Bio-Electrochemical Enhancement of Hydrogen and Methane Production in a Combined Anaerobic Digester (AD) and Microbial Electrolysis Cell (MEC) from Dairy Manure

Amro Hassanein, Freddy Witarsa, Stephanie Lansing, Ling Qiu and Yong Liang
Additional contact information
Amro Hassanein: Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742, USA
Freddy Witarsa: Department of Physical and Environmental Sciences, Colorado Mesa University, Grand Junction, CO 81501, USA
Stephanie Lansing: Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742, USA
Ling Qiu: College of Mechanical and Electrical Engineering, Northwest Agriculture and Forestry University, Yangling 712100, China
Yong Liang: College of Mechanical and Electrical Engineering, Northwest Agriculture and Forestry University, Yangling 712100, China

Sustainability, 2020, vol. 12, issue 20, 1-12

Abstract: Anaerobic digestion (AD) is a biological-based technology that generates methane-enriched biogas. A microbial electrolysis cell (MEC) uses electricity to initiate bacterial oxidization of organic matter to produce hydrogen. This study determined the effect of energy production and waste treatment when using dairy manure in a combined AD and MEC (AD-MEC) system compared to AD without MEC (AD-only). In the AD-MEC system, a single chamber MEC (150 mL) was placed inside a 10 L digester on day 20 of the digestion process and run for 272 h (11 days) to determine residual treatment and energy capacity with an MEC included. Cumulative H 2 and CH 4 production in the AD-MEC (2.43 L H 2 and 23.6 L CH 4 ) was higher than AD-only (0.00 L H 2 and 10.9 L CH 4 ). Hydrogen concentration during the first 24 h of MEC introduction constituted 20% of the produced biogas, after which time the H 2 decreased as the CH 4 concentration increased from 50% to 63%. The efficiency of electrical energy recovery (ηE) in the MEC was 73% (ηE min.) to 324% (ηE max.), with an average increase of 170% in total energy compared to AD-only. Chemical oxygen demand (COD) removal was higher in the AD-MEC (7.09 kJ/g COD removed) system compared to AD-only (6.19 kJ/g COD removed). This study showed that adding an MEC during the digestion process could increase overall energy production and organic removal from dairy manure.

Keywords: biogas; MEC; bio-hydrogen; manure; digestion (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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