Enhancement of carbon dioxide reduction and methane production by an obligate anaerobe and gas dissolution device

Kim, Seung-Jin; Choi, Kwangkeun; Kim, Jong‐Oh; Chung, Jinwook

doi:10.1016/j.nbt.2015.05.004

Cited by 3 publications

(2 citation statements)

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“…Much of the research to date on the power-to-methane route has focused on reduction of imported CO2 using pure or mixed cultures of hydrogenotrophic methanogens in bioreactors designed for this purpose [2][3][4][5][6][7][8][9][10] . Since the CO2 is from an external source, this type of process is known as ex-situ biomethanisation.…”

Section: Introductionmentioning

confidence: 99%

“…To achieve these high volumetric conversion rates and promote the mass transfer of H2, which has a low solubility (~1.35 ×10 -5 v/v) in aqueous media 11 , different reactor configurations have been investigated. These include conventional continuous stirredtank reactors (CSTR) 5,6,12 ; and also packed column reactors 7,8 where extended gas-liquid contact times can be achieved, and biofilm/trickle bed reactors 3,10 where the gases are directly in contact with the culture as a wetted biofilm.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous biomethanisation of endogenous and imported CO2 in organically loaded anaerobic digesters

et al. 2019

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In-situ biomethanisation reduces the CO2 in biogas to CH4 via direct H2 injection into an anaerobic digester, but volumetric methane production (VMP) is limited by organic loading. Ex-situ biomethanisation, where gaseous substrates are fed to pure or mixed cultures of hydrogenotrophic methanogens, offers higher VMP but requires an additional reactor and supply of essential nutrients. This work combined the two approaches in a novel hybrid application achieving simultaneous in-situ and ex-situ biomethanisation within an organicallyloaded anaerobic digester receiving supplementary biogas. Conventional stirred-tank digesters were first acclimated to H2 addition, increasing biogas methane content from 50% to 95% and VMP from 0.86 to 1.51 L L-1 day-1 at a moderate loading rate of 3 g organic chemical oxygen demand per L per day (g CODorg L-1 day-1). Externally-produced biogas was then added to demonstrate simultaneous biomethanisation of endogenous and imported CO2. This further increased VMP to 2.76 L L-1 day-1 without affecting organic substrate degradation. In-situ CO2 reduction can alter digester pH by reducing bicarbonate buffering: the combined process operated stably at around pH 8.0 with 3-5% CO2 in the headspace. Microbial community analysis indicated the process was mediated by bacterial syntrophic acetate oxidation and highly enriched hydrogenotrophic methanogenic archaea (up to 97% of the archaeal

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