Intermittent micro-aeration: New strategy to control volatile fatty acid accumulation in high organic loading anaerobic digestion

WATER RESEARCH

卷:166

Article

Duc Nguyen¹  Wu, Zhuoying²  Shrestha, Shilva³  Lee, Po-Heng²  Raskin, Lutgarde³  Khanal, Samir Kumar¹ 

[1] Univ Hawaii Manoa, Dept Mol Biosci & Bioengn, Honolulu, HI 96822 USA

[2] Imperial Coll, Dept Civil & Environm Engn, London, England

[3] Univ Michigan, Dept Civil & Environm Engn, 1351 Beal Ave,107 EWRE Bldg, Ann Arbor, MI 48109 USA

关键词: Anaerobic digestion;    VFA accumulation;    Micro-aeration;    Oxidation-reduction potential (ORP);    Microbial community;    Metabolic pathway;   

DOI  :  10.1016/j.watres.2019.115080

来源: Elsevier

【 摘 要 】

This study developed an intermittent oxidation-reduction potential (ORP)-controlled micro-aeration system for high solids anaerobic digestion (AD) of lignocellulosic biomass without volatile fatty acids (VFA) accumulation at high organic loading rate (OLR). Traditional AD of Napier grass, a model lignocellulosic biomass, at an OLR of 5 g volatile solids (VS)/L/day resulted in an accumulation of total VFA concentration up to 9.2 g/L as acetic acid (HAc) equivalent, causing rapid drops in pH and methane yield, and driving the digester to the verge of failure. Once intermittent (every 24 h) ORP-controlled microaeration (at ORP of -470 mV) was initiated, the total VFA concentration rapidly decreased to 3.0 g HAc/L and the methane yield improved, resulting in stable digester performance without the need for alkalinity supplementation or OCR reduction. By combining reactor performance results, mass balance analyses, microbial community characterization data, and a bioenergetic evaluation, this study suggested that rapid VFA conversion and CH4 production were carried out by facultative anaerobes and hydro-genotrophic methanogens under micro-aerobic conditions. This novel operating approach can be applied as an effective control strategy for high OLR AD processes especially in the event of VFA accumulation. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

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