Continuous hydrogen production from cofermentation of sugarcane vinasse and cheese whey in a thermophilic anaerobic fluidized bed reactor

Abstract

The co-fermentation of vinasse and cheese whey (CW) was evaluated in this study by using two thermophilic (55° C) anaerobic fluidized bed reactors (AFBRs). In AFBR using vinasse and CW (AFBR-V-CW), the CW was added in increasing proportions (2, 4, 6, 8, and 10 g COD.L−1) to vinasse (10 g COD.L−1) to assess the advantage of adding CW to vinasse. By decreasing the hydraulic retention time (HRT) from 8 h to 1 h in AFBR-V, maximum hydrogen yield (HY), production rate (HPR), and H2 content (H2%) of 1.01 ± 0.06 mmol H2.g COD−1, 2.54 ± 0.39 L H2.d−1.L−1, and 47.3 ± 2.9%, respectively, were observed at an HRT of 6 h. The increase in CW concentration to values over 2 g COD.L−1 in AFBR-V-CW decreased the HY, PVH, and H2%, with observed maximum values of 0.82 ± 0.07 mmol H2.g COD−1, 1.41 ± 0.24 L H2.d−1.L−1, and 55.5 ± 3.7%, respectively, at an HRT of 8 h. The comparison of AFBR-V-CW and AFBR-V showed that the co-fermentation of vinasse with 2 g COD.L−1 of CW increased the HPR, H2%, and HY by 117%, 68%, and 82%, respectively.