Blagojevič Marko, Zupanc Mojca, Gostiša Jurij, Stres Blaž, Šmid Alenka, Dular Matevž, Slemenik Perše Lidija, Gradišar Centa Urška, Bizjan Benjamin, Rak Gašper, Novak Uroš, Likozar Blaž, Kolbl Repinc Sabina
Faculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova cesta 2, 1000 Ljubljana, Slovenia.
Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva cesta 6, 1000 Ljubljana, Slovenia.
Ultrason Sonochem. 2025 Apr;115:107291. doi: 10.1016/j.ultsonch.2025.107291. Epub 2025 Feb 24.
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 cm and 1648 cm, 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.
在本研究中，使用实验室规模的流体动力空化 pinned 盘旋转发生器处理总固体浓度为 0.7% 的废弃活性污泥。测试了五种不同的转子 - 定子配置，重点关注与工业相关的废弃活性污泥的物理化学和流变学参数：常规化学分析、流变测定、脱水性能、界面张力、紫外 - 可见光谱和傅里叶变换红外光谱。在样品测试前，使用水杨酸剂量测定法确认了所有五种配置中自由基的形成。其中三种配置产生的自由基浓度是另外两种的两倍，并且实现的分解程度高出三倍（分别为 17% 和 5%）。毛细管抽吸时间测试表明，所有配置的过滤性能均降低了 14 倍，同时界面张力增加超过 10%。紫外 - 可见光谱的统计学显著变化表明，溶解性有机物的腐殖化、芳香性以及比色溶解性有机物、DNA 和 RNA 的分子大小发生了改变。傅里叶变换红外光谱分析显示在 1537 cm 和 1648 cm 处有特征峰，表明微生物细胞壁受到破坏。流变学分析表明，在低剪切应力区（τ < 5 Pa）表观粘度降低，屈服应力点向较低剪切应力方向移动（未处理样品为 τ = 0.17 Pa，处理后为 τ < 0.14 Pa）。皮尔逊相关性测试表明细胞壁损伤（通过傅里叶变换红外光谱确定）与反应器中的流体动力学条件之间存在强的、统计学显著的相关性，而与自由基形成的相关性在统计学上不显著。这表明流体动力是细胞壁损伤的主要驱动因素，自由基可能具有协同作用。
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