SINGAPORE: The National Environment Agency (NEA) has issued a call for proposals to study the feasibility of recovering mixed landfill materials, in a bid to prolong the lifespan of Semakau landfill.
If nothing is done, the 350ha landfill is projected to run out of space by 2035, said NEA in a media release on Friday (Sep 25).
“The findings would enable us to better understand how we could extend the lifespan of Semakau landfill and avoid future costs of constructing another offshore landfill,” the agency said.
The feasibility study will look into how mixed landfill materials – incineration bottom ash and incineration fly ash from waste-to-energy plants, as well as non-incinerable waste from industries – can be recovered for other uses.
The study aims to understand the “physical and chemical properties” of the materials in the landfill that have “aged over time”.
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“The objectives are to assess the technical and economic feasibility of refreshing the landfill space through extracting the landfilled materials and finding suitable applications for the recovered materials, which could potentially be used as sand or aggregate replacement in various applications,” said NEA.
Under Singapore’s first Zero Waste Master Plan, the country plans to reduce waste sent to its only landfill by 30 per cent each day by 2030. About 2,100 tonnes of waste is transported to the Semakau landfill daily.
“Reducing waste generation is crucial to extending Semakau landfill’s lifespan beyond 2035,” said NEA.
READ: Singapore to reduce Semakau waste by 30% under first Zero Waste Master Plan
Studies are also underway to turn incineration ash into construction 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.
CEO of NEA 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 NEWSand that has been used to make concrete benches, a footpath in Tampines town and the new concrete plaza in front of the Environment Building.
“NEA is spearheading R&D efforts to go even further, so as to truly close the waste loop for the range of end-of-life waste and residues ending up at Semakau landfill.
“This R&D initiative seeks to develop safe and sustainable solutions to turn the trash dumped into a landfill, into treasure that will have new future uses.”
Semakau landfill was formed by joining two smaller islands – Pulau Semakau and Pulau Sakeng – with a 7km perimeter bund enclosing part of the sea in between.
The world’s first offshore landfill was created entirely out of sea space and was opened in 1999.
