Republic Polytechnic (RP) boffins have made significant progress in solving how to deal with mountains of trash once Singapore’s only landfill runs out of space.
The Semakau Island landfill is expected to hit its limit by 2035, which has prompted an urgent search for other options, including assessing if piles of burnt rubbish can be used in construction and cars.
The idea of using incinerated ash to replace sand and stone in construction is not new, but its application has been delayed because of the risk of toxic heavy metals leaching into the environment.
RP researchers have created a chemical that can bind heavy toxic metals to incinerated bottom ash so that they will not pollute the surroundings once exposed to water, sunlight and open air.
RP’s project was one of four that received grants under the National Environment Agency’s (NEA) Closing The Waste Loop research and development initiative.
Dr Goh Chee Keong, the project’s principal investigator, said a tonne of incinerated bottom ash can produce between 900kg and 950kg of material for construction.
He added that the NEA is working to develop guidelines for using incineration ash in construction materials.
The same round of grants is helping Nanyang Technology University (NTU) to develop ways to use incinerated ash to construct catalytic converters in cars.
Associate Professor Xu Zhichuan, principal investigator of the NTU project, said that about 2kg of incinerated ash would be needed to build what is called a ceramic substrate for a car’s catalytic converter.
His team of four received a $1.5 million grant last month (May 2019) and is studying ways to build the substrate.
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Source: The Straits Times, 7 June 2019