This poster presents the first results of the SUBLIMUS project (BRIDGE2019-Innoviris). The objective of this project is to explore the potential of harvesting valuable metals (including precious metals like Au, Ag, Pt) present in urban wastewater treatment plant (WWTP) sludge. Although many recent studies point out the potential value of recycling metals from domestic sludges [1] [2] [3], the step towards an integrated industrial process has not been undertaken yet, mainly because of the sludge matrix complexity. Very first and explorative results of this project are presented here.
Firstly, various types of domestic sludge are analysed for their metal content and show that sludge is enriched in all metals and that highest contents are found in wet oxidized sludge (Techno-sand from WWTP Brussels North, Aquiris).
We then determined the mineralogical characteristics of Techno-sand and its “leachability” according to Tessiers’ extraction protocol. Most metals are associated to silicate and phosphate minerals and are present in the most refractory remaining fraction.
Techno-sands were then used in a bioleaching experimental setup whereby the objective is to pre-clean the sludge matrix from the most abundant interfering metals (Cu, Zn, Pb, …). Various tests include the selection of appropriate bacterial strains and their acclimatization to the techno-sand matrix, the determination of optimal physicochemical conditions (pH, Temperature, …) for bioleaching, and the first evaluation of metal leaching efficiency in a bioreactor experiment.
After these very first investigations, future actions will concentrate on the optimisation of bioleaching techniques and the development of original methods to solubilize and selectively extract precious metals from solution. To be continued…
Original languageEnglish
Publication statusPublished - 7 Oct 2019
EventEuropean Conference on Sludge Management - Université de Liège, Liège, Belgium
Duration: 6 Oct 20198 Oct 2019
Conference number: 5


ConferenceEuropean Conference on Sludge Management
Abbreviated titleECSM
Internet address

    Research areas

  • sludge, metals, recycling

ID: 48252784