Continuous augmentation of anaerobic digestion with electroactive microorganisms: Performance and stability

Abstract

The performance and stability of a bioelectrochemical anaerobic digester (BeAD), continuously augmented with electroactive microorganisms (EAMs), were investigated. The BeAD showcased superior performance, sustaining the high COD removal efficiency and methane production rate of 76.5 % and 0.67 L/(L.d), respectively, in a stable state. Prominently, it exhibited remarkable resilience under hydraulic and organic shock loads, adeptly recuperating from disturbances up to 1000 % of its stable condition. This resilience of up to 300 % shock load was driven by increased levels of electron transport components such as quinones and riboflavins, which act as electron shuttles. However, after extreme shock exposures from 500 % to 1000 %, despite the spike in inhibitory by-products such as humic acids and ammonia, the upregulation of the mtr complex was pivotal in recovering and sustaining methane production. These insights emphasize the BeAD's capability to bolster both performance and stability, thereby providing a potent strategy for practical application of bioelectrochemical systems. © 2024 Elsevier Ltd