Non-Recyclable Waste Could Reduce Carbon Emissions From Cement Production

ISLAMABAD: (News Desk) – Non-recyclable waste that would otherwise end up in landfills could help reduce carbon emissions from cement production by replacing some of the fossil fuels used in industrial kilns, according to a review by researchers at Adelaide University.

Cement is a vital material for constructing roads, bridges and buildings, but its production accounts for around 8% of global carbon dioxide emissions. The manufacturing process requires extremely high temperatures, traditionally generated by burning coal and other fossil fuels.

At the same time, significant quantities of combustible waste that cannot be recycled are discarded in landfills. Researchers say this waste could be converted into refuse-derived fuel (RDF) and used alongside conventional fuels in cement kilns, reducing the industry’s dependence on coal.

The review was led by Geethmi Thisakya, a PhD candidate at the university’s School of Civil Engineering and Construction, with contributions from Dr Navodana Rodrigo, Dr Chamitha Wijewickrama and Professor George Zillante.

The research team examined 211 academic papers published between 1991 and July 2025, with a detailed focus on 48 articles and seven regulatory documents. The review assessed the potential of RDF to support waste management efforts while lowering emissions from cement manufacturing.

However, the researchers stressed that replacing coal with waste-based fuels alone would not be enough to achieve meaningful environmental benefits. Reliable fuel quality, effective regulations and clear evidence of economic and environmental gains are also essential for wider adoption.

The study highlighted confusion surrounding refuse-derived fuel and solid recovered fuel (SRF), a more strictly specified category of waste-based fuel. Inconsistent terminology and quality standards can make it difficult for manufacturers to compare research findings, comply with regulations and maintain safe kiln operations.

The researchers said clearer definitions, stronger quality-control measures and consistent standards could improve confidence in the use of alternative fuels across the cement industry.

They emphasised that reducing waste and recycling reusable materials should remain the priority. RDF, however, could offer a practical alternative for combustible waste that cannot be recycled, helping divert it from landfills while reducing reliance on fossil fuels.

The team recommended further research to improve fuel classification systems and assess the performance of waste-derived fuels across different industries and geographical regions.