Improving EGSB reactor performance for simultaneous bioenergy and organic acid production from cheese whey via continuous biological H2 production.

Abstract

To evaluate the influence of hydraulic retention time (HRT) and cheese whey (CW) substrate concentration (15 and 25g lactose l-1) on the performance of EGSB reactors (R15 and R25, respectively) for H2 production. A decrease in the HRT from 8 to 4h favored the H2 yield and H2 production rate (HPR) in R15, with maximum values of 0.86±0.11mmol H2 g COD-1 and 0.23±0.024l H2 h-1 l-1, respectively. H2 production in R25 was also favored at a HRT of 4h, with maximum yield and HPR values of 0.64±0.023mmol H2 g COD-1 and 0.31±0.032l H2 h-1 l-1, respectively. The main metabolites produced were butyric, acetic and lactic acids. The EGSB reactor was evaluated as a viable acidogenic step in the two-stage anaerobic treatment of CW for the increase of COD removal efficiency and biomethane production.