The use of hydrodynamic cavitation for waste-to-energy approach to enhance methane production from waste activated sludge

• DOI: 10.1016/j.jenvman.2023.119074
• Publication Date: 2023-10-05T22:30:14Z
• Authors: Mojca Zupanc; Barbara Brajer Humar; Matevž Dular; Jurij Gostiša; Marko Hočevar; Sabina Kolbl Repinc; Mario Krzyk; Lovrenc Novak; Jernej Ortar; Žiga Pandur; Blaž Stres; Martin Petkovšek
• Keywords: Biogas; Sewage sludge; Produced water

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 can further improve efficiency. In this study, four regimes for increasing methane production through prior disintegration were investigated using lab-scale cavitation generator and real samples. Three different cavitating (attached regime, developed cloud shedding regime a wake regime) one non-cavitating at elevated static pressure studied detail their effectiveness on physical chemical properties Volume-weighted mean diameter D[4,3] sludge's particles decreased by up to 92%, specific surface area increased 611%, while viscosity (at shear rate 3.0 s−1) 39% 24% all three regimes. Chemical changes more pronounced regimes, where released soluble oxygen demand (sCOD) increase dissolved organic matter (DOM) compounds 175% 122% achieved, respectively. Methane cases, with highest 70% corresponding 312 mL CH4 g−1 COD. However, was not particularly efficient terms energy consumption. The best balance found biochemical potencial 43%.