Author(s)

K. Karim, K. Thomas Klasson, R. Hoffmann, S. R. Dresher, D. W. DePaoli & H. Al-Dahhan

Abstract

Anaerobic digestion of animal waste: effect of mixing K. ~ a r i m ' , K. Thomas lass on^, R. ~offmann', S. R. Dresher2, D. W. Depaoli2 & H. AI-~ahhan' I Chemical Reaction Engineering Laboratory (CREL), Department of Chemical Engineering, Washington, University, St. Louis, MO 63130, USA 2 Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Abstract Six laboratory scale biogas mixed anaerobic digesters were operated to study the effect of biogas recycling rates and draft tube position on their performance. All the digesters performed very similarly with methane (CHI) production rates of 0.40 to 0.45 L per L of digester volume per day. A higher methane production rate was observed in the unmixed digester and an increased gas circulation rate had a negative impact on the methane production. However, there was no difference in the methane production rate for digesters with different positions of the draft tube. Air infiltration (up to 15% oxygen in the biogas) was observed in the digesters mi

Keywords