’s Electrical and Mechanical Services Department for tendering a district cooling system project at Tung Chung New Town Extension (East). Other DBOC users include Network Rail in the UK.

First use for EPD landfill

EPD director of environmental protection Samuel Chui says it is the first time EPD has used NEC for one of its three landfills and their extensions. The others use the government’s General Conditions of Contract (GCC) Design-Build-Operate form.

He says, ‘WENTX is mega project with very complicated technical and interfacing issues. New technologies and management techniques, more stringent compliance requirements on environmental protection and other aspects are emerging rapidly, which cannot be fully anticipated with the GCC form.’

Chui says long-term collaboration, transparency and mutual trust between the project parties are considered essential for the project to succeed. ‘Based on the government’s proven success with NEC contracts, we consider it would be more beneficial to adopt an integrated whole-life delivery solution as provided by the NEC4 DBOC for WENTX given its unique nature.’

The DBOC service manager is the EPD principal environmental protection officer (landfills and development) with Ove Arup and Partners Hong Kong Limited as the service manager’s delegate for day-to-day contract administration and site supervision.

Sustainable design

By using a deep bowl design, where excavation and landfill takes place behind a 30 m high bund built along the current Nim Wan Road, the WENTX site is only half the 200 ha area originally planned. Green buffer zones of 10–30 m wide will also be provided around the site to further reduce visual and environmental impacts.

The contractor expects to capture 90% of emitted methane, which will be burnt as biogas to produce green electricity to meet the site’s needs, such as for leachate treatment. Surplus biogas and electricity generated can then be exported to the municipal grid. Rock excavated from the site will supply about 70% of total aggregate use in Hong Kong, reducing greenhouse gas emissions involved in importing aggregates.

The existing 110 ha WENT site started operating in 1993. It currently receives around 6,500 t of waste a day and is nearing its 61 million m³ capacity, with maximum waste depth now over 100 m. Energy utility CLP started operating a 10 MW biogas power plant on the site in 2020.

NEC training

Chui says EPD is fully aware of the importance for the project team to understand the key NEC principles of collaboration, transparency and shared responsibility. ‘We are encouraging our staff to receive internal or external NEC training regularly, including the NEC4 ECC project manager and NEC4 DBOC service manager accreditation programmes. This will improve project management and help us to achieve a successful project outcome.’

He says EPD and the contractor will also regularly organise partnering workshops to build a good collaborative and partnering spirit for working towards common goals. The first workshop, called the Forward Together Summit, was held in January 2024.

‘Also, supported by senior management of other government departments, the project team is being kept abreast of the latest technology available in the market. This will help us to develop innovative ideas for the project and jointly overcome the challenges ahead, driving progress without compromising the quality of the works and our services to the public.’