3. Results and discussion
3.1. Comparison of cell performance with FWW and SWW at an
applied potential of 0.9 V
Current production using the pre-acclimated anodes and the
SWW was stable at 15.3 ± 0.2 mA (38.2 mA/m2
-cathode), and it
decreased by 10% to 13.6 ± 0.4 mA when the feed was switched
to the actual fermentation wastewater (Eap = 0.9 V, Fig. 1). Overall
COD removal was greater using the SWW (87 ± 5%) than the
FWW (76 ± 6%). The coulombic efficiency was slightly lower for
the SWW (56 ± 4%) than that obtained with the FWW (66 ± 11%).
Hydrogen gas production rates were better for the SWW, with
0.63 ± 0.02 m3
/m3
-d SWW compared to 0.49 ± 0.05 m3
/m3
-d for
the FWW (Fig. 1C). However, the final H2 yields were similar for
the two wastewaters on the basis of COD removal, with
1.01 ± 0.05 L-H2/g-COD for the SWW, compared to 1.09 ± 0.24
L-H2/g-COD for the FWW.