An investigation of ultrasound effect on digestate solubilization and methane yield.
In this study, different ultrasound power intensities of 0.05-0.21kW/L (4.13-16.52kWh/kg TS) were applied at a frequency of 20kHz and for durations of 5-20min to digestate obtained from a domestic wastewater treatment plant. The ultrasonic effect on digestate solubilization was revealed by increased levels of soluble Chemical Oxygen Demand (sCOD), soluble Total Organic Carbon (sTOC), and soluble Total Nitrogen (sTN) released into the solution. The highest material release was achieved at an ultrasonic energy intensity of 0.21kWh/L. Furthermore, the ultrasonic effect on CH4production was studied using the anaerobic digestion process. The application of ultrasound at 0.05-0.21kWh/L provided 1.6-2.3-fold increase in net CH4production. Analysis of the energetics of the system showed that only about 4 and 11% of the energy input was recovered in terms of additional CH4production at 0.21 and 0.05kWh/L, respectively. A comprehensive cost-benefit analysis of the system is required for making a conclusion on the feasibility of the system, and such analysis should include environmental, economic, and societal benefits of the system, among others.
Department of Civil, Construction and Environmental Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA. Electronic address: tgaroma@mail.sdsu.edu.
Temesgen
T
Garoma
Department of Civil, Construction and Environmental Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
David
D
Pappaterra
D000693:Anaerobiosis; D056804:Biofuels; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D008697:Methane / Q000032:analysis*; D062065:Wastewater
D056804:Biofuels; D008697:Methane; D062065:Wastewater
Anaerobic digestion; Digestate; Methane; Ultrasound