The RMIT team’s research was designed to test and review the physical, chemical and mechanical properties of fired-clay bricks incorporating from 10% to 25% biosolid content. Post-production compressive strength testing and analysis of differently-formulated biosolid-enhanced bricks proved that heavy metals are largely trapped within the brick. Something else to consider: the world’s diets vary (as do those of individuals), and as such the qualities and compositions of biosolids are anything but consistent. This means biosolids can have significantly different chemical characteristics. With this in mind, the researchers are recommending further testing be conducted before brick-making firms commence large-scale production.
We’ve Only Just Be Dung
The organic content of the biosolids is a prime factor in reducing brick firing energy demand by up to 48.6% for bricks that incorporate 25% biosolids. Savings in energy costs aside, this attribute alone could considerably reduce the carbon footprints of brick-manufacturing companies. The researcher’s claims and conclusions have been corroborated by results of a comparative Life Cycle Assessment and an emissions study conducted as part of the research. The verdict: biosolid bricks offer a sustainable, practical, alternative approach to addressing the deleterious environmental consequences of current biosolids management and traditional brick-manufacturing industrial techniques.
The research, funded by RMIT University, Melbourne Water and Australian Government Research Training Program scholarships, is published in the “Green Building Materials Special Issue” of Buildings (January 2019, DOI: 10.3390/buildings9010014).
Mohajerani, A.; Ukwatta, A.; Jeffrey-Bailey, T.; Swaney, M.; Ahmed, M.; Rodwell, G.; Bartolo, S.; Eshtiaghi, N.; Setunge, S. A Proposal for Recycling the World’s Unused Stockpiles of Treated Wastewater Sludge (Biosolids) in Fired-Clay Bricks. Buildings 2019, 9, 14.
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