Repinc Sabina Kolbl, Bizjan Benjamin, Budhiraja Vaibhav, Dular Matevž, Gostiša Jurij, Brajer Humar Barbara, Kaurin Anela, Kržan Andrej, Levstek Marjetka, Arteaga Juan Francisco Morales, Petkovšek Martin, Rak Gašper, Stres Blaž, Širok Brane, Žagar Ema, Zupanc Mojca
Faculty of Civil and Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia.
Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia.
Sci Total Environ. 2022 Feb 1;806(Pt 4):151414. doi: 10.1016/j.scitotenv.2021.151414. Epub 2021 Nov 4.
Wastewater treatment plants, the last barrier between ever-increasing human activities and the environment, produce huge amounts, of unwanted semi-solid by-product - waste activated sludge. Anaerobic digestion can be used to reduce the amount of sludge. However, the process needs extensive modernisation and refinement to realize its full potential. This can be achieved by using efficient pre-treatment processes that result in high sludge disintegration and solubilization. To this end, we investigated the efficiency of a novel pinned disc rotational generator of hydrodynamic cavitation. The results of physical and chemical evaluation showed a reduction in mean particle size up to 88%, an increase in specific surface area up to 300% and an increase in soluble COD, NH-N, NO-N, PO-P up to 155.8, 126.3, 250 and 29.7%, respectively. Microscopic images confirmed flocs disruption and damage to yeast cells and Epistilys species due to mechanical effects of cavitation such as microjets and shear forces. The observed cell ruptures and cracks were sufficient for the release of small soluble biologically relevant dissolved organic molecules into the bulk liquid, but not for the release of microbial DNA. Cavitation treatment also decreased total Pb concentrations by 70%, which was attributed to the reactions triggered by the chemical effects of cavitation. Additionally, the study confirmed the presence of microplastic particles and fibers of polyethylene, polyethylene terephthalate, polypropylene, and nylon 6 in the waste activated sludge.
污水处理厂是人类活动不断增加与环境之间的最后一道屏障，会产生大量 unwanted 半固体副产品——废弃活性污泥。厌氧消化可用于减少污泥量。然而，该工艺需要进行大规模现代化改造和优化，以充分发挥其潜力。这可以通过使用高效的预处理工艺来实现，这些工艺可实现高污泥解体和溶解。为此，我们研究了一种新型的 pinned 盘式水力空化旋转发生器的效率。物理和化学评估结果表明，平均粒径降低了 88%，比表面积增加了 300%，可溶性化学需氧量、氨氮、硝态氮、总磷分别增加了 155.8%、126.3%、250% 和 29.7%。微观图像证实，由于空化的机械效应，如微射流和剪切力，絮凝物受到破坏，酵母细胞和 Epistilys 物种受到损害。观察到的细胞破裂和裂缝足以使小的可溶性生物相关溶解有机分子释放到主体液体中，但不足以释放微生物 DNA。空化处理还使总铅浓度降低了 70%，这归因于空化化学效应引发的反应。此外，该研究证实了废弃活性污泥中存在聚乙烯、聚对苯二甲酸乙二酯、聚丙烯和尼龙 6 的微塑料颗粒和纤维。
