Open Access

Incineration is currently the only commercial full-scale technology available to destroy per- and polyfluoroalkyl substances (PFAS) in large solid and liquid waste streams. Given previous experience of dioxin formation during halogenated waste incineration, concerns about the emission of products of incomplete destruction (PIDs) from PFAS incineration exist. The overarching objective of this project is to track the fate of fluorine during full-scale hazardous waste incineration in order to demonstrate the readiness, viability, and level of safety for thermal PFAS destruction in various waste streams. The specific objectives of this project are to enhance our understanding of key variables and conditions on PFAS incineration performance, to identify major PIDs under insufficient treatment conditions, to explore the catalytic role of fly ash and other process-relevant surfaces in thermal PFAS decomposition, and to determine the potential formation of polyfluorinated dibenzodioxins and dibenzofurans

Solar energy has become the world's fastest growing energy source, with global installed capacity exceeding 3 terawatts, it now surpasses all other energy sources. This unprecedented growth transforms vast land areas into new anthropogenic environments that are sun-exposed, nutrient-poor, and subject to extreme temperature fluctuations, conditions that strongly favour extremotolerant microorganisms. Black fungi in particular have emerged as persistent colonizers of photovoltaic panels, where they can reduce energy output by up to 11% within 18 months (Shirakawa et al. 2015). Beyond energy losses, their ability to degrade hard substrates poses wider risks to our cultural heritage. Black fungi are a taxonomically diverse group, yet share common lifestyles and adaptations. To explore how their traits manifest at the biofilm scale, we selected Knufia petricola to represent this group and built an Individual-based Model (IbM) describing cell-level behaviour and localized interactions. The model predicts emergent biofilm properties including spatial organization, radial expansion, and biomass accumulation. To make this possible, we extended the IbM platform iDynoMiCS 2.0 (Cockx et al. 2024) and performed dedicated single-cell and biofilm characterization experiments (Dehkohneh et al. 2026 preprint). K. petricola was cultivated across a range of carbon and nitrogen sources, C:N ratios, and nutrient limitation levels, generating the quantitative data needed for model parameterization. In its current form, the model captures how local nutrient availability shapes K. petricola biofilm development, which is an initial step toward a broader predictive framework for black fungi colonization of subaerial surfaces such as solar panels. Planned extensions include the characterization and modelling of biological responses to drought, UV radiation, and thermal stress, which should ultimately lead to a multiscale model that predicts biological photovoltaic fouling. This multiscale model will inform the design of antifouling strategies and will support the renewable energy transition.

Background: Surface-mediated transmission of microorganisms may lead to severe healthcare or food industry related outbreaks, and antimicrobial surfaces are one of the means to stop or decrease the surface transfer of bacteria. Standardized test methods conducted under idealized conditions and traditionally used to assess the antimicrobial activity of such surfaces do not however accurately reflect the real-life conditions of surfaces used in dry environments and high-touch settings. Previously, we have designed the HydroTouch test, which uses a semi-dry microbial inoculum on a finger-mimetic hydrogel to enable reliable quantification of microbial transfer efficiency under real-use-like conditions on environmental surfaces. Here, the HydroTouch test was refined in terms of microbial inoculum density, post-transfer exposure time and environmental conditions during surface exposure to enable the determination of surface transfer and antimicrobial activity. Results By using metallic copper as a model antimicrobial material, we showed that exposure time after microbial transfer from the finger-mimetic hydrogel to the surface is critical: short contact periods result in insufficient antimicrobial activity, whereas prolonged exposure leads to increased surface kill over time due to desiccation, complicating the interpretation of the antimicrobial effect. Among four bacteria and yeast tested, only Escherichia coli and Staphylococcus aureus showed sufficient surface transfer and viability on controls to enable their reliable use on the HydroTouch test. Organic soiling during surface exposure was shown to have notably enhanced surface transfer of bacteria but at the same time it also reduced the activity of copper surface. Interlaboratory comparison of the method carried out in four laboratories indicated 3–17% bacterial surface transfer in different labs, whereas the interlaboratory differences could be attributed to variability in relative air humidity during touch surface preparation and exposure. During 10 min exposure a modest but significant reduction of 0.30–0.75 log10 in viable cell count on copper was observed by the participating laboratories and also this parameter was clearly affected by humidity of the exposure environment. Conclusions The utility of the modified HydroTouch test for the determination of microbial surface transfer and antimicrobial activity across different laboratories was demonstated with organic soiling and air humidity being the decisive factors for its reproducibility.

Introduction We present the first results of a pilot-scale study on the effect of bulk chemistry, oxidation state and cooling practice on EAF-slag mineralogy, microstructure and leaching behaviour. Methods 24 batches of synthetic EAF-slag were produced (ca. 80-100 kg per batch) by remelting industrial slag in a pilot electric-arc furnace and trimming the chemistry with additives to a suite of target compositions. Two different cooling practices were used for the main batches: 1) cooling under air, and 2) granulation with water. Smaller (ca. 500 g) spoon-samples were taken prior to tapping, with a cooling rate intermediate between the two. The produced batches span a wide range of chemical composition regarding total FeOx content (ca. 20 - 40 wt%), Fe3+/Fe(total) ratio (0.15 - 0.80), CaO/SiO2 (B2 = 1.0 - 2.2), Al2O3/SiO2 (A/S = 0.2 - 0.7) and MgO/SiO2 (M/S = 0.4-1.1). The targeted compositions simulate a) a range of scenarios of operational tap-slag composition, b) high-temperature modification of some of these by addition of SiO2 or Al2O3 to lower B2 or raise A/S after tapping, respectively, and c) variable oxidation state prior to solidification. For the scenarios (a) representing operational tap-slag compositions, the B2, A/S and total FeOx were primary experimental variables, while MgO content was adjusted for each to satisfy a consistently applied saturation criteria in solid Mg-wüstite at operational temperatures, resulting in a range from 7.6 to 16.3 wt%. The vanadium and chromium contents of the slags in those scenarios were targeted at around 1 wt% each. For the scenarios (b), the additions dilute all the other components in the slag. The mineralogy and amorphous content of the slags was analysed with the XRD-Rietveld method, using added metallic silicon standard to quantify amorphous content. The phase chemistry and microstructure was studied with SEM-EDS analysis. Results The air-cooled slags with highest B2 have C2S ± bredigite as the dominant silicate phases, while those with lower B2 have Ca-rich olivine ± merwinite as the dominant silicate phases with minor melilite. The total FeOx content is strongly correlated with the total fraction of crystalline Fe-Mg-Mn(-Cr-Al)-oxides in monoxide (Mg-wüstite) or spinel form, while the spinel/monoxide ratio correlates strongly with the Fe3+/Fe(tot) ratio. Differences in Al2O3/MgO also influence the spinel/monoxide ratio and strongly influence the C2S/bredigite and olivine/merwinite/melilite ratios at high and low B2, respectively. Water granulation of the same range of slag compositions yields products with widely variable amorphous glass content, ranging from < 10 wt% through to 73 wt%. The amorphous content and crystalline phase occurrence is strongly correlated with the bulk chemistry of the slags and, moreover, has a clear link with the predicted phase assemblage from thermodynamic equilibrium calculations (Factsage). The leaching tendency of vanadium is strongly correlated with the mineralogy of the samples, and is well described by a simple multi-linear regression comprising only three variables (mass fractions of key mineralogical phases). Conclusions Suppressing the formation of C2S in favour of more bredigite diminishes the V-leaching tendency, as does suppressing Ca-rich olivine in favour of merwinite. The amorphous content has a strong negative correlation with V-leaching. V- and Si-leaching are positively correlated for the studied slags. This suggests a mechanistic control by the relative ease of dissolution of the V-bearing silicate phases together with their V-content, where the amorphous glass phase corresponds with lowest Si and V leaching tendency, and C2S the highest.

In Deutschland wird Klärschlamm häufig in Monoverbrennungsanlagen thermisch verwertet. Wir haben von den meisten Anlagen Aschen eingesammelt und diese auf deren chemische Zusammensetzung analysiert. Abhängig von der Zusammensetzung können die Aschen in unterschiedliche Kategorien eingeteilt werden, mit welchem P-Rückgewinnungsverfahren diese aufbereitet werden könnten. Sowohl aus diesen Klärschlammaschen als auch aus dem Abwasser und den Klärschlamm können verschiedene Rezyklate hergestellt werden. Dies können Struvite, thermochemische Produkte, Calciumphosphate und Phosphorsäure sein.