Bio-electrohydrolysis as a pretreatment strategy to catabolize complex food waste in closed circuitry: Function of electron flux to enhance acidogenic biohydrogen production

• Designed novel bio-electrohydrolysis system based on self-induced bioelectrogenesis.
• BEH with closed circuit promoted biotransformation of complex organics.
• Pre-hydrolysis showed enhanced hydrogen production in subsequent dark-fermentation.
• Pretreated substrate in BEH documented higher CHP (0.91 l) than control (0.68 l).

A novel bio-electrohydrolysis system (BEH) based on self-inducing electrogenic activity was designed as a pretreatment device to enhance biohydrogen (H2) production efficiency of food waste. Experimental strategy involved two-stage integrated/hybrid operation with hydrolysis in initial stage followed by acidogenic fermentation for H2 production in second stage. After pre-treatment, catabolized food waste from control (anaerobic) and BEH (closed circuit mode of operation) system was used as substrate in a separate bioreactor to evaluate H2 production in dark-fermentation process. Pretreated-waste from BEH showed higher H2 production (29.12 ml/h; 24th h) than control (26.75 ml/h; 16th h). Higher cumulative H2 production and maximum substrate degradation were also noticed with BEH-pretreated substrate (CHP, 0.91 l; COD, 52.42%) than control (CHP, 0.68 l; COD, 43.68%). Under closed circuitry, anode served as an alternative electron acceptor promoting biotransformation of complex organics to simpler molecules through catabolism.

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