Engineers from the Royal Melbourne Institute of Technology (RMIT) have been apart of research involving steel slag being treated with wastewater. Recent studies from Dr Biplob Pramanik have explored the potential benefits from treating steel slag with wastewater from sewage plants. Dr Pramanik has noted that that steel slag can be used to treat the wastewater, removing unwanted phosphorus content.

His study -'Recycling steel slag from municipal wastewater treatment plants into concrete applications – A step towards a circular economy'- delved into the technical nature of the process and identified how steel slag can remove unwanted toxins from wastewater while also strengthening the steel slag itself.

According to the study, the process of treating the steel slag with wastewater significantly altered its chemical composition. The steel slag was then used in concrete as an SCM. The results show that the treated slag aggregates provide compressive strength improvement of 32.5% and 18% at 7 days and 8.2% and 16.8% improvement at 28 days compared to that of raw slag and conventional aggregates.

SEM Image: RMIT

This fascinating process could provide a platform for producers & processors of steel slag to access new markets here in Australia.

At this stage, a plant based in New Zealand uses steel slag in the wastewater treatment industry but with its newly discovered multipurpose use, we may see the trio of steel production, wastewater treatment and construction, work together more frequently.

The study, ‘Recycling steel slag from municipal wastewater treatment plants into concrete applications – A step towards circular economy’, with RMIT School of Engineering co-authors Professor Sujeeva Setunge and Professor Kevin Zhang, is published in Resources, Conservation and Recycling (DOI: 10.1016/j.resconrec.2019.104533).