Abstract
Disintegration by hydrodynamic cavitation has a positive effect on the degree and rate of sludge anaerobic digestion. By applying hydrodynamic disintegration the lysis of cells occurs in minutes instead of days. The intracellular and extracellular components are set free and are  immediately available for biological degradation which leads to an improvement of the subsequent anaerobic process. Hydrodynamic disintegration of the activated sludge results in organic matter and a polymer transfer from the solid phase to the liquid phase, and an increase in COD value of 284 mg·l-1 was observed, i.e. from 42 mg·l-1 to 326 mg·l-1. In addition the degree of disintegration changed from 14% after 15 min disintegration to 54% after 90 min of disintegration. A disruption of bacterial cells by hydrodynamic cavitation has a positive effect on the degree and rate of excess sludge anaerobic digestion. The cells of the activated sludge micro-organisms rupture and addition to the digestion process leads to increased biogas production. The hydrodynamic  disintegration of activated sludge leads to a higher degree of degradation and higher biogas production. Adding the disintegrated sludge (10%, 20% and 30% of volume) to fermentation processes resulted in an improvement in biogas production of about 22%, 95% and 131% respectively.
Highlights
The aim of wastewater treatment is to mineralise organic matter and enhance nutrient removal
The hydrodynamic disintegration of activated sludge leads to a higher degree of degradation and higher biogas production
Addition of hydrodynamic disintegrated activated sludge was examined in order to improve the anaerobic digestion process
Summary
The aim of wastewater treatment is to mineralise organic matter and enhance nutrient removal. Anaerobic digestion is a common method for activated sludge stabilisation resulting in the reduction of sludge volatile matter and the production of biogas. The disintegration pretreatment of an activated sludge process using physical (thermal), chemical (using e.g. acids), mechanical (ball mill, ultrasonic), oxidation (ozone and hydrogen peroxide), or biological (using enzymes) treatment processes, can improve the subsequent anaerobic digestion (Burgess and Pletschke, 2008; Hiraoka et al, 1984; Kennedy et al, 2007; Muller, 2000; Tiechm et al, 1997; Wang et al, 2004). Hydrodynamic cavitation results in the formation of cavities (bubbles) filled with vapour – gas mixture inside the flowing liquid, or at the boundary of a constrictive device due to rapid local pressure drop. Hydrodynamic disintegration can activate the biological hydrolysis process and significantly increase the biogas production in anaerobic stabilisation. The new concept described in this paper is based on the combined process of activated sludge hydrodynamic disintegration prior to anaerobic digestion, with the aim of achieving improved sludge digestion
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
