Methane production improvement and associated methanogenic assemblages in bioelectrochemically assisted anaerobic digestion

Anaerobic digestion and electromethanogenic microbial electrolysis cell integrated system: Increased stability and recovery of ammonia and methane

“…Conventional techniques for biogas upgrading focus on CO 2 removal without changing CH 4 mass [31], while electromethanogenesis performed in MEC allows for the conversion of CO 2 into CH 4 [32][33][34]. An alternative configuration to electromethanogenic MECs, by inserting electrodes in the AD reactor and applying a potential, allows for the in situ biogas upgrading, reporting an increase in methane yield [26,[35][36][37]. An increase of 59.7% in methane yield was achieved in a AD-MEC coupled system compared to the AD alone [38].…”

Handbook of Research on Microbial Tools for Environmental Waste Management

“…There are no major reports of pH controls being set in place for MEC reactors as small fluctuations are usually short-lived if the reactor design is functional. Gajaraj et al (2017) found there was a decrease in pH (8.0 to 7.1) in all digesters during the first 24 h of AD, which recovered due to the rapid consumption of VFAs.…”

“…Yin et al (2016) achieved one of the highest methane yields (360.2 mL/g-COD), which was able to compete with the maximum yield in an anaerobic digester (370.0 mL/g-COD), by feeding with acetate for 3 months. Gajaraj, Huang et al (2017) compared glucose (1000 mg/L) and waste activated sludge (WAS) as substrates in batch-digestion experiments. They found that when sludge was used as the substrate, the digesters showed longer time intervals for volatile fatty acid (VFA) production and degradation, due to the sludge complexity.…”

The role of microbial electrolysis cell in urban wastewater treatment: integration options, challenges, and prospects

“…This finding was further confirmed by the same research group in a follow-up study [60], where increase in cathodic pH (9.5) due to proton consumption inevitably inhibited methanogenesis. The influence of applied voltage (0.3 and 0.6 V) on methanogenic population in MEC-AD system was investigated in another study, and 17.2 times increase in abundance of hydrogenotrophic methanogens was observed at low (0.3 V) applied voltage with enhanced (8-9%) CH4 production [61]. Taken together, these few available lab- the effect of biomass retention versus electrochemical interaction with the electrodes in enhancing methane generation.…”