Steady state and dynamic behaviors of a methane biofilter under periodic addition of ethanol vapors.
Ethanol was added to a methane (CH4) biofilter with inorganic packing materials over three cycles based on increasing the gas flow rates from 3 to 6 and finally to 12 L min-1corresponding to empty bed residence times (EBRT) of 6, 3 and 1.5 min. The steady state performance of the CH4biofilter was studied for CH4inlet loads (ILs) of 33, 66 and 132 gCH4m-3h-1prior and after each ethanol cycle. In addition, the steady state removal of a mixture of CH4and ethanol for a CH4/ethanol mass ratio of around 7.5 gCH4g-1ethanolwas evaluated over three cycles (EBRTs of 6, 3 and 1.5 min). In the absence of ethanol, the CH4removal efficiency (RE) dropped from 35 to 7% due to an EBRT decrease from 6 to 1.5 min. In addition, the presence of ethanol resulted in a CH4RE reduction at a constant EBRT in every cycle. The CH4REs dropped from 35 to 29%, 17 to 13% and 7 to 0% for corresponding ethanol ILs of 4.5, 9 and 18 gethanolm-3h-1over the cycles. Moreover, the periodic presence of ethanol in the CH4biofilter allowed the study of transient behaviors of the biofilter during ethanol addition and the biofilter recovery after each cycle. The CH4RE reduction as a result of ethanol addition in each cycle was instantaneous. However, the CH4RE recovery after completion of ethanol addition took 10, 14 and 25 days for ethanol ILs of 4.5, 9 and 18 gethanolm-3h-1respectively. The recovery time was related to the ethanol concentration in the leachate which were 1100 ± 200, 1100 ± 350 and 2500 ± 400 gethanolm-3leachatefor corresponding ethanol ILs of 4.5, 9 and 18 gethanolm-3h-1, respectively. Based on steady state and dynamic process conditions of the biofilter, the lowest gas flow rate of 3 L min-1(EBRT of 6 min) produced the best performance when both pollutants were present (CH4IL of 33 gCH4m-3h-1and ethanol IL of 4.5 gethanolm-3h-1).
Department of Chemical Engineering and Biotechnological Engineering, Faculty of Engineering, 2500 Boulevard de l'Universite, Université de Sherbrooke, Sherbrooke, J1K 2R1, QC, Canada.
Milad
M
Ferdowsi
Department of Chemical Engineering and Biotechnological Engineering, Faculty of Engineering, 2500 Boulevard de l'Universite, Université de Sherbrooke, Sherbrooke, J1K 2R1, QC, Canada; Centre National en Électrochimie et en Technologies Environnementales, 2263, Avenue du Collège, Shawinigan, G9N 6V8, QC, Canada.
Antonio
A
Avalos Ramirez
Department of Chemical Engineering and Biotechnological Engineering, Faculty of Engineering, 2500 Boulevard de l'Universite, Université de Sherbrooke, Sherbrooke, J1K 2R1, QC, Canada.
J Peter
JP
Jones
Department of Chemical Engineering and Biotechnological Engineering, Faculty of Engineering, 2500 Boulevard de l'Universite, Université de Sherbrooke, Sherbrooke, J1K 2R1, QC, Canada. Electronic address: Michele.Heitz@USherbrooke.ca.
Michèle
M
Heitz
D001673:Biodegradation, Environmental; D000431:Ethanol; D005374:Filtration; D005740:Gases; D008697:Methane
D005740:Gases; D000431:Ethanol; D008697:Methane
Biofilter; Ethanol; Gas flow rate; Methane; Mixture; Sensitivity