Sabina Kolbl (Author), Benjamin Bizjan (Author), Vaibhav Budhiraja (Author), Matevž Dular (Author), Jurij Gostiša (Author), Barbara Brajer Humar (Author), Blaž Stres (Author), Brane Širok (Author), Ema Žagar (Author), Mojca Zupanc (Author), Anela Kaurin (Author), Andrej Kržan (Author), Meta Levstek (Author), Juan Francisco Morales Arteaga (Author), Martin Petkovšek (Author), Gašper Rak (Author)

Abstract

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, NH4-N, NO3-N, PO4-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.

Keywords

hydrodynamic cavitation;waste activated sludge;sludge characteristics;microbial damage;potentially toxic metals;microplastics;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FS - Faculty of Mechanical Engineering
UDC: 532.528:628.355
COBISS: 83741955 Link will open in a new window
ISSN: 0048-9697
Views: 233
Downloads: 89
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Other data

Secondary language: Slovenian
Secondary keywords: hidrodinamska kavitacija;odpadno blato;lastnosti blata;poškodbe mikroorganizmov;potencialno nevarne kovine;mikroplastika;
Type (COBISS): Article
Pages: str. 1-14
Volume: ǂVol. ǂ806
Issue: ǂpt. ǂ4
Chronology: Feb. 2022
DOI: 10.1016/j.scitotenv.2021.151414
ID: 14083824