Anaerobic Digestion of Cattle Manure Influenced by Swirling Jet Induced Hydrodynamic Cavitation

Abstract

In this work, a modified swirling jet-induced cavitation has been employed for increasing anaerobic digestion efficiency of cattle manure. The hydrodynamic cavitation (HC) treatment improved the organic matter solubilization and the anaerobic biodegradability of cattle manure. The degree of disintegration increased by 5.8, 8.9, and 15.8% after the HC treatment at 6.0, 7.0, and 8.0 bars, respectively. However, the HC treatment at 7.0 bars had better results in terms of methane production. This result may be attributed to the possible formation of toxic and refractory compounds at higher inlet pressures, which could inhibit the methanization process. Further, total Kjeldahl nitrogen content was found to decrease with increasing inlet pressures, as the pH and the turbulent mixing favored the ammonia stripping processes. HC treatment decreased the viscosity of the treated cattle manure, favoring the manure pumping and mixing. Considerations on the energy input due to the HC pre-treatment and the energy output due to the enhanced methane yield have been presented. A positive energy balance can be obtained looking at the improved operational practices in the anaerobic digesters after the implementation of the HC pre-treatment.

Pretreatment of Lignocellulosic Biomass Using Vortex-Based Devices for Cavitation: Influence on Biomethane Potential

“…It has to be noted that the energy required for pre-treatment is primarily the function of number of passes and solid loading and not a function of type of biomass. The energy consumption required for the HC pre-treatment considered here compares very favourably with the earlier published results (440-660 kWh/ton total solids, Langone et al 41 ; 280 kWh/ton total solids reported by Zieliński et al…”

“…The lignin lost from the solids during cavitation would enter the liquid phase and therefore could have contributed towards the inhibition. Similar effect of inhibitors on BMP due to over cavitation has been reported in the past by Langone et al in 2018 41 and Garuti et al in 2018 32 . A possible shift in the microbial population due the easily available sugars in the liquid phase may also contribute to a drop in BMP.…”

“…Due to the advantages offered by HC systems compared to AC systems such as energy input and scalability, HC is almost always preferred for large scale processes. For instance, Langone et al reported that LCB pretreatment using HC technologies required 0.44 -0.66 kWh/kg total solids whereas the energy requirement for AC systems was significantly higher 41 .…”

Towards sustainable energy‐crop cultivation: feasibility of biomethane production using a double‐cropping system with various sorghum phenotypes

“…Methane yields and methane production rates were evaluated by BMP tests according to the UNI EN ISO 11734: 2004 standard and described in Langone et al . The inoculum used in BMP tests was collected from an agricultural biogas plant (Reggio Emilia, Italy) and incubated at 38 °C for 7 days prior to use.…”

Anaerobic treatability and residual biogas potential of the effluent stream of anaerobic digestion processes

“…These two facts points out the presence of slowly degradable materials at high proportion in the digestate of anaerobic digester 1. The slow degradation of this digestate can be attributed to the presence of rigid lignocellulosic fibers in cattle manures (Langone, Saldano, Fabbri, Pirozzi, & Andreottola, ) which have low biodegradability (Nasir, Ghazi, & Omar, ).…”