Page 72 - Envision 17

Industry Spotlight & Innovation
Putting
the New in NEWSandTM
Recycling and reusing are age-old
ideas, while the technology to transform waste to resources is constantly evolving. In a country often associated with dynamic transformation, it was only a matter of time before we started transforming waste to building resources.
Li Hong Chew, Engineer, Environmental Technology Department, National Environment Agency
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070
envision
TNEWSandTM is a natural product in a circular economy
he term Circular Economy may have
become the zeitgeist only in recent
years, but many countries, including Singapore, have already been pursuing projects as part of a strategy to close waste loops. Naturally, we would not turn away from exploring the possibility of further reducing the volume of residues going to Semakau Land ll, and prolonging its lifespan beyond 2035. The result of this endeavour has given us NEWSandTM, a form of construction aggregate derived from waste that has been rendered environmentally safe for use in intended applications. NEWSandTM can be derived from treated Incineration Bottom Ash (IBA) and slag, which are respectively the products of incineration and high temperature gasi cation of Municipal Solid Waste (MSW).
Waste as construction
material around the world
The concept of reusing waste as a construction material is not new. In Denmark, France, Germany and the Netherlands, national legislations regulate the utilisation of MSW IBA and there are national targets for generally high utilisation rates.
In 2016, the city of Bottrop in Germany combined IBA with iron silicate sand,
a by-product of copper recycling, to stabilise a 450,000m3 ski hall in Bottrop, Germany (REMEX Mineralstoff GmbH, 2019). Compared to soil, IBA won in terms of high homogeneity, and stability of quality, the latter of which was ensured by regular monitoring. The resultant mineral construction material more than met the technical requirements for stability, water permeability and bulk density.
Elsewhere, in Osaka, Japan, incinerated domestic waste is one of the materials used to reclaim Maishima, Yumeshima, and the New Island in the Hokko District over the period of several decades from 1973 onwards. The initial intent was to secure an offshore site for final disposal of waste, but the resultant reclaimed land has been developed into recreational areas that fit in with the facilities offered by the Port of Osaka (Barry, 2013).
NEWSandTM is being developed with long-term sustainability inmind
In Singapore, as early as 2001, the former Ministry of Environment (MOE) had started looking into the possibility of repurposing IBA, a possible form of NEWSandTM. IBA was aged naturally in the open to stabilise contaminants, before being trialled in Jalan Buroh. However, it was not until 2009, following a road trial spearheaded