Mojca Zupanc (Author), Barbara Brajer Humar (Author), Matevž Dular (Author), Jurij Gostiša (Author), Marko Hočevar (Author), Sabina Kolbl (Author), Mario Krzyk (Author), Lovrenc Novak (Author), Jernej Ortar (Author), Žiga Pandur (Author), Blaž Stres (Author), Martin Petkovšek (Author)

Abstract

Anaerobic digestion in wastewater treatment plants converts its unwanted end product – waste activated sludge into biogas. Even if the process is well established, pre-treatment of the sludge can further improve its efficiency. In this study, four treatment regimes for increasing methane production through prior sludge disintegration were investigated using lab-scale cavitation generator and real sludge samples. Three different cavitating (attached cavitation regime, developed cloud shedding cavitation regime and cavitation in a wake regime) and one non-cavitating regime at elevated static pressure were studied in detail for their effectiveness on physical and chemical properties of sludge samples. Volume-weighted mean diameter D[4,3] of sludge's particles decreased by up to 92%, specific surface area increased by up to 611%, while viscosity (at a shear rate of 3.0 s$^{−1}$) increased by up to 39% in the non-cavitating and decreased by up to 24% in all three cavitating regimes. Chemical changes were more pronounced in cavitating regimes, where released soluble chemical oxygen demand (sCOD) and increase of dissolved organic matter (DOM) compounds by up to 175% and 122% were achieved, respectively. Methane production increased in all four cases, with the highest increase of 70% corresponding to 312 mL CH$_4$ g$^{−1}$ COD. However, this treatment was not particularly efficient in terms of energy consumption. The best energy balance was found for the regime with a biochemical methane potential increase of 43%.

Keywords

hydrodynamic cavitation;waste activated sludge;disintegration;viscosity;methane production;energy balance;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FS - Faculty of Mechanical Engineering
UDC: 532.528
COBISS: 167876867 Link will open in a new window
ISSN: 0301-4797
Views: 168
Downloads: 28
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: Slovenian
Secondary keywords: hidrodinamska kavitacija;aktivno odpadno blato;dezintegracija;viskoznost;proizvodnja metana;energijska bilanca;
Type (COBISS): Article
Pages: str. 1-11
Issue: ǂVol. ǂ347
Chronology: Dec. 2023
DOI: 10.1016/j.jenvman.2023.119074
ID: 20176104