May 2, 2017

« All News

Mary deFlaun Published in World Journal of Microbiology and Biotechnology

Mary deFlaun (New Jersey) co-authored an article entitled "Hexavalent chromium bioreduction and chemical precipitation of sulphate as a treatment of site-specific fly ash leachates" in the World Journal of Microbiology and Biotechnology, online edition on April 7, 2017.

Mary and co-authors from the Department of Microbial, Biochemical and Food Biotechnology at the University of the Free State (UFS) in Bloemfontein, South Africa collaborated on the paper. It details a study undertaken in Mpumalanga, South Africa, to develop a sustainable remediation approach for site specific power station-generated fly ash leachate contaminants.

Mary serves as a Research Professor at UFS, and presented these findings in early April at the 253rdAmerican Chemical Society National Meeting & Exposition in San Francisco.

Mary's co-authors were Errol D. Cason, Peter J. Williams, Elizabeth Ojo, Julio Castillo, and Esta van Heerden.


Most of the power generation globally is by coal-fired power plants resulting in large stockpiles of fly ash. The trace elements associated with the ash particles are subjected to the leaching effects of precipitation which may lead to the subsequent contamination of surface and groundwater systems. In this study, we successfully demonstrate an efficient and sustainable dual treatment remediation strategy for the removal of high levels of Cr6+ and SO42− introduced by fly ash leachate generated by a power station situation in Mpumalanga, South Africa. The treatment consisted of a primary fixed-bed bioreactor kept at a reduction potential for Cr6+ reduction. Metagenome sequencing clearly indicated a diverse bacterial community containing various bacteria, predominantly of the phylum Proteobacteria which includes numerous species known for their ability to detoxify metals such as Cr6+. This was followed by a secondary BaCO3/ dispersed alkaline substrate column for SO42− removal. The combination of these two systems resulted in the removal of 99% Cr6+ and 90% SO42−. This is the first effective demonstration of an integrated system combining a biological and chemical strategy for the remediation of multi-contaminants present in fly ash leachate in South Africa.

More Information

For more information regarding the article, visit:
For more information on Hexavalent chromium bioreduction and chemical precipitation of sulphate as a treatment of site-specific fly ash leachates, contact Mary deFlaun at This email address is being protected from spambots. You need JavaScript enabled to view it..
To learn more about Mary see his profile at: