20.500.12556/RUL-167682 The impact of radicals on physicochemical properties of waste activated sludge during hydrodynamic cavitation treatment In this study, laboratory-scale Pinned Disc Rotary Generator of Hydrodynamic Cavitation was used to treat waste-activated sludge with a Total Solids concentration of 0.7 %. Five different rotor–stator arrangements were tested, focusing on waste-activated sludge physicochemical and rheological parameters of industrial relevance: general chemical analysis, rheometry, dewaterability, interfacial tension, UV–Vis and FTIR spectroscopy. Radical formation in all five arrangements was confirmed using salicylic acid dosimetry before sample testing. Three of the arrangements generated twice the radical concentration of the other two and achieved a disintegration degree three times higher (17 % compared to 5 %). Capillary Suction Time tests demonstrated a 14-fold reduction in filterability across all arrangements, accompanied by an increase in interfacial tension exceeding 10 %. Statistically significant changes in the UV–Vis spectra indicated alterations in dissolved organic matter humification, aromaticity, and molecular size of colorimetric dissolved organic matter, DNA, and RNA. FTIR analysis revealed characteristic peaks at 1537 cm1 and 1648 cm1, signifying microbial cell wall damage. Rheological analysis showed a reduction in apparent viscosity within the low shear stress zone (τ <5 Pa) and a shift in the yield stress point to lower shear stresses (τ <0.14 Pa compared to τ =0.17 Pa for the untreated samples). Pearson’s correlation test revealed strong, statistically significant correlations between cell wall damage (as identified by FTIR) and hydrodynamic conditions in the reactor, while the correlation with radical formation was not statistically significant. This suggests that hydrodynamic forces were the primary drivers of cell wall damage, with potential synergetic effects from radicals. waste-activated sludge hydrodynamic cavitation pinned disc radicals UV-Vis rheology methane environmental engineering odvečno blato hidrodinamska kavitacija radikali UV-Vis reologija metan okoljsko inženirstvo true false true Angleški jezik Slovenski jezik Članek v reviji 2025-03-06 14:16:50 2025-03-06 14:16:59 2026-01-13 12:50:58 0000-00-00 00:00:00 2025 0 0 15 str. Vol. 115, art. 107291 apr. 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 628.3 1350-4177 10.1016/j.ultsonch.2025.107291 228206595 1-s2.0-S1350417725000707-main.pdf 1-s2.0-S1350417725000707-main.pdf 1 54E4B9AD1DA40736A03B17A7A9DE40ED 614a8ceb30e262e6810e448bb289c8f748d85d63f15ea397423212d926685e3e 5bd25d03-fa90-11ef-b232-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=200398 https://doi.org/10.1016/j.ultsonch.2025.107291 1 5b875620-fa8c-11ef-b232-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=200397 Fakulteta za gradbeništvo in geodezijo Fakulteta za strojništvo 0 0 0