Sustainable materials and digitalisation have been key to carbon management during the construction of a major food waste recycling facility.
Currently under construction and due to start operations next year, OPARK2 (Organic Resources Recovery Centre Phase 2) will become Hong Kong’s largest food waste recycling facility.
Using anaerobic digestion technology to convert waste into biogas for electricity generation and fertiliser, it will be able to treat 300 tonnes of food waste per day.
Sustainable design principles have been integrated into the project since it started, with low-carbon practices being employed throughout construction.
Low-carbon materials, innovative technologies, increased digitalisation and careful supply-chain management have all been used to aid the project’s decarbonisation efforts.
Carbon credits have been purchased to offset emissions during the early stages of construction, helping to meet the project’s carbon neutrality goal.
Once completed, additional credits will be procured to cover the civil, structural and architectural construction phases.
Using rebar (reinforcing bar) that’s made entirely from recycled content, as well as ground granulated blast-furnace slag (GGBS) concrete, will account for more than 90% of the carbon reductions made during construction.
Although 100% recycled rebar had been available in the Hong Kong market before this project, its use by contractors had been limited.
The team’s decision to choose 100% recycled rebar and share their experience with other contractors prompted a shift towards its widespread use.
However, this also resulted in material shortages and price increases.
Before construction started, there were no local manufacturers offering GGBS concrete in Hong Kong.
Fly ash, a byproduct of coal-based power generation used to improve the composition and performance of concrete, was also in short supply.
This was due to the ongoing closure of such power plants under Hong Kong’s Climate Action Plan 2050.
To address these issues, the project team worked with local suppliers to source low-carbon GGBS concrete.
There are now three manufacturers in Hong Kong that can reliably supply the material.
Using low-carbon rebar and concrete for the project has not only promoted sustainable procurement and supply-chain management, but also boosted the development of low-carbon material manufacturing and marketing.
Carbon capture, utilisation and storage (CCUS)
In Hong Kong, OPARK2 is at the forefront of adopting CCUS-based technologies for carbon dioxide mineralisation in curing concrete bricks.
CCUS technologies hold great promise in terms of mitigating climate change.
The project team conducted thorough research and collaborated closely with CCUS brick manufacturers to ensure quality and safety.
The procured CCUS bricks were used for non-load-bearing walls in OPARK2’s office areas to assess their performance.
OPARK2 has employed two digitalisation technologies for carbon management:
- the building information modelling (BIM) to Carbon Assessment Tool (CAT) system
- a cloud platform for automatic carbon accounting
This was done in collaboration with the Hong Kong University of Science and Technology BIM research team.
This integration provides valuable information for optimising the CAT system.
The OPARK2 team has also created a carbon neutrality cloud platform that links with the project’s financial system to offer real-time, traceable and accurate quantification of carbon emissions.
Comparative baseline assessments between low-carbon approaches and conventional methods will provide insights for shaping construction standards in the future.
OPARK2 serves as an example of how the construction industry can make progress towards greater sustainability.
It’s hoped that these efforts will accelerate the green revolution in Hong Kong’s construction sector and contribute to the realisation of carbon neutrality in infrastructure projects.