Journal article

Enhancing Toxic Metal Removal from Acidified Sludge with Nitrite Addition

Fangzhou Du, Stefano Freguia, Zhiguo Yuan, Juerg Keller, Ilje Pikaar



The production of sludge (biosolids) during wastewater treatment is a major issue for water utilities. A main issue limiting its beneficial reuse on agricultural lands is the presence of toxic metals. The currently used metal reduction technologies achieve insufficient removal of metals that are bound to the organic fraction of the sludge. In this study, we propose and demonstrate a novel method that involves the addition of nitrite during sludge acidification to enhance metal removal. Using waste activated sludge collected from three full-scale wastewater treatment plants, we found that acidification to pH 2.0 achieved good Zn solubilization of around 70%, but only 3-7% of Cu was being diss..

View full abstract

University of Melbourne Researchers


Awarded by Australian Research Council

Funding Acknowledgements

This work was funded by the Australian Research Council Discovery Project DP120104415. We acknowledge Dr. Beatrice Keller-Lehmann, Mr Nathan Clayton, and Ms Jianguang Li for their help with the chemical analysis. Fangzhou Du would like to acknowledge the scholarship support from China Scholarship Council and Tuition Fee Scholarship from The University of Queensland.