CASE STUDY ON ENHANCED LANDFILL MINING AT MONT-SAINT- GUIBERT LANDFILL IN BELGIUM: PHYSICO-CHEMICAL CHARACTERIZATION AND VALORIZATION POTENTIAL OF COMBUSTIBLES AND INERT FRACTIONS RECOVERED FROM FINE FRACTIONS
Publikationen: Beitrag in Fachzeitschrift › Artikel › Forschung › (peer-reviewed)
The fine fractions account for the largest share of material recovered through (enhanced) landfill mining. These fractions typically present challenging characteristics for processing and valorization methods and, hence, they have been largely discarded in previous landfill mining projects. This situation has hindered the economic and environmental feasibility of landfill mining, since most of the excavated waste has been directed back into the landfill. Therefore, the fine fractions are one of the major challenges faced by (enhanced) landfill mining and suitable material and energy recovery schemes for these fractions need to be further developed and, if necessary, created. To this end, the physico-chemical characteristics of the “Combustibles” and “Inert” fractions recovered from the fine fractions <90 mm through a dry-mechanical process have been determined and their suitability for waste-to-material and waste-to-energy schemes has been evaluated in the MSG case study. The recovered “Combustibles” fractions represented 12.5 wt.% and 9.0 wt.% of the fine fractions <90 mm processed in the optimal water content and dry states, while the recovered “Inert” fractions accounted for 35.5 wt.% and 37.2 wt.%, respectively. According to the EN 15359:2011, the “Combustibles” fractions could be valorized as SRF in (co-) incineration, power and cement plants in both the optimal water content state and the dry state in the EU. However, in Austria these fractions can only be incinerated and not co-incinerated according to the Austrian Waste Incineration Ordinance (AVV), since in some cases they present concentrations of As, Cd, Co, Hg and Pb above the limit values. Therefore, in contrast to conventional (co-)incineration, the plasma gasification process proposed by the NEW-MINE project might offer a potential waste-to-energy valorization route for the combustible fractions obtained from the fine fractions of landfill-mined waste. As for the “Inert” fractions, there is no overarching legislation in the EU to regulate such materials yet in place and, hence, these fractions are solely subject to national or local regulations on recycling building materials. In Austria the “Inert” fractions would need further treatment in order to be valorized as a substitute for construction aggregates according to the Austrian Recycling Building Materials Ordinance (RBV), as they exceed the limit values for hydrocarbons, Cd, Pb, Zn, NH 4 + and anionic surfactants in certain cases. Therefore, suitable waste-to-material valorization schemes for the recovered inert fractions from the fine fractions of landfill-mined waste are to be further developed, while appropriate overarching regulations need to be created at EU level.