Formation and characteristics of a ternary pH buffer system for in-situ biogas upgrading in two-phase anaerobic membrane bioreactor treating starch wastewater. (December 2018)

• Record Type: Journal Article
• Authors: Yu, Dawei; Meng, Xiaoshan; Liu, Jibao; Dian, Liu; Sui, Qianwen; Zhang, Junya; Zhong, Hui; Wei, Yuansong
• Is Part Of: Bioresource technology. Volume 269(2018)
• Page Start: 57
• Page End: 66
• Publication Date: 2018-12
• Subjects: Anaerobic membrane bioreactor -- pH -- Carbonate system -- Ammonia -- Volatile fatty acids; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2018.08.072
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Higher average pH seized over 6% more CO2 in stage-II. Most CO2 ·H2 O converts to HCO3 − and CO3 2− when pH > 7.9. Lack of CO2 ·H2 O limited the hydrogenotrophic methanogenesis. Ammonia is not only an inhibitor but also a pH buffer capacity contributor. Endogenous VFAs regulated pH cycle in stage-II. Abstract: Biochemical biogas upgrading retaining more CO2 from biogas to form biomethane opens new avenues for sustainable biofuel production. For developing this technology, maintaining sustain pH for CO2 ·H2 O is fundamental. This study proposes an innovative control strategy for in-situ biogas upgrading retaining and converting the CO2 in the biogas into CH4, via hydrogenotrophic methanogenesis without external agent. The Biogas-pH strategy limited pH drop over 7.4 by stop feeding and maintained the methanogenesis activity by biogas flow rate over 98 ml·h −1 . Low pH (7.37–7.80) decrease CO2 ·H2 O as a substrate in stage-I, higher pH (7.40–8.41) enhances CO2 to CO2 ·H2 O transfer by 6.29 ± 2.20% in stage-II. Because of that 95% CO2 ·H2 O converts to HCO3 − and CO3 2− when pH > 7.9, higher pH > 7.9 did not further upgrading the biogas. The carbonate buffer system shown open and close system characteristics in gas and liquid phase. The biogas CH4 was upgraded from 67.27 ± 5.21% to 73.56 ± 5.01%.