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SINGAPORE: The National Environment Agency (NEA) has issued a call for proposals to study the feasibility of recovering mixed materials from landfills, in an attempt to extend the life of the Semakau landfill.
If nothing is done, the 350ha landfill is projected to run out of space by 2035, NEA said in a press release on Friday (September 25).
“The findings would allow us to better understand how we could extend the life of the Semakau landfill and avoid the future costs of building another offshore landfill,” the agency said.
The feasibility study will analyze how mixed materials from the landfill (bottom ash from incineration and fly ash from incineration from waste-to-energy plants, as well as non-incinerable waste from industries) can be recovered for other uses.
A dump truck unloading incineration ash from the floating platform at the Semakau landfill. (Photo: NEA)
The study aims to understand the “physical and chemical properties” of landfill materials that have “aged over time.”
READ: IN FOCUS: ‘It’s not easy, but it can be done’ – The challenges of increasing Singapore’s recycling rate
“The objectives are to evaluate the technical and economic feasibility of renovating the landfill space by extracting the materials from the landfill and finding suitable applications for the recovered materials, which could potentially be used as a replacement for sand or aggregates in various applications”, NEA said.
Under Singapore’s first Zero Waste Master Plan, the country plans to reduce waste sent to its single landfill by 30% every day by 2030. Approximately 2,100 tonnes of waste are transported to the Semakau landfill daily.
An aerial view of replanted mangroves in the southern patch of the Semakau landfill. (Photo: NEA)
An excavator unloading incineration ash from the barge into the transfer building at the Semakau landfill. (Photo: NEA)
“Reducing waste generation is crucial to extending the life of the Semakau landfill beyond 2035,” NEA said.
READ: Singapore to reduce Semakau’s waste by 30% under first Zero Waste Master Plan
Studies are also underway to convert ash from incineration into building material called NEWSand, which can be used in non-structural construction, such as road base and sub-base materials or aggregates in non-structural concrete.
NEA CEO Tan Meng Dui said: “We have seen the possibilities of using slag produced from (municipal solid waste), through a high temperature gasification process, as a form of NEWS and which has been used to make concrete benches, a path in Pueblo de Tampines and a new concrete plaza in front of the Environment Building.
A tugboat and a barge moored at the Semakau landfill transfer building. (Photo: NEA)
“NEA is spearheading R&D efforts to go even further, to really close the waste cycle for the range of end-of-life waste and waste that ends up in the Semakau landfill.
“This R&D initiative seeks to develop safe and sustainable solutions to turn garbage thrown into a landfill into a treasure that will have new uses in the future.”
The Semakau landfill was formed by joining two smaller islands, Pulau Semakau and Pulau Sakeng, with a 7 km perimeter beam that encloses part of the sea in the middle.
The world’s first offshore landfill was created entirely outside the marine space and opened in 1999.
