Physico-chemical characteristics of waste, particularly fine fraction (FF), from an old crystal glass waste dump in Sweden were studied to assess recycling or disposal alternatives. Hand-sorting of the waste indicated glass content of 44.1% while sieving established the FF as a more soil-like mix of glass and other materials constituting 33.3% of all excavated waste. The FF was around neutral pH with 24.4% moisture content, low values of Total Dissolved Solids, Dissolved Organic Carbon and fluorides, but hazardous concentrations of As, Cd, Pb and Zn according to the Swedish Environmental Protection Agency guidelines. While the FF leached metals in low concentrations at neutral pH, it leached considerably during digestion with nitric acid, implying leaching risks at low pH. Thus, the waste requires safe storage in hazardous waste class ‘bank account’ storage cells to avoid environmental contamination as metal recovery and other recycling strategies for the glass waste are being developed. The study could fill the information gap regarding preservation of potential resources in the on-going, fast-paced excavation and re-landfilling of heavy metal contaminated materials in the region.

Around former glass factories in south eastern Sweden, there are dozens of dumps whose radioactivity and physico-chemical properties were not investigated previously. Thus, radiometric and physico-chemical characteristics of waste at Madesjö glass dump were studied to evaluate pre-recycling storage requirements and potential radiological and environmental risks. The material was sieved, hand-sorted, leached and scanned with X-Ray Fluorescence (XRF). External dose rates and activity concentrations of Naturally Occurring Radioactive Materials from ²³⁸U, ²³²Th series and ⁴⁰K were also measured coupled with a radiological risk assessment. Results showed that the waste was 95% glass and dominated by fine fractions (< 11.3 mm) at 43.6%. The fine fraction had pH 7.8, 2.6% moisture content, 123 mg kg^-1 Total Dissolved Solids, 37.2 mg kg^-1 Dissolved Organic Carbon and 10.5 mg kg^-1 fluorides. Compared with Swedish EPA guidelines, the elements As, Cd, Pb and Zn were in hazardous concentrations while Pb leached more than the limits for inert and non-hazardous wastes. With ⁴⁰K activity concentration up to 3000 Bq kg^-1, enhanced external dose rates of ⁴⁰K were established (0.20 mSv h^-1) although no radiological risk was found since both External Hazard Index (H_ex) and Gamma Index (I_γ) were < 1. The glass dump needs remediation and storage of the waste materials under a safe hazardous waste class ‘Bank Account’ storage cell as a secondary resource for potential future recycling.

This study investigates the potential for Electrical Resistivity Tomography (ERT) to detect buried glass ‘hotspots’ in a glass waste dump based on results from an open glass dump investigated initially. This detection potential is vital for excavation and later use of buried materials as secondary resources. After ERT, test pits (TPs) were excavated around suspected glass hotspots and physico-chemical characterisation of the materials was done. Hotspots were successfully identified as regions of high resistivity (>8000 Ωm) and were thus confirmed by TPs which indicated mean glass composition of 87.2% among samples (up to 99% in some). However, high discrepancies in material resistivities increased the risk for introduction of artefacts, thus increasing the degree of uncertainty with depth, whereas similarities in resistivity between granite bedrock and crystal glass presented data misinterpretation risks. Nevertheless, suitable survey design, careful field procedures and caution exercised by basing data interpretations primarily on TP excavation observations generated good results particularly for near-surface materials, which is useful since glass waste dumps are inherently shallow. Thus, ERT could be a useful technique for obtaining more homogeneous excavated glass and other materials for use as secondary resources in metal extraction and other waste recycling techniques while eliminating complicated and often costly waste sorting needs.

Glass waste dumps from crystal glass production is an health issue due to the occurrence of antimony, arsenic, cadmium and lead in crystal glass. Recovery of those elements could both decrease pollution and recycle metals in the circular economy. Pyrometallurgy is a potential recovery method, yet limited by high energy consumption. Here we tested a lower-energy alternative in which glass is mechanically activated in a ball mill and leached with nitric acid. Results show that mechanical activation destabilised the glass structure and resulted in 78% lead extraction during leaching at 95 °C. Temperature had the most signifcant efect on extraction, whereas acid concentration, from 0.5 to 3 M, and leaching time, from 0.5 to 12 h, had insignifcant efects. In each experiment, 75% of the fnal extracted amount was achieved within 30 min. The study demonstrates potential for lead extraction from glass waste at lower acid concentration, shorter leaching time and lower temperature, of 95 °C, than traditional pyrometallurgical extraction, typically operating at 1100 °C.