Anaerobic Digestion of Animal Waste: Effect of Mode of Mixing
Laboratory-Scale Digesters Were Operated to Study the Effect of Mixing (Via Biogas Recirculation, Impeller Mixing, and Slurry Recirculation) on Biogas Production. Three Sets of Experiments Were Performed using Cow Manure Slurry Feed with Either 50, 100, or 150 G/L Total Solids (TS) Concentrations (Referred in the Text as 5%, 10%, and 15% Manure Slurry). the Experiments Were Conducted at a Controlled Temperature of 35°C and a Hydraulic Retention Time of 16.2 Days, Resulting in TS Loadings of 3.1, 6.2, and 9.3 G/L D for 5%, 10%, and 15% Manure Slurry Feeds, Respectively. Results Showed that the Unmixed and Mixed Digesters Performed Quite Similarly When Fed with 5% Manure Slurry and Produced Biogas at a Rate of 0.84-0.94 L/L D. the Methane Yield Was Found to Be 0.26-0.28 L CH4/g Volatile Solids Loaded. However, the Effect of Mixing and the Mode of Mixing Became Important When the Digesters Were Fed Thick Manure Slurry Feeds (10% and 15%). Digesters Fed with 10% and 15% Manure Slurry and Equipped with External Mixing Produced About 10-30% More Biogas Than the Unmixed Digester. While the Mixed Digesters Produced More Biogas Than Unmixed Digesters, Digester Mixing during Start-Up Was Not Beneficial, as It Resulted in Lower PH, Performance Instability and Prolonged Start-Up Time. Mixing using Biogas Recirculation System Was Found Not to Be Effective in the Case of 15% Manure Slurry Feed under the Experimental Conditions Studied. © 2005 Elsevier Ltd. All Rights Reserved.
K. Karim et al., "Anaerobic Digestion of Animal Waste: Effect of Mode of Mixing," Water Research, vol. 39, no. 15, pp. 3597 - 3606, Elsevier; IWA Publishing, Jan 2005.
The definitive version is available at https://doi.org/10.1016/j.watres.2005.06.019
Chemical and Biochemical Engineering
Keywords and Phrases
Anaerobic; Biogas; Digestion; Manure; Mixing
International Standard Serial Number (ISSN)
Article - Journal
© 2023 Elsevier; IWA Publishing, All rights reserved.
01 Jan 2005
Office of Energy Efficiency and Renewable Energy, Grant None