Gold and silver from the sewer

Posted on 13 Nov 2019

Last March, the Brussels research project SUBLIMUS started, in which VUB and ULB scientists check whether the Brussels sewage sludge still contains sufficient quantities of precious metals that can be recovered. Innoviris finances this project.

Sludge incineration only option

After the purification of the sewage water, sludge remains, which often still contains heavy and precious metals. Precious metals end up in the sewage through erosion of gold and silver jewelery, disinfectants (silver), pharmaceuticals (gold), repulsion from diesel engine catalytic converters (platinum), and so on. Until now, there was only one option to get rid of this sludge: incinerate it and use it as a support fuel or heat source.

Environmentally friendly purification and recycling

But maybe an option will be added now. Scientists from the Vrije Universiteit Brussel (VUB) and the Université Libre de Bruxelles (ULB) want to investigate how the precious metals that are present can be recovered in an environmentally friendly manner. With the SUBLIMUS project, they will first check whether the precious metals are sufficiently present in the sewage sludge. If this is the case, it will be examined by means of bio-livivation, or “washing” the sludge with special bacteria, whether extraction of those metals is possible without damaging the environment. The purification and recycling of precious metals from that metal mixture should also be done in an environmentally friendly manner. Here is the track to develop gold-binding nanomaterials with magnetic properties. After bonding with a precious metal, it is then a breeze to remove the precious metals from the mixture with a magnet.

Read more: Susanova

© Photo VUB


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